lack of boostz...

[bellios]

Hi Guys,

asking for a bit of help with a particular issue ive got at the moment.

It started with the colder weather recently. ive got a boggo mk5 thats running a bluefin stage 1.

basically when getting up past 3k rpm, it feels like the boost is fluctuating quite a bit. i dont have a boost gauge, and ive already been through the usual suspects for causing running gremlins. The car has had over the past few months (to try and stop this sort of thing, but not cause of this)....

* new coilpacks care of VW
* new sparks last week
* revised PCV which has now beeen replaced with a REVO PCV blank
* rev G diverter
* new cam follower (oold one ws still in good nick).

ive scanned the car numerous times and dont get any errors. to be honest, having had quite a few boosted cars in the past im kind of thinking i have a boost leak of some description.

other points of note the car is only run on optimax and has had a few cycles of petrol now (so not a bad batch of fuel). So, im at a bit of a dead end. I dont think i have an issue with my CAM profile as ive read other places driving the HPFP (apparently when worn it can have a strange effect on the fuel delivery). Im not convinced its MAF related as ive run it with the MAF off, and having had a K04'd B5 S4 in the past that used to eat MAFs, it doesnt seem the same (plus the lcak of implausible signal etc in VAGCOM).

Ive ordered a boost pressure test kit off flea bay which im hoping will help as im guessing it could be something stupid like a vaccum hose has split or something similar. this in itself is raising a quetion as im not sure how air tight the standard engine cover/filter is where it mates to the intake next to the MAF, but the pipework is oval after that point so im ot sure where i can strap on to for getting a good seal.

Anyway, any help or advice appreciated. 

[GTI-Pirelli]

I don't know if you are monitoring your RPM when you accelerate.

I suffer from similar simptoms in cold weather but it is not boost (in my case). I thought that it was originally.
In my case it is the clutch. When I put the foot down, the revs climb constantly up to around 3k then instantly jump to 4k. It feels like the boost has dropped. The revs then drop to around 3.5k then start to climb again (if you have kept your foot down). It happens in cold/damp weather and has been the case for the last couple of years.
As the weather warms up - business as usual!

Just a thought. It will show no errors on diagnostics and feels just like the car isn't holding boost.

Feel free to completely ignore this if you like. Hope you get it sorted

May be worth noting - to do a pressure test, would it not be better to be on the engine side of the turbo as you can closer monitor the compressed air entering the engine? If there is a leak in the air box the incomming air will just bypass the filter but still be compressed.

[bellios]

thanks for responding.

Yeah im monitoring the rev counter (also using butt dyno) - it feels like intermittent flat spots as you climb up the rev range. ive had slipping clutches on other cars before and cant say that it seems like the same sort of behaviour, but im not sure whether DSG would behave differntly with clutch slip.

Are you manual or DSG? your cars probably making more power in the cold weather toasting your clutch 

Im at a bit of a loss what to do now really. the only thing i can think now is to go with my original plan which was boost test and perhaps some logging with VAGCOM.

does anyone know what monitoring blocks to use on VAGCOM for requested vs actual boost?

thanks all for your help.