Tuning Done Right

Thermal Research

Thermal Research Catback Exhaust

[4/23/2008] Reviewed by: Jacob - jacob-todd@hotmail.com

Applicable to: '90 - '97 1.6 liter

Cat back exhaust from thermal research installed on my 1991 Mazda miata 1.6l

I only had trouble with the install as most of my bolts were rusted completely through so i had it put on for a mere 60 dollars at the local muffler shop. Great sounding exhaust. Very steady deep blurble, and when above 2.5k sounds very smooth, deep, and clean all the way through the rpm's. Its chrome tip stenciled with the "thermal research" logo is just the right size in diameter and in length. (it sticks out just enough without looking ridiculous.) It added what i believe to be a very noticeable gain in the higher power band as a smoother easier to climb rpm range. It feels like the car can literally breathe better. Cars happy, Im happy.

I recommend this product to everyone who wants a better looking and sounding exhaust and a few quick hp for a VERY good price.

Under 30 minutes to remove completely


Thermal Research Catback Exhaust

[9/14/2002] Reviewed by: Eamon Millman - emillman@egm.ca

Applicable to: '90 - '97 1.6 liter

Stainless steel thermal research catback exhaust. Quality construction, no visible defects.

Installed almost a month ago, was rather quiet after going on, but once some mileage was put on it grew deeper. The note is subtle and deep, very reminiscent of the OEM system but much nicer. Gave a good boost, worth it's $, to my top end. Torque is much more constant now however, needed to keep an active eye on the speedometer. I'm also running 14o timing on my engine. Only problem is the resonator hangs down a bit and with my lowered miata (5/4") I’ve bottomed out twice so far with it... care is required for speed bumps.

Before the install it sat at my mechanics garage where most visitors attempted to have it installed on their miatas. Big thanks to Chris "the rx-7 guy" for fending off the vultures and doing the install superbly!

Under 30 minutes to remove completely


Thermal Research Stainless Cat Back Exhaust

[9/12/2002] Reviewed by: Matt Deller - khscomp@aol.com

Applicable to: '90 - '97

Thermal Research Stainless Cat Back Exhaust

I recently installed a Thermal Research stainless cat back exhaust on my '93 Miata. The removal of the stock system was kind of tricky because the catalytic converter uses threaded studs instead of through bolts to hook onto the mid-pipe. So, after twisting off both studs (ooops), I simply drilled out the remaining material and used some quality hardware to bolt on the new system. Any future disassemblies will be much easier now. I am extremely pleased with both the look and sound of this system. You can't go wrong with stainless. It produces a similar note to the stock system; however, it's about 10 octives lower. In other words, a nice growl! I would highly recommend this upgrade for Miata owners. The more you drive with this exhaust, the better and better it sounds.

Easy installation, great sound, and awesome appearance!

Under 30 minutes to remove completely


Thermal Research "cat back" system

[5/22/2002] Reviewed by: FormerMazdaTech - 31st330i@roadfly.com

Applicable to: '90 - '97 1.6 liter

"cat back" system for 1.6L M1. purchased from Dan at www.mroad.com.

though the system appears to be extremely well made, I did notice that the bends appear to be compression bends (albeit very good ones) versus mandrel bends. perhaps they are indeed mandrel bends and I just am not familiar with what they are *supposed* to look like. the indents I observed on the inner part of the bends are slight and to be honest, most people would probably not notice them. for some reason, the mid pipe has one less hanger than the original. on the bright side, this means that you already have a spare hanger handy in case one of the remaining hangers breaks. :) so far, the system sounds exactly like the stock exhaust but there is a noticeable bump in mid range and top end HP. I do like stealth performance but was a little surprised by just how quiet this system really is. I'm told that it will develop more tone over time (like maybe two weeks) so I look forward to that. be sure to advance the ignition timing to 14 degrees as well.

EXCELLENT customer service from Dan at M Road and bullet fast shipping!!! great price on a great product. I would highly recommend this system and M Road as the place to purchase it from.

Under 30 minutes to remove completely


[10/26/2000] Reviewed by Tony Forcier - toenail2k@hotmail.com

Applicable to '90 - '97 1.6 liter

Two peice stainless cat back exhaust sytem. Comes with everything you need except rear cat nuts wich they recommend replacing. System is one of the better looking ones on the market. Subtle, not BOY RACER. Excellent fit and finish. Very high quality welds.

About 45 minutes total to install. Now that it's been on for a few days here's what I think I found; A little loss of power in the 2k to 4k range, an increase that is progressive from 4k till redline. This seems to benefit ripping through the gears but doesn't do much for around town daily driving. I also noticed an increase in interior resonance(boomy)as I passed from 3k to 4k. Both of these problems were solved when I advanced the timing to 14 degrees shortly afterward. This has brought back the bottom end and helps the tach sweep right through the dreaded boomy zone making it almost not noticed. To hear it coming down the street you would think it was a much larger, more powerful car. The closest sound I can compare it with is a modified M3 I heard at an autocross event. As with any exhaust modifications I'm sure the addition of a header and intake (on order) will really compliment the package.

