Exhaust Systems

Last updated: March 29, 2000

I have saved a lot of posts on the topic of cat-back exhausts, and thought I would summarize them. I did not input any original material here, so don't flame me if you disagree with the comments. Just send me your input and I will add it to this summary. This was one of the first pages I did, and at that time I did not save everyone's names on their posts, as I did not know I was going to do a Web site.

I grouped everyone's comments by the exhaust vendors; I hope this doesn't upset the original posters. These included: John Duff, Chuck Brousard, Carlos Iglesias, Richard Thompson, Greg Lackey, Bill Geiger, Tosh Desai, Peter Hsieh, DeanCRacer, Carl Houseman, and Chris ??? (sorry if I left anyone out - let me know). I borrowed John Duff's format for the bottom line summary.

There was some discussion in these posts on whether removing the cats was good or bad, but you will need to keep yours if you need to worry about emissions. I bought an ASP, and will keep my current stock cat-back exhaust and cat for bolting back on for the test.

The air pump can then be disconnected once the main cat is gone. The Pettit, Rotary Peformance, or Greddy pulley kits can be used too, and a different belt will be required.

Cat Back Exhaust Comparisons

Other Exhaust Info


est.  $480		34 lbs		flow:  poor	tone:  quiet
(46 lbs including the cat - I weighed mine.  --Steve)


John Duff writes:
The PFS system is the lightest, best flowing, and (even considering the occasional heavy discounting of others) the least expensive cat-back system available that is 3" mandrel bent from tip to tip and is ALL T304 stainless. It flowed flawlessly on the 3-rotor car, which was making over 500 horses and 400 lbs/ft. of torque.


From: Tuck
Date: Mon, 11 Nov 1996 23:56:42 -0500

The PFS exhaust system looks beautiful, highly polished T304 stainless steel, with a nicely sized tip at the end, that strikes a good balance between being big without looking like you're driving a good looking Honda. In terms of sound the PFS muffler sounds nice to me, not much louder, but a little more throaty, compare the voice of Marilyn Monroe to the voice of Jane Mansfield. Holding everything else the same, it's good for a noticable horsepower increase and a pound of boost or so. The PFS induction system is pretty nice, it consists of a two-piece black glossy fiberglass box with all the necessary hookups for the air pump etc and a massive K&N filter element. It also has a little scoop-like thing that pulls cool air directly from the radiator inlet, overall I think it's good for something like 15 horsepower or so as I recall (and I could be wrong, advice from the list is great, but you ought to call PFS and Pettit to ask them too).


(someone else writes:)
I just replaced my RB exhaust with the PFS exhaust. First impression...quality piece of hardware. Thanks for the speedy delivery John. For those that don't know I've got no cats on my car. The PFS pipe is noticeably louder than the RB one, which is o.k. with me, but think I'll have a hi-flo cat fabricated to cut down the volume a little (and be legal). The bends are more gradual (straighter) than the RB. SS all the way w/ a highly polished muffler and single ~4" tip. The PFS note is a bit deeper and it's probably about 15lbs. lighter than RB, too. I still think the RB exhaust is a good buy but I'm glad I swapped.

$595	19 lbs		flow:  very good	 tone:  sporty


Comes in 4 flavors. Mild steel single 4" tip, mild steel dual 3" tip, stainless steel single tip and stainless dual tip. According to the catalog, the s/s systems are constructed completely of T304. Prices for the s/s systems from MazdaTrix are $600 and $660 for the single and dual tip, respectively. These are somewhat heavier than the PFS system as they come in two pieces with an additional flanged joint. Supposedly this system is a bit quieter than the PFS, with a higher pitched tone. Someone with first hand experience (not me) should comment on the flow and power characteristics.

It comes in two boxes--one with the muffler and one with the pipe. The piping is 3" and the bends are a little more pronounced than Pettit's(sent it back because it was too loud--droned). I have had no cats and the stock exhaust in place while I waited for the racing beat exhaust. The car is very quiet with the stock cat back and has no droning. With 3" SS downpipe and midpipe, the car is not loud but "tinney". Sounds like a whimpey 4 cylinder.

The racing beat exhaust is no louder than stock exept during acceleration. Cruising speeds at 80 have absolutely no droning. Also, it clears all beams nicely. As far as flow, I am not sure. I dont think it flows quite as good as Pettit's(because of the bends), but Pettit's also fit too tight and banged under the car.

>The RB system is not T304. It's lesser grade material. I was out there all day working on a few CATs and was looking at the RB SS stuff and the material is not T304. Maybe that's why there is no life time warranty.

Peter Hsieh writes:
This person doesn't know crap about what he's talkin' about. (see RB brochure) Their SS unit *IS* made of T304 material. What does 'lesser grade material' means, anyway?!

The exhaust tips are rolled like the PFS unit and the sound is only loud during WOT. No droning at all. I will say that the Racing Beat exhaust probably does not flow as well as the Borla or ASP because it is not as strait. I will say that the bends serve a purpose for clearing a crossbar underneath the car because the borla fit too close to the frame and would drone and rattle on the frame. I have no problems at all with the Racing Beat. Hope that helps.

The RB has a very sporty rumble to it at start up and idle, but not loud enough to make all the neighbors look to see what the h*ll is going on. Interior noise is a little higher than stock. On acceleration, the RB sounds much sportier than stock, more like other expensive sports cars that I've heard. At highway cruising, interior noise levels are about the same as stock.

Again this is my assessment after about a month of use.

I expected the exhaust to be louder than it is, but after living with it for a month, I'm very happy with the noise levels. I think a louder exhaust would become annoying on my 1/2 hour commute to work stuck behind other cars. But when I open it up, the sound is nothing like the stock exhaust could ever produce.

I went with the mild steel version instead of the SS for cost, figuring if I liked the RB exhaust, when it's time to replace it I'd then go with the SS version.

I should also mention that the install was a piece of cake. The two piece design made getting the new exhaust on a lot easier than getting the old one off. Took me about an hour total.

Racing Beat said there was no difference in flow between dual and single tips.


From: "Houseman, Carl W. x1323"
Regarding the switch, let me say it was far easier to pull the old exhaust off and put the new one on than to change the plug wires! My car is never driven in salt or snow, so the bolts holding the exhaust to the main cat were like new (after 2.5 years & 23K miles) and I needed nothing special - not a single drop of WD40 or Liquid Wrench - to break them loose. A little liquid dishwasher detergent on the rubber hangers and the old exhaust slipped right off. Removal took barely 30 minutes and I was taking my time.

