Has anyone tackled this one before? I was thinking about the issues involved with using an LT1 pcm on the TPI. Pretty much everything I came up with is solvable, except for the danged opti-spark ignition. The pcm needs to know which cylinder is firing in order to coordinate the injector pulse but there's no way to do that with a standard distributor. Any ideas out there?

Steve

 

There's at least a couple of people who have transplanted the OptiSpark "guts" (i.e. the optical sensor disk and pickup) into the base of a conventional distributor housing, and then managed to mount the cap and rotor above that.

I haven't personally seen the end product, but those who have done it said it wasn't too hard, if you have access to a lathe and some basic machining skills.

It's been done with both the large-cap and small-cap HEI bases.

I was sort of leaning in that direction a couple of years ago, but decided that for me, SEFI and individual cylinder fuel trim wasn't worth being forced to run MAF, or having to stop the car to reflash vs. being able to tune in real time.

But yes, you can run an '8051 on a regular SBC, if you're inclined to do so.

 

I understand the 8051 ran with both a MAP and MAF and that it can run with the MAP alone just fine. I dont want to run a MAF either. Stopping the car to reflash the 8051 is no problem to me, in fact certainly much easier then reprogramming the eprom and then plugging it into the ecm. I'm running a 4l60e tranny with a separate pcm just for it now, so getting both the injection and the transmission controlled by one box would be a much cleaner setup.

Have any of these guys put that distributor info on the web?

 

Yes, the '8051 will run in SD. I wouldn't say it "runs fine" though. The bummer is that AE seems to be disabled when it's in SD. Hopefully someone will develop a patch to remedy this, but I don't think that's been done yet.

If you already have a 4L60E, the conversion makes a lot of sense, IMHO.

AFAIK, there is nothing posted on the web regarding the distributor mod.

On the P4 ECMs, with a Romulator, or AutoProm, there's no stopping to change chips. Can't beat tuning on the fly! I assume you could socket an '8051, then use an emulator to get the same effect, although I haven't really looked into that.

HTH,

 

In back to back testing, with big injectors, batch ususally is as good as if not better then SEFI. Firing the injectors 2x as often get more fuel atomized then in SEFI mode.

Having run the 8051 in MAP only mode, seemed like the AE worked just fine to me. When doing the 8051 stuff I always carried a spare. Just like when doing chips, carry a known good backup.

 

Hmmm.....verry interesting. I just assumed that SEFI would be more efficient, not so much because of individual injector firing, but because of the second 02 sensor tweaking the other side of the engine. But when I look at my plugs now, both banks burn great. So maybe there's no real gain to be had here. I'm always looking for that extra 1mpg.

 

In the world of manufacturing a million or so cars a year and dealing with the EPA, and CAFE numbers then every .00001 MPG counts.

If your running the stock closed loop strategy, it's so sloppy at cruise, there are other remedies. Trouble with max MPG is it's not the healthiest thing for the engine long term.

 

Interesting! Guess I need to revisit that issue -- when I'd tried it, I had some stumbling & popping on accel, although the car was fine at idle & light cruise. I didn't spend much time messing with it.

A friend of mine who spent a lot of time in SD getting the VE tables right on his Impala, thought the same thing. I wonder if there's a difference between different GM cals?

One of these days, I'll get an '8051 working on the bench, and try it again. Have a few too many other irons in the fire at the moment, though!

 

Alot.
I started with a 4th Gen F Bod cal, for an Impala..

 

Would love to know how to do that. Wonder who's hiding that information nuget. I can't find much info bout it. Just hear that "somebody" has done it.