Just wondering if anybody has converted their stock GTP38 into a hybrid using the 88mm compressor wheel and 38R compressor housing -OR- machined their stock housing?

I realize theres more benefits to the 38R, but the $1400~1600 price tag isn't attractive either.

 

Sure sounds interesting, bump...

 

Can the compressor housing off a 38R bolt right on? Still seems that if it was possible and you bought the 1.0 exhaust housing, the compressor housing, and the wheel... it still would be spendy

Here is a bump...

 

Its about $250~300 for the wastegated 1.0 A/R turbine housing. Wheels sell for about $100. I'm not sure how much the 38R comp. housing would cost OR even if its a direct bolt-on, definately gonna be less than the BB version.

 

Just get a van turbo. Nearly the same performance... I'm maybe 50 hp & less than 5psi under what I'd have with an extra ~$800 for the 38r. And I can rebuild my own turbo for $100 instead of being out a turbo for a week plus, and almost a $1,000....

 

Does the van turbo run a larger comp. wheel than stock SD? I think I remember reading it has a larger A/R.

 

It has a slightly larger exhaust wheel and much larger 1.15 A/R exhaust housing. Compressor side is the same size, but with an ATS housing it's pretty much impossible to surge it, and it's safer running more boost because the drive pressures are way down compared to stock. 35psi is sustainable on a van turbo. I'm running a bit more than that with my 238cc/100% over hybrids, and have been for some time now (about a year).

 

Is this one a good canidate? http://cgi.ebay.com/ebaymotors/98-FO...mZ160475906992 If not what do I need to look for?

Whats the safe limit with boost with stock components before you blow head gaskets and have to do head studs, etc...

As a machinist by trade, I thought it might be kinda fun to machine the stock compressor housing to accept the 88mm wheel, I would still have to find a larger turbine housing though...

 

That would be okay if you had an EARLY 99 truck. Wrong turbo for the late 99 & up.

40psi is generally the limit for head studs.

As far as machining the stock housing for the larger 38r wheel, have you measured to make sure there is enough material? Have you checked to see if the wheels are even interchangeable on the shaft? Depth of stock wheel vs. 38r wheel? The 38r has a ported housing -- what about machining an ATS ported housing? Lots of things to verify first, and any of them would kill the deal.

 

Did you mean head bolts? I thought is was 45 psi.

 

Thanks for the info.

I thought the early '99 had the flange fitting like the GT38 OBS PS, where that van turbo had the V band style?

As far as machining a stock or ATS ported housing I would have to have parts in hand to make measurements. Its 6mm bigger or about .240"/2=.120" wall removal. Most parts have that much or more in castings.

I was nervous about going away from a wastegated housing for fear of overboosting. It should be pretty easy to keep her under 40psi


Head studs/bolts...its all the same. We use "studs" in the turboed sled world.

 

bolts are what is in your motor. Studs is what you would upgrade to... LOL

 

If you can find a van turbo for cheap it would work well, but I would suggest injectors or you will have a laggy pig. I wouldn't say that the 38R and the van turbo are almost the same performance because they aren't. The 38R spools much fast, moves more air, and can handle much more abuse than the van turbo, but with fuel the van turbo will give you lower EGT's and backpressure and more mid to top end pull than your stock turbo.

The early 99 turbo is still a GTP38 but is a mix of OBS compressor side and SD exhaust side with the same center section as the SD.

Studs and bolts aren't the same thing. Everyone speculates how far you can push the stock bolts, but unfortunately you don't know till you go too far. I would suggest to do it before it bites you in the butt if you are getting over 35 psi.

The compressor housing on the 38R is different than on the 38, so you would at a minimum need the complete compressor side to swap. IMO, by the time you get all the parts try and make it work, at best you have a journal bearing turbo with an 88mm inducer.

My opinions come from running an E99 turbo, Late Turbo, van turbo and 38R.

 

Thanks for the input, looks like you have tried turbos of every style.

I realize studs and bolts are not the same thing. Its just the common term in the sled world.

I'm happy with <30psi, a 1.0 A/R housing might just be the ticket to shed some EGT's. I'm torn on the van style or SD style, I already have the high flow outlet for the SD style so I leaning that way.

 

A 1.0 A/R and a DP would give you a nice addition on stock injectors and keep a smile on your face, IMO.