INjector Guide

[SekiguchiUeno]

http://www.rceng.com/technical.htm

[alimonos]

VERY HELPFUL SITE M8!!!

[banpei]

Very good link indeed.

[firehawk]

Wow, it seems that the bigport 4A-GE injectors are a pretty "close fit", as according to this formula it seems that 192cc/min injectors at 3kg/cm2 fuel pressure need to run up to 82% duty cycle ("brake specific" value set to 0.475) to produce 124hp.

This means that pretty much any performance upgrade would require at least larger injectors and quite possibly an ECU remap (or a piggyback) to get mixtures set up correctly in idle and partial throttle.

Using the same values for max. duty cycle and "brake specific", with the 250cc/min redtop injectors and stock FPR, the engine could go up to 162hp.

The TRD Levin&Trueno Bible says that the gr.A AE86 used 250cc/min injectors and the dyno plot shows the engine doing 170hp, so the TRD ECU must run the injectors quite to the limit - up to 86% duty cycle, apparently.

[peter møller]

Oh man...please help me find a link to where i can see the flow capabilities of the different 4age/4agze injectors. I have 4 yellow/orange in the shed, and i suspect that they may be 250cc.

[SekiguchiUeno]

but the redtop injectors dont fit, the bluetop MAP ecu has only 1ohm impedance its right? injectors from honda d16a6 are 240cc with 1Ohm, are ideal fit.

but i dont know about afm bluetops, i think they have imoedance 2ohm
it was thread about it here.

[firehawk]

Injector data here (wow, looks like the bluetop ones are 182cc and not 192 as I remembered - this means that they go up to 86% duty cycle);

http://www.geocities.com/MotorCity/Pit/9...ctors.html

I believe it's possible to replace low-impedance injectors with high-impedance ones, but not the other way around. The AFM bluetop has a ballast resistor pack which needs to be replaced with shorting wires to do this. The MAP bluetop doesn't have the resistor pack but the people over at Club4AG were confident that the MAP ECU would be able to run high-impedance injectors as-is. We'll be trying this out on our AE82 racecar so hopefully they're right.

[ZaX]

It would be nice to merge this new info about injectors with this old one to have all on one place
http://www.aeu86.org/viewtopic.php?t=500...t=injector

[SekiguchiUeno]

yes zax right you have

also the bluetop inj are 2ohm? iam totally dumb about electric.
320cc injectors from s13 they are also 2ohm i think, will they fit?.

[Morten]

That calculator is missing one important thing: max. rpm

Reason is that when the rpm increases the time available for the injector to spray the needed gasoline is decreasing. Hence a engine with max output at 9000rpm needs injectors 50% bigger then an engine with max output at 6000rpm to support the same amount of horsepower (at same dutycycle).

I would think the calculator is based on a "normal" rpm of 6-7000, but it does not state anything about it.

Just a little something to keep in mind when choosing injectors.. :wink: