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hi peeps just installed a boost gauge on my '93 R32 Gtst M-Spec and i noticed that when i flat stick it it hits 10psi but then starts dropping (not keeping constant pressure) any ideas why this might be happening? thanks mowie

edit: sorry typo error

Edited by --{TRYDIS}--

Stock turbo i'm assuming?

The turbo is getting past it's efficiency range and dropping boost.

Get an electronic boost controller to get it to close the wastgate up at higher revs to try and retain boost.

Your gauge install is fine, and its the correct reading!

Cheers, Bart.

Stock turbo i'm assuming?

The turbo is getting past it's efficiency range and dropping boost.

Get an electronic boost controller to get it to close the wastgate up at higher revs to try and retain boost.

Your gauge install is fine, and its the correct reading!

Cheers, Bart.

How could the stock turbo be going past its efficiency range when it comes out factory as 10psi? It should hold 10psi fine unless there is a vacuum leak or something. I would of thought something like 14psi would be past its efficiency range... :D

mine does it too...my guess, is that it is just old age, some do it, some dont...mine does it. try to block off you BOV. it helped mine a bit. mine went up then only dropped off a little after that. just means that you'll have to get a new turbo, no harm there. It shouldnt be a problem, just means not as much pull top end.

You'll probably find that out of the factory the boost wont hold to redline without the aid of some sort of boost controller closing the wastegate, as the manufacturer would aim more at driveability and midrange than top end, i say the boost drop is totally normal.

As already mentioned i'd be checking your BOV and also Manifold studs/gasket, aswell as any holes in your exhaust. Friend of mine with a 4 door 32 was dropping boost, very similar problem to yours, and it turned out he had rooted manifold studs and a hole in his exhaust.

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