Twin precision 7675s on a 402
03-09-2019, 02:02 PM
#3
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Looking to break 1k hp maybe max 1200..just didnt wanna end up too laggy. I've got th400 with transbrake behind it so I think I could make them work just couldn't really find any results with them as twins on anything LS based smaller than like a 427
Last edited by turboed370; 03-09-2019 at 02:11 PM.
03-09-2019, 03:01 PM
#5
I'd like to add that it depends on your planned usage of the car and what internals you have. If you go on YouTube, there is a TransAm running a 425 with twin CAST 7675's make 1800 running low 7's. He's also PUSHING those turbos hard. Plenty of guys making 1000whp on twin 66's and 67's around 20psi.
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03-10-2019, 06:37 AM
#8
I met Tiago in Houston back in 2002 or so at a car meet in Houston, TX. He had his hood open on his beautiful 2002 (?) TransAm. I walked up from the side and jaw dropped when I saw he had two symmetrically positioned TC76's mounted there. He walked over and said Hello. I asked how much he was making with this setup and he said 1300 wheel. If you're not familiar, the TC76 are small housing Turbonetics that are something like 76/65 or something like that. Tiago had raced that at the Texas mile several times. I think he's moved on to other turbos now. Just a spectacular car in my opinion. I think you'll easily exceed your expectations with those turbos. I think there's some guys on here that have made 1000 or more with much more modest Twins.
03-10-2019, 09:48 PM
#10
I met Tiago in Houston back in 2002 or so at a car meet in Houston, TX. He had his hood open on his beautiful 2002 (?) TransAm. I walked up from the side and jaw dropped when I saw he had two symmetrically positioned TC76's mounted there. He walked over and said Hello. I asked how much he was making with this setup and he said 1300 wheel. If you're not familiar, the TC76 are small housing Turbonetics that are something like 76/65 or something like that. Tiago had raced that at the Texas mile several times. I think he's moved on to other turbos now. Just a spectacular car in my opinion. I think you'll easily exceed your expectations with those turbos. I think there's some guys on here that have made 1000 or more with much more modest Twins.
Last edited by TT427; 03-11-2019 at 03:17 PM.
03-11-2019, 08:54 AM
#12
Lol... I'm assuming that either packaging concerns (the smaller housings of the TC) or perhaps he just had a couple of TC76 sitting in his shop might be why he used those units. I think they were about $7xx.xx apiece back then. I bought one for my first turbo effort in my 96 Z28 using the LT1. Made 574rwhp at 11psi on the first dyno using a pcmforless mail order tune. Remember, this was back in 2008 or 2009.
03-13-2019, 12:19 PM
#14
I learned the hard way, TC is garbage, they can't build a turbo to last at all.
Rebuilt two TC billet ball bearing units smoked in 6 months. They only lasted about a year from TC.
Switched to borg s300s , no issues, make more power, and more reliable. I will never recommend TC units to anyone.
Rebuilt two TC billet ball bearing units smoked in 6 months. They only lasted about a year from TC.
Switched to borg s300s , no issues, make more power, and more reliable. I will never recommend TC units to anyone.
03-14-2019, 07:57 AM
#15
So TC is a company? I bought my TC76 (A Turbonetics unit) from ForcedInductions.com, recommended by Jose. So did TIago. Are you saying they're the same units?
I learned the hard way, TC is garbage, they can't build a turbo to last at all.
Rebuilt two TC billet ball bearing units smoked in 6 months. They only lasted about a year from TC.
Switched to borg s300s , no issues, make more power, and more reliable. I will never recommend TC units to anyone.
Rebuilt two TC billet ball bearing units smoked in 6 months. They only lasted about a year from TC.
Switched to borg s300s , no issues, make more power, and more reliable. I will never recommend TC units to anyone.
03-14-2019, 08:50 AM
#16
Yes they are the same. The TC is The **** with the 68mm turbine. A ridiculous pairing to the big compressor
Flip that bias like with a s366 where you have more turbine and less compressor and it does absolutely everything better
Flip that bias like with a s366 where you have more turbine and less compressor and it does absolutely everything better
03-14-2019, 08:51 AM
#17
I learned the hard way, TC is garbage, they can't build a turbo to last at all.
Rebuilt two TC billet ball bearing units smoked in 6 months. They only lasted about a year from TC.
Switched to borg s300s , no issues, make more power, and more reliable. I will never recommend TC units to anyone.
Rebuilt two TC billet ball bearing units smoked in 6 months. They only lasted about a year from TC.
Switched to borg s300s , no issues, make more power, and more reliable. I will never recommend TC units to anyone.
Running 7s at real weight speaks for itself
03-14-2019, 08:04 PM
#18
I did always wonder about back pressure because it was always blowing out the header gaskets on the LT1(all forged 355, TFS heads w/2.08 intakes, 1.60 exh). It got into boost quick but never really MPH'd that great in the quarter. I think at the time, I was not only a newbie but worried about packaging with stock F-body radiator/power steering/Air conditioning. Thanks for the info.