Really need some help on boost creep (external gated)
#1
Really need some help on boost creep (external gated)
Ok it's a home built s5 to4b vtrim hybrid, I blocked off the internal gate to the outlet, took out the flapped and enlarged the ports 1"+ each, drilled a hole in the back plate, and welded a 1.5" runner to the wastegate. I'm running a tial 38mm wastegate with the small green spring .5 bar 7.25psi. Engine is a large street port s5 TII and race port exhaust. Stock tmic, rtek 1.7 550/ID1000, aeromotive 340lph, 3" tid, 2.5dp, 3" straight single exit. It's creeping past 15psi in 3rd 1/2-3/4 throttle. I'm not going past 6500rpm. I have a afc that I trimmed up 3000-8000rpm on the high side. I'll have my wideband in soon. Maybe I just need to go all out to a aftermarket mani :/ idk
#5
Rotary Motoring
iTrader: (9)
This still had boost creep to 17psi with 3 1/2" exhaust, but it did hold down to 12psi with a 3" RB RevII turbo back exhaust.
Porting the manifold and turbo runners up to the wastegate passages will drop the velocity and improve flow to the wastegate runners, but it will decrease the turbo response as well- so do that as a last ditch measure.
Porting the manifold and turbo runners up to the wastegate passages will drop the velocity and improve flow to the wastegate runners, but it will decrease the turbo response as well- so do that as a last ditch measure.
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