At this point I am very happy with Flyin' Miata and Thermal. The product looks and sounds great. It provides an increase in performance that I can build on. It is very affordable considering the build quality and pleasure one gets from using it. It sounds like a totally different car that will definitely not get you pulled over. Can't ask for much more than that!

Under 30 minutes to remove completely


[2/26/2000] Reviewed by Rich Goyette - richg@silverstream.com

Applicable to '90 - '97 1.8 liter

Cat-back stainless steel performance exhaust system from Thermal.

Installation was very simple. Removal of the old system was accomplished bin less than 20 minutes (the bolts at the flange of the catalytic converter were soaked with penetrating lubricant ahead of time). My dad & I were able to install the new system with ease using the supplied hardware (2 flange gaskets and a nice set of hardened bolts to attach the pipe to the muffler).

It sounds great on my 94 R and adds a nice amount of volume to the exhaust. It's noticably louder riding in the passenger seat vs the drivers seat. Hard to tell what performance gains there are as of yet as I just put it on this morning.

For the $399 including shipping, this setup was an excellent modification to the car.

Over 30 minutes to remove completely


[1/3/2000] Reviewed by Michael Kemp - tikveh@wt.net

Applicable to '90 - '97 1.8 liter

This is a stainless steel cat-back exhaust system. With 2.25" pipe and highly polished connecting pipe resonator, muffler and 3" tip. Thermal R&D etched on resonator and tip.

The package arrived at my office nicely packed with absolutely no dents or dings! Went to a neighborhood muffler shop and they did the install for $75. Everything fit perfectly. This is a nice quality system you really couldn't ask for better, solid welds and hangers are very sturdy. Once the job was finished I fired up my '96 and immediately noticed a deeper tone, nice! This system is not much louder than stock as of yet, but it is more aggressive sounding. One thing you have to allow time for is the odor. Wow it is strong, but as indicated from other reviews it should go away soon. I didn't notice any loss of torque, I was a little concerned about that possibility . The motor does rev more freely throughout the power band without any flat spots!

Overall this is a nice product. It is made well and it works. I would certainly recommend it.

Under 30 minutes to remove completely


[9/16/99] Reviewed by Eric S. Mashburn - emashburn@earthlink.net

Applicable to '90 - '97 1.6 liter 1.8 liter

Polished stainless steel cat-back exhaust purchased from The M-Road manufactured by Thermal R & D. Includes muffler, mid-pipe, and required bolts and nuts.

Took it in to my local muffler shop for installation. When the mechanic drove it around, I could hear the difference. A lower toned, almost V8 like, burble. At idle, the exhaust was quite mild, yet with a hint of something sinister lurking within. As I left the muffler shop and got on the gas, the most beautiful engine music began to fill my ears. A deep, melodious tune that rose to a howl at the redline. I absolutely loved it! Running through the gears had become a spiritual experience. I drove the car over 180 miles that day just to hear it sing. Although the exhaust note is definitely louder, it is not too loud as I did not notice any undue attention from bystanders or other drivers. At highway speeds between 3k and 4k rpm, the sound was only slightly louder than stock. I haven't heard all the other systems, but I doubt if there is one that sounds any sweeter. By the way, the engine also revs more freely, especially above 4k.

As you can tell, I was very pleased with my purchase and would highly recommend this product and The M Road. My buddy says it's the best thing I've done to my car. He said now it sounds like a real sports car. I know it is now a whole lot more fun to drive.

Over 30 minutes to remove completely


Reviewed by: Anonymous [8/1/99]

Thermal CatBack Exhaust System for M1 series Miatae; kit consists of 2-1/4" pipe from CATalytic converter and oval muffler canister unit with (slightly) larger, polished tip engraved with "Thermal" logo.

Our Thermal CatBack system was sourced from MRoad and installed on our '96 M-Edition as a demonstration sponsored by the Miata Club of Austin, Texas at their local Mazda South dealership. The Thermal CatBack is all stainless-steel and highly polished; the fit and finish are superb. After removal of the OEM system, installation is straightforward; there is a threaded insert for the sensor. Standard mountings are used - you may need to loosen and adjust the left-rear tubular chassis brace to improve clearance. After installation, thoroughly clean off all fingerprints, grease, etc. from the pipes and canister: the S/S pipes will turn gold, the canister and tip remain shiny, chrome-like. The new system requires some breaking-in... you will notice an odor and perhaps a few bits of packing coming out when you first fire-up... About 100 miles of continuous highway driving will "cook" it; the odor disappears, the pipes will begin to take on that golden tint.

There is a noticeable improvement in performance above ~4000 RPM. The "tone" is deeper than the OEM system, but not much louder. There is no "raspy", Borla-like sound; nor is there any "ringing" evident. Indeed, this system passes the "wife test" while giving a visceral feeling to the driver ;-)

This is a very high-quality product, about $400., sold by reputable Miata tuners: Flyin' Miata http://www.dlralt.com/   and MRoad http://www.mroadster.com/

Under 30 minutes to remove completely


Reviewed by: Anonymous

Polished stainless steel catback system. Kit includes muffler and resonator pipe, plus bolts and gaskets required for installation.

