S5 tubo hotside on S4, boost gauge line location
04-03-08, 09:28 PM
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S5 tubo hotside on S4, boost gauge line location
I recently made a thread on boost creep and no vacuum readings. The reason for another thread, is because the other thread doesn't seem to be getting any attention and I must know this asap.
I originally put the boost gauge hose on the top nipple on the UIM, then was told to put it on the bottom. But there was already a hose there, and it looked bigger. On the top nipple I had no vacuum readings, and boost was reading 6.5psi up to 4k rpm then jumped up to 10psi!!?? So I just decided to T the boost line for the gauge into the pressure sensor line going into the side of the UIM, so that I could read vacuum. This location read 5.5psi consistently. My question is which boost reading location is more true? This is an 87 t2, ported wastegate, full REV TII rb exhaust, rb fuel cut controller.
I heard putting the s5 turbo hotside on my s4 turbo would reduce boost creep for sure, along with the manifold. Just to double check, is the manifolds that are required the UIM and LIM? Just the UIM? Or the exhaust manifold? When I heard about this, I didn't get an answer on this. Thanks
I originally put the boost gauge hose on the top nipple on the UIM, then was told to put it on the bottom. But there was already a hose there, and it looked bigger. On the top nipple I had no vacuum readings, and boost was reading 6.5psi up to 4k rpm then jumped up to 10psi!!?? So I just decided to T the boost line for the gauge into the pressure sensor line going into the side of the UIM, so that I could read vacuum. This location read 5.5psi consistently. My question is which boost reading location is more true? This is an 87 t2, ported wastegate, full REV TII rb exhaust, rb fuel cut controller.
I heard putting the s5 turbo hotside on my s4 turbo would reduce boost creep for sure, along with the manifold. Just to double check, is the manifolds that are required the UIM and LIM? Just the UIM? Or the exhaust manifold? When I heard about this, I didn't get an answer on this. Thanks
04-03-08, 10:05 PM
#2
nothing wrong with tee'ing the boost gauge into the pressure sensor IMO. Now, I prefer not to tee in the blowoff valve and the pressure sensor on that side nipple... caused some compressor surge problems on my car. so what is the "correct" boost? If you had it on one of the top nipples on the back of the UIM before (the ones that don't even see vacuum), and now you have it tee'd into the pressure sensor nipple, I would trust the way you have it now more. But some may disagree with me.
To answer your question directly, if you just want to control boost then you need to port the wastegate on the turbine housing you already have. An s5 wastegate is bigger, yes, but if you have the full racing beat 3" exhaust it will likely still creep.
The s5 turbo swap should have the s5 turbo manifold. You don't have to swap the intake manifold.
see http://fc3spro.com/TECH/FAQ/ZVK/zvk.html , near the bottom
To answer your question directly, if you just want to control boost then you need to port the wastegate on the turbine housing you already have. An s5 wastegate is bigger, yes, but if you have the full racing beat 3" exhaust it will likely still creep.
The s5 turbo swap should have the s5 turbo manifold. You don't have to swap the intake manifold.
see http://fc3spro.com/TECH/FAQ/ZVK/zvk.html , near the bottom
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