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B21FT ignition upgrade

242Bleek

k-jet groupie
Joined
Jul 18, 2005
Location
Brooksville/Tampa, FL
Hello. I have an 83 245T with an M47. It has a T3/T4, gold injectors, still K jet (and keeping it that way) running about 18psi. The car runs strong and performs well. However to get it to run that way I had to grind the boost retard stop down in the distributor and set the base timing way advanced, around 28 degrees or so.

As you can imagine this makes the engine act very erratic at idle and low rpms. I would rather be able to set the base timing back to the factory 10-12 degrees and have some sort of ignition system that could advance or retard timing with boost in a linear manor with some level of adjustment. I know about the msd 6btm. That seems like a very dated setup and I don't love the idea of my advance being done by the distributor and the retard being done separately at the ignition module. I figured by the year 2020 there has to be some sort of stand alone ignition set-up that can be fine tuned for boosted cars. Any ideas? Thanks
 
Microsquirt seems like one of the easiest options for what you’re trying to do.
 
it'd be more than 3 wires, but it wouldn't be much. you'd need the map sensor, a 3 wire distributor (or lock out the vr input in the b21 distro, either or), and an ignition module with it's associated wiring. While you're at it, I'd probably hook up other things to at least datalog what you've got, but those would be the minimums. You could do it with an old ms1 as well, which has an onboard 2.5 bar map sensor (good to about 22psi or so), I may even have one of those things laying around. if you go the ms1 route you'll want the 3 wire distributor for ease of installation.
 
Thanks for the suggestions so far. That 123 ignition setup is tits. Had no idea that existed. I just happen to have an old MS1 lying around too. I'll see what I can make happen.
 
Because its for this car. Its mostly original. Trying to stick with that theme here. Believe me 10 years ago I would have ripped it all out. Already did that to my 242.
 

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I dont remember the exact part number but they are brass and come from an inline 6 Mercedes. Seems to not lean out as bad under boost. I cant verify actual flow numbers.
 
0437502047, adapted some to run on a 144gl -74. Much finer atomization than the old steel ones. The brass injectors does not flow more btw, fuel quantity is controlled from the fuel distributor outlets ;)
 
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