Hi, my car is currently making around 450whp with 1000cc RC Injectors and I do not plan to go more than 500whp. So should I downsize to about 750cc cos its running very rich even at 1% duty cycle at idle - basically fouling the plugs sometimes ...

Car is dyno tuned on Crome Pro btw.

 

Well, I don't know a ton about this stuff but I can tell you my experience. Im running 1000cc Bosch injectors with a Walbro 400 with a base press of 60psi. With my set up on E85 (70% ethanol right now) I am putting 507whp and running a duty cycle of about 97% only for a few seconds in the peak RPMs. I believe that the Bosch injectors are somewhat adjustable through running whereas the RCs are a true 1000cc (or what ever they are rated at). You could always bet a Bosch or ID 1000 cc injector and tune it down to a 750cc if Crome will support that, and I think it does. There are equations out there that let you plug in injector size, fuel pump rating, base press, and duty cycle. Playing around with those things and making adjustments, will change the "size" of your injectors. Please correct me if I am wrong on any of this. Like I said, I know little about this and there are some pretty smart people out there that are great with this stuff. Good luck.

 

need a better tuner, some injectors are worse then others with their idling characteristics thats why im going with id1000 when i get ready to do my build and hope for 550whp but do you have a wideband on your car? i would buy one to leave hooked up at all times and i bet ur car is idling pig rich to be fouling plugs

 

tell us about the rest of your fuel system too.

 

What heat range plugs are in the car? If there to cold that could be causing a foul condition also. Whats the a/f at idle? i know precisions and RC 1000's require a rich idle to have any kind of idle quality generally high 13 a/f ratio otherwise they cause misfires and pop and bubble out of the exhaust ths is if your running peak & hold injectors with just a resistor box. If your running them with a peak & hold injector driver like the aem unit of FJO unit then idle qulity can be like stock. if your running saturated then they should be able to tune the idle pretty decently

 

Turbo LS, I am running the peak and hold with a resistor box and its tuned on Crome. Spark plugs are BKR7E gapped at .025 - I will make a note of the AF Ratio when I start it up again either today or tomorrow and let you know...

 

Walboro 255 fuel pump ....

 

RC has excellent injectors, I would not downsize. You need a better tune on the car to hold a better, leaner idle. You cant really have too much injector (within reason of course)

 

Ok I might try leaning out the idle fuel map a little...

 

Any idea what your fuel pressure is at idle? You may be overwhelming your factory fuel pressure regulator with the pump.

 

*giggles*..

@ 35-43psi of base pressure, the RC1000s have a terrible spray pattern, which is probably why your car is having a hard time idling..

http://www.youtube.com/watch?v=oK2LGTPw2ls , watch the entire video.. They won't label the 1000CC injectors they test, but they are in fact, precision 1000's, which are pretty close to the RC's. @ 15:00 is where they test the "1000" injector.


Its very informational to understand HOW important a spray pattern is. UPGRADE to the ID725's. RC's were good back in the day.. There are better designed, better flowing injectors out now.. Atomization is more important then what most people care to inform the general public.

 

Try working with the tune. I am running RC 1000cc injectors with the same fuel pump and running conservatively at 370whp. Better to have too large of injectors than too small.

 

^^I have heard good things on ID injectors too! I might try those down the road.

 

people swear by that "russ collins" spray your fire hose at the back of your valve for maximum atomization crap still to this day, yet it shows time and time again in new injector design that you get better efficiency through atomization at the injector nozzle then anything else. ID750's FTW.

 

Its really amazing how some people miss on the important stuff.


Also would like to note, go to a better program. Duty cycle calculating in crome is off, way off. I give people the option of crome when a budget is tight, or for mild to stock tunes.. Using Crome on a car such as yours is probably one of the reasons its so hard to get the car to idle without pissing fuel on the piston. Crome doesn't have alot of the built in options Neptune or eCtune or even hondata has. Injector offsets, battery offsets, all the preloaded information that helps make tuning more easier is not there. This is VERY important when tuning a car..

 

i had a picture of a bench test of RC 1000 injectors somewhere here....i gotta see if i can find it

 

Great video, super informative

 

Ok, so think a Hondata S200b should be better? I can get one for cheap ...

 

fuel doesn't ignite, vapor does. that's why atomization is such a big deal. the closer you can make gas to vapor form the better.

 

Generally from what I've found the rc's and precisin 1000's like a base pressure of 50 for better idle and still require you take out a ton of fuel and really like a 13ish a/f ratio at idle. they will go leaner but you hear popping and gurgling out of the exhaust and its gets annoying after a while. Also you should be tuning the car with the fuel maps reading duty cycle. it should be reading milliseconds and get it down low enough to make the car idle well enough and not foul plugs. Or just sel them and get a better injector

My ID1000's idle better than stock 240's IMO flawless idle quality and i have kept my base statisc pressure at 50psi (with vacuum line off of the ragulator)

 

Why would you have the line off the regulator?

 

Exactly. Fix the tune.

 

Is he saying "IDRC" injectors?...

 

UGH...anything but RC's. I Cringe at people using RC's. but its whatev. Every issue your having is tune related. Ive tuned several cars on Crome with 1000's that idle at a good 14.5-15.0 AFR at 900rpm. It does take a little time to get it set up right, but it can be done. By far the best injectors i have tuned on are ID's. Ive put 2200's on a stock car and easily got it idle amazing, drive around perfect...no problems. As far as power, with a single in-tank walbro255 and PTE 1000's ive made right at 550whp. So get at your tuner and tell em to spend more time cleaning that thing up.

 

That is how you set the static fuel pressure. line off the regulator set the pressure tighten the locking nut and then hook the line back up