Engine is a 93 12 valve in a 98 suburban w/NV4500. I'm posting in 1st gen forums because it's a VE pump. BD uses a 57 mm secondary (s300g) and they list the primary as a 64/74 mm with a 1.10 A/R turbine housing. I have a HY-9 (54/60 mm) with a HE341/351 turbine housing for the secondary and a Silver bullet (66/74 mm) for the primary. The bullet has a 0.80 A/R housing (the number cast on the turbine housing) and I think flows ~80lb/min. I think the silver bullet turbine housing is a little tight but it has dual internal gates. The HE341/351 wastegate hole has been enlarged to a 1" diameter (flapper is ~1 1/4") My goal is to achieve low air temps and fast spooling. Both these turbos would be operating low on there maps with a 40 psi peak boost aim, so boosted air temps should be relatively low (compared to a HX-35,HE341/351) The questions I'm trying to figure is what is the smallest injector I could get away with? ( I have 430HP 8.3L nozzles on my 12V bodies I could use), Do you think the 0.80 primary turbine housing will slow my secondary spooling?

 

I guess it depends on what your ultimate HP goal is. I think it would help to define that first.

And I'm no expert by any means, and haven't even messed with twins yet, but I have a hunch that yep, your primary is going to be too big, especially if you're only wanting to max at 40 psi... or is that 40 psi for each turbo? (my bad)

 

I actually belive the 66mm compressor on the SB is going to be the limiting factor here....It just doesn't sound right as most Primaries have in access of 75mm Compressors. But i see where you're coming from with the Small fast spooling chargers, That'd be awesome.

But truthfully I don't think it's ever been done....I know an HX35/HX55 has been done which is a relatively small setup for twins. "stacksx2" did it

 

Actually Crossy's son a 66mm primary is bigger than BDs towing primary (see link http://www.dieselperformance.com/pro...r_Sizes-23.jpg) My horsepower goal is under between 300-400 HP. Total system pressure 40 psi.

 

It will work, get some 5x14's throw the twins on and tune it a little.

 

Isn't this the setup Mo'Powa is going to run? Not sure but I thought it was something close to this.


Funnily enough, what you're trying to achieve is exactly what I'll be attempting when I get the money to put it together; same HP goals for a tow rig, utilising a small set of twins to not overstress either turbos or head, (I see no reason to stud it if I'm only running 35 - 40 psi) and keep things as cool as possible.
Maybe we could get away with running an HE351 single, (which will be my secondary of choice, for various reasons) but I just like the idea of splitting the load between two turbos. Possibly my reasonings are flawed?

 

hey-Hey!!!,
Take a look at two critical things on the compressor maps, one the surge line and two the highest efficiency island. The twins allow half the pressure ratio for a given boost level and that will deliver higher pressure at lower mass flow w/o surge. That this may not be in the most ideal efficiency zone can be addressed by adequate charge air cooling; if the compressors are making a bit more heat than is ideal it is simple brute force cooling to address it.

How to pick exhaust housing size for a compound set up or anything like that I am a bit out ov my ability. Two compressors in series will deliver more pressure w/o surge v. a single and that seems like a universally good thing.
cheers,
Douglas

 

I say try it and see how you like it. Sounds like it'd spool quick and would work. Like Soggy said, get some bigger injectors and tune your pump and I'd retorque your stock head bolts and should be good to go

 

I would probably try some 90hp sdxII's with that setup.

 

I think you will see it chock at high RPM we built a similar set on my sons 91.It had almost instant spool but chocked out under heavy load .We ended up switching the bottom charger out to an HX55 and at 407 HP cant hit 1000* towing a heavy trailer before it was nice getting a load going but now we can keep the fuel to it with no issues

 

Yeah, that's what I like to hear!

 

FWIW I will be running a a he351ve over top of a ht60 with a 20cm waste gated turbine housing. Should prove to be a very tunable quick spooling set up.

There was a guy on competition diesel who was running a he351ve and hx55 with good luck. Said it had great spool up too.

 

What pn HX-55 are you using? I've got a number for a HX-50 with a 66 mm inducer and a 16cm turbine housing.

 

I don't have a VE pump, but I did build a WH1C/HX55 setup on the 12 valve that replaced my 24 valve engine.

Modified 12cm wastegated exhaust housing, drilled divider. I don't have numbers on it, but the HX55 is probably has the largested wheels you can get. The compressor is around 77mm IIRC. The exhaust housing is a wastegated 19cm.

Max boost is unknown, gauge goes to 50, boost goes past that, need to get a 2nd gauge in there so I can see the primary pressure. It's still in need of some tuning, but its been very drivable for just throwing it together and going. Spools up very nicely.

 

Ya may want to talk to Mike Holmen In the Alberta chapter
Very good info from him