Loose boost around 3-4000rpm at wot. Could it be the N75? Video added!

[rayman85]

I have a chipped mk5 gti 2.0tfsi that looses power around 3-4000 rpm at full trottle

I can hear the DV flutter a litle bit around 3-4000rpm at WOT, and can feel the powerloss.
Can also hear e litle whistle/whining sound at this rpm.


I have connected the vagcom han checked the requested and actual boost (block 115) Testing in 3 gear

Requested boost: 21,7 psi dropping to 14,9 (3-5500rpm.peak at 3500rpm)
Actual boost: 17,8 psi dropping to 14,9 (3-5500rpm. peak at 3000rpm)

But the requested boost drops from 21,7 psi at 3500 rpm to 15psi at 4200rpm.
Is it normal to drop so fast?

Video:

-My car is chipped, have a full turboback exhaust with a racecat, and a intake.
recently done to my car : OEM Bosh sparkplugs.
Changed Oil.
Changed the DV valve to the OEM "D" valve.


What to do next?
Cange the PCV? N75? map sensor? manual boost controller parallel with the n75?

Pleas help me :) Sorry for the bad english ( i'm from Norway :p)

[bacillus]

Are you saying that actual boost never reaches the requested value?

[rayman85]

As you see in the video the actual boost reaches the recuested boost after 4000 rpm.
I can hear the DV valve flutter sound and a whistling sound coming from the intake  between 3-4000rpm at wot. I think this is why i dont reaches the recuested boost. Because the DV valve flutter out the boost.

[edd666999]

log it, rather than a video.

have you replaced the dv because of this issue? or has this issue appeared after the replacement

[56OctyVRS]

Also fit a G revision dv and not the D. The D does not make as good a seal and could be letting the boost through.

[rayman85]

No engine codes, but it sometimes goes in to limpmode...

I will do a boostleak test when this arrives [urlhttp://www.turboboostleaktesters.com/servlet/the-42/PRO-dsh-Kit-cln--VW-2.0T/Detail][/url]
Hopefully find a leak

I also want to buy a vagcom so I can boost log. Whish type is the cheapest one that are able to do that?


And BTW, i dont know if the "tststs" sound the car makes between 3-4k rpm at wot is flutter sound or surge sound.

It is the same sound as if you give it full trottle and the turbo is boosting and you let of the trottle but then give just a litle bit of trottle again..
It is not possible to hear it with the original intake.

[E30Dom]

Sound like it's pullign back the timing to me.. th N75 is controlling the boost hence the fluttering, but just sounds flat... sholdn;t be going into limp mode... what map and who set it up?

[rayman85]

It is stage 1 optican tuning. 

[Hedge]

If you get the opportunity to do some logging check the fuel rail pressure actual vs requested.

[percy]

I had  a similar problem as mine was the n75 aas i am using the forge valev setup sp got a new one and then it was all sorted, so could be worth swapping it!

[rayman85]

I was working on my gti, looking for leaks etc. and then i rememberd that I read on a forum once that one guy with a Scirocco had similare problems, and he was also struggling finding out what the problem was.

But one day he disconnected the airmass sensor, when motor running, and then connected it again, stopped the engine, connectet vas, and delited the fault code. and that solved hes problem! ?
I thought that sounded strange, sins i dont have any codes. but I gave it a try.

and guess what.? The probleme is gone!!! and the gti pulles gooood! :)

thanks for trying to help me :)