Too much boost?

[Majorcina]

I was driving my s4 2 days ago and i was giving him a blast,but something strange happens with boost
The car is stage 1+ Prj map which shud show full boost at 1.6(on gauge shows 1.7 which shows only 0.1 atmospheric presure-told by prj) but that day he hit 2 bar boost(on displey 2.1)
I am not sure what could do this?Since then i didnt drive fast becose i was afreid for the engine
Any hint's guys?

[RoadKill]

posted on wrong page

[quattro-nick]

check your n75 valve (for wastegate) or the little hoses on it for leaks
check also your wastegate membrane for leak

[Majorcina]

i am geting to much boost,so i doubt its a leak?Shud show less boost if it leaks?

[AndyP]

Check the hose on the side of the wastegate, the one with the yellow cap in this picture

http://www.s2forum.com/forum/showpost.php?p=180379&postcount=7

If this has a leak there will not be enough air to open the wastegate and you'll get too much boost.

[newsh]

Yes, cracked N75 or leaks in the pipe to the WG or leak in the WG diaphragm will give too much boost!

[UrS4boy]

N75 Wastegate Frequency Valve (WGFV) info

Check the hose on the side of the wastegate, the one with the yellow cap in this picture. If this has a leak there will not be enough air to open the wastegate and you'll get too much boost.

This photo might be better (below):

N75 WGFV info http://forums.quattroworld.com/s4s6/msgs/20987.phtml

[UrS4boy]

The car is stage 1+ Prj map which shud show full boost at 1.6(on gauge shows 1.7 which shows only 0.1 atmospheric presure-told by prj) but that day he hit 2 bar boost(on display 2.1)

Are you talking about the digital boost gauge in the board computer? If so, it is absolute, not relative pressure *AND* because the Stage 1+ means that the MAP sensor has been changed to a 3 Bar (300 kPa) unit, the calibration of the OE digital boost gauge is wrong (and it can't be changed). Get a good mechanical analogue boost gauge that goes to 2 Bar (or 30 psig) and report back.

[Majorcina]

Yeah dave the digital one. Probably i shud buy a gauge

[newsh]

Are you talking about the digital boost gauge in the board computer? If so, it is absolute, not relative pressure *AND* because the Stage 1+ means that the MAP sensor has been changed to a 3 Bar (300 kPa) unit, the calibration of the OE digital boost gauge is wrong (and it can't be changed). Get a good mechanical analogue boost gauge that goes to 2 Bar (or 30 psig) and report back.

Dave, not sure but it's possible, with his level of attention to detail, that Dmitri recalibrates the dash gauge in the SW

[UrS4boy]

Dave, not sure but it's possible, with his level of attention to detail, that Dmitri recalibrates the dash gauge in the SW

I would imagine that he would try to do that but I had not heard that he actually has done that. That digital gauge is too slow anyway and it is absolute rather than relative. Marko is better off to get a good mechanical 2 Bar boost gauge (with a substantial vacuum portion as well)

[newsh]

I agree a proper gauge is best.

[newsh]

Marko, if you dont have a leak in the line from the N75 to the WG or a leak in the line from the turbo to the N75 or a split in the WG diaphragm then it could just be that your N75 is sticking, you could try washing it out with WD40.

[Majorcina]

First i will see to buy a gauge and then i will be 100%sure.
I drove her tonight for 120km and was pulling good,also the boost levels was like before