Had the car dyno tuned by David in Feb at 26.5max boost. I've been doing some pulls since March and now the boost is running at 21.9max boost. Had boost leaks checked with none showing. Could there still be a boost leak or could the boost controller (Buschur Manual) somehow backed down?

I could always adjust the boost controller, but wanted to get inputs before doing so.

EVOScan Pull

 

Is there a way it could have gotten turned down? Do not just adjust it back up yet because if it is a boost leak you may end up over boosting by turning it up to compensate even though the leak would still be present. Is there a possibility the throttle body shaft seals are leaking.

 

The colder denser air will cause the car to increase its boost level. The same can be held true the other way. Now that the temperatures are starting to rise your boost may go down. 5psi does seem like a lot however I think its only because of the change in temperature.

 

I also live in PA, and I adjust my MBC constantly. As the weather warms up, and it gets more humid, expect to turn your MBC up.

 

I did mistyped my #s. It was 21.9 max PSI. Though still 4.5psi off from where it was. Thanks Falcon. I'll slowly increase boost and continue to log.

 

Did a couple more pulls today at 10:30 and it was showing around 22.3max psi. Up .4psi, but still about 4psi off tune.

 

What are the temperature differences from when you got tuned and today?

 

Tuned in Feb 4 around < 30F vs today around 65F. So around 35+ degrees.

 

That will do it. When I self tuned my car in Feb, I had the same weather as you. Once I hit 70 degree weather, my car went from hitting 27 psi to about 23.

Turn up the boost ann you are good to go.

 

agreed.

 

Well after much adjusting of boost pressure yesterday, I wasn't satisfied with the results.

Did another boost leak test today. Apparently there is a major leak at the coupler on the outlet portion of the FMIC. It was tucked up between the pipe and lip it was pretty hard to tell.

 

Update with no luck. Fixed the coupler and did another test. The only air leaking now is coming out of the MBC vent hole which lots have told me is normal.

I noticed that I'm only boosting till about 24psi which is close to the 25psi of the FP Black actuator. Could this give anyone insight into my issue.

There does not appear to be any other boost leaks now. Again, I'm able to boost to 24psi but I don't hit 24psi until 6800rpms. Just takes a long time to build boost.

Just as an edit, here is VDR comparison of the car back in Feb until one recently. Keep in mind the comparison one rarely reaches as high on whp as it did on this one. But you can see how LAZY the car feels.

 

Where are you sourcing the MBC's boost reference signal from, the compressor housing outlet pipe's nipple, or did you "T" into the line that runs from the IM to the DV?

 

you by chance running forge wastegate?

 

seems like a wastegate issue. maybe its getting stuck in a half open position.