Engine/Transmission (1994 - 1998) P S 66 / 12 is this posible?

[TwinTurboDave]

Hi guys iam wondering if anyone has ever tried running a 12 housing with their 66 mm turbo? If you do, whats the eficency egt wise, and power wise? Iam just trying to keep the fast spool up of a 12, while gaing a little from the 66 wheel. just trying to see what you guys think. .

 

[zstroken]

I would not do it on a 12V, HTT did some on some third gens with good luck. Surging can be an issue. I would look at a 62 with a larger turbine wheel.

 

[BradyWilliams]

I would say a Super Phat Shaft 62/80 but we can make you a Phat Shaft 62/70 if you want. The 70 housing is close to the 12cm housing that you are asking for. The Super Phat Shaft 62/80 is better for lower turbine drive pressure which helps EGT,s Thanks

 

[Forrest Nearing]

you could "do" a PS66/70, but I doubt Industrial would actually build it for you as you'd probably be sending it back shortly. even a PS or SPS66/80 is going to be prone to surging on a stock 12v head/cam, the smaller turbine side is only going to amplify the problem. PS62/70 is a decent turbo, but my buddy quickly outgrew his.

 

[bmoeller]

Well, how 'bout adding an external wastegate to the manifold, to run the smaller housing?

 

[Forrest Nearing]

the exhaust flow isn't the issue, it's the compressor trying to feed more CFM (not boost) than the engine will accept... it's akin to putting your hand over a vacuum cleaner... it speeds up really fast, then it'll start to make boost, then the engine wont' take it, then it'll speed up, etc. the boost needle will bounce, you'll hear a woof woof, and it's called compressor surge and it's very hard on turbo bearings.

 

[TwinTurboDave]

Hey guys thanks for the response.

You know thats what i was thinking, adding a turbo guard would solve my problem. I think i will be settling with the 80 trim for the 66 for the least surging, and top it off with the blowoff valve. Does anyone have any experiences with the bd turbo guard valve or any others?