After so many boost leak tests, I still have an issue..

[PieEyedPiper]

Oldman, and VBGSX have been very helpful in helping me diagnose my problems in the past, however, my original problem remains.

More commonly, though not limited to, when the car is real hot (100F outside) I will hit max boost (12-13psi) and somehow not one bit of that boost will make it through the intake mani and into my engine.

It feels as if my turbo kicks into overdrive, to maintain the 12-13psi, yet the car doesnt actually go any faster, it's like an n/t all the way. I can clearly hear the turbo working harder to keep the boost up when I experience this problem.

I have a very leaky 2g bov, it leaks at 4-5psi preventing any boost leak test from building up any more pressure. Knowing this is clearly un healthy I'm waiting for an auction to end on a 1g bov. I'm just not sure if my current bov could provide a path so unobstructed for all my boost to just pass right through and circle back through my turbo.

My theory is when it gets that hot outside, the plastic bov expands creating a far worse leak, thus expelling all the boost I make through the dump tube. However, that contradicts why I had this same issue last night when the car was at normal temps and the ambient air was ~70F.

I will hve to wait to recive my 1g bov to see if it is the culprit, but I have this problem today. So any input or advice would be appreciated. More information upon request.

Thanks for reading my excessively long post!!

 

[Bostedquest]

Stock 2G BOV are junk.
That is the first thing that should be replaced.

 

[PieEyedPiper]

I'm aware its bad and needs to be replaced, hence the ebay auction I'm waiting on. I'm just skeptical about my bov causing this massive boost issue. I'll just have to wait till the bov arrives and then I'll know for sure.

 

[DSM90AWD]

I'm aware its bad and needs to be replaced, hence the ebay auction I'm waiting on. I'm just skeptical about my bov causing this massive boost issue. I'll just have to wait till the bov arrives and then I'll know for sure.

Think of it like this, your T-25 is small and inefficient to begin with. Making it work 40% harder (i.e. it's generating 20psi at the compressor outlet - 2psi loss thru the SMIC - 5psi loss thru the leaking BOV = 13psi at the manifold) is generating more heat = less dense air = richer AFR = poor performance.

Take it one step at a time and get that known bad BOV replaced and see where you stand

 

[oldman]

Round two. Subscribing to see if BOV solves the problem.

 

[VBGSX]

Round two. Subscribing to see if BOV solves the problem.

Sign me up also!

I think DSM90AWD is correct and I believe it was mentioned in your last thread .
As he said, the turbo is working overtime to make up for the lost air.
At the very least, it will severely hinder your performance.
I hope it takes care of it.
Good luck

 

[PieEyedPiper]

Well after waiting forever for the 1g bov to arrive, I installed it this morning. I had my MBC set to ~11-12psi. As soon as I installed my new bov I was boosting to 16psi. I tell ya, I'd never thought my car would pull so hard with a T-25!! I plan to only run 14-15psi though.

Anyways, as amazing as it is having solved one problem, I still have the same one I originally started posting about months ago. But I think I know what it is now!

I just went for a 2000 mile road trip to Canada. During this time I learned a little more about my problem. Sometimes the car would pull hard, others I'd hit full boost and I'd not know it unless I looked at my gauge. I hooked up my logger and sure enough I was getting my timing pulled to like -10 degrees.
If I let off the gas and get back on it, my timing would jump back up to ~ +10 at around 4k and I would get full timing advance (~ +24 degrees) by the end of my pull.

I think I'm suffering from phantom knock. While I was away I got new tires, and new front rotors. I also had my fluids changed while they were at it (who wants to change their own oil while on vacation?!?!). I had them switch me to Synthetic to see if I could ditch my lifter tick. It didnt help much, so I added half a bottle of lucas to my oil. I know experience the problem half as much as I used to, but those lifters are damn noisey.
As far as I can tell the only solution is 138 bucks worth of new lifters and 2 hours of my labour. Is there a way to just disable my knock sensor temporarily?

Unless you guys have any further reading or suggestions for me, I'm just going to live with the problem and save for the new lifters ( I'm sooo broke right now so it might be a while!).