The RB SS exhaust is a piece of art. Fully polished, and with flanges and bends that defy one to find defects. It comes in two pieces so you can mount the main pipe first, and the muffler later. I had a little trouble getting the main pipe's hanger hooked and ended up removing the rubber hanger from the car, putting it on the exhaust, and then hooking it back on the car. When mounting the muffler, it was amazing how perfectly the muffler and main pipe flanges met with barely any encouragement. Total install time was about 45 minutes. New gaskets for both joints were included.

Appearance: I got the dual-outlet model. Off the car, the dual outlets looked big compared to the stock exhaust. On the car the outlets look like stock - to the untrained observer, this is a stock exhaust. I wasn't really out for the stealth look - I was more interested in avoiding the coffee-can/sewer-pipe look (yes even 4" single exhausts look hokey to me).

Noise: a nice low rumble at idle. More interesting, but un-obtrusive noises at high revs. In between there's a little bit of bassy drone when maintaining level progress in 5th gear at about 75 - which vanishes by 85. My average speed on the interstate may be assisted by this "feature"! Also I found that this minor droning seemed to vanish after 10 minutes or so - I think my brain eliminated it.

Performance: I have minimal intake mods - a K&N and a small 1.5" hose supplying supplemental air from the passenger side oil cooler inlet to the stock airbox. I still have both cats. With the stock exhaust I could get 12 PSI before 4500 but after that barely 10 PSI, and then 8 PSI after 6K. With the new exhaust, I'm hitting 11 PSI _easily_ from 4500-6000, after which it drops back to 9 and not to 8 until 7K. Seat of the pants says it's a lot smoother during the turbo switchover and definitely more interesting to get on the 2nd turbo now. How many HP is 1 to 1.5 PSI good for at the high revs?

Disappointments? I didn't receive any hardware to secure the rear hanger to the muffler. However, I received twice as many bolt/nut pairs as needed to connect the main pipe to the muffler.


Date: Wed, 30 Jul 1997 20:17:21 -0400 (EDT)
From: HYPURONE@aol.com (Chuck)

Well once again I am blown away by a Racing Beat product! I purchased the twin tip cat-back from Peter at Elitemotorsports, and installed it today, after having admired it for 3 days...LONG story. I fired it off and loved the sound IMMEDIATELY!! Very deep and purposeful. Install was a snap(did it on the floor in my garage)with a floor jack/stand and simple tools, ya gotta LOVE IT!


Date: Wed, 25 Feb 1998 01:06:51 -0800
From: "Hung-Jen Hung"

>Racing Beat out of Anaheim California makes a
>REALLY nice dual tip setup for the 3rd Gen.

Actually it's made by RS*R in Japan and their phone number is 714-779-8677. They also have a web site, but it's one of the worst web pages I've ever seen , http://www.racingbeat.com/ .


Date: Wed, 25 Feb 1998 20:45:05 -1000 (HST)
From: F8LDZZ

> What? Are you sure? I always thought that RS*R was a
>subdivision of Racing Beat! In all of their ads, it always
>says, "RS*R by Racing Beat." Can anybody clear this up for me?

RS*R is a Japan company that primarily makes exhaust systems. Racing Beat is a US company that resells RS*R product; some rebadged under the Racing Beat badge (i.e. 3" Racing Beat full exhaust is a RS*R unit rebadged). All of Racing Beat's exhaust systems for 3g (FD's) are RS*R stuffs.


From: "Steven N. Burkett" (sburkett@ooi.com)
Date: January 31, 2000

On the exhaust upgrade page you list the Racing Beat (RSR) SS cat back exhaust as "< 24" pounds. I think that whoever posted this was only including the weight of the actual muffler, but the assembly is in two parts, which, together, replace the stock catback. Mine weight in at about 31 pounds total, only a few pounds lighter than stock. Yeah, I know, picky, picky...


$600		24 lbs		flow:  ???	tone:  quiet    (mild steel)
$660 <24 lbs flow ??? tone: quiet (SS)


Date: Thu, 12 Mar 98 10:00:00 -0500
From: "Linthicum, Sandy"

Pettit TKT exhaust is CATback only. 2 - 3 inch depending on which exhaust you choose.


Date: Tue, 5 Aug 1997 16:53:55 -0500
From: "Kevin T. Wyum"

Quick run down. All T304 Stainless mandrel bent 3" tubing. Replaces both the main cat and muffler section. It is the equivalent of a cat back and midpipe in one. It is much lighter than any other combo out there weighing in at 22 lbs with an Ultraflow attached. I have three RX7's locally using them and have yet to hear about it banging on anything. My guess is when it was installed it was twisted a little too far in one direction. These normally sell for $700 which is a good deal compared to anything else that replaces both. As I stated I have nine of them left that I want to get rid of. With the muffler attached (Stainless Ultraflow 3" in and out) $550. If you want it to be quieter you can buy the system without a muffler attached and put on your own. Any gas station could weld the muffler to the pipe. This is the entire system without the muffler, so all flanges and hangers etc. are there for $450.


I bought an ASP exhaust from Kevin and recently installed it. Here are my comments: 1. It is loud. This is subjective, however - I don't mind it at all. It has a nice deep tone to it. Others have said it is too loud on their cars. YMMV. 2. It does weigh 22 lbs for the entire unit. Compare with the stock unit's 46 lbs. 3. The hardest part about the installation is taking off the stock exhaust. Installing the ASP is pretty easy. 4. Mine didn't come with any hardware, e.g.- gaskets, bolts, hangers. It sounds like it should have from Kevin's note above. My box did have a hole in it, so these items may have fallen out during shipment. Not a big deal - about $12 for the gaskets and bolts. 5. It is not quite all SS. The flanges appear to be mild steel (I am sure Kevin will correct me if I am wrong ;-) 6. Mine does bang against the body. Kevin said to loosen the bolts and rotate it away from the body. I had to drill the holes in the flanges between the mid-pipe and the catback section into slots so I could rotate it away from the body. I also used a washer and small hose clamp to pull the back mounting stud over to the left. --Steve, Feb 16, 1998


Date: Sat, 09 Aug 1997 00:17:15 -0400
From: Clint Fong

I did a best stock 1/4 mi run 2.185 sec 60' ET, 14.06 sec @ 98.83 mph.

Then I installed the currently available ASP exhaust and did 2.182 sec 60' ET, 13.518 sec @ 105.24 mph. 0.4 sec quicker and 6.4 mph faster in the 1/4 mi, on nearly identical short times with just the ASP pre-cat-back system and an OEM-style K&N filter in the stock airbox, no other modifications.

Date: Mon, 11 Aug 1997 21:24:41 -0400
From: Clint Fong

Hi all,

I returned from a weekend away from my PC (Internet withdrawal kicked in) and got back to catching up on the digests I've missed in the past 5 days or so. Holy volumes of exhaust system flames (not out the tailpipes either)...

