I installed precision 780cc injectors recently.

Since my car is obd2.b, I measured the resistance of the stock injectors: 12ohm.

Then I measured the resistance of the precision 780cc injectors: 2ohm.

Then I measured the resistance of the honda resistor box (I don't know what model/ trim level car it came out of, but have heard they're all the same): 5-6ohm.

Then I measure the 10watt/ 10ohm resistors from radio shack: 9ohm.

So..... doing the simple math, it looked to me like the inline resistors would put me closer to what I needed to be at: 12ohm minus 9ohm = 3ohm?

Using the honda box would've been 12ohm minus 5-6ohm = 6-7ohm?

The car seems to run fine (other than the injectors being oversized for my application). Should I have used the honda box instead? Why or why not?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">The car seems to run fine (other than the injectors being oversized for my application). Should I have used the honda box instead? Why or why not?</TD></TR></TABLE>

I think people suggest a Honda resistor box for that OEM or "clean" look. But I've read about variations in the amount of resistance with each box. I guess that's what you get for buying a used resistor box.

 

the resitor box would be a hell of a lot cleaner, and wiring wise would look a lot nicer. i would say the box would be better at disapating heat than the RS resistors. also the box was made for this application.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pennhatch &raquo;</TD></TR><TR><TD CLASS="quote">the resitor box would be a hell of a lot cleaner, and wiring wise would look a lot nicer. i would say the box would be better at disapating heat than the RS resistors. also the box was made for this application.</TD></TR></TABLE>


.....my concern is more with the proper ohm's.

The heat is negligible, imho.

 

The Honda resistor box will put you where you need to be. A little cleaner in the installation. The resistors you can buy from Radio shack are not the correct ones you want to use. Specifically for heat purposes they will eventually burn out. You want to use some sort of a potted resistor that can dissipate the heat better. Another thing you can do is use the AEM Injector box. So you can convert the saturated injector into a peak and hold injector.

 

Interesting. I wired inline resistors 3 years ago and its worked out just fine. I dont understand the "not clean" argument. There are little tiny boxes wrapped in electrical tape in the middle of each of my injector wires. You can barely see them, and if you just wrap the resistors/wires, it looks totally clean.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rtype16 &raquo;</TD></TR><TR><TD CLASS="quote">The Honda resistor box will put you where you need to be. A little cleaner in the installation. The resistors you can buy from Radio shack are not the correct ones you want to use. Specifically for heat purposes they will eventually burn out. You want to use some sort of a potted resistor that can dissipate the heat better. Another thing you can do is use the AEM Injector box. So you can convert the saturated injector into a peak and hold injector. </TD></TR></TABLE>


What do you mean by the honda resistor box will put you where you need to be comment? Are you saying the inline resistors won't?

And why do you say specifically for heat purposes they will eventually burn out?

I'm not taking to task what you have mentioned, but would like further clarification. The resistors are rated up to 250deg F, which I would think is plenty due to where I've located them.

Are you also saying the ohm delta is negligible between the oem box and the inline resistors?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rory Breaker &raquo;</TD></TR><TR><TD CLASS="quote">I dont understand the "not clean" argument. </TD></TR></TABLE>

nor do I. I have my resistors in the wiring harness in some wire loom. You can't even tell they're there. Looks a lot cleaner than that extra box in your engine compartment IMO. I've been running inline resistors for over a year w/ no problems.

 

There's been threads about this before........There were better results with the honda box because of the correct resistance. Whether that's theory or truth you can decide, but like Rtype 16 said, the Honda box will put you where you need to be.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by racinskittle &raquo;</TD></TR><TR><TD CLASS="quote">There's been threads about this before........There were better results with the honda box because of the correct resistance. Whether that's theory or truth you can decide, but like Rtype 16 said, the Honda box will put you where you need to be.</TD></TR></TABLE>


Please link me to a thread if you can - I'm doing a search now.....

But I don't see how the honda box can have the "correct resistance" when I measured it with a VOM and it was off more than inline resistors.....

 

I don't know much about electronics, but I do know that in my car a resistor box works better than inline resistors...

When I first installed my turbo I used inline resistors (10 watt 10 ohm RadioShack), I soldered them in and shrink wrapped them, then put loom around them etc... (looked clean by the way, you couldn't even tell they were there.)

But, I noticed that most of the time it took my car a few turns to get started, like most of the time it would take 2 or 3 turns to start up...

So I did some research and read that the inline resistors are different than an OEM resistor box (don't ask me how, I don't know much about ohms and watts and resistance LoL)...

I bought a resistor box off eBay for $10 and wired it up... now every time I turn the key it kicks over on the first turn... So, in my experience although the inline resistors work, the resistor box works better... I guess...

I just got tired of it taking my car a few turns to start up and thought I'd try to fix it... I like it better now that it starts right up... but this is only my experience, it might be different for others....

 

Here's what I found:

https://honda-tech.com/zerothread?id=1044257

"you can take a meter and measure the resistance on a fuel injector. my stock type r injectors measured 14 ohms, my rc engineering measured 3.9 ohms...so I used 10 ohw 10 watt sand block resistors. its not the same for every injector setup but basically you want to check the resistance on the stock setup and install resistors to maintain the stock resistance."


And another relevant thread:
https://honda-tech.com/zero...65728


Modified by Black R at 11:11 AM 3/16/2005

 

nobody has anything to add?

 

i used the radioshack resistors and i soldered them but i had a funny idle.. i got a honda resistor box and my idle is perfect..

i also wondered about the difference in resistance.. my stock injectors were 11.9 ohms. my dsm's were 2.5 plus the resistor box 6 ohms.. i had a total of 8.5 ohms. what im thinking is the low resistance injectors will need more current to open with a low duty cycle for the idle.. thats why the resistor box is not going to bring you back up to 12 ohms like your stock ones are, they will keep the resistance lower to allow more current.. (ohms law) if your car runs well on the radioshack ones then keep um, but i liked the honda reistor box well becuase its an oem unit and my car idles better on them.

 

Good info, i am planing on buying the 10wat 10ohm inline resistors from radio shack. I am using 440cc R32 SKYLINE injectors which were 2.5 ohms, my stock 240cc injectors measured at 12.2 ohms, would anyone see a problem in using this setup? at 70psi on the 240cc and 4.2psi of boost the car was 13.2 on the wideband which was lean i need to slap these injectors on asap!


Modified by JDMerzxCEO at 4:29 PM 3/29/2005

 

Someone should measure the resistance of the stock Honda peak&hold injectors that the Honda resistor box was designed to work with. See how close they are to 2 ohm.

That being said... I don't think it matters so much in circuits like these. You are more worried about the impedence, not the resistance.

If the resistor you use is too high, the injectors might not open all the way. Too low... and you overheat the injector drivers in the ECU.

Anyway... Just thoughts.