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-   -   Running RC 1000cc Low Impedance injectors w/mspnp (https://www.miataturbo.net/megasquirt-18/running-rc-1000cc-low-impedance-injectors-w-mspnp-46340/)

FastColt 04-17-2010 12:38 PM

Running RC 1000cc Low Impedance injectors w/mspnp
 
Ok.....dont think this has been done before. I was wondering what the biggest low impedance injector anyone has run on mspnp. I talked to the guys at DIY this week, then told me since im on low rez i can run low imp injectors with out resistors, by changing the pwm time threshold, and the pwm current limit. But since they are so big i should expect shitty idle and shitty normal driving. Any truth to this? I was also thinking about just selling these 1000cc injectors and going with those stupid expensive 720cc high imp that 949 sells. Thoughts? Advise? PLEASE HELP!!!

ZNuT 04-17-2010 12:58 PM

I've heard of people running 740cc's. The larger the injector you go the shorter your PW (pulse width) with have to be at idle and part throttle. An injector takes a short time to open and close so there is only so short you can get the PW's. If you get to the threshold where you can not open and close the injector fast enough you will either be too rich at idle or not getting fuel at all. This is all depends on the quality of injector you get, the fuel pressure, the ecu, and the motor. I would think the 720cc's would be big enough for most built 1.6's. My guess is that with the right fuel pressure they would be capable of 450-500wrhp. Good luck

About the low impedance running with altered threshold and current limit it does work. I have run it both ways. However for safety of the injectors and electronics, and for safe of mind, I usually run resistors inline and left the pwm and current to full. This was with 29v firmware which was back in the day though.

Savington 04-17-2010 01:01 PM

stupid expensive, lol. The ID injectors are so far and beyond the RCs it's not funny. I switched when I called RC and was told I couldn't run more than 65psi of fuel pressure, and I couldn't run E85 unless I wanted to pickle my system.

I called ID and they RECOMMENDED 90psi, said I was safe to 130psi, and said that methanol wouldn't be a problem.

FastColt 04-17-2010 01:04 PM

I may just sell the rc's and buy the ID ones from 949. I dont mind forking over the extra money for a good product.

Savington 04-17-2010 01:30 PM

My ID1000s idle the same or better than the RC750s did.

cjernigan 04-17-2010 01:50 PM

I hadn't seen those yet. They are stupid expensive but you get what you pay for. At least we're not buying direct injection injectors. They're far more expensive then what we're complaining about.

cjernigan 04-17-2010 01:50 PM


Originally Posted by Savington (Post 557770)
My ID1000s idle the same or better than the RC750s did.

At what AFR?

Cspence 04-17-2010 02:20 PM

Please tell me those are $488 /set and not ea.....:facepalm:

Savington 04-17-2010 02:24 PM


Originally Posted by cjernigan (Post 557775)
At what AFR?

I try to get them around 12:1. I am using a stock FPR and a walbro 255, so my idle AFRs are a bit wonky on any injector. The minimum times right now are like ~1.7, supposedly they are stable to 0.9ms.

They are $488 per set, I'm pretty sure. Either that, or I got a smoking deal on mine. :fawk:

FastColt 04-17-2010 02:27 PM


Originally Posted by Cspence (Post 557788)
Please tell me those are $488 /set and not ea.....:facepalm:

Stupidity has got to be in our towns water Chris, because I was thinking the same thing LOL.

Cspence 04-17-2010 05:11 PM

Whew....I was gonna say ;)


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