Putting an HY35 turbine into an HX35 with .63 T3 housing

[dougs951s]

Hi guys, my name is Doug, just joined the forum to get a little DSM love and absorb some of the knowledge here. I'm from Rennlist.com and my question is concerning my Porsche 951. It is a 2.5 liter 8 valve sohc engine with a great header, long runners on the intake, and factory setup for an external wastegate. These cars are torque monsters with plenty of stroker guys making 500+ wheel tq on boost that would be considered very low here. Most guys dont run more than 17-18 lbs on pump and most never go above 23-24 on E85. Meth injection is not popular and nitrous is shunned heavily. Holset turbos are also looked down on by most drivers. I am building a bolt on HX35 for my car using a turbonetics 8cm/ .57 A/R T3 exhaust housing produced with my car's factory bolt pattern. It was designed to accept a garrett chra so milling down the holset 2mm where it slides into the hotside should allow it to fit. My concern though is that even with the larger displacement of my porsche engine compared to you guys, the full HX35 will be slow to spool with the stock turbine. I am looking for full boost in the 3000 rpm range. The HY35 is not suitable for use because the large Vband on the hotside would prevent it from bolting up. My question is, is it possible to pull an HX35 apart and replace the turbine with one from an HY35, then just reassemble with my T3 hotside and be done? If not, I have also heard that the HY turbine and compressor wheels can be placed into an H1C cover and CHRA which can also be made to work in my car despite the fact that it has the Vband compressor connection. Is the HY compressor the same as the 60 lb/min 7 blade HX35 compressor? Sorry for asking so many questions and for being confusing, but the porsche circle is no help in this matter. Plenty of garrett gurus there, but If I ask about a holset most people respond with "use a garrett."

 

[miguelmcv]

Here is some information regards the HY35 and HX35.

Hope this helps.

http://www.dsmtuners.com/forums/turbo-system-tech/360067-hy35-compressor-housing.html

 

[JusMX141]

My question is, is it possible to pull an HX35 apart and replace the turbine with one from an HY35, then just reassemble with my T3 hotside and be done?

As long as the turbine housing is machined for the HY35 turbine, then yes.

If not, I have also heard that the HY turbine and compressor wheels can be placed into an H1C cover and CHRA which can also be made to work in my car despite the fact that it has the Vband compressor connection.

You don't want to use the H1 CHRA unless you have to. Thrust system isn't as durable.

Is the HY compressor the same as the 60 lb/min 7 blade HX35 compressor?

Correct.

 

[dougs951s]

Thanks, but I already read through that thread. I just want to know the interchangability of the HY and HX turbine wheels. That information about compressor covers is irrelevant to me because I will be using either an HX35 cold side ( if the turbine from the HY will fit onto the shaft ) or an H1C coldside ( again, if the HY turbine wheel will mate to the CHRA. ) I'm looking for 52-60 lb/min flow with the spoolup of the HY turbine inside a .63 housing. FWIW the HX35/H1C turbine are very close in size to a garrett stage 5 wheel, while the HY35 turbine is very close to a garrett stage 3 wheel.


Edit: Thanks JusMX, that is the info I wanted! My t3 hotside is setup for a garrett stage 3 wheel so getting it machined for the slightly larger HY turbine wont be an issue. One more question. Can the 7 blade HX35/HY35 compressor be retrofitted onto an 8 blade HX35, or is this impossible because the wheel is slightly smaller? Even if not I would be very happy with 52 lb/min bolt on turbo with an HY turbine. big plus too that if I decide later that the small turbine is choking me, its a simlple matter to machine the hotside bigger and swap in the bigger HX turbine. Thanks again!

 

[JusMX141]

Can the 7 blade HX35/HY35 compressor be retrofitted onto an 8 blade HX35, or is this impossible because the wheel is slightly smaller?

Ever put a standard piston into a +.040" bore? Putting a 54/78mm wheel in place of a 56/83mm wheel would be essentially the same thing.