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My compound turbo set-up

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What would a compound setup be like on a 2.3 or 2.4? I wonder if its possible to have too much torque? :hmm:

Did someone say they are running 8s with 600 hp compound setup? That's impressive :hellyeah:
 
What would a compound setup be like on a 2.3 or 2.4? I wonder if its possible to have too much torque? :hmm:

Did someone say they are running 8s with 600 hp compound setup? That's impressive :hellyeah:
I would think compounding would be even better on a lower revving stroker engine. There's no such thing as too much torque as long as your drivetrain stays intact. :p

Yeah, Kevin (95GSXracer) is running 8's in his compound turbo'd 1G.
 
Oh, I totally agree. BUT my point to this matter is our cars make around 200 crank HP and put down around 160awhp take or give. SO IF it's around 30-40 hp then how does it increase?
You can't take the 15% number and continue to use it, otherwise when your making 1000Hp your loses are around 150? I think not.

I'm not trying to rain on anyones parade at all just trying to get the facts.

Loss is measured in a percentage. Not a raw hp or tq number.

You have a loss through Gearing {as partially explained by the helical gear analogy}

But everything increases as you make more power. Load, RPM, Friction, Heat..

How can you not understand how this equates to more overall lost power?

Your transmission wastes power changing the direction of movement. Everytime a change of direction is made, power is lost. This is measured in a percentage.

So obviously, if you make 200hp stock and lose 30hp to the wheels, thats 15% drivetrain loss.

Easy way to see this on a dyno is to do both positive power and negative power pulls.. You can accurately calculate drivetrain loss through this method. Works best on inertia dyno's as you are using drivetrain drag as the brake for the drum.


in the end, people need to realize HP doesnt really exist. Its just a representation of tq thought up by Automakers to sell cars! {ok not really} but i digress. Too much emphasis is put on DATA and not enough is put on PERFORMANCE.
 
I would love to do this kind of setup on the 2.3L that I am having built right now. I don't have the fab skills so will have to hire that out. Firstly though I'd like some guidance on turbo sizing. My goal is mid 600s WHP. I know Paul did that with the turbos he had and has now sold. Should I just use those or is there something better/cheaper/etc that I should consider? Second any recommendations of someone to do the fab? Probably help if they are somewhere in Colorado. Or if not a person how about some idea of what I need to ask a shop/welder in trying to find someone to do the work?
 
Its not. It got sold while I was in the process of closing on and moving into our new house. That would have been nice, to be able to pick up a complete working setup.
 
Loss is measured in a percentage. Not a raw hp or tq number.

You have a loss through Gearing {as partially explained by the helical gear analogy}

But everything increases as you make more power. Load, RPM, Friction, Heat..

How can you not understand how this equates to more overall lost power?

Your transmission wastes power changing the direction of movement. Everytime a change of direction is made, power is lost. This is measured in a percentage.

So obviously, if you make 200hp stock and lose 30hp to the wheels, thats 15% drivetrain loss.

Easy way to see this on a dyno is to do both positive power and negative power pulls.. You can accurately calculate drivetrain loss through this method. Works best on inertia dyno's as you are using drivetrain drag as the brake for the drum.


in the end, people need to realize HP doesnt really exist. Its just a representation of tq thought up by Automakers to sell cars! {ok not really} but i digress. Too much emphasis is put on DATA and not enough is put on PERFORMANCE.

It takes the same power to spin a gear set no matter what setup or level of performance is in front of it. Yes that number stays the same.

And yes, heat and friction losses increase as you increase the speed of change (horsepower). But if you have a 20% stock drivetrain loss, at stock power levels, and carry that percentage through to 400whp; you run in to a conundrum. Say you loose ALL power via just drivetrain movement and not via friction at stock power level: 38hp (0.2 X 190hp). At 400hp, you've increased the drivetrain heat to 42hp ([0.2X 400] - 38) . That is over 31,300watts of heat! (745.7 watts = 1hp) My 120vac arc welder functions at a much, much lower wattage than that. There has to be a curvature. The friction losses can NOT be a linear increase to power output, simply because our transmissions would see welding temperatures FAR earlier than 400whp, even with a substantial portion of the heat generation being manifest in the rear gearing and tire friction.

So no, you can not assign a consistant percentage or linear assumption to drivetrain loss, even with the heat/friction aspect of the loss.
 
The heat generated from the arc welder is concentrated to a much, much smaller area. The heat generated by the transmission due to friction spreads throughout the gears, shafts, bellhousing, etc, so you cannot really compare the temperatures of the transmission to the temperatures of an arc welder.

Friction increases in the drivetrain when making more power/torque because a higher force is applied to the gears. The coefficient of friction remains the same, but the higher the normal force, the higher the friction force.
 
It's officially sold today. It'll be on a 2G in West Virginia now.

Ripley - I'd recommend a 16g or 20g for the primary (using the 10cm T3 td05 turbine housing) and feed it with anything larger than a 35r.

My next set-up is officially going to use a 20g and a GT4094r. Shooting for around 700 WHP and 650 TQ, and I should be able to do it with around 40-42 psi. I'm going to start the build sometime this winter after I buy a Tial turbine housing for the 40r. :)
 
So an HX40 would work for the secondary. That's kinda where I am leaning. What exhaust manifold would you recommend? And what would be the deciding factor between the 16g or 20g?
 
16g and HX-40 on a stroker or 2.0L would be sick..just puttin that out there.

