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Ya I'll get a picture of the engine bay. The snorkel currently does not have those little plastic hold down clips in it. But when I had them in, it still did it. Air filter is fresh too. Had it installed while I had no issues with boost.
Here is a 3rd gear pull rolling into the throttle. Solid boost until 6000 rpm, then down to 6 psi. Top line is tps, middle is rpm and bottom is boost.
This proves that it can hold boost and should not be a boost leak. It's the magical 5500-6000 rpm where it drops, every, single, time....
Zoomed in on the boost area. Instant bye bye boost.
Oh yes, you can feel it. No question about that. You can see it on the mechanical boost gauge too. If I stay in it in 3rd gear to the point where boost is cut, I feel like it will never hit the rev limiter, even going downhill, with a tail wind. Feels like it gets cut to 25% throttle. You can also hear the boost getting bypassed when it happens. It honestly sounds like the BOV opens up.
The only thing I can come up with is there is some kind of restriction in the intake, but that doesn't get support from the higher gears holding boost ok. Something is bleeding off the boost.
As soon as Turbosmart tells me my BOV is in, I am going to go pick it up and install it. That way I can eliminate one more big item off the list. I am stumped so far though. Hopefully someone else has had an issue like this and knows the fix!
I brought home the smoke tester tonight and smoked the engine. No leaks to be found that way. I'm going to wait for the BOV to show up and try it. If I still have the same issue, I'll do another boost leak test.
Ok so what youre saying is dont waste my time with a boost leak test and that if this BOV/DV does not solve my issue, I should probably buy a HTA71 for the next step?
Last edited by Lumpy Sticks; Oct 26, 2018 at 06:37 PM.
Update - Turbosmart bov/dv is in. Guess what? It's worse now...
From my initial inspection, the stock dv has more spring pressure then the TS. That would make some sense why its opening sooner. So what does this tell me? There is probably an issue with the hose or port going to it. I mean the only reason the valve should not stay closed is if isn't seeing the right amount of line pressure right? Aka a cracked/leaking/blocked line.
I'm about to go pick up some tires but will check all the lines when I get back. If they dont hold 30 psi, that should be it.
I put some miles on the car tonight getting the new tires. I have to say, I dont really like the new valve. The transition from on boost to off is rough. Makes the car do one big buck (part throttle only). Even if it's at .5 bar boost and I let off, it's a pretty violent buck. The hole/piston in the TS valve is a lot smaller then the OE valve. That brings something else up I forgot in the last post. So yes, it still drops boost and does it sooner BUT it doesnt drop off as much. It seems to go down to about 11 psi instead of 5-6 psi as before. I think this is cause the diverter hole is about half the size. No time tonight to run more test but at least I now know where the problem seems to be.
Also, on my test drive tonight, I did some other tests i haven't done before. I held it at 5k in 2nd and mashed the throttle, instant low boost. Did the same at 6k with the same result. Tried it at 4k and right as it hits 5k, boost dump. Start it at 3k, still dumps at 5k. Still seems like its still rpm related. Also, when boost dumps, the afr stays in the 11s. Not a fuel cut issue.
Oct 23, 2018, 06:40 PM
