3.5" down pipe?
FormerVendor
Joined: Dec 2001
Posts: 2,444
Likes: 2
From: WWW.SPEEDINC.COM
Originally Posted by torchz06
How much power can I make through a 427 C5R in a corvette with a t-76 Q and a 3.5" down pipe. Can I make 700rwhp with the 3.5" downpipe? 
My LT1 is at 760rwhp @19psi with an Innovative GT80, 3.5in downpipe and exhaust, through the original muffler and tailpipes. (muffler opened up for 3.5in intermediate pipe).
So, yes, 700rwhp is no problem for a 3.5 downpipe, but IMO, the exhaust side of a T-76 Q is going to be a bit restrictive on a 427.
Thread Starter
Teching In
Joined: Dec 2003
Posts: 17
Likes: 0
Originally Posted by INTMD8
My LT1 is at 760rwhp @19psi with an Innovative GT80, 3.5in downpipe and exhaust, through the original muffler and tailpipes. (muffler opened up for 3.5in intermediate pipe).
So, yes, 700rwhp is no problem for a 3.5 downpipe, but IMO, the exhaust side of a T-76 Q is going to be a bit restrictive on a 427.
So, yes, 700rwhp is no problem for a 3.5 downpipe, but IMO, the exhaust side of a T-76 Q is going to be a bit restrictive on a 427.
What do you think would be the best turbo?
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Torched...give me a call. I have a C5 single turbo kit for sale: T71 GTQ, BB, big FMIC, 3" DP. Currently making 580/580 @ 12psi on stock cubes. The T71 is rated at 880fwhp.
Phone: 248-842-3309
Phone: 248-842-3309
Staging Lane
Joined: Oct 2003
Posts: 83
Likes: 0
From: Land of the lost
Being a 427, not 346...thus t88 is what I'd use...judging by the maps I've played with lately..that would be fairly efficient depending on the rest of you set-up. Get that air pump pumpin'.
Twin,
This is definitely the bigger is better crowd.
I'd like to make a couple of points: The GTQ T71 is rated to 880fwhp. Its efficient in the 600 - 650rwhp range. Beyond that, I believe you are going to be testing the limits of the pcm and fuel systems currently available for the C5. I haven't seen anyone running higher than 50lb injectors on a C5 and fuel pump setups that I have seen are good to 800fwhp (racetronix and boost-a-pump). If one wanted more power a GTS T76 is good for about 1100fwhp. No one in a C5 is going to come close to needing/using more than that. The current offerings for tranny's and rear diffs. have trouble handling anything north of 600rwhp. Last point of discussion: having a T71 under the hood of C5, I cant see a big frame turbo fitting. My "little" T71 is a tight fit. If I am correct, the T74/T76 are all in the same family and are therefore sized comparatively close. I think it would be difficult to fit a T88 in a C5 engine bay. I'm interested to hear some of the other "experienced" turbos guys views on this.
This is definitely the bigger is better crowd.
I'd like to make a couple of points: The GTQ T71 is rated to 880fwhp. Its efficient in the 600 - 650rwhp range. Beyond that, I believe you are going to be testing the limits of the pcm and fuel systems currently available for the C5. I haven't seen anyone running higher than 50lb injectors on a C5 and fuel pump setups that I have seen are good to 800fwhp (racetronix and boost-a-pump). If one wanted more power a GTS T76 is good for about 1100fwhp. No one in a C5 is going to come close to needing/using more than that. The current offerings for tranny's and rear diffs. have trouble handling anything north of 600rwhp. Last point of discussion: having a T71 under the hood of C5, I cant see a big frame turbo fitting. My "little" T71 is a tight fit. If I am correct, the T74/T76 are all in the same family and are therefore sized comparatively close. I think it would be difficult to fit a T88 in a C5 engine bay. I'm interested to hear some of the other "experienced" turbos guys views on this.
FormerVendor
Joined: Dec 2001
Posts: 2,444
Likes: 2
From: WWW.SPEEDINC.COM
Originally Posted by Earl H
Twin,
This is definitely the bigger is better crowd.
