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resistance of stock rb25 injector


bryan01

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really quick, anyone know what this is?

 

or can anyone do me a HUGE favor and go and measure it on their car? i don't have my stock injectors anymore, i found info for an rb20 and rb26 on here, but not the rb25 ... i also found info in a rb repair manual, but it said it was the same as the rb26, which would mean it's a low imped injector just like in the rb26, which it's not. i found a spec sheet for some aftermarket injectors for the rb25 that say they're 11.4 ohm's, so i'm assuming the stock ones would be around this level. just want to check to make sure,

 

thanks.

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i found that earlier too, but i was thrown off by the title of the page being "top feed injector". the stock rb25's are side feed. maybe i'm just being picky :)

 

 

 

the rb25's are high impedance, just to clarify. i was saying that IF my r33 manual were correct, then the rb25 and rb26 injectors are the same, and they're resistance is 1.3 ohm's each. but it's not correct. EVERYTHING else online says that rb25's are high impedance and rb20's and 26's are low, including that link to that chart. it says that rb25's are 14.6 ohm's and rb26's are 2 ohm's.

 

i found a different chart that was linked to some 550cc injectors being sold as rb25 direct replacements, and it's got 11.4 ohm's. it also only says there's 4 injectors, so i dont know how accurate it is (then again, i'm picky :) ) ... and they're not stock, but to be a direct replacement it'd have to be in the range that the computer could read, and thats a decent amount from 14.6 ... can the stock computer really support that range?

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I have some GTR444 injectors top feed injectors that were used in the RB26.

They are 1.3 ohms when measured.

Usually the larger injectors are low impedance. The smaller injectors used in the RB20 (270cc) are high impedance. They are around 13 ohms.

If you need to have a dropping resistor inline with the injectors then the injectors are low impedance. If you don't need the dropping resistor such as the RB20DET then the injectors are high impedance. Look at the schematic that comes with the RB26 and RB25 FSM it should show the dropping resistors in the circuit. icon12.gif

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cool, that means i'm at least right about the rb26's. the rb25's are high impedance and don't show a resistor pack inline to the injectors on the wiring schematic.

 

the reason i'm asking all of this is because i'm finally setting up my apexi FC to run my low impedance injectors. the apexi FC is setup like the stock computer, which runs a high impedance system on the rb25. if i knew exactly what the stock injectors' resistance was, i could calculate the size of the resistors i would need inline, just like you said chris, to drop the voltage and run low Z injectors on a high Z system.

 

i bought some resistors tonight online that should get me in the ballpark, and i'll test them out and post the results. who knew 25w resistors were so hard to come by.

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