Cost-effective Ignition Retard idea? - Nitrous Oxide Forum

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Cost-effective Ignition Retard idea?
Tuesday, February 13, 2007 10:00 AM
Is it just me or does it seem like everyone who runs a large shot of nitrous uses an MSD- DIS2 box to control timing retard while spraying?

I heard an idea off another website about a guy who used his coolant temp sensor to richen his fuel mixture under boost, I was thinking of a modified version of this idea,

this is a schematic drawn by the guy who uses this mod on his miata to increase fuel under boost-




hook the sensor up to a switched circuit with a resistor(to trick the ECU about the temperature via the voltage) and a capacitor (to smooth the transition) which would be cause the ECU to pull timing just like the it does when it is in cold start mode (open loop mode). I understand the ECU only pulls a few degrees but wouldnt that be sufficient to run a 100 shot? (2 degrees per 50hp shot?)

Also my coolant fans should stay on automatically right? This is on a 2.4 (LD9) Engine.

If the coolant temp mod is a bad idea,
Has anyone used one of these with success? the'yre only 135 bucks shipped compared to 250-500 bucks for a MSD Dis-2
Click Here

Looking for some feedback or any info Thanks!






Re: Cost-effective Ignition Retard idea?
Tuesday, February 13, 2007 5:32 PM
im sure people have used them, but not on a distributorless car.




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Re: Cost-effective Ignition Retard idea?
Friday, February 16, 2007 6:33 PM
Interesting concept that could actually work, except that you have all your facts wrong.

Before we get to that, no the cheaper MSD won't work.


Your idea is neat except the the PCM does not retard spark when its cold.
I just looked a couple of different J cals and it will either advance when cold, or do nothing.
But hot, like 250°F hot, it will pull 2° to 4° depending on the program.
It will also command a much richer A/F ratio at those temps.


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Re: Cost-effective Ignition Retard idea?
Friday, February 16, 2007 10:30 PM
Screwing with sensors instead of doing it the right way.... well, that's pretty much going to get you a blown engine.

I've found that most people who "do it right" with an MSD to retard the timing don't blow their motors... at least, not right away.





Re: Cost-effective Ignition Retard idea?
Sunday, February 18, 2007 2:31 PM
Quote:

Your idea is neat except the the PCM does not retard spark when its cold.
I just looked a couple of different J cals and it will either advance when cold, or do nothing.
But hot, like 250°F hot, it will pull 2° to 4° depending on the program.
It will also command a much richer A/F ratio at those temps.



Hmm, well I wonder if there is a way to up the voltage with a step up transformer or something, instead of lowering it, thereby causing ignition retard?

The only thing I would be worried about is richening of the a/f ratio, do you think it would cause puddling or nitrous backfire?

Call me suicidal, but If it wasn't a HUGE incease in fuel or didnt clip my stock injectiors I think I might try it just to see what happens





Re: Cost-effective Ignition Retard idea?
Monday, February 19, 2007 7:48 PM
it probably wouldn't affect puddling, because if it does richen up fuel, then its not because of fuel pressure but it would change injector pulse width for the added fuel (this would have no effect on the fuel going through a wet system nozzle)..and also you would be able to counter it using smaller (probably not that smart) jet for fuel in the fogger.

i hope that made sence




Re: Cost-effective Ignition Retard idea?
Saturday, February 24, 2007 7:37 AM
See the cable it does all you need plus more and ALL your sensors remain intact and functioning properly.








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