Just to add my $0.02 and be done w/ it on my end, I have one of the 1st ASP systems that was available for sale, so I know I've had it on my car longer than most others. The car has been driven in the rain, it's been washed and hosed off underneath, etc. Sure the flanges are slightly discolored by surface corrosion and it is a bit louder than the cat-backs I've heard. But I love the exhaust note, and all of my car-nut friends seem to agree :) There is no rust on the pipe surfaces or the muffler. I've never had a problem removing it from the car which I do every year prior to emissions inspection, so anything at/near the flanges that is corroding is obviously not corroding enough to impede easy removal from the car. The 3 year old HKS exhaust I have on my other car is aluminized steel, and it is still in very good shape. That other car is my daily driver and sees rain, snow, you name it, and is not garaged now that the RX7 occupies it. The way I look at is is if the aluminized HKS system on my other car is still quite good considering its exposure to the elements, the ASP system which may not be 100% stainless in every detail will still last much longer than my other car's HKS system. A friend of mine has an HKS system w/ a polished stainless muffler and Drager stainless tip. It is already exhibiting small (1mm dia) pits of surface rust at only 3 months of usage, and that system cost quite a bit more than the ASP system.

The ASP system fits fine on my car, no banging, no rubbing. I took my car out on the highway in bright sunlight with 2 of my friends following me in another car a month ago, one with a camcorder zoomed in to the exhaust tip. I then repeatedly downshifted from 4th to 2nd at 50 mph and proceeded to rapidly upshift to 3rd at the buzzer and back up to 4th. The tip moves very little (max oscillation appears to be about 1-1.25" by looking at the movement of the tip in comparison to the 3.5" OD).

Some may feel that the exhaust noise and inspection hassle is way too much of a PITA to deal with, and would opt for a quality cat-back system instead of the ASP. I have no argument against that decision. I've knocked a consistently solid 0.4 sec off and gained a consistent 6.4 mph in the 1/4 mi over stock with just the ASP exhaust and a K&N panel filter in the OEM airbox (which isn't doing much for performance I'm sure). Typical runs are 2.1-2.1 sec 60' ETs, 13.4x-13.5x @ 105.2-105.3 mph. My best stock runs were on the same 60' ETs, albeit at 14.06-14.1 sec @ 98.8x mph. I can't complain, and probably never will.

About a year ago I raced a guy w/ a 94 PEP late at night on the NJ Turnpike N. I wasn't sure which exhaust he had on, but it was decidedly aftermarket and I could hear it as he barelled past me. I gave chase, managed to get behind him and then he'd take off on me at around 70 mph in 3rd gear. I matched his speed by the buzzer in 3rd and walked past him at 2-3 mph relative speed, got it up over 120 and promptly threw out the anchor (no traffic, I was being as safe as one can be at those speeds). He'd blow by me and we ended up repeating this scenario, with him never letting me line up directly with him before taking off, 3 more times before we reached a rest stop where we introduced ourselves. He had the PFS intake, exhaust and PMC, and said he was starting in 3rd gear and shifting at the buzzer, just as I was. I walked him each and every time in 4th from a 1 carlength trailing position, with just my K&N airbox filter and ASP exhaust. He couldn't believe it, I didn't know what to think because back then I hadn't been to the strip w/ the new exhaust yet and this was the *first* (believe it or not) 3rd gen who actually *wanted* to race. Maybe something was wrong w/ his car, I don't know. He said his boost gauge read 9.5-10psi across the rev band, basically the same as what I see. Then again, he doesn't have as loud a car and he doesn't have to worry about emissions fines or inspection each year. But he loved the system and asked me for ASP contact info. Unfortunately he wasn't/isn't on the RX7Net. The performance was what I wanted first and foremost from the exhaust, and I feel I got just that.

Now, if some would lend me their cat-back or other midpipe exhaust systems, I'd love to do a comprehensive dragstrip test with the other systems. I just don't have enough $$ to go purchasing other systems to test out, as much as I'd be interested in the results. I'm sure others would love to see dragstrip and dyno runs on the same car at the same strip on the same day, etc...


Someone else writes:

Though different than the others because it is a pre-cat back exhaust, I think its an excellent system. All SS, light, and only the very nominal restriction of an Ultraflow (SP?) muffler.

The ASP system is not what I (or many others seem to) consider to be "streetable" due to its noise level and fitment concerns. As Rob had stated in his evaluation (long before this recent incident with Kevin, when everyone was more objective), the PFS system with a center section performed as well, if not better than, the ASP system. It also offered a better fit, a higher level of construction, AND a more desirable noise level.

est.  $700	30 lbs	flow:  very good	tone:  Race car loud


Date: Sat, 31 Jan 1998 21:16:45 +0000
From: "David Lane"

Tri-Point has a stainless steel downpipe available with or without a pre-cat. They also have a midpipe which incorporates a high-flow cat. Early feedback from customers indicates that the power loss with this midpipe is minimal when compared to a similar straight pipe. As of this writing Tri-Point has not verified this with its own testing. I am not qualified to make comparisons from brand to brand, but I can say that the flanges (milled mild steel, 1/2 inch thick) are impressive, and the build quality seems excellent. I don't have a price for these things, but I understand that they are significantly less costly than stock Mazda replacement parts. They are working on a cat back muffler system which will be in the catalog.


To Greddy exhaust page

Pettit sells either the Borla or Greddy systems. The Greddy cat-back is a good system, but is only 2.5 inches inside the muffler, and is NOT full T304 stainless.


Date: Fri, 15 Aug 1997 11:27:10 -0700
From: Andrew Lu

I have a Greddy cat back on my 93 and I know for fact (I measured) that the diameter inside the muffler is 3 inch. In your webpage some one wrote it as 2.5 inch in the muffler...

est.  $650	32 lbs	flow:  good	tone:  mellow


Greddy is the North American subsidiary of Trust, but this was posted specifically as a review of the Trust unit, so I kept it separate in this summary.

3" pipe Trust Cat back exhaust with pre-cat and main cat in place: Good power, (much better than stock), a bit louder especially at WOT.

I just dumped the Racing Beat mild steel unit in favor of the Trust SS because it was too quiet, and there is no noticeable difference in flow, but this is a seat of the pants evaluation. The noise level is greater, but not by much and the exhaust doesn't "drone" as others have complained about. The sound is much lower, but not any more metallic like I thought it would be. In a nutshell it is louder but deeper. There should be no difference in flow since both units are of 3 inch straight-through design.

price ?		? lbs	flow:  ???	tone:  ???


The Borla is VERY restrictive and expensive, and uses a clamp to hold the muffler to the cat-back pipe. Ask Dave Bell about his old unit. Pettit sells either the Borla or Greddy systems.

