422 LSX w/ Twin PT76's on KYTP kit
04-27-2011, 01:58 PM
#1
422 LSX w/ Twin PT76's on KYTP kit Back in Nov of 2009 I started the original build thread for my buddy Steve Smith's 99' Formula twin turbo build found here:
https://ls1tech.com/forums/forced-in...c78s-kytp.html
We determined that the TC78's were pretty much maxed out at the best 7.8 pass shown here.
http://www.youtube.com/watch?v=n3oJpcz409g&feature=fvsr
Sure, we could've squeezed a little better 60' out of it but turning up the boost really didn't yield any better MPH.
Josh @ KYTP came to Steve with a REALLY good price on these PT76's.
So the logical question is, why PT76's if you out grew the 78mm's?
The answer is, because they make more power and we are told that they will replace the TC78's without ANY fabrication.
How does a smaller turbo make more power?
The TC78's have a cast 78mm compressor wheel, .81 A/R exh housing with a 68mm turbine wheel.
The PT76 have a billet 76mm compressor wheel, .81 A/R exh housing with a 75mm turbine wheel.
The key factors are the billet wheel and the larger turbine wheel. The billet compressor wheel wont flex at high speed and the larger turbine wheel should drop back pressure. These turbos are supposed to be good for almost 200 hp each.
I'm sure that Steve will get these on quickly. If so, we should have some results by the end of next week.
https://ls1tech.com/forums/forced-in...c78s-kytp.html
We determined that the TC78's were pretty much maxed out at the best 7.8 pass shown here.
http://www.youtube.com/watch?v=n3oJpcz409g&feature=fvsr
Sure, we could've squeezed a little better 60' out of it but turning up the boost really didn't yield any better MPH.
Josh @ KYTP came to Steve with a REALLY good price on these PT76's.
So the logical question is, why PT76's if you out grew the 78mm's?
The answer is, because they make more power and we are told that they will replace the TC78's without ANY fabrication.
How does a smaller turbo make more power?
The TC78's have a cast 78mm compressor wheel, .81 A/R exh housing with a 68mm turbine wheel.
The PT76 have a billet 76mm compressor wheel, .81 A/R exh housing with a 75mm turbine wheel.
The key factors are the billet wheel and the larger turbine wheel. The billet compressor wheel wont flex at high speed and the larger turbine wheel should drop back pressure. These turbos are supposed to be good for almost 200 hp each.
I'm sure that Steve will get these on quickly. If so, we should have some results by the end of next week.
Last edited by 98Z28CobraKiller; 04-27-2011 at 05:08 PM.
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04-27-2011, 03:04 PM
#10
Nice. We tossed around the idea of running the .96 A/R housing. We were told that this turbo with the .68 housing would still outflow the the TC78 w/ the .81 housing. We figured that we'd see what it did with the .81's and if it's still choked, then he'd just swap the housings. Just don't want to get into a lazy spool situation.
04-27-2011, 04:07 PM
#13
04-27-2011, 05:26 PM
#14
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this is awesome! I think i may have to try this as well! if and when i outgrow this TC.
Awesome build guys, ive been following it since it started, and cant say enough about how bad *** this car is!
In for results! This is gonna be bad ***!
any ET goals or MPH goals?
Awesome build guys, ive been following it since it started, and cant say enough about how bad *** this car is!
In for results! This is gonna be bad ***!
any ET goals or MPH goals?
04-27-2011, 07:28 PM
#20
Bung gets welded on the hot pipe between the header and the exhaust housing. Then you screw in copper tube with a compression fitting and run it a few feet away to get rid of the heat and then to a 5 bar MAP sensor which is being logged by the Holley Dominator EFI system. This will be our first time collecting this data but that's how we intend to do it. Seems to be the general consensus of how it's done.