High to low Impedance Conversion

[jrd450r]

I am not sure if this has been covered but I cannot get the new search to work so I will ask, I have a rb25 which obviously has the stock side feed high impedance injectors. My question is; I am switching to a top feed system as the injectors are much less expensive going top feed, but the problem is that almost all of the large top feed injectors are low impedance, how can I run low impedance injectors on this motor? I know the rb26 has a resistor pack to accomplish this but they are near impossible to find and expensive. Is there any other way to do this? The motor is going to be running on Nistune if that matters... Thanks!

[240z4u]

Run big 10 ohm resistors in series with the injectors. I got mine from rat shack. http://www.radioshack.com/product/index ... Id=2062291

[meet07]

-top feed fuel rail for the rb25det
-6.8 OHM/10 WATT resistors
-injectors

[FinkenS14]

How does the GTR resistor box, or any other one for that matter, plug into the harness of the car?

And does anyone have an links to some good top feed high impedance 1000cc's

[Carl H]

DO NOT USE 10ohm resistors, they will throw off your lagtime to the point it is SUPER hard to tune properly.
You need to use a 6-6.5ohm resistor inline with each injector power wire...
I can supply a low impedence injector resistor pack that is identical to the gtr pack at a fraction of the price.

finkens14 - it does not plug in, you have to manually wire it in.

[240z4u]

I had my latency testing done on my injector with that size resistor inline, should have said that. My bad.

[Carl H]

werd.
i had 10 ohm 10w resistors on my 20 for ages...could never figure out why i couldnt get the stock ecu's fuel maps to match actual.
swapped over to a proper resistor pack and problems dissapeared.

[240z4u]

Carl, that kind of suprises me. When I checked my resistance of my stock injectors I just did the math and used 10 ohm resistors to come out with something close. I guess it jacked up the latency but maintained the driver current. I had witchhunter do the latency testing. Dirt cheap at $25. Very fast turnaround.

[Carl H]

thats what i did with my injectors...measured stockers, then measured the new ones and adjusted as needed...but that was before i really understood how different injectors work and using low imp injectors on a high imp system you kinda need that little bit of 'spike' in the current to make it work properly.
with the stockers ohming out to ~13ohms i added 10 ohm resistors inline intially but then when i had my hands on a 26 resistor pack and measured came out to be around 6 ohms...
been rocking out a 6 ohm pack for ages now and the wideband readouts follow the map almost perfectly!

[240z4u]

Carl, just to double check I called witchhunter and they used 8 ohm resistors when they did the latency testing! I am glad you mentioned this. I installed 8 ohm resistors tonight in preparation for some tuning.

[jrd450r]

So I guess there is no definite answer on this? Some are saying 6, 8 or 10. Any way we can find out a definite answer on this? Would it be possible for someone measure the resistance of a rb26 box?

Carl H:
Is that 6 Ohm measured from the rb26 resistor box?

[240z4u]

If you run these; http://cgi.ebay.com/ebaymotors/120LB-12 ... ccessories

and 8 ohm resistors, I can provide you the correct latency values.

In my opinion, your kind of leaving fate to the wind by running a huge injector/resistor setup and hoping the latency value is correct. IMO choose your injector, get the latency tested (if its not published) and run the resistor they use in the test setup.

Evan

[aero1310]

You say to use 6-6.5 ohm resistors so the stock ecu could read the fuel maps correctly. Im using the AEM ecu, think that changes anything? Also Ive been reading on other writeups on how to make your own resistor pack and they say you want a current of around 1 amp, but (correct me if i did the math wrong) with the 6ohm it comes out to 1.5amps. That just seems a little much and Im not sure I wanna risk frying my 1800$ ecu lol..

btw I have denso 550cc injectors that run 2ohms on a RB26DETT w/ AEM. Unfortunatly the engine didnt come with the resistor pack :P

Yeah Im just a little unsure what route to take, 10ohm, 8ohm, or 6ohm lol You make a good point but not sure if that only applies to the stock ECU...10 ohm sounds like ppl have trouble tuning.. anything bad about 8 ohms?

[aero1310]

ok well just went to the junkyard and got a resistor pack off of an old acura legend with a honda v6. Has 6ohm resistors... just fyi