dizwiz24

what all do I gain w an aftermarket ecm vs. A 93's stock computer.

I imagine id be able to refernce the extra fueling/spark to actual boost, not just to rpm. For a smoother transition.

Better control over afrs based off of realtime wideband afrs.

Is there other benefits too in addition to that?

Whats the best one to use? Fast? Accel dfi?

Any help is appreciated.

MikeGyver

I would definitely recommend converting to a '95 pcm and do a 2 bar tune, and using tunercats and datamaster.

87DJP2001

Short answer....NOTHING, just throw the money on the street for the same results.

97FormulaWS-6

Or just look into the 24x conversion where you can use a LSx PCM which has a lot more tuneability.

dookie454

I had the stock ECU 2Bar all worked out, the last problem I ran into, if you call it a problem, was the IAT sensor. It did not consistently adjust fuel up and down the 90-120F range, and nobody could find tables to control it.

I noticed my WOT runs on my manual trans were leaning out just a bit every time I shifted. I found the tables that you can set to 0 out the leaning, but I worried winter weather would cause my tune to get all messed up.

I abandon the stock ecu for fuel and went Megasquirt due to the price and features. They have full sequential support using the stock Opti, the code is beta right now but should be released full stream soon.

The thing with the fast and Accel, others, they only use the low res opti signal for spark, The Megasquirt uses the high and low res signals like the stock ECU. Since Im using the MSD opti Im running batch fire mode with the Megasquirt and letting the stock PCM control spark since it has the spark knock system still working.

The Megasquirt software is pretty great, I havent found anything it doesnt do that the more expensive systems do. I tuned my car in about 2hrs to a better point than I had the stock ECU after 2 yrs! haha. It's due to the real time tuning, no more logging, guessing, adjusting, changing, loading/waiting, starting, relogging.. etc. I adjust all values in realtime or let the autotune take over for me.

For the price, it's more than worth it but you do have a bit more work to do (learning, etc).

MikeGyver

Interesting, is there more info on the new megasquirt system anywhere?

4SFEDZ

yea where you get yours and how much?

dookie454

I got mine from here: http://www.diyautotune.com/catalog/m...led-p-435.html

Wiring the Opti is here: http://www.msextra.com/doc/ms3/optispark.html

That one is assembled, but you can save about $200 and assemble it your self. You could also save more money and assemble your own cables.. just wire what you need and save $ and clutter, but the DIYAUTOTUNE cables are nice.

I also purchased a JimStim to I can simulate tons of sensors on the car from my desk to help learn and setup. Very useful.

I still have the stock PCM controlling spark for the knock sensor signal, stock PCM also controls everything it did before, just not the injectors. Eventually I will pass all of the other functions (dash gauges, fans, fuel pump, etc) to the MS3... but this does not affect engine control so it's low priority.

The LT1 Full Sequential is in beta, but it's been shown to work very good with a stock OPTI on my test setup... but I have a MSD Pro Billet in the car and it's just different enough that the MS3X code does not recognize the signal. It does work in batch fire mode though and runs better than the stock PCM did (had some bucking at about 45mph that the MS3 removed.

I have since learned all of the very expensive ECU's only use the single low res wire signal, and they may be able to do sequential fuel with the low res signal but the stock PCM uses the high res signal to fine tune the ignition events. MS3X also uses the High Res signal so unless I hear different, I would say the MS3+MS3X would have more accurate timing when setup to control ignition in full sequential mode.

To get mine running, I did this:
Wired the IAT sensor (stole it's wire from the stock PCM)
Piggybacked the Opti Signal going into the stock PCM to keep the spark for knock detection signal of the stock PCM
Replaced the dash gauge coolant sensor with a two wire and used this for the MS3 from http://www.diyautotune.com
Wired the Injectors to the MS3X (stole them from the stock PCM)
Plumbed a vacuum line to the MS3
Opened an example sbc 350ci tune, updated the Injector size and engine size, and it started right up.

Since then, I've added a second fuel pump to turn on at over 4000rpm and WOT using one of the MS3 outputs, connected Wideband O2 Input. fine tuning Accel Enrich, MAT fueling, etc in attempts to combat a pre-existing detonation problem that started when I upped the boost from 10 to ~13psi but this doesn't have anything to do with MS3 since I had the problem with the stock ECU and figured now was the time to swap since I installed a second fuel pump and soon will be adding Meth and needed something to control both of these.

TGGodfrey

The problem with Megasquirt (i have been running and building them for about 10 years now) is that the code is constantly getting updated (except MS1). Just when they release a stable version, a few months later another change comes out. It seems like no matter what code version you have, its never the last. You would expect the new code verson to not make a huge difference since most updates are tiny but you end up retuning anyway.

Not trying to steer you away from it because I do enjoy it either way but if you want to install, tune and be done.........you dont want a megasquirt. I retune 2X a year and datalog sporatically and retune throughout the season. If you enjoy that, then you will like it.

If you have never dealt with a standalone and want to learn....Megasquirt is great becuase it is setup very simple and cheap but you get what you pay for. it does have every option you can imagine but you will need to build and add the circuitry and configure it. You dont just take the the nitrous wiring out of the harness and hook them up like some larger commercial units.

Terry