Boost Drop at redline

[murat]

stock rs2
at full throttle boost builds up to 1.1-1.2 bar then after 5000 rpm it reduces to 0.5 bar

car runs rich, and you could smell unburnt fuel, no problems at part throttle.

mark h mod, and hks ssqv is installed recently, but problem is still there

checked turbo, and there is no shaft play in both directions

help me!!!!

[A80Avant]

hmmm are you sure about the boost?1.1 and 1.2bar for RS2 is too low.On stock ECU boost on the RS2 is 1.4bar from 3d gear and on until 6th.You get 1.1bar on 1st and 2nd gear only.

[murat]

vasilis, yes the most boost ı have seen on the gauge is 1.25 , usually 1.2 after 3rd gear

[Ross]

If there's unburnt fuel, and the car hasn't been remapped or chipped (badly), I'd suspect that air is leaking somewhere post-MAF. Have you checked for leaks or pressure-tested to ensure you're lot losing air somewhere? That would account for both the rich running, and a drop in boost pressure...

Cheers
Ross

[murat]

is it safe to check boost leak by pressurizing system from the inlet of the turbo?

the previous owner changed the timing belt before he sold the car to me, could there be a problem about cam timing?

[murat]

what is the stock boost of rs2??????

[maarten]

1.7 iirc

[murat]

and also how much boost should it hold @ redline???

[murat]

what is the stock boost of rs2?????? and also how much boost should it hold @ redline???

please I need a sure answer...........

[A80Avant]

stock boost of the RS2 is boost gauge figures)
1st gear no more than 1bar
2nd gear up to 1.2-1.3bar dropping gradually to 1bar
3d,4th,5th,6th gear 1.4bar dropping gradually to 1bar

you may sometimes see 1.5bar on 5th or 6th gear but that is only momentum or else overboost

more or less this is correct.Any ECU gurus may chip in,but top figures on RS2 is 1.4bar slowly dropping towards the red line

[murat]

thank you vasilis
cheers
murat

[murat]

could my low boost problem caused by incorrect wastegate setup, maybe the old owner changed the setting of the wastegate?

how can i check if its correct????

cheers
murat

[A80Avant]

is your car trembling while heavy acceleration?If not and it is smooth but doesnt go over 1.2bar then it is probably a leak.A leak could be from the intercooler,intercooler connection,hoses etc.

A torn wastegate membrane usually causes stuttering acceleration,and vibration.

[murat]

i dont mean the wastegate diaphram but the mechanical change of the wastegate nut in order to increase decrease boost

[A80Avant]

from my experience turning that nut delivers the boost sooner or later depending on the ECU program you have.I have never heard that it would cause bar reduction