THis boost is annoying me!!!

[00s4slvr]

so as many of you know i have been having major boost issues on and off. Currently i am on the stock setting with the giac x ecu. Last week i changed my n75 to a race n75 and the 710n's. I did some runs last week and my boost was at 9-10 taper down to about 5-6 then back up to 9-10. also i had my o2 sensor changed the other day and it ran fine 8-9. Also i just had an exhaust installed yesterday. Today i just did some runs on the highway and local roads and my boost is like at 6-8 taper down to 5 then back up to like 6-8... I dont get it...

any suggestions??

[gointoscott]

For stock settings boosting to 8-9 psi is normal. I'm not exactly understanding what problem you are having. Maybe I read your post wrong.

One thing I will say is that i have heard that the race n75 valve has caused issues of over boosting or irregular boosting with some chip tunes. I dont remember which ones, nor which ones worked fine with the race valve.

[00s4slvr]

lol sorry im trying to say is that all of a sudden yesterday my boost was at 6-7 taper down to 5 then back up to 6-7... but just the other day it was fine.

where di you hear that about the race n75. ECS tuning told me it would be ok.

[gointoscott]

I want to say it was ecs where I was looking at buying the race valve. and basically they said they woudlnt sell it to me for my S4 because it caused overboosting issues. That was awhile ago so maybe things have changed.
Anyway if its only boosting to 5-6 psi then maybe its in limp mode. Do you have any codes? I know when I tried running my mbc in standalone it was overboosting and caused it to throw a code for overboosting and put the car in limp mode. Once I shut it off and turned it back on, it would run fine until I really got on it again then it went back into limp mode.
When did you notice the problem? was it right after you installed the race valve? or a different part?
have you tried changing ecu to chipped mode does it boost better then?

[00s4slvr]

im gonna try changing the ecu to pump performance before i go back out again and do some runs. the boost problem started happening after i had a shop change my exhaust to the asp true dual 89mm. I do have en exhaust leak because they didnt tighten the clamps tight enough but i dont think that would affect my boost.

[00s4slvr]

also i just scanned the car for codes and there werent any.

[00s4slvr]

ok so i did some runs on pump performance mode and my boost goes as follows. i am in second gear going about 40, my boost was holding 15 steady then as it gets towards the redline it tapers down to about 12-14 then when my car shifts it spikes to about 17-19 then holds 15 again and repeats this process throughout the gears.

does this sound normal?

[gointoscott]

That sounds normal to me.

It might depend a little on which chip you have, with GIAC I thought that chip was a little more aggressive so maybe it should hold at 16-17 instead of holding at 15. But I dont have a GIAC chip so I cant say for sure.

to recap,

if in stock mode your car should boost to 9psi and hold or drop a little from there as you go through your gears

If in chipped mode it should boost to 17-19 and hold or drop off from there depending on which chip you have.

So by going off what you've said so far, I dont think you have really much of a problem unless I missed something.

Best thing to check is to go to vag-com and log block 115 which shows requested boost with actual boost to make sure they are about the same. That is if you have vag-com I dont remember if you do or not.

If you dont know how to log this, let me know and I will give you instructions, its pretty easy.

[00s4slvr]

i do have vag com and i dont know how to log. How do you log?

[00s4slvr]

also when my car is idling the vac used to be at 20 now its more at 21ish and i dont know why...

[gointoscott]

the greater the vacuum the better so 21ish is a good thing

I'll get some screen shots a little later about how to log and post them. Gotta go eat now.