H.P. Estimate on combo

Y

yipekiya

Turbo Yoda
Joined
May 30, 2001
I am trying to get a ballpark on how much power my engine should make. Need to decide which fuel pump to buy.
Combo
Stage 2
3:590 crank 6.5" Rod
9-1 compression
Chapman ported CNC aluminum Stage 2 heads Flow 307 @ 550 lift the cam is a 576 lift on both224 duration both 112 lobe sep
96 pph injectors
FAST fuel managment
Precision fm
dequick headers and 4" downpipe
pt 72 .96 tang

around 20 psi..

Any help a/o reccomendations appreciated
 
You had me in 4 digits until I got to the turbo. That turbo is going to surge like crazy with that motor behind it.
 
Are you going to street this a lot?

The cam shaft is really small for a stage 2 headed motor.
I don't think a 4 inch down pipe is needed with a 72 turbo.
PTE's web site says that you can make 850hp with that unit.
You should get that pretty easy.

What are you going to use the car for and what are your
et goals? Also what have you purchased already?
Maybe we can save you some money getting you what
you want from your car.

I have never had a surging problem so I can not comment.

I have run a 3bolt 70 with a 224 cam and M&A heads with
a stock block motor. That thing rocked!!!
 
Sounds like this combo is targeted for what, 800-900 hp at this boost level?

900 hp @ 0.5 BSFC = 450 lb/hr fuel

Assume your fuel specific gravity is about 0.7, then fuel density is about 43.7 lb/cuft.

450/43.7 = 10.3 cuft fuel per hour, or 77 gal/hr.

So, at a bare minimum, you would need a pump that can supply at least 77 gal/hr of fuel at (45 psi static + 20 psi boost) = 65 psi fuel rail pressure.

To be conservative then (you don't want a pump that can only do exactly what you need), get a pump that is maybe about 100 gal/hr @ 70 psi.

If you get the itch to turn up the boost someday, making say 1100 hp @ 28 psi boost, then go through the same calculation and you get a requirement of 94 gal/hr @ 73 psi. For conservatism sake then you would want a pump around maybe 120 gal/hr @ 80 psi.

If you don't like one of those assumptions (maybe you want to size for a 0.6 BSFC), then you'll get an even bigger pump as an answer. So, use your judgement, but somewhere in that ballpark is probably a good answer.

John Estill
 
I have the engine complete, the headers and downpipe are on order, I have the F/M, have the turbo, still need to buy the injectors, FAST, Throttle Body and Fuel System, the reason I chose a tight cam is to move the power down in the powerband, Red at Comp helped design the cam it is very similar to the cam in his car it is a stage 2 powered corvette and he loves it...

Rob
 
Just a thought.

In my experince if you have good flowing stage II heads you may not be able to make 20 lbs of boost with a 72 turbo. It may be possible with that small of a cam but I would guess more in the 15 to 16 lbs of boost max. I understand the thought of the small cam but seems to take the motor out of the its natural power band. Best of luck with the project.. Dave
 
Not surging, I just blurted that out. Thats actually something that happens when you've got much much too large a turbo for your engine's airflow. Ignore that.

It just seems like a VERY small turbo for that combination IMO. I have a pair of Chapman ported Stage heads sitting right next to me (anyone wana buy 'em ;) ), and they are NO joke. A 72 turbo will be so out of breath that you'll be blowing some SERIOUSLY HOT air at your motor at only like 15lbs of boost. I can see running a 72 on a GN1/MA headed motor for a *really* responsive street car, but a turbo that small would be terribly inefficient on a stroked Stage 2 headed car.

This is totally just my opinion. It'd definately get the job done for 700 to 800 hp reguardless.
 
Thanks for the input.. Time will tell ont the turbo, my thought process was I wanted to be able to run on the street with minimal lag and still be able to run high 9's, with reliablity!!!. I can always go bigger on the turbo, it should take a few passes before 9,s seems slow I hope. The turbo is also the easiest part of the combo to change..I was going to buy the 88 but when talking to Joe Lubrant he indicated that it is no fun on the steet , he just loved his 72.. The question at hand is I have the aeromotive pump Flows 500 lbs. per hour at 12 volts and 45 psi, It is the one below the eliminator..Is this going to do the trick...
 
Originally posted by yipekiya
The question at hand is I have the aeromotive pump Flows 500 lbs. per hour at 12 volts and 45 psi, It is the one below the eliminator..Is this going to do the trick...
Click to expand...

No.
 
Thought So..Which do you think is a better pump the weldom or the pro series aeromotive???
 
Hey Rob,

I've done a little research into the Weldon C2015-A and the Aeromotive Pro-Series #11102 for my Syclone. They are a little tough to compare since Weldon rates their pumps at 14.0 Volts to Aeromotive's 13.5 Volt rating. Regardless, the Aeromotive appears to flow more at lower pressures. At around 60 psi or so the Weldon starts to flow more. Pretty much a wash overall until you exceed 70 psi since the Aeromotive's higher flow at lower pressures is just getting returned to the tank anyways. Of course Weldon offers a couple of other pumps that flow a lot more than the Aeromotive Pro-Series. The Aeromotive is available in Canada through Mopac as I am sure you are aware. The Weldons are available through Sean Hyland Motorsports in Ontario. Good Luck. I look forward to terrorizing the streets with you this Summer. :cool:
 
Rob,

I don't exactly remember our conversation, but if I said I loved my PT 72 on the Street, it was a 10.10 car at 3650-3700# with 200r4 trans, GN-1 Heads Stock Intake, 70mm TB. 236-236 PTE Hyd. Roller set-up.
For you:
I would recommend as a minimum the 236-236 cam, and at least a 76mm or 80mm built on the 88 type turbo platform.

I run the Weldon 2015 pump, and it seems to support my current combo nicely without any hint of lack of fuel.
The 2015 will support 1200hp easily. I run -10 from stock sumped tank to filter-pump and -8 to the fuel rail with stock feed line as my return.
 
You must log in or register to reply here.
Top