Hello all,
I have built a turbocharged 385 SBC. Realistically, I am shooting for 450 HP, hopefully 450 or so on the torque. It will be going into my 1985 Trans AM. It was a factory 305 5 speed car. The last motor we ran in the car was a BBC on alchahol with a P/G. We raced the car in Super Pro class.
Well, the car is going back to street duty. Needless to say, no computer, wiring, etc. exists anymore. I wasn't even sure if this is the right forum to ask this, but here goes.

Since "basically" all a ECM does is:

Fire the injectors
Control the pulsewidth
Control the ignition

The ignition can be taken care of (MSD box). Firing of the injectors can be taken care of (crank trigger). The only thing I cannot do is control the pulsewidth.
Now, would it be possible to run a 36 lb injector, and use a boost/vacuum referenced FPR to increase or decrease the fuel enough to make it driveable? Basically what I am trying to do is use Electronic Injectors but control them mechanically. What are these things I keep finding on EBAY?

http://cgi.ebay.com/ebaymotors/SAFCI...28011720QQrdZ1

I am aware of the $1000 and up Holley, Eddy, and other complete fuel controllers. I also am aware of Megasquirt and tuning the factory PCMs. It's not that I'm scared of the technology, it's just that I would like to keep it simple.

I work at a GM/Chrysler dealership, so I check out all the parameters on the TEC2 and DRB3 everytime I get a car with a driveability problem. If there was just some way I could mechanically control the pulsewidth.......

Any ideas?
Thanks,
Mike

 

never happen. You can't mechanically control injectors other than to fire them. The pulsewidth has to change for every rpm/engine load, etc... - There's really no way to do this w/o a computer. Simply firing the injectors would fire them the same amount all the time, thus only allowing them to fire more often for more rpm. You'd have to change the amount you fire them for a given rpm. Plus just the difference in a full tank and empty tank, ambient air temp, etc. w/o a computer, to adjust accordingly. You'd either be ridiculouly fat at idle(probably to much to run) or ridiculously lean at WOT(we all know what that does...) - If you don't want to go computered, you'd be better off running a regular mechanical injection, just set-up a couple of electronically trigger lean-outs for cruising/low rpm useage. - Otherwise, bite the bullet and look into the Megasquirt set-up. You could just set it up to control fuel and stick w/ a regular old mechanical distributor. - MS is cheap and it works well and it's easy to operate/install.

 

Get a MegaSquirt. It will take care of fuel injectors and ignition. On the fly tuning and tons of extras. Reasonably priced. See MSEFI.com

 

Actually, I have already ordered a MegaSquirt kit and have had it sitting on the shelf for about 5 months now. I have not put it togather yet though. I was looking on EBay and ran across all of these "Fuel Managemant Units", but I don't know anything about them. Are they a piggyback unit, or can they run the engine on there own?
I was really hyped about the MS, ordered one, but lost interest after I read about the Holley Commander. I have a laptop to tune with also. I have always been around Mechanical nozzles and alky injection and such, just thought there may be a way to convert EFI injectors to mechanical control.
You guys don't think it would be possible to use a boost/vacuum referenced FPR to raise and lower the pressure enough to compensate?
Maybe I'll start putting the MS togather tonight then.
Thanks

 

which MS did you get? the MS II 3.0 is better than the 950, especially for boost applications, and its cheaper...

 

You know, I don't even remember. I have my receipt here in front of me. I got it as a kit, along with the stimulator and the 6 ft. cable.

MS122-k is the Megasquirt kit
MSStim-k is the Stimulator

I bought it from

diyautotune.com


It is probably MS2. I wanted to be able to control boost, not a big need for timing. Now that I am going back into the site again, maybe I should upgrade to the one that will control timing also.

So, this is it huh?

 

MSI22 is the MS Version one with version 2.2 pcb. This is the most common. It is able to run spark also. You will need to run MSnS-extra code on this for spark all of the additional features:

http://megasquirt.sourceforge.net/extra/

You could also upgrade your current stuff to MSII by getting the processor and daughter board.
I would recommend getting the relay board also. It makes the install a lot easier, neater and safer.

 

If you're going to run boost, then I would reccommend the ecm controled timing. Then you can boost reference and have the computer pull timing for higher boost levels. - I'd agreee on the upgrade. Just MS and then you wont have to look back...