Want to kniw what injectors to use on your c4?
#1
Want to kniw what injectors to use on your c4?
I contacted the excellent support team at RC Injection they are pricey but very well worth it. Any problems they will walk you through it. And the knowledge they have is rediculous. Either way, no matter what brand you buy, this info is the same info you need to pick your injectors.
This is a copy of the email I got after asking what they recommend.
Hello Mr. Woods,
The stock injectors on your 1990 Corvette L98 motor flow approximately 225 cc/min (22 lb/h) at 43.5 psi of fuel pressure. As stock replacements, RC Engineering can supply you with a set of 225 cc/min injectors that will drop directly into the stock position on your motor.
http://www.rceng.com/Saturated-Injec...225-P27C6.aspx (225 cc/min, 22 lb/h)
With bolt-on modifications that increase airflow, ignition, exhaust, and compression, most motors will be able use the extra fuel provided by a set of 240 cc/min (24 lb/h) injectors. Even a nearly stock motor will be able to idle normally with this slight injector upgrade.
http://www.rceng.com/Saturated-Injec...240-P21C6.aspx (240 cc/min, 24 lb/h)
If you plan on increasing compression, installing higher lift and/or longer duration cams, boring and/or stroking the motor for horsepower gains, then the largest set of injectors that the stock computer can handle and idle on the street with will flow 270 cc/min (26 lb/h). A set of of 270 cc/min injector will idle rich, so using an adjustable fuel pressure regulator to drop the fuel pressure for street driving and then resetting to a higher pressure for motorsports/track driving may be desireable. (If you have a built-up motor with very high lift or long duration cams, the motor may idle rough regardless of the fueling.)
http://www.rceng.com/Saturated-Injec...270-P28C6.aspx (270 cc/min, 26 lb/h)
Lastly, if you reprogram the stock computer or if you install and tune a programmable computer, then you can use any size injectors that you'd like. In this case, I'd recommend installing a set of injectors that are bigger than your highest horsepower target. For example, a 550 cc/min injector can easily handle 100 horsepower, so eight 550 injectors can support 800 horsepower. So, if I have a stock L98 now but I know I'm going to build it to be a 700 horsepower supercharged motor later in the future, then I'd suggest getting the 550 cc/min injectors now and having a tuner de-tune and pull-back injector timing for now. And later when I build the internals, drop compression, and install the blower, then all I have to do is take it to the tuner to re-tune for the higher fuel and different ignition needs.
http://www.rceng.com/Saturated-Injec...550-P31C6.aspx (550 cc/min, 52 lb/h - will easily supply enough fuel for 800 crank horsepower)
http://www.rceng.com/Saturated-Injec...750-P63C6.aspx (750 cc/min, 72 lb/h - will easily supply enough fuel for 1200 crank horsepower)
This is a copy of the email I got after asking what they recommend.
Hello Mr. Woods,
The stock injectors on your 1990 Corvette L98 motor flow approximately 225 cc/min (22 lb/h) at 43.5 psi of fuel pressure. As stock replacements, RC Engineering can supply you with a set of 225 cc/min injectors that will drop directly into the stock position on your motor.
http://www.rceng.com/Saturated-Injec...225-P27C6.aspx (225 cc/min, 22 lb/h)
With bolt-on modifications that increase airflow, ignition, exhaust, and compression, most motors will be able use the extra fuel provided by a set of 240 cc/min (24 lb/h) injectors. Even a nearly stock motor will be able to idle normally with this slight injector upgrade.
http://www.rceng.com/Saturated-Injec...240-P21C6.aspx (240 cc/min, 24 lb/h)
If you plan on increasing compression, installing higher lift and/or longer duration cams, boring and/or stroking the motor for horsepower gains, then the largest set of injectors that the stock computer can handle and idle on the street with will flow 270 cc/min (26 lb/h). A set of of 270 cc/min injector will idle rich, so using an adjustable fuel pressure regulator to drop the fuel pressure for street driving and then resetting to a higher pressure for motorsports/track driving may be desireable. (If you have a built-up motor with very high lift or long duration cams, the motor may idle rough regardless of the fueling.)
http://www.rceng.com/Saturated-Injec...270-P28C6.aspx (270 cc/min, 26 lb/h)
Lastly, if you reprogram the stock computer or if you install and tune a programmable computer, then you can use any size injectors that you'd like. In this case, I'd recommend installing a set of injectors that are bigger than your highest horsepower target. For example, a 550 cc/min injector can easily handle 100 horsepower, so eight 550 injectors can support 800 horsepower. So, if I have a stock L98 now but I know I'm going to build it to be a 700 horsepower supercharged motor later in the future, then I'd suggest getting the 550 cc/min injectors now and having a tuner de-tune and pull-back injector timing for now. And later when I build the internals, drop compression, and install the blower, then all I have to do is take it to the tuner to re-tune for the higher fuel and different ignition needs.
http://www.rceng.com/Saturated-Injec...550-P31C6.aspx (550 cc/min, 52 lb/h - will easily supply enough fuel for 800 crank horsepower)
http://www.rceng.com/Saturated-Injec...750-P63C6.aspx (750 cc/min, 72 lb/h - will easily supply enough fuel for 1200 crank horsepower)
#2
Should have talked to Jon at FIC free info and much much better pricing. I got a set cheaper than three of them!!!!!
Last edited by antfarmer2; 06-25-2016 at 12:57 PM.
