Compound boost.

[Jaden]

I think we've derailed WTF86's thread enough so I decided to start a compound boost thread here in the FI section.

I had been planning on doing a compound boost setup on my car for a while. I'm in the process of building up a block for handling that much boost and have been working on another project while I was doing that one.

I had been planning on using a LARGE turbo feeding into an edelbrock eforce.

But I just had an epiphany and have decided to try something different.

Being in Cali, my point of using the eforce was for the carb sticker.

Then using a large remote mounted turbo feeding back up into an intercooler and then into the eforce.

But I've changed my mind. I think instead I'm going to get a works carb turbo and then get a large procharger to feed into the turbo.

The size of the turbo won't matter as much and we all know that prochargers are easily capable of 1000+ hp.

One reason to compound boost is to increase the pressure of the air for smaller displacement motors.

There's no way in hell that a 2.0 liter motor is going to take 70lbs a minute of airflow at 8 psi from say a Paxton Novi 2500.

But you take 10 psi from the paxton and 12 psi from a t3/4 hybrid and it can all of a sudden handle the airflow at 27 psi.

There some other benefits to this method as well.

The compressor map for the paxton novi 2500 is so broad it's friggin crazy, it can provide 50-60 lbs of flow at like 5 psi of boost.

So you could have it setup to provide 5 psi of boost at 3500 rpm with a total boost of 12 psi at 7500. Combine that with a quick spooling medium sized turbo running at about 12 psi and damn...

That should give you 20 psi at 3300 rpm with the air flow to be making 450-500 hp. Then max out boost at like 35 psi sending through 80-90 lbs a minute of air. Now the fa20 likely won't be able to use more than about 75-80 of that but hell, I'll settle for 750 hp with 500hp at 3800 rpm lol...

hmmm. I'm definitely going to try this once I get my engine built...

Jaden

[Matt@Cosworth]

sounds like a good project
with that amount of poke I'm presuming that you are going to link the engine straight to the axle and not bother with a transmission?


on a more serious note one thing to bear in mind that you don't overwhelm the edelbrock IC core with that level of airflow as I don't know what its rated for but I doubt its 750 bhp worth

might need a bigger throttle too......

[Jaden]

Originally Posted by Matt@Cosworth

sounds like a good project
with that amount of poke I'm presuming that you are going to link the engine straight to the axle and not bother with a transmission?


on a more serious note one thing to bear in mind that you don't overwhelm the edelbrock IC core with that level of airflow as I don't know what its rated for but I doubt its 750 bhp worth

might need a bigger throttle too......

With the original design I was only thinking about doing 600-650hp through the edelbrock...

I'm talking about using a centrifugal s/c like a large paxton or vortech as the primary and pushing that through a turbo as the secondary. The S/C can go through a large front mount intercooler.

Jaden

[Spartarus]

What are you building it for? ... Truck pullin' ...?

On a more serious note, what's your transmission plan? And how are you going to make the oil pressure to support that kind of torque?

I have more irritating questions if you like

[nickw14]

+1 to "what are you doing with your transmission".
Sure, build an engine to handle 750. The transmission still won't.

[Jaden]

Originally Posted by nickw14

+1 to "what are you doing with your transmission".
Sure, build an engine to handle 750. The transmission still won't.

Actually the autos with a good trans cooler can handle quite a bit, but that's why I have a spare... I ain't gonna be dailying it at 750...lol... I'll have 3 or 4 tunes with flex fuel...

Jaden

p.s. I'm eventually planning on putting a 996 transaxle and getting rid of the rear seats and converting to mid engine mounting, doing a twin smaller radiator on either side with custom fabbed body panels made out of hemp cloth...

I think people will be scratching their heads when I pop the hood to fill the gas tank.

[Mr.ac]

Lol. Compound boosts are a nice idea on paper. But.....!
5 laps and your over heating. its nice for drag or very short runs.
I seen it happen in every compound charged car. They show up to the track, do about 5 laps and call it quits cause they don't want to blow up.

But eh, time and money. You got both go for it.

[Spartarus]

Originally Posted by Jaden

Actually the autos with a good trans cooler can handle quite a bit, but that's why I have a spare... I ain't gonna be dailying it at 750...lol... I'll have 3 or 4 tunes with flex fuel...

Jaden

p.s. I'm eventually planning on putting a 996 transaxle and getting rid of the rear seats and converting to mid engine mounting, doing a twin smaller radiator on either side with custom fabbed body panels made out of hemp cloth...

I think people will be scratching their heads when I pop the hood to fill the gas tank.

Ok, Henry Ford, now I'm 99.9 % sure you're trolling.

I think you mean 987, because the 996 transaxle will work great for rear engine mounting... The 986 and 987 are your midengine friends.

Problem is, cylinders 3 and 4 will foul the trailing arm mounts. The axles are at the front of the transmission case. So prepare for a suspension redesign. I'm actually pretty sad about that. I measured. Always wondered why the 987 was 4-corner struts.

Also, I feel like we need to have a chat about compound boost, and why a person would implement it... And the relationship between compressors, because I think you've got boost and flow all inside out and backwards.

Aaaaand why you wouldn't use a centrifugal supercharger as a primary.

[Mr.ac]

Originally Posted by Jaden

Actually the autos with a good trans cooler can handle quite a bit, but that's why I have a spare... I ain't gonna be dailying it at 750...lol... I'll have 3 or 4 tunes with flex fuel...

Jaden

p.s. I'm eventually planning on putting a 996 transaxle and getting rid of the rear seats and converting to mid engine mounting, doing a twin smaller radiator on either side with custom fabbed body panels made out of hemp cloth...

I think people will be scratching their heads when I pop the hood to fill the gas tank.

Lol going midengine with a compound charge set up. Good luck.
A few of the MKI MR2 guys have done it successfully. More of a show car though. Actual function on the street is doable. Track very limited.

The best set up is to keep front mounted for better air flow/cooling. I'll add some water to air inner coolers with a meth injection kit. Then maybe, maybe you'll have something that will not over heat after 5 laps.

Or just drop in a V8 slap a turbo or supercharger. And call it a day.
But eh, time and money. If you have both go for it.

[FRS Justin]

But why go compound when your hp goals can be met with a single turbo setup

[Irace86]

Trolling

[JustAnEngineer]

Originally Posted by FRS Justin

But why go compound when your hp goals can be met with a single turbo setup

I think it's more about area under the curve than peak numbers,

[FRS Justin]

Originally Posted by JustAnEngineer

I think it's more about area under the curve than peak numbers,

I could understand that but its not like its usable anyway trust me, unless your drifting you won't use it....

[EAGLE5]

He's not trolling. He's fantasizing.