The Pettit exhaust has not been made by Borla for some time. They do also sell Greddy products, so if you wanted a Greddy exhaust they could get one.


Lazarus surveyed the folks on the mailing list to get impressions on the Borla cat-back. He collected these and forwarded them to me. --Steve


Date: Wed, 24 Sep 1997 19:01:08 -0400
From: "Lazarus J. Vekiarides"

Here goes: I omitted some due to the sales pitches... :-)

From: "Drew"
Date: Fri, 19 Sep 1997 11:53:54 -0700

I have the Borla single tip exhaust...in fact, my R1 was the test car for Borla (for design, install and field test)!

I have no complaints, looks good and is well made. They gave it to me free to make up for the four days that they had my car.

It's hard to tell of a 8.6% increase of power (for any car)...but you can sure hear it whoosh out of the exhaust under max boost.

____________ Date: Fri, 19 Sep 1997 15:13:05 -0400
From: Tuck

Unlike the offerings from PFS and Pettit, the Borla system is only 2.5" whereas the others are 3". The PFS (and I think the Pettit) are full T304 stainless steel, so they effectively have a lifetime warranty. Any cat back system will give you a little bit more grunt, but as long as the cat is there and boost stays stock, it's not going to change much. The PFS one is the best looking one I've seen. It's no secret that I don't get along with Kevin Wyum, and as I understand it the piping and muffler in the system he sells are stainless, but the flanges are mild steel so they can rust. PFS, Pettit, and Borla are full stainless.


From: "David Ieroncig"
Date: Fri, 19 Sep 1997 16:07:40 -0500

I've got a single tip on my 3rd gen and it's holding up terrifically. Nice unit.

However, it is not a 3" dia pipe. As far as HP goes... I couldn't tell you what the figures are in terms of increase.

I was pleased when I got the unit a few years back and I still am today.

The sound however... I can comment on. It's wonderful. You can't go wrong... just right. Not too loud and not too quiet.

As for cost... I bought it from a Canadian supplier and it is hard for me to tell you what the US cost really turns out to be.

No matter what you end up paying for it... it will always seem like quite a bit of cash for a pipe and muffler. You might want to have a custom exhaust done up for you a reputable muffler shop at a fraction of the cost.

In conclusion... I like the Borla.... even with the single 3.5" tip... none of this Bazooka stuff. ;-)

_____________ (Editor's note: Trey works for (or owns?) Rotary Performance in Dallas, and is a vendor. I just point this out so people know who is a vendor and may have a vested interest - not saying he does. --Steve)

From: "Trey Cobb"
Date: Fri, 19 Sep 1997 15:58:04 +0000

We've tried the Borla system before and found it to be a bit restrictive and our welder really didn't like the workmanship. We've been using the GReddy cat back with much success. I should have pics of it online shortly but if you are interested in it or anything else we might have, please stop by at http://www.rx-7.com.


Date: Fri, 19 Sep 1997 17:10:44 -0400
From: Mark Tsai

I have Borla systems for both my 2nd and 3rd gen cars.

The Borla for the 3rd is a bit difficult to install (the stock exhaust uses a removable hanger...the Borla system has the hanger welded to the can). The tips stick out further than the stock system, but have a slightly different shape. (I have the dual tip system).

It makes the car louder (deep bassy tone), but I haven't substantively measured the performance increase yet.

______________ Date: Fri, 19 Sep 97 18:17:01 -0500 From: Brooks Weisblat

I have had good experiences with Borla. I had the dual tipped version on my car for a long time. It ran mid 12's with street tires with the Borla... and some other mods...


est.  $700	23 lbs	flow:  fair	tone:  raspy


Bob comments on the new SuperDragger. Comments on the older style below. --Steve

Date: Thu, 14 May 1998 20:32:16 -0400
From: "Bob Miller"

Hi guys, just wanted to let anyone know that may be interested that I recieved my NEW HKS Super Drager exhaust. They exchanged it for the older 2 chamber (restrictive) design, which they said was "accidentally" shipped over here instead of Japan(where they run no precat...just a down pipe I believe). Who knows, anyway if this may affect you and your HKS, give em a call.

Their turnaround was 1 day and the exhaust looks just like the Super Dragers that I've seen on Supras....straight-thru just like the Power extreme.....Hmmmm...I asked the guy if there was a noticable difference between the old (Jap), design and he said that it did.


The HKS Superdragger doesn't flow any better than the stock muffler and is very heavy (almost as much as stock). It is also very expensive and is also only 2.5 inches in inside diameter. Ask Nathan Freedenberg about his old muffler.


Date: Sun, 31 Aug 1997 07:28:14 -0700
From: Daniel Huang

Whatever you do, don't get the HKS Super Dragger. I switched to a plain old Trust exhaust just a couple days ago because it is completely straight through in the muffler. Not only do I get almost an extra pound of boost, the car feels MUCH faster. If you ever get a chance to look at a Super Dragger, take a look at the inside of the muffler. It's dual chambered and not straight through. Inside those chambers are filled with metal insulators to reduce noise. The only good thing about the S.D. is that it is quite a bit quiter than a Trust but I'd rather just keep the stock unit since the S.D. doesn't seem to perform no better than stock. As for the normal HKS exhaust and not the Super Dragger or Priest, I've heard good things about it but I've never actually tried one to know. Perhaps a good idea is to wait for the Greddy Power Extremes. Those look very good.


Date: Sat, 14 Feb 1998 18:53:54 -0500 (EST)
From: Jim Child

Last April I had my car at Passen Motorsports in Columbus Ohio where they were helping me diagnose a boost problem on my car. There was another 3rd Gen there that was also having boost problems. My problems were vacuum line related, but the other car's problems were finally traced to its Super Dragger exhaust. I don't remember the exact numbers, but with the Super Dragger the car could not make full boost and turned embarrassing numbers on Passen's dyno. They removed the Super Dragger and the problem was solved. With the Super Dragger off the car it turned similar dyno numbers to mine (after being fixed) which turned 230 hp at the rear wheels. My car is completely stock except for a Greddy/Trust cat-back. When I left they were talking about opening up the Super Dragger and completely gutting it, since the car wasn't too loud with it completely removed. I don't know if they actually did it.

Date: Thu, 26 Feb 1998 20:16:49 PST
From: "Nick Cruz"

I have a SuperDragger exhaust on my car at this time.

