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Here is some pic of my pre-turbo intake piping. One observation i made is that the EVO bov ive been using is so stiff i cant push the valve open with my thumb.
Does this need to be a softer?
I have an older style HKS SSV Bov that vents to atmosphere im considering testing also. Its adjustable so might help and at the moment any change to this gives me a lead to how to cure it.
Attachment 9026
Attachment 9027
Are your wastegates plumbed with equal length hose from a T junction? Have you verified that both wastegates are cracking open at the same pressure?
Neither of the above should affect the partial boost issue you're seeing, FWIW. Sure sounds like typical compressor surge to me. There are fixes posted for that, none of them particularly pleasant. kywhitelightning's fix was essentially controlled boost leaks, one of the other fixes was a huge air hose between the turbo outlets, another fix is to go back to SMICs (obviously some custom work required there, heh)...
The wastegates hoses are unequal length from the T junction.
I would have to check the opening of the under boost to confirm if they both are opening at same pressure or not.
I am considering making up a reservoir within the pre turbo intake system to catch the surge before it hits the MAF.
Reckon if i can catch it with a baffled reservoir then it should allow enough time to allow the motor to digest the pressure in the system.
Failing that I have a HKS SSV bov and Turbsmart manual boost tee.
I just chucked it on the car earlier today and am hoping that somehow this will help.
I doubt it but im trying anyway.
The BOV is adjustable so im thinking i have it soft and allow pressure not able to be digested in the motor to vent out that instead.
Aside from all that then i'll get onto a switch solution as used by kywhitelightning and fastfalcon94.
Using Chrome ECU I have a spare output that should be able to be configured to do the job of making a small boost leak within a certain set of parameters.
Quote:
Originally Posted by DocWalt
So I figured out what was going wrong with my setup.
Its wasn't an inherent Compressor surge issue but rather was caused by a couple of things.
Boost spiking caused by too much load (untuned) Target load were too high for the turbo's and causing them to spike high and that would cause the motor to backfire and jerk and stumble then the car would go into Limp mode (CEL)
Its scary how many times I had this happened but after a good tuning session and reducing the target load table in the ECU rom and modifying the WGDC tables I had the car holding steady 7-8lbs boost like it should without knock.
I also suspect that this problem I had was not helped by a dodgy fuel pump (Walbro 255 l that could have been a cheap knock off) and Narrowband O2 sensor that was not grounded correctly so my feedback trims were not updating correctly.
I will post up the logs of before and after.
I still need to somehow find the correct scaling for ecuflash for the Apexi MAP sensor I have been using as it is showing some funky boost pressure readings (otherwise I will just find another MAP sensor to hook up instead perhaps)
Thanks
Dougal