i'm curious as to if i can run 10psi on my car. its a 91 N/A with a S5 TII motor, intake, full turbo back exhaust, walbro 255lph fuel pump, FCD, and boost controller.

is it safe to run 10psi without tuning? i did search before asking and couldn't find anything definate.

 

I would do it.

 

with your mods and everything i have read it is safe for your combination

 

thanks guys. what would you considder the absolute most it could go to? i'm thinking the 12-14psi mark without tuning.

 

problem is..... you will regularly hit more than 10 psi with your stock wastegate

 

well the injectors are the only things limiting you in the end. Then it's turbo(higher psi limits).

I am running some what the same setup you say and will hope everything will be ok.

 

even with a boost controller i'll get spikes?

 

boost controllers only raise boost. you can't lower it.

chances are you will be over 10psi in 4th and 5th.

10-11psi would be max for your current setup. if you are hitting over that if means you can't floor your car untill you upgrade some more stuff.

 

boost controller will do nothing for you with this setup. It can only raise the boost, it cannot lower it. You will get boost spikes up to like 12-13 psi with your stock wastegate. You need to worry about the fuel. i would stick bigger secondary injectors and like Safc to controll em.

 

oops sorry i thought we're talking about s4 here. S5 wastegates are little bigger. Still if you wanna feel safe in the 12-14 psi range you would need like fmic

 

thanks guys for the help. was everything with the S5's better then the S4's? it sure seems like it from what i've read.

 

definatly port your wastegate as big as you can, then put on a boost controller. i have a similer setup, and could creep to 14 psi occasionally, now the highest creep ive seen is 9 psi in 4th at WOT. I wasnt getting any detonation at 13 psi, but i wont run anything higher than 11 without injectors and a SAFC, maybe 12 if im at the track and my engine isnt heat soaked.

 

is there a flange inside the wastegate like in the Greddy Type-S BOV? if not then whats the largest i can port the wastegate?

 

i ran 12-14 with my s4, (2 1/2 turbo back, safc, profec e01, stock tmic, 93 oct fuel, air pump and acv removed) no probs after a little boost of fuel from the safc. but the other night running wot in fourth somehow i lost voltage to fuel pump and now my motor is dead. Might wanna consider fuel pump rewire. i would hate for someone else to be in the same boat!

 

Were you running stock fuel pump?

 

Were you running a stock alternator?