I had a little "chat" (with a little voice raising on my part) with an HKS rep. I asked him what the deal was with the Dragger and why it was bad. He tells me that the exhaust is baffled because in Japan they do not have cats (something about the emmissions) and that HKS needed to come up with a way to lessen the sound coming from the exhaust tip. this is how they decided to use the Baffle design. So, therefore would be a good exhaust without the cat or precat and would kep the noise level to a minimum. He also mentioned that they are in the works of making a US version of the Dragger that will be straight through.

est.  $750	42 lbs	flow:  fair	tone:  quiet 

Note: The HKS Turbo was said to be 27.5 lbs - don't know if it's the same as the Superdragger


This one sounds like it qualifies as a "RiceBoy" add-on. It may be one of those "my tip is bigger than your tip" exhausts. Rudy's post doesn't mention flow. --Steve

Date: Wed, 25 Feb 1998 04:08:09 EST
From: RudylRx7@aol.com

I have the Tanabe exhaust on my 93 Touring and all I can tell you is that don't get it if you are trying to get past the insurance agents. It attracts more attention than the GReddy and the HKS exhausts. I get Mitsu and Acura racers asking about my exhaust all the time. It's a 5 inch oval tip with "G Power Medallion" on the side. On the muffler itself, it says, "Tanabe Made in USA". I've had it for 3 mo. now with 2000 miles on it. Still looks brand new (polish it every time I wash my car, which is once a week). It performs extremely well and sounds very nice. In conclusion, get it if you want looks and performance, but you'll not get past the agents...


Date: Wed, 16 Dec 1998 10:05:11 EST
From: RudylRx7@aol.com

Just serfing on the net and found that my post regarding the Tanabe brand exhaust was on it. I believe my original post was to answer whether a person installing a Tanabe exhaust will get past an insurance agent's inspection or not. No, the Tanabe doesn't look THAT rice boy-ish when compared to the GReddy and the HKS units.

I purchased the Tanabe on December of 97 for $550. Reason being that I didn't like the huge rounded tips found on the HKS Super Dragger or the GReddy series. Also, I didn't want to have a catback system that every rice boy in So Cal has on their Honda or Mitsu. Anyway, the catback system is made out of stainless steel, 3 inch piping, and has a 110mm oval shaped tip. The catback system weights a little bit lighter than the stock system, estimate weight of about 38-40lbs. The flow is significantly better than the stock unit as I am currently getting 11.5-9-11psi of boost with the catback along.


Date: Thu, 26 Feb 1998 11:45:26 -0600
From: Thad King

I have owned a 93 base for about 6 months and am beginning to feel the need to upgrade. I recently installed a Blitz cat-back and noticed some nice performance improvements over the pathetic glass pack the previous owner installed. (snip)


Date: Sun, 27 Dec 1998 19:41:15 -0500 (EST)
From: Stephen J Lee

SOUND: Very loud without silencer. Very quiet WITH silencer. The difference is simply amazing. I can't tell the difference in power between the two modes.

POWER: I'm not the right person to ask, too much interference between my buttdyno and the seat:-) Actually, I have streetporting, downpipe, and GT and I didn't notice a huge difference in power. I did get about a 1PSI increase in boost after installing the beast.

NOTE: Me thinks an aftermarket air filter would help ALOT. Also, my main cat, I suspect and have been told, is heavily clogged. I think after I fix these two things, the power will increase dramatically, even more so because of the exhaust.

I like the thing alot. Good build quality. Welds are ground in the flange to the main cat and I don't like that. But everything else seems fine.


Date: Mon, 1 Mar 1999 17:18:37 -0600
From: "Chow, Thom"

...However, I have a question about a different setup. The Apexi N1 dual cat-back has a single pipe starting from the main cat flange and forks into two smaller pipes with a dedicated straight thru muffler for each. Some say this design provides more usable (low-end) torque. Is this true?


Date: Wed, 28 Apr 1999 12:33:08 -0500
From: "Judy Britton (214-443-8065)"

WOOHOO! I received the APEX'i N1 dual tip cat-back yesterday evening. I had it installed early this morning at a muffler shop. The install went smoothly and they didn't have any problems with the fit. This is a very nice system! What a great drive to work it was this morning! The exhaust note is pronounced, but not overwhelming. I really love the way it sounds, it's somewhat comparable to the GReddy Power Extreme. But the N1 will howl when the petal is to the metal. I'd have to play around more with the car in acceleration, but it seems that mid-range torque is more peppy.

It was hard to decide on which system to purchase, but I am pleased with the workmanship, looks and exhaust note of the APEX'i N1.


Date: Wed, 28 Apr 1999 12:41:12 -0500
From: "Chow, Thom"

I finally received mine (from the group deal) yesterday. Box was a bit damaged, and there was a blemish on the side of one of the SS mufflers, but it cleaned up pretty good. According to my digital bathroom scale, it weighs 29.5 lbs. I'm not sure what the stock exhaust weighs.

My initial impression is consistent with all that I've heard. Good quality welds, craftsmanship, etc. There was a plastic package that contained the exhaust gasket, an N1 Muffler sticker, and instructions in Japanese. For those who participated in this deal and received their unit, did you get anything else in addition to what I just listed? Reason why I ask is b/c on the hard plastic package that contains the instructions, sticker, and gasket, there is a round, pre-formed area that bulges out of the backing which looked like it may have contained something else (bolts??). That area of the package was empty on mine.

As an xtra, with exhausts on all my cars, I spray painted a coat of bright silver high heat paint over the piping part which was already coated with some sort of dull gray paint. Much nicer looking IMHO.


Date: Thu, 30 Apr 1998 09:25:41 -0400
From: "Ryan W. Schlagheck"

Just wanted to let you know that JapTrix has one of the best values around on a downpipe/midpipe kit. Tom Walsh directed me to David @ JapTrix where I found out about the Applied Research & Technologies downpipe kit. The "kit" is composed of a downpipe and midpipe for the 93+ RX-7. The pipes are 3" diameter, T-304 Stainless Steel, and mandrel-bent. There is a threaded receiver for the O2 sensor as well. The flanges are approximately 1/4 inch thick, maybe a little thicker. Fit was perfect, though I _did not_ use the included bracket to secure the midpipe to the former catalytic converter mounting point. The sound at WOT is full and loud (it'll be louder when I'm running at 10-11psi, right Shane?), and at rest it's about as quiet as a stock FD3S with cat-back only.

From what I gather, Applied Research & Technologies is primarily in aftermarket exhausts. Their bread and butter was the (gasp) Grand National crowd for some years, and they've spread out into other makes and models as well. They also sell a cat-back exhaust for the FD3S, though all I know about that is that it's really loud and also rumored to be the same thing that Pettit sells. That's what I hear (and not from JapTrix either).


JapTrix: (561) 963-8700, ask for David
Part Number: AR&T downpipe kit for the FD3S Mazda RX-7
Price not including shipping: $395.00 (yes - for both downpipe and midpipe!)
Shipping weight is 20 lbs.

