View Full Version : Power estimate and big enough injectors ?

12-03-2005, 07:51 AM
Okay, were currently building a S14 SR20DET for alot of horsepower and need a power estimate and we are wondering if the injectors will do...

Setup :

TOMEI 270 deg 12,5mm intake and exhaust cams with adjustable cam pulleys
TOMEI Rocker arm stoppers
TOMEI 1.5mm headgasket
TOMEI Valve guides
TOMEI Mechanical lifters
TOMEI Dual valvesprings
TOMEI Retainers
GReddy Intake manifold
NISMO 740cc injectors
Arias pistons
Eagle rods
ARP bolt-hardware
Garrett GT3076R-WG

Think thats about it...

We will be running approx 36 PSI and 9000 RPM's

Power estimate and injector size estimate ?


Kjetil Riisnes

12-03-2005, 12:15 PM
No reason to run 9000 RPM, as the engine won't make power up that high with that turbo. This isn't a Honda....

As for injectors, maybe something around the 800cc area. Doing some math isn't hard though, 370cc injectors are relatively "safe" at 250rwhp, so that gives you a "safe" ceiling of 540 rwhp with the 800 cc inj. In reality you probably won't be able to go over 500rwhp without a really high duty cycle.

BTW - I don't know so much about 36 psi with that turbo. Sounds a bit high... Have you done compressor maps with it?

12-03-2005, 12:25 PM
What RPM would you recommend then ?

800cc yeah.. We got 740's on it now, but we were quite unsure on those, though the car will be dynoed properly, but we will look into it..

I do have a compressor map of the turbo, but i'm not very good at reading it :P

Any1 know where i can upload it ?

12-03-2005, 01:04 PM
740's might be fine if you're looking for ~420-450rwhp.

As for RPMs, I'd imagine you'd want to keep it under 8.5k RPM even with a solid lash kit. It might still make power up there, but my bet is it'll be falling off.

I just looked at the compressor map, you probably aren't going to want to run that turbo over 24 psi. At 8000 RPM it is nearing the edge of the map, so that's a good indication it will probably fall off up there.

If you want big numbers on big boost, then I'd look into at least a GT35R. Even then, the compressor map gets crappy after about 26 psi.

Where did you get that 36 psi from?

12-03-2005, 01:18 PM
I forgot to add that the intake manifold, head, exhaust manifold and turbo is ported, and we got uprated bearings on the crank....

I got 36 PSI from making max torque, though max HP might be at 24 as you say yes...

12-03-2005, 01:26 PM
I wouldn't take 740s over 500rwhp and that is with those babies maxing out. I'm running PE 850cc this year cause my power FC said I was at 90% duty near 500rwhp (T67-25G 8^cm) @ 24-25psi.
Speaking of fuel what pump is going to be driving this setup?
What a/r is this internally wastegated turbo? Looking at your turbo you might not need more then the 740s because I don't think you'll be able to punch much pass 500rwhp even with race gas.

12-04-2005, 05:14 AM
We will be running a Bosch 044 on this setup...

Using PowerFC..

Cant remember the A/R right now, ill check it out..

12-04-2005, 06:29 AM
You will make 450ish WHP at 25lbs. of boost at 7200RPM... 740s will be fine...