boost fall off in high rpms???
 

I have the greddy 15g and manifold and type -s b.o.v. I have a uberdata chipped ecu and for some reason.. in high rpm's in 2nd and 3rd gear boost goes to 10 but when I go past 5500 or 6k, boost falls off to around 7 or 8psi?!?!?.

I thought maybe the cat was causing a restriction but I hollowed it out plus I have a thermal 3in cat back so I know flow is not the issue.

I tested the bov and it does not leak... I tested the couplers all fine. the pipes are all good.
I have heard the wastegates tend to leak a bit in high rpm's..

Unless something it wrong with my map on the chip which I doubt, I cant figure this out..

Please help !!

Thanks,
Tony

Re: boost fall off in high rpms???
 

since the 15g is a rather small turbo it loses its efficiency up top...for having a fast spooling time you sacrifice top end. this problem is very common with the 15g kit...i have heard that if you free up the exhaust flow it will perform better than before in the higher rpms...i think kteller makes a direct bolt on 2.5 in. dp...and with 2.5 exhaust all the way back should help

Re: boost fall off in high rpms???
 

Reading is good.

Re: boost fall off in high rpms???
 

yeah....my bad...it still could help to up the size of dp off of that turbo

Re: boost fall off in high rpms???
 

I have a 2.5 in dp already...

if I got another wastegate would that help. or no???

I had a 14b on my old car and it ran fine all the way to redline...? and it's a small turbo!

maybe I am mising something.. who knows.

if anyone else has input please let me know.

Thanks,
Tony

Re: boost fall off in high rpms???
 

the 14b has a bigger compressor in it i think though...

Re: boost fall off in high rpms???
 

the 15g is smaller, only a td04, 14b is a td05.

weird issue, i ran the stock dp with 2.5" from the dp-back, and could hold 11psi from spool to redline solid as a rock.

Re: boost fall off in high rpms???
 

I dont know what else it could be then.. I mean what else is there???

-Tony

Re: boost fall off in high rpms???
 

im having the same extact problem i had a t3 super 60 and it never did it put a 15g greddy turbo on yesturday and at about 5500 its starts stuttering only if your flawing it i also have a greddy type s bov i think it has something to do with adjsuting the bov

Re: boost fall off in high rpms???
 

are you guys not understanding that the turbo is to small??? its so small its falling off on top cuz its losing efficiencly... its over working its self and can't handle it. get a bigger turbo...