what would the down side be of having a #50lb injector,
when a #30 is needed?

of course programming is needed, gas mileage would go down, is there anything else?

jesse

 

I would like to know also. It seems that you could over inject a car. Say you got no mods. You put some huge 60lb injectors on it and reprogram the PCM just for the injectors. The pulse width is going to be very short. Maybe 1-5 ms all the time instead of the normal 5-15 ms. I would think that once you get the injectors going on/off this fast they wouldn't be very accurate. Maybe I am wrong. Just a thought.

Jeff D.

 

Idle control will be really hard to get tuned

 

Yeah, tell me about it. I've noticed that mine is also harder to crank (although that's probably attributed to a poor tune). I talked to several guys with Mustangs, and they have the same problem, seems the injectors spray a little bit even after the engine is shut down. Plus, when you start it cold, the computer will add even more gas and it just becomes a bear to start. Other problems that I'm aware of... you could potentially wash out your rings and get gas in the oil. Poorer performance. Wasted $$ in buying injectors that are too big and the cost of crappy fuel economy. The list is larger I'm sure, but I don't feel like running through it.

 

thanks for the info

what about on FI cars?
little to no boost is being made at idle on turbo/supercharged cars.
cars with dry nitrous systems have BIG injectors also

do they have to deal with all the idle/starting problems also?
or is it all in the tune?

jesse

 

Mostly it's in the tune. My car is running a Vortech V1 S trim at the moment. On a supercharged car, the boost builds with RPMs so you can increase your fuel maps accordingly. A turbo is a little tougher cause it can produce full boost at like 2000 RPMs all the way up to redline and beyond. This requires a little more attention. N2O is relatively simple to program for if you use a window switch which will only allow the juice flow between x and y RPMs. For the best outcome, you need to dyno tune with wide band O2's.

 

so theoretically i could run #50 injectors on my NA heads/cam lt1, as long as i had a good tune, correct?

jesse

 

It's all in the "tune".... but the stock PCM and high impedance injectors have limits. The lower limit on pulse width seems to be around 1mS. Use too large and too slow an injector and the PCM just can't turn it on and off fast enough. Obviously, its idle where this problem shows up. You can get an add-on black box that allows the stock PCM to drive low impedance injectors, when they start getting really large.

One of the advantages of aftermarket ECU's is the improved, high resolution injector drivers, coupled with low impedance injectors that open and close faster. I run the equivalent of 78# injectors, and the engine idles fine at 800rpm, with a 230/242 cam. It's all in the hardware (MoTeC M48Pro) and the tune.

 

thank you, fred


jesse

 

Why would you wanna go that big for?? I got a friend with 30# on his 02 LS1 with No2,heads, cam and true duals going 10.8's. Thats all he got in the POS Ls`1. Lucky ****

 

Is he running wet or dry N2O?.... wet doesn't affect injector size. And, remember, the LS1 runs at 58psi fuel pressure.