Making the stock Diverter Valve hold boost for cheap

misfit77 · Jun 10, 2015

I searched and since the search feature isn't the greatest, I couldn't find anything.

When I had a VW GTI, there was a trick in making the diverter valve hold higher boost and make a louder whoosh!
We would reverse the valve. The boost is no longer pushing the valve open, but instead is hold the valve closed.

I just adopted a stock 96 GS-T Spyder and noticed how slow it was. Removed the notorious valve and noticed how easy air gets by in the standard direction, but holds in the reverse. Installed backwards (see attachment) and now I can spin tires in first.

I am going to try and keep the car as stock "looking" as possible, so I am going to keep the stock valve till it breaks. I have a Turbo XS on standby when it goes.

I have a long road of work ahead of me.

donniekak · Jun 10, 2015

The stock valve was not designed to operate that way. It's not going to release properly in that configuration. It may be ok on the t25 at stock boost, but at higher than stock boost pressure, the release issue will be worse, and will accelerate wear on the turbo.

lasthope05 · Jun 11, 2015

Im supprised people still run the stock 2g bov. Those things leak at idle. If you want a stock looking bov that holds boost, find a used evo 9 unit.

jimsgsx · Jun 11, 2015

I'll tell you a cheap way to hold boost. Get a 1g bov, crush it. Cheap and easy.

KeithAZ · Jun 11, 2015

How much psi do you plan on running? A stock 1g BOV is reliable and a great piece for the money.

portum89 · Jun 12, 2015

Agree with the rest here, if you want optimal performance even at stock boost, upgrade to a 1g bov or atleast get an ebay type-s bov for stock turbo its really w.e, itll hold just fine and avoid leaks.

misfit77 · Jul 1, 2015

Been looking, seems like the 1g BOV aren't $10 anymore.

I really don't plan on modding it much. I am trying to keep it stock looking. Of course I will go a little extra boost and a few tasteful or hidden things here and there.

As for longevity, I ran my VW GTI @ 20 psi with a backwards diverter valve for years before buying a Forge brand. Sold the car with 185K+ miles (bought at 155K) with out any issues.
My turbo'd Miata has a backwards one too, but only runs 8 psi.
I won't drive this beautiful time capsule much.

Once I get a boost gauge I will check for leaks and go from there.

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Making the stock Diverter Valve hold boost for cheap

misfit77

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