TPC Racing

***Introducing TPC Racing GT3 Exhaust Conversion Kit! (BOLT-ON)***


For GT4 owners wanting OEM GT3/Cup ominous scream and fury at WOT while maintaining civilized sound control on the fly, we are proud to offer a fully developed and dyno tested bolt-on conversion kit!



Disclaimer: The muffler assembly shown in the photo is not included, it is shown for the purpose of giving reference to the conversion kit

TPC Racing has been spending vast amounts of time in-house engineering and dyno testing our new Cat-back/header-back conversion kit for the GT4. We created this product for Power / Torque and ATTITUDE! The OEM Valve design allows for active sport exhaust control for sound flexibility. Additional benefit is weight savings of 7 lbs when using OEM GT3 steel muffler.



Disclaimer: The muffler assembly shown in the photo is not included, it is shown for the purpose of giving reference to the conversion kit




Folks, we know you are on the edge of your seat for dyno results, so here it is! Stock GT4 vs. same GT4 with this conversion kit and TPC Racing Stage 2 custom Cobb Accessport tune. Our GT4 now puts out north of 363 HORSEPOWER and ~ 300 ft/lb torque at the wheels across the entire powerband (not just at the peak).




TPC Racing Exhaust Conversion Kit is priced at $2195. This kit includes:

• In-house made aircraft seamless stainless steel mid-pipes

• In-house made aircraft mandrel-bend corner pipes with sound active valves

• CNC machined exhaust-to-transmission bracket

• Stainless steel band clamps and hardware


All stainless steel material is 100% USA and aircraft-certified from Woolf Aircraft Company, TIG Welded in-house at TPC Racing in Maryland, USA.

This kit is intended for use with OEM GT3 muffler (or any aftermarket equivalent). The muffler, straps, tips, side flanges, and gaskets are not included in the conversion kit as this kit is intended for users/installers to source their own muffler assembly. We can provide a new OEM muffler assembly upon request. While OEM tips are suitable, we do offer custom polished stainless steel exhaust tips available upon request for $399, the tips are for appearance only and DO NOT affect performance.





Contact us for all your questions and inquiries about the new product at info@tpcracing.com (410)-799-7223.

As stated before, this kit is intended for users/installers to source their own GT3 muffler assembly, it can be OEM new or used or aftermarket variant. For your convenience the OEM GT3 muffler assembly (steel version) comprises of the following items/part numbers:

Leuz

That looks sexy! Are you planning on supporting aftermarket headers and offering tuning too?

TPC Racing

Yes, we have a custom Cobb tune for this exhaust with Clubsport catless headers which the tune will work well with other catless headers.

ajw45

This is great, very exciting! Any results for gains from the exhaust alone (no tune)? Tune alone? Is the oem GT3 exhaust much louder on the GT4 than the stock GT4 exhaust?

I've been wondering if dropping the stock exhaust could open up more hp on my 4l build. Going with a GT3 exhaust which we know is designed for 500hp sounds like a really great option vs an aftermarket GT4 solution with unknown design parameters....

ExMB

And what are the numbers without the custom Cobb? Apples to apples and no mix of oranges.

Mech33

+1. Mixing a tune in with an exhaust is a bit misleading IMO. Most folks don't want the tune, I would imagine, and would be interested in the impact of the exhaust alone (which I would suspect are minimal).

Bill Lehman

I agree 100%. According to some tuners claims, all of the gain shown on the dyno could be the tune.

TPC Racing

We appreciate the feedback and thank you for your comments. We do agree that not all exhaust mods produce a gain over the OEM GT4 exhaust. Not to say that it can’t be done but it is not easy to outsmart the OEM engineers with the OEM exhaust doesn’t seem to be too restrictive for the factory spec engine output. The idea of our GT3 muffler conversion started back in one morning this Spring during a track day, with us and a group of our local GT4 customers/friends on pit lane hearing a GT3 equipped with TPC active side muffler bypass blasting down the front straight. Simultaneously, we all looked at each other lusting for that awesome rich sound and then nodded and agreed we all want that. So we developed and did this conversion originally for our car and for our local customers taking advantage of the good deal on second-hand GT3 mufflers at the time. Even before this Spring we have been a fan of the OEM 997/991 GT3 muffler design having used variation of it from air-cooled street rod builds to Porsche Motorsport 4.0L Cup cars. It’s no secret that this muffler was factory designed for 450+hp engines. Which made our development process easy- leaving us only to make and test different diameter connecting pipes that doesn’t impede the flow of the muffler yet not lose mid-range torque on the GT4 engine. All the GT4’s we did this conversion for already has our TPC Stage 1 tune to uncork the factory ECU de-tune. The muffler conversion alone is worth only 5hp at best using OEM GT3 steel muffler with factory spec ECU. Even though the muffler itself was designed to support more power the factory spec tune isn’t taking advantage of the flow potential. With a tuned ECU to increase output however the situation changes. To depict the GT3 steel muffler gain by itself in an environment that’s ideal to have a better flowing exhaust-





The three runs overlay in the dyno sheets are:
Blue: Stock
Red: TPC Stage 1 tune
Green: GT3 steel muffler, TPC conversion kit, TPC Stage 2 custom tune


Please keep in mind that this conversion kit is offered without the muffler assembly. It is of the car owner's choice to use OEM GT3 muffler, or aftermarket GT3 muffler, or even GT3 bypass pipes which all can and will ultimately change the results. Thus, we feel that illustrating the potential with a tune is not a bad idea. We love our conversion as much as our local customers love theirs. We all feel that with the exhaust and tune is how the GT4 should have been in the first place. There are shops that have done this conversion by custom fabrication and welding to each car, they too are happy with the results. For those who know that they specifically want a GT3 type muffler, we offer this bolt-on conversion kit for clean installation without hassle.

TPC Racing

We have an in-car track day video to share with a GT4 that has the Muffler conversion kit with a GT3 muffler!


The GT4 also has the DSC Controller with TPC Racing offset adjustable toe links, TPC Racing caster bushings, the TPC Racing setup, as well as the TPC Racing Stage 2 tune to get the most out of the GT3 conversion exhaust.

Enjoy the thunderous sound of a GT3 Cup car on this GT4 from DAS Sport.

Yargk

Thanks for the additional info. Are the dyno runs taken with 91 oct or 93 oct fuel? Also, how goes the progress with the GT3 intake manifold?

Tom@TPC Racing

Thanks for following.

All runs are on 93 octane pump gas.

We are circling back to the intake manifold next as our stage 3 in a systematic approach. We will of course introduce the new product in a separate thread.

Yargk

Cool, sorry if this has been asked before, but did you make a 91 oct map and what were the gains?

Tom@TPC Racing

Good question. No we haven't. The TPC Stage 1 tune doesn't matter because there's no change to the ignition timing from stock. TPC Stage 2 tune does add minimal degree of timing to take advantage of the bigger exhaust mid pipes and GT3 muffler. More timing is added when custom tuning for catless headers in order to optimize the package, it is here that I reckon it will produce 5-7hp less with 91 oct.

Yargk

Awesome, it's great to hear the timing isn't touched by stage 1 for those who want to stay close to stock.

needmoregarage

We chose TPC for our 991 GT3RS. Very pleased with the result. The obvious quality of the exhaust was apparent, and it’s just what we wanted. Zero cabin drone.