$395	20 lbs	flow:  unknown 	tone:  loud


You forgot what is arguably the best cat back exhaust made from a performance and quality design point of view, no matter who resells it as their own: Turbo-Tuff.

I did not include the Turbo Tuff and ASP systems for the following reasons. The Turbo Tuff system is similar to the PFS one, yet is a bit heavier and (unless discounted) costs more. It has a bigger tip, which as we all know, has no influence on performance.

It has a nice sound slightly above stock however comes to life when the pedal hits the metal...pops a little bit...not to bad...till you ad a mid pipe. I might add looks great with the 5" tip... as far as weight I'm sure its got to be within 5 pounds of the PFS... It seems to be open all the way through..I think there a little holes on the piece of tube going through the muffler?? At the time (Pre internet) that I bought it, I liked the way it looked better than the PFS and the price was within $50 and I figured perfomance wise it would be close(not very scientific eh).

est.  $650	mid 20's lbs	flow:  good	tone:  aggressive    

DIY (Do It Yourself)

I had my dual tip system made up custom. It's mandrel bent, aluminized steel, 3" pipe, slp muffler, with two 2.5" tips. It was ~$350.

The shop where I had it made would have made up a set of all stainless exhausts for me to sell for about $400. However, I don't have the time for that sort of endeavor. But I'm sure that anyone who wants a new exhaust, could find a local performance exhaust shop, who would be glad to make up a system, and they would save $100s.

price ?		? lbs	flow:  ???	tone:  ???


>Is it LEGAL to replace the cat-back system with a straight pipe? I saw yes, it's legal (mufflers aren't emmisions devices), it's the thing to do for SS..it's much cheaper than an aftermarket muffler, and the guy at the local muffler shop should be able to do it for min. $$.

Whoa! I don't know what state you live in, Andy, but please be careful in giving out legal advice.

When this discussion started the question was about whether it was legal in the context of SCCA stock class Solo 2 rules to replace the muffler with a cat back straight pipe. The "legality" in question was not about state laws.

And yes, in Solo 2 rules, in the stock class (or street prepared) you may modify you exhaust from the cat back in any manor, includine a straight pipe. My 3rd gen (primarily auto-crosser) has a straight pipe from the cat back. Cost me $90 from a local muffler shop. Its cheap, flows better than any muffler. The main cat provides more than enough muffling of sound.

price ?		? lbs	flow:  ???	tone:  ???


Date: Tue, 3 Feb 1998 14:10:35 -0800
From: Seth Bibler

Check out Random Technology. As far as I have seen they make the best hi-flow cats on the market (read in magazines, on the net, etc..). I am not sure about their claims that the cats are better (higher flow) than a straight pipe set up, perhaps under certain conditions. Sport Compact Car installed one along with a full Racing Beat set up in their Project RX-7 (a '83 that they are street modding). Gain was somewhere around 6-7 HP from the stock set up that they had (Random Technology has a quote about that SCC article on their website).


Date: Thu, 14 May 1998 12:04:18 -0500
From: "Chow, Thom"

At around $300-$400 I have basically decided (the high-flow cat) wasn't worth it. However, at $195 (for the AT&R cat), it's making me think it over again.


Date: Thu, 14 May 1998 10:38:27 -0700
From: Spencer Hutchings

I got a 3" cat from Sumitt for my Talon TSi for like $95.


Date: Tue, 21 Dec 1999 16:44:31 -0800 (PST)
From: Fred Jin (chohakai@yahoo.com)

I know that both RandomTechnologies and RP sell very good high-flow cats, but they are both $500. I talked to Nick at N-tech yesterday who sells his drop-in high flow cat for $310, which I'm almost ready to get. I also saw that Pettit sells one for $299, but it doesn't look like a drop-in one, and considering their normal mark-up is pretty high, I'm not too crazy about it. All of the fore-metioned cats are stainless steel units. I know Dynomax makes a 3" one for ~$140, but it's not stainless, don't know how long it would last.


I (Steve Cirian) am looking for a replacement cat for my car. I have the ASP exhaust, which includes the catback and midpipe. The midpipe is a custom piece (i.e.- not a direct replacement for the stock cat). So I would need a custom cat section if I want to bolt it in with the ASP catback section. I will need just the cat, with no pipes or flanges, so I can get a custom cat section made at a local shop.

* My email to Random Technology: *

I have a '95 Mazda RX-7. It came from the factory with an air pump that is used in conjunction with the main cat. I would like to remove the air pump, to free up the horsepower it is using to turn the pump. This would require the use of a cat that does not require the air pump. From reading the tech section of your site, it appears that your cats do not require an air pump. Could you confirm?

If the car is equipped from the factory with an air pump, and you remove it but at the same time replace it with a cat that does not need it, would the car then be legal? (Note: there are two kinds of legal - Legal 1: I am sure it would pass the sniff test w/o the air pump, but, Legal 2: I am pretty sure the law prohibits the removal of the pump regardless of it doing anything or not.)

* Response from Random Technologies: *

Use of pumps to deliver air to a catalytic converter is a means of increasing the oxygen available for the oxidation of hydrocarbons and carbon monoxide. In most applications, a converter with no air tube provisions can be used to successfully meet exhaust emissions requirements.

Technically it is illegal to disconnect the air pump. If the engine is well tuned and/or you can alter air/fuel ratio, you can probably pass an emissions test with no problem.

My recommendation would be to use our Super High Flow converter, part number 903018, which does have air tubes. However, the converter is supplied with plugs, so you can connect the air system or not, at your discretion. By all means, leave the air pump in place. You'll need it if you decide to sell the car. Whether or not you keep a belt installed to drive the pump is another matter entirely. However, I don't think the pump consumes enough power as you might think.

Another possibility is to install an electric air pump as used on some vehicles.

* My follow-up: *

I will probably want the cat w/o the airpump tubes. I race it in autox, and can run w/o the airpump and even the cat. I will need the cat for emissions purposes when I get it inspected every two years, but in between that, it really isn't driven on the street. I will keep all the old parts in case I ever decide to sell the car, but have no plans on the immediate horizon for that.

Which part number do you recommend for no air tubes, 3", and no flanges? I will need to have the cat welded into a mid-pipe section, i.e.- I will have to get a custom pipe made for the cat to mate up with the downpipe and catback I currently have. These are not stock parts, so I can't get an off-the-shelf cat for it.

* Random's response: *

Part number 923000 is a 3" high flow converter with no air tube and no flanges. It sells for $229. Just a suggestion-- if your stock converter is at all close to bolting up, you may be better with our part number 903018. It may wind up to be cheaper to modify that than to start from scratch with a custom mid pipe.

* My follow-up: *

Do you sell these directly, or do I need to locate a distributor?

