6 Days at Heffner Performance.
- Thread starter ChipBeck
- Start date
Great write up as usual, Chip. Thanks for sharing in such intricate detail.
Few questions: This is first TT setup I've seen with cats in that location. Have others gone this route as well? Are you utilizing any heat shielding there? Also how much power does Jason estimate that the cats rob at the 840 rwhp level?
Thanks,
Sanjay
Few questions: This is first TT setup I've seen with cats in that location. Have others gone this route as well? Are you utilizing any heat shielding there? Also how much power does Jason estimate that the cats rob at the 840 rwhp level?
Thanks,
Sanjay
Catalytic converter horsepower cost.
Sanjay,
The only heat shielding is the ceramic coating on the exhaust system. A number of TT GTs have been built with these catalytic converters (Elite Autos #65 White/Blue TTGT has them) and there have been no problems to date. That may not be the ideal spot to place a catalytic converter but it is the only place where they will fit on this system. Because they add slightly to the length of the exhaust system it had to be tilted toward the engine instead of straight up and down (as Jasons non-cat system is built) so that it clears the clamshell. The majority of Heffner TT GTs do not have catalytic converters.
Jason's dyno testing shows that these cats result in a loss of 30 hp at this level. In addition, dyno testing also shows that my 91 octane tune (as opposed to a 93 octane tune) results in the loss of another 30 hp. So if I lived in Texas were I could buy a better gasoline and not have to deal with emissions inspections, my car would put out about 901 hp on pump gas.
The TT system on my car is a slight improvement on those built before #32. The exhaust pipe just downstream of the header collector is 1/4" smaller in diameter than previous systems. That small change in diameter results in an approximate 20% increase in exhaust velocity upstream of the turbocharger. The result is less turbocharger lag and apparently a very small increase in top end horsepower. Jason had initially experimented with a larger diameter exhaust system. Instead of the expected gain he experienced a much greater turbo lag and no increase in power. So he went the other direction and bingo, a slight improvement.
Chip
Sanjay,
The only heat shielding is the ceramic coating on the exhaust system. A number of TT GTs have been built with these catalytic converters (Elite Autos #65 White/Blue TTGT has them) and there have been no problems to date. That may not be the ideal spot to place a catalytic converter but it is the only place where they will fit on this system. Because they add slightly to the length of the exhaust system it had to be tilted toward the engine instead of straight up and down (as Jasons non-cat system is built) so that it clears the clamshell. The majority of Heffner TT GTs do not have catalytic converters.
Jason's dyno testing shows that these cats result in a loss of 30 hp at this level. In addition, dyno testing also shows that my 91 octane tune (as opposed to a 93 octane tune) results in the loss of another 30 hp. So if I lived in Texas were I could buy a better gasoline and not have to deal with emissions inspections, my car would put out about 901 hp on pump gas.
The TT system on my car is a slight improvement on those built before #32. The exhaust pipe just downstream of the header collector is 1/4" smaller in diameter than previous systems. That small change in diameter results in an approximate 20% increase in exhaust velocity upstream of the turbocharger. The result is less turbocharger lag and apparently a very small increase in top end horsepower. Jason had initially experimented with a larger diameter exhaust system. Instead of the expected gain he experienced a much greater turbo lag and no increase in power. So he went the other direction and bingo, a slight improvement.
Chip
Kelly-X1
Ex GTX1 Owner
Had the pleasure of spending a little time with Chip and a few of the Phoenix area guys and gals at the Pavilion Saturday night and saw firsthand the perfection of that turbo, and the exhaust note is just right. Pictures are great but just don't do it justice. I'm sure he's itch'n to spin them up and I hope to be there for the big day.
Congrats on the set up, sweeeeeet.
Congrats on the set up, sweeeeeet.
Triheart7
GT Owner
Chip, thanks for posting the article. Great read. I can see you would be excited with the TT.:thumbsup
- Feb 22, 2006
- 370
Chip,
I can't thank you enough for the excellent coverage of the build, giving us the opportunity spend the week with you or for having us build your dream car. It was truly our pleasure to have had you with us throughout the build process and I'm very happy to hear that you are enjoying the car so thoroughly. Please keep us up to date as you become more acquainted with your new toy.
To answer a few of the questions that I saw:
The water that runs through the turbo center section is the engine coolant and is circulated by the factory water pump.
The oil pan is removed so that we can weld in the turbo oil return fittings.
The turbo oil feed comes from the engine and is tee'd in by the oil pressure sending unit.
Again, thank you, Chip and thanks to everyone else for being so excited for Chip and his GT!
I can't thank you enough for the excellent coverage of the build, giving us the opportunity spend the week with you or for having us build your dream car. It was truly our pleasure to have had you with us throughout the build process and I'm very happy to hear that you are enjoying the car so thoroughly. Please keep us up to date as you become more acquainted with your new toy.
To answer a few of the questions that I saw:
The water that runs through the turbo center section is the engine coolant and is circulated by the factory water pump.
The oil pan is removed so that we can weld in the turbo oil return fittings.
The turbo oil feed comes from the engine and is tee'd in by the oil pressure sending unit.
Again, thank you, Chip and thanks to everyone else for being so excited for Chip and his GT!
Beach-GT
GT Owner
Do you have to provide some sort of regulation for the oil pressure? On my Air research turbo, they recommended 40 PSI and since I have an 80lb pump in my stang I had to put a valve in the line and a guage to set it at 40 PSI. Maybe the Garrets can take what ever they get?
- Feb 22, 2006
- 370
Beach-GT
GT Owner
PL510*Jeff
Well-known member
FlorIdaho Chris
Yeah, I've got one.
Congratulations Chip, and welcome to The Dark Side! :cheers
I assume you are not going to run C16 with those race cats are you?
Can't wait to see it in person. Nice write up!
I assume you are not going to run C16 with those race cats are you?
Can't wait to see it in person. Nice write up!
ObeyMyFast!
GT Owner's son
Cats.
Chris,
No, I know that would screw them up. But I will probably have Heffner build me a 2nd exhaust without the cats so that I can use the good stuff on special occasions like the Mile.
I liked the Silver intake of your Camilo/Heffner TT GT so much I had mine painted the same way. I think that Red-White TT you drove at Rally IV is the best looking GT that exists. I wish I had the money to bid on it at Rally III. :cheers Are you coming down for Barrett-Jackson?
Chip
Chris,
No, I know that would screw them up. But I will probably have Heffner build me a 2nd exhaust without the cats so that I can use the good stuff on special occasions like the Mile.
I liked the Silver intake of your Camilo/Heffner TT GT so much I had mine painted the same way. I think that Red-White TT you drove at Rally IV is the best looking GT that exists. I wish I had the money to bid on it at Rally III. :cheers Are you coming down for Barrett-Jackson?
Chip