Two of the quickest spooling (for their effeciency ranges of course) turbo's mated together with the right manifold and gate set-up.. hmm
 
The heat generated from the arc welder is concentrated to a much, much smaller area. The heat generated by the transmission due to friction spreads throughout the gears, shafts, bellhousing, etc, so you cannot really compare the temperatures of the transmission to the temperatures of an arc welder.

Friction increases in the drivetrain when making more power/torque because a higher force is applied to the gears. The coefficient of friction remains the same, but the higher the normal force, the higher the friction force.
Dont confuse static friction with sliding, or further lubricated sliding friction. Take a look at the second rule of thumb of Lubricated Sliding Friction: click. The X ^.5 = Y formula is simple and shows a falling off of slope as X increases: click.

The first rule is very interesting as well. Torque increases the normal force, but normal force doesn't matter much with lubricated sliding friction.
 
It's officially sold today. It'll be on a 2G in West Virginia now.

Ripley - I'd recommend a 16g or 20g for the primary (using the 10cm T3 td05 turbine housing) and feed it with anything larger than a 35r.

My next set-up is officially going to use a 20g and a GT4094r. Shooting for around 700 WHP and 650 TQ, and I should be able to do it with around 40-42 psi. I'm going to start the build sometime this winter after I buy a Tial turbine housing for the 40r. :)

Would you consider selling the specs to punishment racing or some other vendor that does good welding so we can purchase this? Could even name it after you. I'd love to see some compound setups working their way through the scca and misc other road racing divisions.

d
 
Would you consider selling the specs to punishment racing or some other vendor that does good welding so we can purchase this? Could even name it after you. I'd love to see some compound setups working their way through the scca and misc other road racing divisions.

d
Honestly, any of the vendors here that dabble in fabrication, would be able to construct a compound system for the right price. I'm sure none of them would be interested in the specs of the system that I made. They would be completely capable of locating the turbos where they see fit and plumbing the rest from there. It's like a header - everyone makes them and they're all a bit different from each others. A compound turbo system would be no different.
 
What manifold are starting with Paul?
I'll be building one from scratch using sch-10 bends. I want to locate the 20g much lower and closer to the tranny. That will give me more room for the 40r to sit above and behind it. I already have the collector finished, and I have a head flange and a few bends purchased. Just waiting til I can afford a Tial turbine housing, and I'll get started on all of the fab work.

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Dont confuse static friction with sliding, or further lubricated sliding friction. Take a look at the second rule of thumb of Lubricated Sliding Friction: click. The X ^.5 = Y formula is simple and shows a falling off of slope as X increases: click.

The first rule is very interesting as well. Torque increases the normal force, but normal force doesn't matter much with lubricated sliding friction.

That's interesting. But in the case of drivetrain components, the friction isn't sliding friction, it is rolling friction, which is very similar to static but with the coefficient of friction significantly smaller.

I'm sure there are many other factors that influence the losses thru the drivetrain that may or may not make the relationship between drivetrain loss and power linear or non-linear. However, I find it hard to believe that it becomes easier and easier to make more power when you are putting down enormous amounts of power, as would be the case if friction were related by the square root. The opposite should be true.
 
That's interesting. But in the case of drivetrain components, the friction isn't sliding friction, it is rolling friction, which is very similar to static but with the coefficient of friction significantly smaller.

Gear teath slide as each act upon the other; not roll. Bearings slide around journals. Thrust bearings are sliding surfaces. Of course, there are races in a transmission. Yet, we donot break them nearly as frequently when we blow our transmissions due to overpowering. They typically stay together, or their damage is a consequential failure due to carnage from broken gears. And yes, this is because the coefficient of friction is FAR less than that of static, and noticeably less than that of the sliding friction squareroot function. Turbo ball bearing technology is more effective with much larger turbos than 50trims and GT35Rs.

I'm sure there are many other factors that influence the losses thru the drivetrain that may or may not make the relationship between drivetrain loss and power linear or non-linear. However, I find it hard to believe that it becomes easier and easier to make more power when you are putting down enormous amounts of power, as would be the case if friction were related by the square root. The opposite should be true.

In bold is also interesting :) . This subject is getting a bit off topic AND is appearing to travel down a path of opinion. I'm willing to agree to disagree. Every setup ought to be measured in wheel horsepower anyhow :p.
 
Ah, you are right. Gears are sliding. I apologize for getting off topic, and I agree with your last statement. Power at the crank is relatively useless compared to power put down to the wheels.
 
Paul would you comment on how the wastegate setup in more detail? It looks like you used two, but Kevin is using three according to this:

Compound Turbo Charging - Yellow Bullet Forums

Its a good read too if you haven't already seen it. Kevin goes into a lot more detail on his build.
 
Paul would you comment on how the wastegate setup in more detail? It looks like you used two, but Kevin is using three according to this:

Compound Turbo Charging - Yellow Bullet Forums

Its a good read too if you haven't already seen it. Kevin goes into a lot more detail on his build.
It's just like any single turbo set-up. You want a wastegate before each turbine wheel to direct exhaust gasses around the turbine wheel. Kevin only has 2 gates on his 50-trim because 1 gate wasn't getting the job done on it's own.
 
Would you use steel or aluminum for the tubing? And if steel, mild or stainless?
 
A very interesting read (just finished reading through from post #1). Congrats to Paul on the success & best of luck on the second setup.. This is really out of this world.
 
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