Hello all got a mk1 octy vrs chiped it boost to 19 psi and drops off to 16 psi and holds but some times it drops off to 10 psi slowly any ideas

how often does it do it and is it repeatable in smae gear or just all the time??

sounds like possibly dv on its way out

Welcome to my world (of misery!).

I had my VRS remapped 3 weeks ago and got the same boost spikes and surges. Mine goes to 22psi, then surges about between 8 and 16psi.

Have a look at your Diverter Valve but I would say it's more likely to be your N75 (Wastegate controller valve), or (as in my case) a crap remap.

I replaced N75, DV, and MAF before it was confirmed that it was just the remap and how it was requesting boost. :(

who remapped your car? if its just losing boost sometimes and not surgeing up and down then as said start checking dv,pipe etc......

Longyear there is a difference between surge and Boost loss most likely oem dv giving up!! Test it before replacing!! Let us know how you get on i will advise more after you try this ;-)

P.s longyear if you had logged the car you wouldnt have wasted mo.eu ;-)

The boost will peak low down about 3krpm at 20 psi

Hold 15/16 from about 4-5.5k rpm

Then start to tail off after around 5.5k rpm dropping slowly to around 11/12psi at the redline!

It drop off due to running the stock down pipe

So i change at 5.5k rpm

Longyear there is a difference between surge and Boost loss most likely oem dv giving up!! Test it before replacing!! Let us know how you get on i will advise more after you try this ;-)

P.s longyear if you had logged the car you wouldnt have wasted mo.eu ;-)

The car has been logged many times as part of the problem, eg. requested vs actual boost tests, MAF tests, etc.... don't know where you got the idea from that it wasn't logged. ..... it is the fact that VAG-COM logs haven't brought about any conclusions that has meant trying new components, and subsequently reaching the point that it can only be the remap.

Edited 12 June, 201214 yr by Longyear

sorry buddy wasnt meant to be a moan lol

surely your actual and requested would have shown it was the map??

combined with your duty cycle and requested etc should give you a pretty good understanding of the fault

Well anger man has sumed it up just like he has said.

It was mapped by AMD essex (and it makes the car fly) .

I have fitted a cold air feed, forge rec dv, stainless exhaust from cat back,

Is it worth fitting a 4 bar fuel and maybe a electronic boost controller (is there a how to guide)

Looks like i will fit a after market down pipe and if i use a cat replacement pipe will any lights come up.

Also is it worth changing the n75 valve

cheers for you help

Edited 11 June, 201214 yr by lotuscorsa

Dont need 4 bar reg !! Boost controller not needed

When adding things like de sts etc you should really get map tweaked ;-)

What about the n75

No your n75 will be fine ;-)

is it worth buying the uprated n75 or not

and what about the down pipe

no leave standard n75 on

and yes if you can put an uprated dp on would be a good mod to do