Hi
i want to buy new fuel system but when i see the RC injectors
i found 2 different injector:
1-Peak and Hold Fuel Injectors
2-RC Saturated High Impedance Fuel Injectors
wich one best for 600hp and what the different in both?
thanks

 

You are going to need something around 1000cc, and good luck finding something that high in flow rates that is high impedance

 

so the second one is the best high impedance thats will be best?

 

High impedence does not require a resistor box, but 750cc is the highest i've seen in high impedence and for running 600+ you should be running 1000cc injectors which will be low impedence and require a resistor box.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by trickeng &raquo;</TD></TR><TR><TD CLASS="quote">High impedence does not require a resistor box, but 750cc is the highest i've seen in high impedence and for running 600+ you should be running 1000cc injectors which will be low impedence and require a resistor box.

</TD></TR></TABLE>
okay thanks
i`ll use the peak & hold 1000cc

 

you could use 750cc/min high impedence an turn up the fuel pressure to around 60-75psi that would make your 750's flow like 900-1000cc/min injectors. its just personal pref really

 

but i think the 1000cc way easy and both can use for 600hp, so i think i will use 1000cc with walbro 255lph high pressure pump will do the jop too

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">you could use 750cc/min high impedence an turn up the fuel pressure to around 60-75psi that would make your 750's flow like 900-1000cc/min injectors. its just personal pref really </TD></TR></TABLE>

do NOT do this... those injectors are problematic when pressures get above about 50-55psi.. i have lost 2 motors due to rc 750cc saturated injectors locking up when we went to high boost.. needless to say we dont use them anymore.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">

do NOT do this... those injectors are problematic when pressures get above about 50-55psi.. i have lost 2 motors due to rc 750cc saturated injectors locking up when we went to high boost.. needless to say we dont use them anymore.</TD></TR></TABLE>

what was your dwell and duty cycle and how much were you boosting also was your complete fuel set-up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">

do NOT do this... those injectors are problematic when pressures get above about 50-55psi.. i have lost 2 motors due to rc 750cc saturated injectors locking up when we went to high boost.. needless to say we dont use them anymore.</TD></TR></TABLE>

So what do you recommend instead?

 

instead of 750cc just get precision 880's or any 1000cc injector

both motors were making less tha 450 hp. standard setups nothing special, walbro pump stock lines, 45ish psi base pressure. duty cycle on the first was about 75%, about 85% on the 2nd one. both were confirmed by RC that they were locking up when the pressures came up. 15psi of boost on the first, 18 on the 2nd. neither saw over 60psi of pressure. the 1st motor cylinder 1, 2 and 3 were perfect, 4 was melted all to ****. the 2nd it was cylinder 2 and 3 with destroyed pistons, 1 and 4 were perfect. as i said.. we sent the injectors and fuel pumps to rc, they confirmed what i had suspected in each case, the injectors were locking up at 50-60psi of fuel pressure. now they have a big sticker in the box that says DO NOT RUN OVER 43.5PSI OF FUEL PRESSURE

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">instead of 750cc just get precision 880's or any 1000cc injector

both motors were making less tha 450 hp. standard setups nothing special, walbro pump stock lines, 45ish psi base pressure. duty cycle on the first was about 75%, about 85% on the 2nd one. both were confirmed by RC that they were locking up when the pressures came up. 15psi of boost on the first, 18 on the 2nd. neither saw over 60psi of pressure. the 1st motor cylinder 1, 2 and 3 were perfect, 4 was melted all to ****. the 2nd it was cylinder 2 and 3 with destroyed pistons, 1 and 4 were perfect. as i said.. we sent the injectors and fuel pumps to rc, they confirmed what i had suspected in each case, the injectors were locking up at 50-60psi of fuel pressure. now they have a big sticker in the box that says DO NOT RUN OVER 43.5PSI OF FUEL PRESSURE </TD></TR></TABLE>

Wow pretty surprising, thanks for sharing that.

 

wow that sucks now i know not to run RC's or atleast 750 sats

oh i forgot what was your dwell and pulse width that could F-you big time

 

I run Semen Deca 880cc injectors and love them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">do NOT do this... those injectors are problematic when pressures get above about 50-55psi.. i have lost 2 motors due to rc 750cc saturated injectors locking up when we went to high boost.. needless to say we dont use them anymore.</TD></TR></TABLE>

My 750cc sat RC's see 58 psi of fuel pressure at idle...no problems yet. I wish I could take it down after reading this but the car was tuned at that pressure

My gauge is probably off athough I doubt it...how long did those injectors last in your cases Jdogg?

 

I have ran these injectors for a while in a bunch of cars with no problems, its just that i have lost 2 motors and RC confirmed what i suspected on their flow bench. i have never had this problem with any of their other injectors, ONLY the saturated 750's

the 2 i have seen failed immedatly when the pressure went up. it seems like if they work good they are fine, but im still changing them out on customer cars to precision 880's just for piece of mind

 

From what I've seen, heard and read its always better to go a little bigger on your injectors with in reason. I think 1000cc would be good for your setup.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">you could use 750cc/min high impedence an turn up the fuel pressure to around 60-75psi that would make your 750's flow like 900-1000cc/min injectors. its just personal pref really </TD></TR></TABLE>

i wouldn't do that. Generally and safely speaking you should not run more fuel pressure then what the manufacturer has tested the injectors for. Granted they may work at higher psi but you also increase the chance of failure.

Hey JDogg. Quick question that you'll probaly know. Most injectros are rated for ~40psi or so now when you go into boost the FPR is usually a 1:1 so if your running 20psi of boost now you have 60psi fuel pressure at full boost.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93b16hatch &raquo;</TD></TR><TR><TD CLASS="quote">From what I've seen, heard and read its always better to go a little bigger on your injectors with in reason. I think 1000cc would be good for your setup.


i wouldn't do that. Generally and safely speaking you should not run more fuel pressure then what the manufacturer has tested the injectors for. Granted they may work at higher psi but you also increase the chance of failure.

Hey JDogg. Quick question that you'll probaly know. Most injectros are rated for ~40psi or so now when you go into boost the FPR is usually a 1:1 so if your running 20psi of boost now you have 60psi fuel pressure at full boost. </TD></TR></TABLE>

you disagree then say that your running at a higher fuel pressure an yes i know most injectors from the factory are rated at 43.7psi BUT they can do more it involves doing some math if you know your cars MFR, VFR, and density ratios you can find out how much pulse width you can add or need to take away also JDogg was getting good duty cycles with his injectors im suspecting that it was the customers fault more than the product. i've built imports and domestics the most psi i ever put on a injector was 80psi but that was serious work and a car that sees road time 2 times a week

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">I have ran these injectors for a while in a bunch of cars with no problems, its just that i have lost 2 motors and RC confirmed what i suspected on their flow bench. i have never had this problem with any of their other injectors, ONLY the saturated 750's

the 2 i have seen failed immedatly when the pressure went up. it seems like if they work good they are fine, but im still changing them out on customer cars to precision 880's just for piece of mind</TD></TR></TABLE>

sry for the double post but i now see what your saying its because the injectors where high impedence that they melted down