Will you post up a link? I've looked a lot at their site in the past few days and I don't see any.
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Explanation of drive pressure
- Thread starter dordtrecht5
- Start date
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Doesn't sound like it's out yet, been in the works for a couple of years
I wonder if when it becomes available if the comp exducer &/or the comp housing is going to become a limiting factor
It will be limited at a certain point, but more free to keep drive lower at a higher rpm than a 96mm exducer at the same size of a/r housing.
I'm looking for a nice sized s400 compound atmo for a tow rig that'll support nothing less than 850hp max effort while keeping drive and egts in check, perhaps even in a smaller 1.10 housing for kick in the pants spool. If I have to triple I will, but twins are so much easier.
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I'm looking for a nice sized s400 compound atmo for a tow rig that'll support nothing less than 850hp max effort while keeping drive and egts in check, perhaps even in a smaller 1.10 housing for kick in the pants spool. If I have to triple I will, but twins are so much easier.
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The way I am understanding the limiting factor on all of the larger BW chargers is the exducer, not the a/r of the housing. As i stated above, a 100-110mm exducer on the turbine would reduce drive in the upper rpms while maintining given max flow of the comp wheel. I could be wrong, but that's how I read it and what I've learned from others. That's why a lot of the big HP guys go up to a S500 frame or run Garrett.
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Man smokeshow is on a mission, internet warriors... my best advice is seek people's opinions with tools to test theories and repeat results on a fixed platform-engine Dyno.
Time and time again what looks good on paper fails to meet expectations on the dyno.
Time and time again what looks good on paper fails to meet expectations on the dyno.
As an engineer (married to another engineer), I can honestly say that a degree is a piece of paper. How you choose to listen and learn AFTER school is the true indicator of how smart you are.
^^^ I agree whole heartedly. I think its the same in any trade craft. You can read all about and learn principles, but the true craftsman is made by doing it and learning right from wrong in the real world.
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That does seem very well thought out, but I'm having a hard time with a couple of aspects of the argument. An engine will break up total flow of the compressor wheel into cylinder size bites so to speak. If a 4 cylinder and an 8 cylinder are running the same turbo at the same flow rate, the "bites" the 4 cylinder takes of the total air flow would have to be twice the size as the 8 cylinder at the same RPM. In order for his theory to hold up, it seems to me the RPM of the 4 cylinder would have to be double that of the 8 cylinder just to have the same size spikes and make everything equal. Maybe I'm looking at it wrong, but that's just how it works with my thinking.
All this drive pressure discussion is missing the fact the turbo in single format vs turbos in compounds is not the same. Throw a gate in the mix and it is different as well. That is the importance of having a gate as to tune your whole system/ engine for peak performance.
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Josh, I get where you are coming from and the statement you are making. However, he explains the difference with the two different engines theory. One being the v8 and the other a straight 4. With the v8, it is having more output volume of exhaust at longer intervals between pulse.
If we take a hypothetical 250 ci 4 cyl against a 500 ci V8 with same size valve on the exhaust side and rev the 4 cylinder to 7000 and the V8 to 3500....theoretically it outs out the exact same amount of exhaust.
Clear as mud?
I think that us what he is trying to establish. And, that's why the 4cyl with use the same size turbine more efficiently.
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I agree and that's why I am going to use a gate on my compound.
How much does a compound affect drive pressure? I wanna learn cuz that's where I'm going. I'd appreciate your input.
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What about small displacement, high revving v8s? What about v12s? Would they be more efficient at driving a large turbine?
Im currently working on a 2JZ-gte vvti 3.0 I-6. We are trying to figure out how guys are running GT45s & s480/96 on the street and this kind of makes sense of it a tiny bit. Theyre turning max 7-9000 rpm, but they drive around like normal with huge turbos.
Im currently working on a 2JZ-gte vvti 3.0 I-6. We are trying to figure out how guys are running GT45s & s480/96 on the street and this kind of makes sense of it a tiny bit. Theyre turning max 7-9000 rpm, but they drive around like normal with huge turbos.
One other thing that I think is worth mentioning, the graph that is posted in that thread is a turbine housing flow map. The pressure ratio listed there is the ratio of the exhaust pressure on the inlet of the turbine housing in relation to the exhaust pressure on the outlet side of the turbine housing. I was reading through that thread and noticed some guys mentioning drive to boost ratio in relation to the discussion about turbine flow, and that really doesn't have much to do with it.
My opinion, smaller displacement v8 (4.8 ls) is a great motor to boost.
On EFI gas or ethanol the 480/96 works great on the street and track because most of those guys are gated and they run a turbo smart, or a variation of, boost controller. They have tunes to tool around town and street race, as well as track tunes. Most of those jags run a DBB turbo like Garrett or PTE, just for spool up.
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On EFI gas or ethanol the 480/96 works great on the street and track because most of those guys are gated and they run a turbo smart, or a variation of, boost controller. They have tunes to tool around town and street race, as well as track tunes. Most of those jags run a DBB turbo like Garrett or PTE, just for spool up.
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Help us understand what you're saying, and why you disagree, Josh. I wanna learn...and if there's an argument against what the man is saying...
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