TurboTommy

It's got to be the turbo. It's tired and packed it in.
Unless there's something up with your boost control/wastegate combo (somehow the wastegate is opening up excessively prematurely)
It could only be one of the two.
If you ruled out your exhaust (there's no potato stuck in the pipe after the turbo), and checked for major intake leaks. By the way, in order to rule out the BOV, you have to pressure test the intake after the turbo (maybe you did; I didn't read the entire threads).

Paulyy

yep i pressure tested it, no leaks. only leak was the black rubber tube from the turbo to the hard pipe. there was no leak to 20 psi, after 25 psi it had a small "ssss" sound, that was it.


Im waiting for the batery to charce so i can crank it to pressure test it.

onspeed

He said he hasn't checked the exhaust manifolds yet.. which happen to be notorious for cracking, assuming you're still running stock.

Paulyy

I checked, no cracks, nothing that the eye can see, no black sut any where.

Black51

You have to take the heat shields off to check for cracks.

Paulyy

I did take them off

Compression test:
Cylinder - Psi
1 - 154
2 - 145
3 - 150
4 - 145

333pg333

Block of wood under your accelerator?

Paulyy

Cannot remove that, Melbournes P Plate restriction rule!

fast951

I see two items that may be interlinked (or not). The AFR going leaner then the added 100RPM in spoolup.

Did you assume the change in fuel blend was the reason your AFR was leaner? Did you check and verify that all the sensors are operational before adding the 5% fuel? Was the AFR leaner under load or across the RPM? Are you able to richen the mixture only where it's needed instead of across the board?

Didn't see where you examined the inside of the X-over pipe. You can run a small ball inside the pipe, you'll know if it hits something (collapsed inner pipe).

Did you examine the MBC (black ****). I have seen them fail and cause a delay in spoolup.

Paulyy

With the AFR it leaned out across the whole board. the way i noticed this was it hesitated to spool. when i checked it with the wideband thats when i came across the AFR went leaner through out the whole range. so when i bunped it up 5% it was back to how it was originaly on 98 octane. i assume the reason behind this was the 10% ethanol in the blend i was running.

With the Xover pipe, i put a 22 or 24mm(un sure) socket in it and it rolled around good. might be better to put a golf ball in it though to be 100% sure.

With the black **** i havn't examined it yet but would it show up by when the wastegate opens?

fast951

The output from the MBC will affect the open/close of the WG which affects your spoolup. If you were using the MBC when spoolup was fine, then if the MBC malfunctioned it could cause a delay in spoolup.

Paulyy

Thought so, It should be good then, or it would of showed up in the bench test i did with the wastegate connected to the MBC.

fast951

How did you come to the conclusion that the MBC is fine?

For a dual port WG such as yours, the MBC is a "bleed valve". If it's malfunctioning in a way that no air is getting to the WG till enough pressure builds on the IN side of the MBC, (acting like a ball & spring) then spoolup will be delayed.

Take the MBC out of the loop and run the same pressure on both sides of the WG, see if spoolup is affected. WARNING - you will be running in uncontrolled & unlimited boost!! Just try this for testing the spoolup and not how much boost it'll hold or for how long. Your right foot will be the boost control, so be careful to lift quickly..

Paulyy

The way i came to that conclution is the wastegate stayed closed untill the pressure gauge said ~18 psi when it started to open.

I'll keep that in mind and probably the next thing i do after i put everything back to gether again.
Thanks for that tip John

fast951

This tells me that the MBC is doing it's job. So you actually did test it as part of the system, just not by itself.

Good luck!