I'd like to make a couple of points: The GTQ T71 is rated to 880fwhp. Its efficient in the 600 - 650rwhp range. Beyond that, I believe you are going to be testing the limits of the pcm and fuel systems currently available for the C5. I haven't seen anyone running higher than 50lb injectors on a C5 and fuel pump setups that I have seen are good to 800fwhp (racetronix and boost-a-pump). If one wanted more power a GTS T76 is good for about 1100fwhp. No one in a C5 is going to come close to needing/using more than that. The current offerings for tranny's and rear diffs. have trouble handling anything north of 600rwhp. Last point of discussion: having a T71 under the hood of C5, I cant see a big frame turbo fitting. My "little" T71 is a tight fit. If I am correct, the T74/T76 are all in the same family and are therefore sized comparatively close. I think it would be difficult to fit a T88 in a C5 engine bay. I'm interested to hear some of the other "experienced" turbos guys views on this.
This is definitely the bigger is better crowd.
I'd like to make a couple of points: The GTQ T71 is rated to 880fwhp. Its efficient in the 600 - 650rwhp range. Beyond that, I believe you are going to be testing the limits of the pcm and fuel systems currently available for the C5. I haven't seen anyone running higher than 50lb injectors on a C5 and fuel pump setups that I have seen are good to 800fwhp (racetronix and boost-a-pump). If one wanted more power a GTS T76 is good for about 1100fwhp. No one in a C5 is going to come close to needing/using more than that. The current offerings for tranny's and rear diffs. have trouble handling anything north of 600rwhp. Last point of discussion: having a T71 under the hood of C5, I cant see a big frame turbo fitting. My "little" T71 is a tight fit. If I am correct, the T74/T76 are all in the same family and are therefore sized comparatively close. I think it would be difficult to fit a T88 in a C5 engine bay. I'm interested to hear some of the other "experienced" turbos guys views on this.
HP rating for turbos are nice to talk about, but usually people concerned about efficiency don't build a combination with the intent of maxing out a turbo. If someone has the money to build a turbo 427, there's no reason to limit yourself to the limitations of a stock pcm. (unless you're Harlan
) IMO, a twin turbo setup is probably the best option for a C5 with a 427 in terms of packaging and efficiency. A 427 with the proper turbo(s), could probably do around 80lbs/min @1 bar. If a PT76 GTS compressor map is similar to my Innovative GT80, than it's going to be around 2bar @80lbs/min near peak efficiency. It's just not a good match IMO.
Earl
We've discussed this setup already...
https://ls1tech.com/forums/forced-induction/119170-what-size-turbo-427-a.html
See that for reasons and recommendations.
And the new GTQ wheels do seem to be flowing closer to the next size up older wheels. But if you look, he's looking for 700rwhp max on a 427. Kind of wierd combo for it if you ask me, but that's what he wants.
And we all know how much power the y-car driveline eats compared to the F-car. So he's probably looking closer to 850 at the flywheel to get there.
We've discussed this setup already...
https://ls1tech.com/forums/forced-induction/119170-what-size-turbo-427-a.html
See that for reasons and recommendations.
And the new GTQ wheels do seem to be flowing closer to the next size up older wheels. But if you look, he's looking for 700rwhp max on a 427. Kind of wierd combo for it if you ask me, but that's what he wants.
And we all know how much power the y-car driveline eats compared to the F-car. So he's probably looking closer to 850 at the flywheel to get there.
Staging Lane
Joined: Feb 2002
Posts: 93
Likes: 0
From: Dearborn
Hey Harlan do expect any problems with all that heat right below your hood. The resason I ask is I'm looking at a similiar kit for the C5 with turbos mounted quite similiar to yours. Do you think that setup could withstand 25mins. of roadracing.
Moderator
Joined: Nov 2001
Posts: 3,048
Likes: 12
From: Raleigh, NC
Originally Posted by DetroitZ
Hey Harlan do expect any problems with all that heat right below your hood. The resason I ask is I'm looking at a similiar kit for the C5 with turbos mounted quite similiar to yours. Do you think that setup could withstand 25mins. of roadracing.
With a view like that, he better keep it exposed for oohs and ahhs!
Just kidding!
