Why not. Two hx35's

Cummins Driver

Cummins Driver

THE Cummins Driver
Well, i got to thinking tonight(step back)

Why couldnt you run two HX35's?

Setup #1)

Flip the manifold upside down, run the exhaust out of the first 35 into the inlet of the 2nd one(which should fit under the hx35 on top), then out the exhaust. Have the compressor piping Y together, and seperate air intakes off each turbo so that each compressor side worked independent of the other. You would have 2 air filters. Then maybe run a external wastegate, and bigger exhaust housings on both turbos. Seems to me this would give you twice the airflow of one HX35. One HX35 will support 300hp pretty easy, so why wouldnt 2 of them support 450-500hp with great spoolup? Im thinking drive pressures might still be high with this setup though.

Setup #2)
Run two manifolds at 3 cylinders a piece, and hang an HX35 off each manifold. Same deal. Y the compressor piping together and have seperate air filters, and run the exhaust together since each turbo would then have its own exhaust pipe. Run 12cm housings since you would only be running 3 cylinders worth of exhaust through each one. This seems like it would be a slightly more complicated, but better setup, and I dont think drive pressure would be a problem at all with this setup.

Both should cool pretty decent with a good volume of air, and spool great.

So shoot me down, but id love to try one of these.

Eric
 
That sounds like alot of effort to make a little bit of hp. Plus a stock HX-35 will make the same amount of drive pressure: boost pressure ratio whether it is being fed by 3 cylinder or 6, so it will not be to any advantage to run either setup. You are still doubling the cylinder pressure.
 
SEOHPowerstroke said:
That sounds like alot of effort to make a little bit of hp. Plus a stock HX-35 will make the same amount of drive pressure: boost pressure ratio whether it is being fed by 3 cylinder or 6, so it will not be to any advantage to run either setup. You are still doubling the cylinder pressure.
Click to expand...

450-500hp is more than a little bit, and if it is towable with great spoolup and decent EGT's then that is a pretty good feat. I have more time than money, and you cant buy an SPS 62 or the like for what you could do this for. Heck I dont care what the drive pressure is if the EGT and power are good.


It seems to me everyone likes to knock this idea but no one has tried it.
 
If drive pressures don't matter put one per cylinder. But believe me, drive pressures do matter. Not trying to discourage your innovation, but I would invest elsewere.
 
Cummins Driver said:
Well, i got to thinking tonight(step back)

Why couldnt you run two HX35's?


Setup #2)
Run two manifolds at 3 cylinders a piece, and hang an HX35 off each manifold. Same deal. Y the compressor piping together and have seperate air filters, and run the exhaust together since each turbo would then have its own exhaust pipe. Run 12cm housings since you would only be running 3 cylinders worth of exhaust through each one. This seems like it would be a slightly more complicated, but better setup, and I dont think drive pressure would be a problem at all with this setup.

Both should cool pretty decent with a good volume of air, and spool great.

So shoot me down, but id love to try one of these.

Eric
Click to expand...


Im guessing it would be like running about a 110mm single charger with a very large turbin housing. When you run turbos in paralel like this they tend to be smaller than you may think.
 
Poor spoolup. If you could valve the other one off. Then it would be ok. Figure it will spool at twice the rpm it does now.
 
zstroken said:
Poor spoolup. If you could valve the other one off. Then it would be ok. Figure it will spool at twice the rpm it does now.
Click to expand...

Nice, easy way to explain it;)


As far as the drive pressure thing, it would also alleviate the drive pressure issues with HX35's...since you have 2 turbine sections to split the pressure with, it will basically cut the "potential" pressure in half...not too mention that the wastegates would actually be able to keep up.

If it were me, and I was bored, I'd use two HY35's with external gates, or some of the ricer custom housings on HX35/40 hybrids with External gates.

I might do something like this on my 4BT...but I'm leaning towards a GT2554R/GT3782R twinset:D
Chris
 
turbos aren't magic... an HX35 will support 300hp at a given pressure ratio. that doesn't mean two will support 500 and three will support 700 and so on.

an HX35 is out of its efficiency range at 35psi... two HX35's with parallel compressors are out of their efficiency range at? 35psi... but now they take twice as long to reach 35psi
 
Right...but the Mass Air flow from two would be higher than one, so it would support more power. Probably not double, but I'd bet 450-500 would be do-able...I've seen tractors set up this way, and it does work very well in that application!

The only way to really find out is to do it!
Chris
 
Signature600 said:
Right...but the Mass Air flow from two would be higher than one, so it would support more power. Probably not double, but I'd bet 450-500 would be do-able...I've seen tractors set up this way, and it does work very well in that application!

The only way to really find out is to do it!
Chris
Click to expand...

right, but the CFM flow of the engine would be the same... that cylinder head and camshaft are only going to allow so many CFM... the only way to increase the Mass at a given CFM is to increase density... and since you're dealing with a fixed density level (35psi) You're dealing with essentially a fixed mass air flow...

I've got no problem with trying to reinvent the wheel, but when you talk about making it square shaped, I feel obligated as a fellow human being to try to keep you from wasting your time
 
That what kinda what I was thinking too...I didn't go that far though. The head is still the limiting factor for the airflow of the two chargers...I guess I should have continued my thoughts and saved you a post:D

Chris
 
BTW, Eric...if you're looking for 450-500 towable, fast spooling twins...go with a HY35 with an external gate, and a 66mm or 71mm S400/GT42 and a 1.10 A/R W/G housing. Sometimes you can get lucky and find them on E-bay cheap, and have a super fast spooling set of towing twins!

Chris
 
If I remember correctly, member hdm48 tried this over on TDR in the 1st gen topics about 4 years ago. I think it spooled very poorly.
I'll have to look it up.
 
Forrest Nearing said:
right, but the CFM flow of the engine would be the same... that cylinder head and camshaft are only going to allow so many CFM... the only way to increase the Mass at a given CFM is to increase density... and since you're dealing with a fixed density level (35psi) You're dealing with essentially a fixed mass air flow...
Click to expand...


The CFM flow of the engine is always the same. You are not changing the cylinder head and camshaft by putting any turbo on it. By putting an aftermarket turbo on a truck you are increasing the density and volume of air available. Two 35's would be twice the volume of one, with an air density probably as good as any if kept at 35psi. Im not talking about making a 800hp truck, and i think 450-500 is plenty doable with 2 of them. Heck, people make a hot smokey 400hp on one HX35 every day.

Im not saying this would be the best thing since sliced bread, I just havent seen an opinion that has changed my mind about it yet.

I think ZStroken might be right about bad spoolup on setup #2 though.
 
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