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Dswoods3 (06-25-2016)
#3
Lol, yea, for those injectors it was more about the internals than pricing. If I can ever get this thing started again..... and work out all my wiring issues.... a procharger kit will be next. I wanted a product that could withstand a beating and a product that came with incredible customer service. I screwed up one of my O-rings..... and couldn't get the injectors seated right.... they sent new rings and clips... got them in two days... with that kind of severe I will spend thousands at a store even if I can find them cheaper lol
#4
Lol, yea, for those injectors it was more about the internals than pricing. If I can ever get this thing started again..... and work out all my wiring issues.... a procharger kit will be next. I wanted a product that could withstand a beating and a product that came with incredible customer service. I screwed up one of my O-rings..... and couldn't get the injectors seated right.... they sent new rings and clips... got them in two days... with that kind of severe I will spend thousands at a store even if I can find them cheaper lol
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Dswoods3 (06-25-2016)
#6
Hey, I am not arguing who is better, the first was just an opinion. The only real reason for the post is to give an insight to the Ibs to use for what you want to accomplish for the car. I just thought it was good info worth sharing that's all.
#7
Not arguing at all. If you want to know what to use, look at a chart or calculator. The injector guys are really just middlemen. You like to buy from jegs, or summit? Kind of thing.
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Dswoods3 (06-25-2016)
#8
Yea, not saying anyone is arguing.... just making it known I'm not. And I agree, to each their own. However, buying injectors based on what you have is easy to calculate, buying injectors for things you want but don't have yet is a little harder to calculate. So I was sharing insight.... why buy new sets everytime you want new parts when you could have planned for the future and bought one set..... js
#9
They are rated in different ways and a tuner will help you pick depending on your build. IE a guy here had the same motor as me and made like 800hp+ using 32# injectors, everyone else at the range uses 48- 60# or what ever. Depends more on the tune. A tuner can change the duty cycle of the injector and play with that stuff. In other words they can stretch or reduce the performance of injectors with the tune.
I think it's good you got some new info out there for people. I only used fic because of this forum.
I think it's good you got some new info out there for people. I only used fic because of this forum.
Last edited by pologreen1; 06-25-2016 at 11:40 PM.
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Dswoods3 (06-25-2016)
#11
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Would those be #150822s?
When I switched mine to Accels (21#) it was in conjunction with a dyno session. So, if there was a difference it was handled then. Injectors, fuel pressure, & timing changes need to be "dialed in" for optimum performance. Switching injectors isn't often "plug and play".
Just sayin... It might be the resulting setup and not the (Accel) injectors 'per se'
#12
Correct, so having a dyna is always the way to go.... however.... for those like me that have to drive 4 hours to get a dyno..... and u just able fuel pressure regulator is the key. The old drive then adjust. Plus injectors alone are gonna get anyone anywhere noticeable, easy to make your car run worse than to make it run better. Is it possible that the accel injectors are a down grade from what you had or did you have factory injectors still? Is your car chipped? When I bought mine I didn't know I had a stage 2 chip in it till I opened it up lol.
#13
Team Owner
Could be the way the are measuring poundage. IIRC, it is often set at 43.5 psi so it might be 22pph at 55 psi but much less at 43.5 and if your tune is based off 43.5, well..... To a point, the ECM can adjust but outside of that window, I think you are going to have to spring for bigger injectors if needed. Some people are comfortable running at 90+% duty cycle, others prefer a lower duty cycle.
#14
Team Owner
Correct, so having a dyna is always the way to go.... however.... for those like me that have to drive 4 hours to get a dyno..... and u just able fuel pressure regulator is the key. The old drive then adjust. Plus injectors alone are gonna get anyone anywhere noticeable, easy to make your car run worse than to make it run better. Is it possible that the accel injectors are a down grade from what you had or did you have factory injectors still? Is your car chipped? When I bought mine I didn't know I had a stage 2 chip in it till I opened it up lol.
#16
Team Owner
Without major changes like complete intake, heads and cement, the rest is small enough it might not make enough difference to justify a complete tune.
#17
To need one... nope always another way. But to utilize your parts yes.... let's say you put a cold air intake.... well your car turns it's self back to run like it did before the cold air intake..... so your money is wasted until you tune it..... your car is programed to run within certain parameters. If somthing changes on your car your car will try to change it back. New exhaust? Hope you just wanted sound because your car is going to tune that back too. Then at the point your car can't adjust anymore, it's at its max.... it's gonna run like crap or you will do damage. Point is, no such thing as putting small parts on your car, everything changes somthing and your tune doesn't like hardware to change.
#18
Team Owner
To need one... nope always another way. But to utilize your parts yes.... let's say you put a cold air intake.... well your car turns it's self back to run like it did before the cold air intake..... so your money is wasted until you tune it..... your car is programed to run within certain parameters. If somthing changes on your car your car will try to change it back. New exhaust? Hope you just wanted sound because your car is going to tune that back too. Then at the point your car can't adjust anymore, it's at its max.... it's gonna run like crap or you will do damage. Point is, no such thing as putting small parts on your car, everything changes somthing and your tune doesn't like hardware to change.
#19
Ummm.... I believe I explained that already, but here we go.... the vehicle tries to adjust itself to fit within the specified parameters...... so to explain that more, the car changing timing (advance) and or fuel to air ratio......
#20
Team Owner
I agree with what you said. What I seem to notice is that there is SOME improvement with say a set of intakes and/or headers. Just that you don't get the full effect. What I seem to hear you saying is that there will be zero improvement.