Both dyno happened in two differen places, two differend kind of dynos and two different weather conditions.

Boost curve is a lot different than each other tho. As far as I know there is no leak in the system (I did not check the bottom of the exhaust mani tho. But sounds like no leak or anything.

I have some different parts in the first and second dyno but i do not thing that's the reason, because I have this problem lately.

Any ideas or is there a internal problem that cause the boost not build up early ?

1st dyno boost curve;


2nd Dyno Boost Curve;



1st dyno, I have 20psi boost @ 4500 rpm
2nd dyno, I have 20psi boost @ 5600 rpm

What's going on ?

 

What octane are you running, and are you running a mbc?

 

mbc and 93octan. I have this boost issue about a month I think. I tought Iwas justimagingbut when I checked the two dynos there is the truth.

 

I wouldn't worry to much about it. Some of it might have been the weather, or just the dyno, a loading dyno will change the boost a little.

If you are worried, log your boost with Vag-com & see if the actual & requested is the same.

I would be more worried about adding a little more fuel in the top end, it's getting a little on the lean side.

 

the second one is mph not rpms?

 

I would be happy to pull those numbers.

 

you need to lean out your afr from 4500 to 6000. should be at 11.5 on the first dyno
on the second dyno it looks like you go lean at wot

 

what turbo are you running???

 

what turbo are you running???

 

most chip tunes have it overly rich on boost onset that i have seen. Plus lemmi will only let you change overall fueling, not selected rpm range. But like 2k s4 said, the first dyno is more of a load bearing dyno and creates boost sooner.

But you have a laggy turbo. some people on vortex have gtrs' and dont hit 20psi till 4k and 25psi until 4500rpms. A gt2871r with a .86 turbine will spool faster than that and make 75-100 more hp.