disconnect your maf see if it makes any difference

look down the back of the engine, you se that metal boost pipe? the one thts picks up from the turbo with a rubber elbow, then drops down into the dark bit?

 

.between there and the pancake pipe, the gods at VAG decided to put a stupid clip type joint which I found to be the main boost leek on mine.

is it still running just the standard N75 to actuator setup? (smaller hose from that metal pipe mentioned above, goes into the N75 valve on the intake pipe, then makes its way down to the actuator on the turbo) I tried fitting a manual boost controller in parallel with the N75 (as it is too harsh to use as a daily driver without the N75). That gave identical symptoms you described in the first post.

 

It is like the ECU is not able to decide how much boost it wants, more.. less, more.. no, too much!... bit more.. ahh, no i'm scared, back it off, more....

 

the actuator may also have been adjusted badly on the turbo, the pipe may have a leek, or have come off.

I found I had a few improvements when I fitted an uprated SMIC, I cleaned the MAP sensor when I fitted it, as this was covered in carp. might help.

look down the back of the engine, you se that metal boost pipe? the one thts picks up from the turbo with a rubber elbow, then drops down into the dark bit?

 

.between there and the pancake pipe, the gods at VAG decided to put a stupid clip type joint which I found to be the main boost leek on mine.

is it still running just the standard N75 to actuator setup? (smaller hose from that metal pipe mentioned above, goes into the N75 valve on the intake pipe, then makes its way down to the actuator on the turbo) I tried fitting a manual boost controller in parallel with the N75 (as it is too harsh to use as a daily driver without the N75). That gave identical symptoms you described in the first post.

 

It is like the ECU is not able to decide how much boost it wants, more.. less, more.. no, too much!... bit more.. ahh, no i'm scared, back it off, more....

 

the actuator may also have been adjusted badly on the turbo, the pipe may have a leek, or have come off.

I found I had a few improvements when I fitted an uprated SMIC, I cleaned the MAP sensor when I fitted it, as this was covered in carp. might help.

sounds like something to investigate..... would be a lot easier up on a lift!    I may just bite the bullet, buy a FMIC and get my tame mech to do all the pipes.....

 

its running quite well at the moment since the fixes, its quite fast, but still feels like it wants to boost more then backs off....... especially if you boot it in 3rd from low revs.... I'll try and get to all the bits you mention, and check them out.

To be honest, I found the side mount to be the better option - mainly less reworking of pipe routes, less pipes and joints to spring a leek, much less chance of a stray stone or bad judgement leaving a hole in the intercooler! Unless you go for a BAM manifold, then the pipework is a little easier.

 

After a chat with my bosses rally car mechanic I solved the stupid clippy pipe problem with a 70mm to 60mm silicon reducer pushed over the joint, thus no more leeks! (ebay item 

 

361454040418 - £7.50)

 

Do you have a boost gauge installed? if not, my first boost gauge was crude but effective - go to a petshop, buy about 2m of silicone airline and a t piece, go to shed, dig out a boost gauge you haven't seen in 8 years, cable tie boost gauge to windscreen wiper arm, t in to the fuel pressure regulator pipe, shut bonnet and watch.....don't use the wipers!

 

see if the power loss comes with, before or after boost drops, to determine if power is cut to lower boost, or if something is going wrong (misfire etc) causing the turbo to slow down, then causing a pressure drop. Hope that bit makes sense

To be honest, I found the side mount to be the better option - mainly less reworking of pipe routes, less pipes and joints to spring a leek, much less chance of a stray stone or bad judgement leaving a hole in the intercooler! Unless you go for a BAM manifold, then the pipework is a little easier.

 

After a chat with my bosses rally car mechanic I solved the stupid clippy pipe problem with a 70mm to 60mm silicon reducer pushed over the joint, thus no more leeks! (ebay item 

 

361454040418 - £7.50)

 

Do you have a boost gauge installed? if not, my first boost gauge was crude but effective - go to a petshop, buy about 2m of silicone airline and a t piece, go to shed, dig out a boost gauge you haven't seen in 8 years, cable tie boost gauge to windscreen wiper arm, t in to the fuel pressure regulator pipe, shut bonnet and watch.....don't use the wipers!

 

see if the power loss comes with, before or after boost drops, to determine if power is cut to lower boost, or if something is going wrong (misfire etc) causing the turbo to slow down, then causing a pressure drop. Hope that bit makes sense

my tame mech and I have done some detailed diagnostics, and could only find " loss of boost pressure between turbo and inlet manifold" .... , everything else appeared to be working correctly. servicing the 007p, and replacing the N75 cured almost all of it, and its much better, but still not right,,,,,, only thing i havent done is smoke test ...... so I'm fairly confident, its a boost leak somewhere ... just got to spend the time and effort to replace it! ....

 

onto another of your points, you say you are running an "uprated" SMIC , do you have a link to such a thing? I only really need FMIC to go stage to (and a new map of course) but I obviously need the car running correctly first .... hence my idea to just go at it and replace the pipes and intercooler..... may be easier IF a SMIC can provide the same performance for stage II ?

I had a big smic, a turborevs one and they come off the same line as more expensive brands, pretty impressed with it. Should be on ebay, goes straight in, just make sure the diameter for the MAP matches up and I got ssome neoprene washers for bolting the thing on. It fills the space that's for sure, I cut down the air scoop and cable tied it in position.