black300zx

This is not on a Z but I'm hoping to get some help from the turbo experts here. Last weekend I helped a friend of mine install an aftermarket BV and boost controller on his VW GTI 20th Anniversary edition (1.8 Turbo motor). We also installed a boost pressure gauge since it doesn't have one from the factory. The directions were not that great but I think we got everything right.

The problem is the car runs fine and pulls hard to redline for the first few minutes. After a little while it revs very slowly past 4K and then almost stops, not wanting to rev higher. The stock setup is 6psi and we upped it to 10psi. There are no idle problems, we adjusted the blow off valve as instructed. The boost controller seems to work fine because we're able to dial it up and down with no problem.

What can cause this? Is something installed incorrectly? I would think it would stall or run rough or we wouldn't be able to adjust the boost pressure if we didn't install them right. The only thing I can think of that's not correct is that we left the factory boost controller plugged in, but it's only connected to the intake tube not to the lines that go to the waste gate. Our next step is to remove this completely (probably will get a check engine light) and lower the boost to normal.

But in any case, shouldn't we be able to increase it by 4psi with the stock parts? As I mentioned it pulls hard and you can feel the added power at first, so is a matter of keeping it like that! If this keeps happening after we lower the boost can the BV cause this? It's strange that it runs fine for a few minutes and them changes.

I'm not too familiar with turbo setups, any help will be appreciated. I had fun installing this and the BV sounds nice!

He's trying to keep up with my Z We'll see!

Thanks,

Eduardo
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03 350Z Performance

apsilon

What a great way to blow a motor. Just turn up the boost without checking anything else.

That aside it is a bit strange that it seems OK for the first few minutes. I assume you've tried it multiple times and it happens each time?

It's not clear from your post but does it happen now at stock boost levels? If so I'd reverse everything you've done. If it still does it then you've probably broken something.

Sharif@Forged

iTrader: (92)

I am not familiar with the VW's turbo setup, but yeah....I don't think its advisable to just turn up the boost by 70% without some other adjustments to timing, fuel delivery, etc.

apsilon

Just got back from a friends who happens to own a mechanical workshop and mentioned this to him. He's not familiar with VW but suggested the ECU is probably detecting the extra boost and activating a safety measure.

black300zx

Thanks apsilon. My friend is also checking on this and got similar feedback. I think with the current setup the ECU does not have a boost reading at all.

He can't get a hold of the person that recommended this setup to him, hopefully it'll get fixed.