The system was ordered through MRoadster. It was very well packaged and surprisingly light. The "Thermal R&D" logo is laser-engraved on the exhaust tip, and that looks really cool. The installation was straightforward, but since no instructions were included I had to refer to the Enthusiast's Manual for reassurance and tightening torques.

The system appears to be well-made and is very attractive. The exhaust tip is larger than stock, but not akwardly so, like some other systems. I am particularly pleased with the mellow bass note that the exhaust has now. It is not loud or offensive, and I have a lot of fun playing with the exhaust note by modulating the throttle in the various gears. It's like a musical instrument. This was installed along with a JR header and cat. There is a noticable improvement in torque below 3000rpm, and the engine now revs freely through 7000 rpm with no evidence of the flat spots in the torque curve that it had with the stock exhaust. It's important to note that my '90 is normally aspirated and otherwise completely stock.

Buying aftermarket parts for the Miata can be a complex process. There are a number of good vendors and manufacturers to chose from, and it can be hard to be sure that you've bought the "right" parts. In general they're almost all good...so it gets to be a question of which one is the best to suit your particular needs. In most cases...selecting the right part is easy if you have a good idea of what you expect to get from it. Ask yourself..."Why am I buying this part?". In this case, my OEM catback was working fine. But I'd just replaced my cracked OEM header and rattling catalytic convertor with a JR header and cat. I wanted a replacement catback system that offered both a performance gain and an appearance upgrade. After a lot of research, that meant that I had to chose between thw MRoadster system and the JR polished system. Normally cost isn't an issue for me...but I couldn't escape the fact that the MRoadster system cost about $250 less than the polished JR system. I was concerned that the MRoadster system might not be tuned to work optimally with the JR header and cat. I quizzed Dan about that pretty thoroughly. And, as it turned out, they work together very well. I think the MRoadster polished stainless steel catback (made by Thermal Research and Development) is both a great system, and a great buy.

Under 30 minutes to remove completely


Reviewed by: Justin Rank - therankfamily@hotmail.com

I bought the 8"x14" stainless oval muffler and 4" slant tip. Both come with a polish so good that you can literally count your teeth or shave while using the muffler as a mirror(if that's what you do under you car...). The muffler is a straight through design rather than the staggered approach made by Mazda

When I bought the products from Dan at MRoadster, he was more than curtious with my e-mails and never once became impatient. The next day I phoned and ordered the parts, and he called Thermal so that I could just show up at their shop and pick up the parts. Once I secured my muffler and tip, I went to a local muffler shop in Costa Mesa that I trusted would do a go job (and they did it even better). The muffler shop custom fabbed a 2.25" catback using my muffler and tip. My whole experience was no muss, no fuss. Excellent service by EVERYBODY: MRoadster, Thermal R&D, and Custom Muffler of Costa Mesa.

The one thing that does take getting used to is the sound. This thing is MUCH louder than the Pacesetter exhaust I had priviously used, but not in any bad way. If you love getting attention,then this is your exhaust!! One thing I found out after installation is that it will attract the local police. After only one month, I have a ticket in my wallet for 'modified exhaust'. Parts and installation cost only $255. Thats less than half the price of the JR BEFORE installation.


Reviewed by: Peter Rasmussen - pjraz@hotmail.com

2.25" pipe diameter, 14" x 8" oval muffler with 4" polished exhaust tip for my 94 "R" package. Purchased from MRoadster. Muffler arrived after about 1 week. Dan at MRoadster was very helpful answering my e-mails and helping me decide on a product.

I had it installed at a local Midas muffler shop for $100. The factory muffler had to be cut out and two connecting pipes had to be crafted to connect the muffler to the existing pipe and to install the new exhaust tip. The Midas mechanic also had to weld on brackets to attach into the rubber mounts (these brackets do not come attached to the muffler). The whole job took about 1 hour.

The sound from the new muffler is fantastic. I do not know how it compares to other aftermarket exhaust systems, but I am really pleased with the sound. I have heard other cars with aftermarket exhausts drive by and you really hear a high pitched kind of buzz. This muffler is much deeper and "throatier" than that. Also, the 4" exhaust tip looks great with the rear skirt on my 94 "R" package.

As far as performance gains are concerned, it is slightly noticable. About one week before installing the muffler, I installed a Racing Beat CAI and there was a noticeable growl and performance increase there. After the exhaust was installed, these features were amplified.

Overall I am very pleased with the muffler and tip. However, I wish MRoadster or Thermal Research could have provided Miata specific connecting pipes and brackets, it would have made centering the exhaust tip much easier. Also, I have noticed a tiny speck of what appears to be rust on the exhaust tip. I have only owned this product for about 3 weeks now and I hope this is not a problem I will have to constantly contend with.

Over 30 minutes to remove completely


Back to Product Reviews 8 June, 2008


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