Too much back pressure?
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Joined: Dec 2019
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Were those T3 or T4?
I did ~600whp on a baby cam 4.8 with a pair of 5056 turbos in .63 A/R T3 on a heartbreaker dyno at 17 PSI.
Backpressure wasn't an issue, power was still climbing but didn't rev it out too far.
I did ~600whp on a baby cam 4.8 with a pair of 5056 turbos in .63 A/R T3 on a heartbreaker dyno at 17 PSI.
Backpressure wasn't an issue, power was still climbing but didn't rev it out too far.
Thread Starter
Staging Lane
Joined: Jan 2016
Posts: 56
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it could be the higher compression on the flat top pistons and the stage one cam pushing more air. I’m not too sure.
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Staging Lane
Joined: Jan 2016
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Likes: 14
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Holy **** those are tiny!
I'm no expert but I think that might be an issue.
I think it would be in your benefit to install some sort of way of monitoring back pressure, even if you did it on only one.
Can you swap to a different turbine housing?
I'm no expert but I think that might be an issue.
I think it would be in your benefit to install some sort of way of monitoring back pressure, even if you did it on only one.
Can you swap to a different turbine housing?
Thread Starter
Staging Lane
Joined: Jan 2016
Posts: 56
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LOL yeah I posted pictures so people would get the point of how small these housings are I had them for a different project, but they ended up on this LS
you can get them in 64 82 or 105
The 105s are a bit fancier in stainless but that’s the ones I’m going to order.
the same turbos on a few set ups make 800 to 1000 hp pretty easily but they’re probably running the bigger housings
Last edited by Fallguy; May 7, 2021 at 01:56 PM.
Thread Starter
Staging Lane
Joined: Jan 2016
Posts: 56
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I’m excited to see how much power it will picked up from the bigger housings.
I know a pair of 6262’s can make over 1000whp on a LS. And I have seen a L33 make 725whp at 17psi. Don’t know what housings he was using.
I know a pair of 6262’s can make over 1000whp on a LS. And I have seen a L33 make 725whp at 17psi. Don’t know what housings he was using.
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I made 600whp with those exact same housings and backpressure wasn't a factor. Could've made more power with more boost.
It ran mid 10s banging gears at ~3500 lbs.
Could very well be your cam's response to them.
It ran mid 10s banging gears at ~3500 lbs.
Could very well be your cam's response to them.
Guy I know makes nearly 600 wheel on a audi 2.7t v6 on a single 6062 with .64 v band in the 30 psi range. Granted that would be more based on ethanol fuel but I believe his backpressure was in check. Different engine but still seems clear you should be ok, but testing is better than guessing.
I have turbonetics old cast wheel 6265 in the .82 dual v band housings and made 1000 at 19psi with ethanol but that’s on a 6.3 10.2:1 engine with porting and cam. I wouldn’t change them out yet, but if you do I can’t see the need to jump to the 1.02 housings on a 5.3. I guess it depends on your goals.
I have turbonetics old cast wheel 6265 in the .82 dual v band housings and made 1000 at 19psi with ethanol but that’s on a 6.3 10.2:1 engine with porting and cam. I wouldn’t change them out yet, but if you do I can’t see the need to jump to the 1.02 housings on a 5.3. I guess it depends on your goals.
Thread Starter
Staging Lane
Joined: Jan 2016
Posts: 56
Likes: 14
Thread Starter
Staging Lane
Joined: Jan 2016
Posts: 56
Likes: 14