FP Red BB boost creep
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From: Central PA
Interesting, I cant recall ever seeing an FP Red have that issue. Even with an O2 dump it doesnt seem to be an issue. I am with you though, if the actuator throws more it might be causing some issues.
Im tuned for 28. But i was having a big overboosting problem and it was due to a cut in my vacuum line so when i was tweaking my mbc back up to 28 i hit 12 then 18 then 25 and the finally 28 all without creep.
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^ I don't think its the vac lines cause I inspect them good. Also when I set boost at 25 psi, its not laggy at all and full boost is at 3800 rpm.
I think the issues is no one have tried to run 20 psi with FP red yet
I think the issues is no one have tried to run 20 psi with FP red yet
You might try disconnecting the actuator rod. Just pop out the cotter pin and pry the turnbuckle off its home on the flapper pivot arm. You should be seeing 7-9 PSI this way(it's gonna be noisy though). Otherwise, if it is much higher, you are just gonna have to port the **** out of it. Is your housing not ported at all? Probably mondo back pressure then.
Last edited by sparky; Jan 19, 2013 at 08:11 PM.
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honda-guy: What were you and Aaron talking about with regard to your O2 housing? Does your hsg have the standard divider wall with a crossover port for the bypass exhaust gas to rejoin the turbine exit flow? I am just trying to understand and visualize how your housing is designed internally. You don't think that the housing might be contributing to your creep issue?
Aaron pointed this out that the standard turbo shop turbine housing porting job opens up the turbine inlet area and unshrouds the exducer. They all do a pretty good job of this nowadays. It improves flow straight through the scroll, reducing back pressure and increasing shaft speeds.
However the turbo shops usually leave the wastegate bypass ports untouched. Exhaust flow through the turbine has been improved. But, bypass flow which is perpendicular to the main flow through the housing is neglected. So, wastegate performance can't bleed off sufficient exhaust gas from the main axial flow through the scroll. So there is more and higher speed exhaust hitting the blade tips. Thus, shaft speeds increase dramatically.
The bypass ports are barely up to the task of slowing down a stock MHI 16G turbine wheel. But there is no way they can bleed off enough exhaust flow for the much larger, higher inertia, lower back pressure FP Red/Black turbine, especially in "as cast" configuration. The bypass port needs to be ported.
However the turbo shops usually leave the wastegate bypass ports untouched. Exhaust flow through the turbine has been improved. But, bypass flow which is perpendicular to the main flow through the housing is neglected. So, wastegate performance can't bleed off sufficient exhaust gas from the main axial flow through the scroll. So there is more and higher speed exhaust hitting the blade tips. Thus, shaft speeds increase dramatically.
The bypass ports are barely up to the task of slowing down a stock MHI 16G turbine wheel. But there is no way they can bleed off enough exhaust flow for the much larger, higher inertia, lower back pressure FP Red/Black turbine, especially in "as cast" configuration. The bypass port needs to be ported.
Last edited by sparky; Jan 19, 2013 at 09:41 PM.
honda-guy: What were you and Aaron talking about with regard to your O2 housing? Does your hsg have the standard divider wall with a crossover port for the bypass exhaust gas to rejoin the turbine exit flow? I am just trying to understand and visualize how your housing is designed internally. You don't think that the housing might be contributing to your creep issue?
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From: Central PA
Aaron pointed this out that the standard turbo shop turbine housing porting job opens up the turbine inlet area and unshrouds the exducer. They all do a pretty good job of this nowadays. It improves flow straight through the scroll, reducing back pressure and increasing shaft speeds.
However the turbo shops usually leave the wastegate bypass ports untouched. Exhaust flow through the turbine has been improved. But, bypass flow which is perpendicular to the main flow through the housing is neglected. So, wastegate performance can't bleed off sufficient exhaust gas from the main axial flow through the scroll. So there is more and higher speed exhaust hitting the blade tips. Thus, shaft speeds increase dramatically.
The bypass ports are barely up to the task of slowing down a stock MHI 16G turbine wheel. But there is no way they can bleed off enough exhaust flow for the much larger, higher inertia, lower back pressure FP Red/Black turbine, especially in "as cast" configuration. The bypass port needs to be ported.
However the turbo shops usually leave the wastegate bypass ports untouched. Exhaust flow through the turbine has been improved. But, bypass flow which is perpendicular to the main flow through the housing is neglected. So, wastegate performance can't bleed off sufficient exhaust gas from the main axial flow through the scroll. So there is more and higher speed exhaust hitting the blade tips. Thus, shaft speeds increase dramatically.
The bypass ports are barely up to the task of slowing down a stock MHI 16G turbine wheel. But there is no way they can bleed off enough exhaust flow for the much larger, higher inertia, lower back pressure FP Red/Black turbine, especially in "as cast" configuration. The bypass port needs to be ported.