* Their response: *

We sell them directly. Just call us at 770/978-0264.

I also checked with Nick at N-Tech, and got his response. It sounds like this is not the Random Tech piece, but a different vendor that should also do the trick:

Yes, I sell the cat canister by itself. It is 3", and stainless. Price is $150.00 for it. I believe it is a bit smaller than the Random unit. It flows incredibly well. I verified this myself. It does not change how much noise the car makes, really.


And a response to the note I sent to Rotary Performance:

I can sell you what we call a "blank" cat. It's a cat without flanges. The Bonez 3" Blank runs $300. I'll let you know though, while it's easy to make some cars pass the emissions test without the air pump, it's a bit tricker on the rotaries. In some states, they put the car on a dyno which will be VERY hard to make the car pass without the air pump. You'll need to lean out the mixture alot to get the extra oxygen.

I don't know if this will answer your question of not but you can run the Bonez cats without an airpump. It's will be difficult, however, to pass some emissions tests with ANY cat without the air pump. This is simply because of how the RX-7 is. The option I think would work best for you, which the gentleman at Random suggested as well, is to use an electric air pump. I believe some GMs come with this. If you're looking to have something to pass emissions with, I think having the electric air pump woudl be a requirement.

Anyway, I have these blanks in stock. They come with the air pump pipe capped.


Date: Tue, 28 Mar 2000 17:55:39 -0500
From: "Edward H Kim" (ehkim@erols.com)

After putting up with the vile smell and the noise of a straight-through exhaust for months, I finally got around to replacing the midpipe with the Rotary Performance's Bonez Performance Main Cat replacement(AKA hi-flo cat) last night.

The RP hi-flo cat is priced at $495. I also purchased the optional $20 bolt and gasket kit which includes the two gaskets and 4 each of the bolts, washers and nuts needed to make the installation less painful.

As expected the hi-flo cat was not completely made of stainless steel. There were two sections of the 3" pipe which passed the "magnet test". The heat shields, the converter itself, the flanges and small sections of the 3" pipe failed the "magnet test". The converter itself may have failed the "magnet test" possibly because of the inner working components. The welds were acceptable but very rough. It would be very easy to get an abrasion by rubbing the welded areas. The inner surface of the 3" pipe was rougher than the Tripoint midpipe which I was replacing. It weighes 16 lbs.

It took me 1 and 1/2 hour to complete the replacement from start to finish. This includes looking for the right tools. In the future, if I decide to put the midpipe on for a tracj event, it should take less than 1 hour to do this. The most difficult part was in removing the main cat from the rubber hanger thingie.

There were no problems with fitting. The only possible problem was that the hi-flo cat is very close to the "tunnel" that runs down the middle of the car. There was only about 1/4" clearance here.

In terms of suppression of noise and and the vile fumes from the exhaust, I am very satisfied. My car is still LOUD but now it's tolerable. The exhaust doesn't smell like perfume but now I can breathe inside and outside the car without getting a headache.

Currently, I am not running the air pump but I plan to soon which I hope will clean up the exhaust more.

As far as performance goes, it is unclear to me whether there is a decrease in the HP. The car does feel slower only because it is not as loud. I am planning to dyno the car in the next month with the hi-flo cat. Perhaps, within another 2-3 months, I will put the midpipe back on to dyno it for comparison.

I heartily recommend this de-modification to anyone who is tired of the noise and the stink of a straight-through exhaust.


Date: Tue, 28 Mar 2000 19:38:42 -0500
From: "kevin kelleher" (kellehkj@earthlink.net)

> The flanges and small sections of the 3" pipe failed the
> "magnet test".

Lots of exh stuff is made from 409 ss, which is ferromagnetic. Expect it to brown quickly, but not rust rapidly like carbon steel.

Even some 300 series stainless becomes magnetic if cold worked enough.


Date: Tue, 15 Feb 2000 19:43:04 -0800
From: Max Cooper (max@maxcooper.com)

I have an N-Tech high flow cat and I am very happy with it. I took some pics if you want to look at one.

Some notes since I wrote the page:


Date: May 11, 2000
From: "Ulen, Robert S" (Robert.Ulen@PSS.Boeing.com)

Well, a few days ago I brought up the question if it was really necessary to ceramic coat a stainless steel downpipe or not. After doing *alot* of research, and talking to someone in the coating industry who I deemed competent in his answers and apparent research/testing, I have come to the conclusion that yes, it is advantageous to ceramic coat a stainless downpipe.

Now you have to understand that not all ceramic coatings, and the process that is used to apply them, are all the same. These two factors can make a big difference in how a coated downpipe will perform.

Apparently, if the right coating and process is used, the coating acts two fold. One as a heat barrier (it has a *very* low conductivity) and two, as a lower radiative heat surface. I was always under the impression that the thermal barrier was negligible because it was so thin, but apparently some of these coatings are thicker than others and can cut the outside surface temperatures way down. One test shows surface temp reduction from 1100 deg F to 450 deg F with the same exhaust gas temp. It basically works like thermal wrap in this respect.

This in turn, also cuts the radiation heat way down too (radiation is a function of the temperature to the 4th power), but it sounds like the thermal barrier aspect of the coating is doing the most.

See tests @ http://www.hpcoatings.com/hightemp.html.

I want to mention also that polished stainless steel has a pretty low radiation emissivity (about 0.10), but after it has been heat cycled alot, and oxidizes (turns that cool gold color), the emissivity goes up to about 0.60 (six times). Plus the outside surface of a non-coated DP will be at a much higher temperature (no thermal barrier) which caused more radiation, and more connective heat transfer off the tube than a coated one.

I believe a correctly coated downpipe will make the most difference when driving around town in traffic when there is not much airflow past the downpipe. So, based on my research and heat transfer experience, I am definitely getting my SS downpipe coated.


Date: Fri, 19 May 2000 16:43:02 -0700
From: "Ulen, Robert S" (Robert.Ulen@PSS.Boeing.com)

...someone was asking about wrapping header tape on top of the ceramic coated DP, and what that would do.

Essentially, that would be insulating the DP even more, since the header tape would provide another layer of good insulation. In this case the outside temperature of the header tape would be even lower which would cut down even more natural convection off the DP, plus it would cut the radiation heat leaving the surface because the surface temperature would be cut way back again, no matter what its surface emissivity properties where.

The actual surface temperature of the DP (or header tape, or whatever is on it) has a biggest factor on the amount of convective and radiative heat coming off the surface.

