what's the max HP that i can possibly get w/ 750 cc injectors w/o maxxing them out?? i'll be running hondata w/ my sc61 this season..

thanks..

 

At 2 psi rail pressure they won't flow too much, according to the nifty injector worksheet at http://www.rceng.com. Sorry I couldn't be of more help!

 

What ben told me, he said they can support over 400whp

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis &raquo;</TD></TR><TR><TD CLASS="quote">At 2 psi rail pressure they won't flow too much, according to the nifty injector worksheet at http://www.rceng.com. Sorry I couldn't be of more help!</TD></TR></TABLE>

LOL

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by redturbocivic &raquo;</TD></TR><TR><TD CLASS="quote">What ben told me, he said they can support over 400whp</TD></TR></TABLE>

They definitely can but the amount of power they can support depends on the pressures you run. So they can support quite a bit more than 400whp.

 

I used a set of greddy 720cc injectors and at 65psi rail pressure and 25psi boost at 8krpm and 450whp they were at 95% duty cycle.

 

not to take over the thread. How do you know what pressure to run?

 

Static fuel pressure + amount of boost you run (with a 1:1 regulator)......ie if you set the fuel pressure for 45 psi at idle, it will run 55 psi @ 10 pounds of boost.

From what I've calculated, with the right fuel pressure 750's should be able to support over 500 whp.

 

I just made 417hp on 720cc inj. they were only at 76% duty cycle.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tthame1 &raquo;</TD></TR><TR><TD CLASS="quote">Static fuel pressure + amount of boost you run (with a 1:1 regulator)......ie if you set the fuel pressure for 45 psi at idle, it will run 55 psi @ 10 pounds of boost. </TD></TR></TABLE>

No.

If you had 41 psig (stock) fuel rail pressure with a stock/aftermarket 1:1 FPR *with the vacuum line disconnected* you would have 37-38 psig fuel pressure at idle.

Further, at 10 psig boost you might have 51 psig fuel pressure at the rail, but with the 10 psig intake pressure working against it you have an effective 41 psi worth of pressure across the injectors.


When you are calculating for injector size, run use what your rail FPR is set to with the vacuum line disconnected, and don't worry about how vacuum/boost affects it. When you are looking at what your maximum fuel pressure should be, with an eye to stresses on the fuel pump, you should look at fuel pressure as it is modified by the FPR under peak load conditions... the fuel pump doesn't see boost pressure, y0, so you work it harder with higher rail pressures.


Hope I didn't come off like a dick.. I've had to work on one built VTEC engine today, and I'm off to work on another... VTEC makes me a cranky boy

 

That's not what I was told by RC Engineering