Fueling questions for 320-360 hp.
 

I'm shooting for 320-360hp for my FD that I will be tracking. Im using stock non-seq. twins. Should I just replace the fpd, eliminate it, or upgrade the rail and fpd to a CJM(or other kit). Also, what injectors should I use?

I would go ahead and upgrade to FFE step up kit which upgrades the secondaries. I got mine from IR performance and really happy with the kit. i got the Bosch 2000s with the kit.

for that power level I just replaced the fpd with a new one and used 850 injectors in the primaries and 1300 in the secondaries in the stock rails.

I'm going single with a new fuel system I can sell you the whole 850/1300 setup if you want it.

I dont think that in this power range you need biger injectors.

i am at 370-380 hp with non sequencial and i just installed an after market fuel pressure regulator. with this i uped the fuel pressure from 3bar to 3.6 and i have all the juice i need. also if you install a biger gas pump you will get evn more fuel.

i lately installed a bosch fuel pump and i had to lower my fuel maps by 20-30%

Stock injectors and pump are fine for this level. Just hotwire the pump so that you can ensure it has 13-14V at WOT compared to 10-12V on a stock setup (dependent on your wiring's condition). That should provide enough fuel. As said above, you may have to increase the fuel pressure a touch but probably not much or at all.

interesting...

Thanks for the info guys. This helps simplify things for me!

I wouldn't rely on bumping fuel pressure and some 20 years old injector to reach your power goal, at the minimum you should get a step up kit and upgrade fuel pump and pump wiring.

Here is a link to a fuel calculator, I hope this will help.

Calculations

Any changes to the fuel system that are STILL using EV1 (or modified EV1) style injectors at this point is just being cheap and/or lazy imo.

EV14 style injectors have been out long enough that you can get good quality injectors using the new technology at a reasonable price. I would *not* suggest using old-style injectors at all tbh..


The OP could probably get away with a minor pump upgrade, rewired (always good) of course, and 550/1600 injectors.

You do realize that as fuel pressure INCREASES the actual flow rate decreases (and creates additional heat/stress), right? (If you don't believe me run a test... Time how long it takes you to pump 5 gallons of fuel at 43psi, then again at 52psi. Jump your test car with another running vehicle so you can maintain 14v. Compare times... I'm willing to bet it will take LONGER to fill the higher your base pressure goes...)


Bumping up the base fuel pressure to mimic larger injectors is a bandaid solution in my opinion. If you want to run 850cc injectors at 52psi base fuel (up from 43psi) so that they'll act like 1000cc injectors why not just spend the little bit extra to get 1000cc injectors an do it right from the start?

I recall being told back in the UK that bumping up the base pressure yielded a better spray pattern, but honestly if you're using quality components from the start then you don't need to worry about that. Oh, and your fuel economy will thank you.

Again, running a larger, dedicated, power wire to the pump is always a good idea. However you want/need to have some room up top for longevity sake. Pushing the old factory injectors above 80% IDC is just not a good idea for long term reliability. His best bet would be to take a good look at his entire fuel system to ensure that the entire thing will be able to handle the rigors of racing it. Why cheap out and cut corners to save a couple hundred bucks up front, only to be out $5k for a rebuild because your fueling sucked?

Upgrade all injectors to EV14 style, run a 550cc and 2000cc set up.

this will have plenty of fuel even if you want to run more power and use the latest technology for best idle quality and smoothest fuel delivery.