When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I want to share with you a few mods done over the past month. Ever since hearing Chasen’s GT4 with the GT3 center muffler I knew I wanted to go that route. I fell in love with the sound. I contacted Tom @ TPC Racing (local to me) a few months ago to run several ideas by him. If you don’t know Tom, he is fantastic, salt of the earth type of guy, always lending a hand, and extremely knowledgeable. Tom ran through the “do’s”, “don’ts” and “wait for now” items with me. Being completely honest and open with his advice. The exhaust system has been enhanced as follows:
- Dundon race headers. These are a piece of art, gorgeous build quality, and really cleaver design with their scavenging. Thank you Jamie and team at DMS for producing an excellent product.
- GT3 Center. Bought Tom’s 997 center off of him. He even cleaned and shined it up for me!
- New valved exhaust elbows for closed or open operation using factory PSE switch.
- New TPC Mid-pipes. TPC spent a lot of time testing various mid-pipe dimensions / designs to maximize power.
- New longer TPC exhaust Tips (factory GT3 tips are a tad short for the GT4 rear)
- Custom Tune (Cobb).
The result is magnificent. The power curve is smoothed out - way better than stock and the 3k dip is eliminated. Dynographs attached at bottom along with a few pics.
Blue = Stock
Red = Headers + Tune (stock exhaust)
Green = Headers + GT3 Center + TPC Mid-pipes + Tune
Total Max HP increase = 21 HP & Total Max TQ increase = 13 HP. We all know peak max HP & TQ isn’t the real story… under the entire curve is what is eyeopening… the deltas from stock, majority of it is due to the Dundon headers although in some spots we are seeing an extra 10 HP and TQ increases with the GT3 center and midpipes. Amazing! And the GT3 center is 7 LBS lighter than the stock exhaust.
3700-3800 RPM = 31 HP & 44 TQ
4900 RPM = 36 HP & 39 TQ
6400-6500 RPM = 22 HP & 20 TQ
7300 RPM = 24 HP
The experience: The system feels strong! Smooth power all the way to redline. Throttle response is sharper, quicker. The sport mode throttle blip is noticeably faster and lively, more rev happy. The sound… the sound is epic. Its transformed the car into a screaming rabid beast. PSE off is still noticeable but livable especially on highway cruising at 70-80mph. PSE on… its GT3 cup car screaming crazy. Raspy, loud, really really loud. The overrun crackling/burbling no longer sounds enhanced/fabricated as in stock form… its straight race car with extremely forceful pops and snaps (I wonder if flames are shooting out the rear). Lift off the throttle while rolling to a stop; it crackles for days. Downshifts are mean, you will startle drivers behind you. Full throttle will deafen them - drivers will swerve towards the shoulder when passed. If you live in Great Falls, I apologize in advance for the rally car race happening outside your home. The best comparison I can find to the sound:
The new TPC GT3 center conversion kit consists of valved elbows, mid-pipes, muffler brackets, and optional longer tips. In addition to the wonderful exhaust enhancement, the TPC Team installed a DAS roll bar complete with 6-point harness. The fit looks stock. They also reworked my chassis settings adding TPC front caster bushings and TPC rear toe links.
Awesome tuning by TPC!!! They really invested in the development of the mid-pipe to make it all come together w/ custom tune. Can't wait for the TPC intake goodies to become available
Nice! Will you be recording any video of this setup from inside and outside the car?
Originally Posted by BealeAss
Would love to hear an actual clip
I don't have any audio outside the car. Happy to do a few drive by recordings one day. Any local NoVA volunteers? Here is a clip from inside. Lots of wind noise, still gives you a sense of it.
I don't have any audio outside the car. Happy to do a few drive by recordings one day. Any local NoVA volunteers? Here is a clip from inside. Lots of wind noise, still gives you a sense of it.
- highway driving. Windows up. Open and closed valve comparison at speed. There is no drone (when open it's just loud so I can't tell) closed. Closed is fairly muted. Apologies in advance for filming the vents... better than filming my ugly mug.
07-22-2017, 09:12 AM
TPC Awesomeness. Headers + mid-pipes + GT3 center....
