Boost vs backpressure

In the instance I have shown both the hp curve and drive pressure for, the S400 made slightly more power.
 
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Being heavily involved with the turbo/gasser world, I agree that the Supra guys, among others, are a smart bunch. But, as stated, their whole combination is vastly different than what we run, so it's tough to apply their technology to our application. Yes, it's been done where a GTX55 on an Ecotech 2.0L goes sixes in a dragster. They probably spin it 12,000 as well. No more useful than Indy car specs offered here. Simply making a point and example to prove another's statement wrong in a specific application doesn't help. Let's try to learn from the testing done by others so we can all go faster and not have to try each combo ourselves to get the results. I like having the smart guys here and willing to share.
 
I'm running a GTX4202 and a GTX5533-94 with 2 45mm gates on the manifold and one more around the primary. My drive:boost ratio is always 1:1 up to about 100psi drive then the drive creeps up a little. The highest I've ever seen it is just under 1.2:1.
 
Little 6, do you mind sharing what a/r is on the 4202? Is this a 5.9 or 6.7? Very similar to what I have in mind. Actually interested in both turbine housings if you don't mind....
 
Goinbyyabig said:
Little 6, do you mind sharing what a/r is on the 4202? Is this a 5.9 or 6.7? Very similar to what I have in mind. Actually interested in both turbine housings if you don't mind....
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The GTX42 has a 1.01 but I'm gonna try a 1.15 on it. I'm not running an 11 blade comp wheel either though. The GTX55 has a 1.0
 
There's more to it than cubic inch and rpm. Changing fuel can make a big difference in bqck pressure gas vs alcohol. Small turbine housing big turbine your going to have higher back pressure.
 
The s400-s500 turbine comparisions are single turbo application with a limited compressor side.
 
V1BDH_zpsvfs7quvx.jpg
 
little6cylinder said:
I'm running a GTX4202 and a GTX5533-94 with 2 45mm gates on the manifold and one more around the primary. My drive:boost ratio is always 1:1 up to about 100psi drive then the drive creeps up a little. The highest I've ever seen it is just under 1.2:1.
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What are your gates set at for opening pressures?
Are you tying the two gates off the manifold into the hot pipe, or to the atmosphere? (I'm guessing into the hot pipe....one gate though...or both?)
What is the gate in the hot pipe set at for opening pressure on the primary?
 
Extended Power said:
Sorry...was this of the BW 80/96/1.32, or the BW 88/110/.85? Again...single application, correct?
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No, it was a large frame turbocharger in a single application. What it shows is that drive pressure can be a good thing in the power department depending on the turbine wheel design.
 
Joesixpack said:
There's no revelation there, the 96mm/1.32 outflows the 110mm/.85.
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Extended Power said:
What are your gates set at for opening pressures?
Are you tying the two gates off the manifold into the hot pipe, or to the atmosphere? (I'm guessing into the hot pipe....one gate though...or both?)
What is the gate in the hot pipe set at for opening pressure on the primary?
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Both manifold gates dump into the hot pipe and I'm running 45mm Turbosmart hyper gate HP's. I've played with the springs a bit and settled on 35 psi springs in those but heat, pressure on the face of the valve, and pressure from the hot pipe all change that. That's just the springs that work best in my application. The primary gate is a standard 45mm Hypergate. That one is controlled using a boost controller. I don't have any pictures of just the gates but you can see them in these.

E7968993-9641-4CCE-A0BC-26D9ECDBDE9C_zpsuxzdxh87.jpg


63EBA4C6-64C5-4826-945E-D3B50E66537B_zpsrpergkji.jpg
 
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