4AGTE issue - Engine is boosting fine, but revs are slow to pick up

[maxhag]

Car: AE86
Engine: 4AGTE (T25G)
Here is my query....

After my last hillclimb competition round, I noticed the car didn't seem it's usual self when I was driving home from the event.

The engine doesn't seem to be picking up the revs as quick as it was before, but the boost levels are normal.
Ie; as I drive along, it boosts normally to 15psi, but the actual engine revs (from 4000rpm onwards) does not speed up as quick as it used to. I makes a new noise too. When the boost is getting high, it's making sort of like a BOV (ssshh) sound, before I have backed off the throttle, yet no sign of it on the boost guage. The actual BOV then works as normal when I back off the throttle.. It's NOT blowing any smoke either


I Have never had blown turbo before, so I dont quite know what to expect if it was that. But I wouldn't imagine a blown turbo would even produce any boost at all tho???????

Cheers

[trikzlane]

vacum leak, boost leak, exhaust gaskets, faulty wastegate or BOV acuator

[jaz_ae86]

Boost leak, compressor outlet temp high because turbo trying to compress too much air (ie out of effecient range), lack of power from high air inlet temps?

[Dish]

Check all your joiners on your cooler piping. Seems strange that it will reach normall boost pressure if it is leaking, unless there are a couple of very small splits/cracks that only really open up at 15psi.