s5 turbo question
#7
Rotary Freak
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I have 3" downpipe with full exhaust and an aftermarket cat on my S5 TII. Also have an aftermarket boost gauge.
Gears 1-3 I get about 6.5psi (which is what stock boost should be I was told this by a master rotary tech). 4 & 5 it CAN creep up to 8-8.5 if I really draw the revs out but never hits the fuel cut. I was told this is common and nothing to worry about.
S5s handle it a lot better than S4s and if you are running stock boost you probably shouldn't worry about porting the wastegate.
However on the other hand porting it wouldn't hurt anything and would only make the situation better. You do run the risk of messing up your wastegate if you screw up the port job though.
Gears 1-3 I get about 6.5psi (which is what stock boost should be I was told this by a master rotary tech). 4 & 5 it CAN creep up to 8-8.5 if I really draw the revs out but never hits the fuel cut. I was told this is common and nothing to worry about.
S5s handle it a lot better than S4s and if you are running stock boost you probably shouldn't worry about porting the wastegate.
However on the other hand porting it wouldn't hurt anything and would only make the situation better. You do run the risk of messing up your wastegate if you screw up the port job though.
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#8
Engine, Not Motor
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The S5 turbine has two wastegate passages, one for each runner. The S4 only has a single passage from the rear runner. So the S5 will handle the increased airflow better as others have mentioned. You will reach a point, however, where the boost starts to creep. Turn the boost up to around 10 PSI and the wastegate won't be able to handle it.
#9
Pop Pop BANG FIRE!
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I have a cat-less 3 inch turbo back single and it will hit 8 psi sometimes before fuel cut comes into effect. Yet i have only had this happen twice since im not beating the car because i dont want to hit fuel cut because it could potentially blow my engine. This week i plan on getting my rtek 1.7, some 720cc injectors, and a walbro in because i have an autocross coming up. Should be interesting to see what happens as far as boost goes. This is all also on a S4 stock port turbo. I'm looking for an S5 ported turbo though.
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