Let's just look at the radiation factor, and I'll show you how a big drop in surface temperature help in two ways. The heat due to radiation only is basically equal to:

    Q = (e)(sigma)(T^4)


e     = the "emissivity" factor (unitless between 0 and 1 -- 0 gives
        no radiation, and 1 gives "blackbody" radiation, which is the most 
        it can radiate at the temperature T).

sigma = a constant called the Stefan Boltzmann constant (the
        mad scientist who discovered heat radiation physics)

T^4   = absolute temperature to the forth power

I will give you a couple of examples of how this can be used to compare different conditions, related to DPs.

Case 1

Stainless steel DP, uncoated with many miles. The e factor will be approx. 0.65 per a couple of references. Assume the surface temperature is at 1200 deg F (1660 R). Therefore,

    Q = (0.7)(1x10^ -9)(1660)^4
    Q = 5315 Btu/ft^2/hr  (so every sq. foot of the surface will radiate 5315 Btu/hr)

Now if the e value went to say 0.4 with the surface temp still at 1660 R, Q would decrease to 3037 (or basically cut by the ratio of 0.4/0.7 = 57% of 5315).

But, even though a lower e has decreased the radiation, the surface temp is still 1660 R, and it will be naturally convecting heat at the same rate. The convective heat amount is still huge in this case.

Case 2

Stainless DP with hi-tech ceramic coating. Lets assume the coating also has an e of 0.65 so we can see how just a lower surface temp affects the radiation level too. But in this case, the ceramic coating has decreased the surface temp from lets say 1200 deg F to 600 deg F (1060 R), which is what tests have shown by the coating industry. Now,

    Q = (0.65)(1x10^ -9)(1060)^4
    Q = 821 Btu/ft^2/hr

This is (821/5315)(100) = only 15.4 % radiated heat as compared to the uncoated stainless DP -- even though the e is the same. Since the radiation heat is a function of T to the 4th power, a reduction of surface temp (due to ceramic coating or header wrap) will cut the radiation way down. If header wrap was put on top of this, the surface temp and radiation would drop even more. Even if the e was maximum at 1.0 for the ceramic coating, Q = 1262, which is still only 24% of the radiation off an uncoated SS DP at the same temp.

But, on top of the radiation reduction, the natural convection heat (due to coatings or wrap) is also way down because the surface temperature is way down. Its a two fold gain. If header wrap was put on top of ceramic coating, it would cut the convection down again.

Theoretically, you could insulate a DP with so much insulation that you could probably put your tongue on it, but the material coating on it and/or wrap around it would end up very thick. IMO, it would be overkill to do both. One or the other (depending on the situation) should be a huge difference.

What it boils down to is how much do you want to spend, and how pretty do you want it to look? Ceramic coating is the way to go, especially on mild steel, since it also provides a corrosion barrier. On stainless steel, you could use header wrap since stainless is very corrosion resistant by nature (header wrap on mild steel is not good), but if you are getting a new DP, you might as well have it coated before its installed.


Date: Tue, 21 Mar 2000 16:00:36 -0600
From: "Westbrook, Chuck E." (CWestbrook@tmh.tmc.edu)

The ideal method is to have the DP ceramic coated and also thermo wrapped. This prevents any trapped moisture from rusting the pipe and minimizes heat transfer. That's what I did to my mild steel DP.

If you want show and not go, that is your choice.


Date: Fri, 23 Jan 1998 06:32:34 -0600
From: Richard Sheveland (shev@pdq.net)

I have got many different opinions from credible sources on what works best for insulating the downpipe and lowering engine bay temps.

I have a stainless T-304 downpipe that RP sells. I have decided to go with the wrap. XS Engineering said to use a good quality wrap finished with a VHT High Temp Paint coating to seal the wrap. I used 1" wide wrap and overlapped strips by 1/2". Every 6" I would used a metal clamp to secure the wrap in place. The pipe was wrapped the entire length. I used almost an entire can of VHT to get a good thick coating, then I baked it in the oven for about 15 minutes ("Blackened Downpipe", "Smoked Downpipe", "Wrapped & Smoked Downpipe") Nevertheless, it was baked to perfection. Fortunately for me, my wife was not home to see this. We will keep this our little secret.

Has anyone compared wrap to coatings? I used Thermo-tech wrap which did indicate on the box that is for use for rotary engines. It is rated to 1500F. The VHT is rated the same. I have noticed a decrease in underhood temps.


I bought some of the AutoPro wrap from Racer Wholsesale. (I think it was the 2" wide stuff x 50 ft. I'll post details when I get it on. Cost $29.99. --Steve


Date: Wed, 5 Aug 1998 14:59:00 -0500
From: "Westbrook, Chuck" (CWestbrook@tmh.tmc.edu)

(The wrap) is OK for stainless steel, but not too good for regular steels. It traps in the moisture and causes the non-stainless steels to rust faster. If the pipe was ceramic coated and then wrapped, it would be very effective. One of my friends has his stainless steel downpipe wrapped to reduce heat.


This was posted for the second gens, but applies to anything. Just wanted to save people asking about parts mentioned here that may not apply to the 3rd gens. --Steve

Date: Fri, 27 Feb 1998 11:00:49 -0600
From: "Zack" (zubenubi@inetport.com)

I'd estimate the thickness of the coating (inside and out) at 1 millimeter.

The heat conductivity of these ceramics is an order of magnitude less than that of stainless steel, (two orders of magnitude less than aluminum). So the coating cuts the rate of conductive heat transfer through the exhaust piping by something like 2/3rds. You get -much- cooler temperatures under the hood and around the exhaust pieces under the car. Also, since the air column inside the exhaust pipe is better insulated, you get better exhaust flow and scavenging, since a hotter gas is lighter and has a higher sound velocity. Typical quoted HP increase you can expect to see is around 3% vs. bare pipes. Not earth shattering, but nothing to sneeze at either.

The other obvious benefit is your pipes will last practically forever. Everything is sand-blasted, degreased, and then acid dipped prior to spraying and firing. The ceramic -sticks- like nothing I've seen, and is pretty hard stuff to boot.

Be forwarned that most header coatings are NOT rated for the 1600+ exhaust temp on our cars. HPC and Jet-Hot are the only two companies I know about that will do coatings rated to 2000*. You cannot afford to go with anything rated lower than this, lesser coatings will crack and disintegrate under the onslaught of your rotary's heat. Also, your headers will not look sexy with the 2000* coating.

Finish choices are extremely limited (that almost ubiquitous, pretty looking silver finish that you see advertised in magazines, for example, is -not- available in the 2000* stuff, nor are any of the fancy colors. My headers are dull, flat-gray).

It ain't cheap, I think it cost me $400 to do the headers, both pre-silencers, and the pipes back as far as where the mufflers attach. The HKS tailpipes that come with the Mazdatrix setup are aluminized already, so I skipped the coating on them.



Thanks to StJames515@aol.com for a lot of these links.

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