I would appreciate those with more experience than me reading and replying to this.

I am determined to learn how to tune an EFI car. I bought a 96 automatic car this evening. Part of the reason I bought this car was because I think it will be a perfect candidate to learn how to tune.

Here are the specs on what I know about the engine.

1996 LT1
Eagle 383 stroker kit (crank, rods, pistons)
Comp XR264HR-12 cam
Proper springs for cam installed on stock heads w/3 angle valve job

I am pretty sure everything else is stock. Engine was assembled at a machine shop that has done this many times. Installed by another shop. Car is running stock tune.

I drove it home for 2.5 hours, no check engine lights during the enntire trip. (did get a nagging service LTPWS light though pretty much the whole trip)

Car flat out hauls ***. More than I even imagined it would.

Has a very mild surge at idle (+/- 200 RPM or so). Runs flawlessly at all other conditions.

I am taking it to a dyno tuner maybe as soon as this week and will pay close attention to what he does. Plus he is always happy to explain things to me.

So here are my questions:

1.) What are people most commonly using to tap, log, and dyno tune an LT1? HP Tuners? LT1 Edit (is there such a beast?) I have a laptop for tuning.

2.) Is there anywhere on the net that can explain what is in place from the factory for the car to operate the factory fuel injection? What I mean is, I see people throwing around Speed Density mode and such but is there anywhere that explains in detail how an LT1 operates? For example, something that says:

"When not in closed loop, speed density mode takes over. The MAP sensor works in conjunction with the MAF sensor to determine the amount of air entering the car and then uses this information to tell the injectors how long of a pulse width is needed to provide the proper amount of fuel for the engine"

Granted, that was completely ad-libbing but that is the type of information I am looking for. The more detailed the better.

I am pretty familiar with the components of GM's EFI systems but I am looking for some good education on how it works and how it can be manipulated, with as many details as possible.

I am determined to learn how to control the system at will and I am looking for some support in doing so.

Thanks and all the help is well appreciated.

 

I'm not as familiar re: tuning with the LT1 set up and speed density; I've got an '87 MAF set up. I use the AutoProm from Craig Moates (along with TunerPro RT) and love it (though it may be for OBD1 only). I also use an LM1 A/F meter, which is EXTREMELY helpful.

I found this book to be an excellent resource:
http://www.amazon.com/Corvette-Injec...e=UTF8&s=books

 

bbL98, I just ordered the above and one other book, hopefully by end of this week maybe I can too get smart.....I know, I dangle my participles.....wife thinks it's cute though.....



but as in the other thread from a guy with similar problems....where do I get the enulator?? and how much$??

thanks for any/all help guys, I have to do all the pass compartment side of the wiring to get this together again with stock 1227730 computer, so it's going to be a couple daze of wiring, at least I have most of the engine compartment straightened out again....disaster....

 

I still reference that book every now and then - it is very comprehensive.

IMHO, you can't beat Craig Moates' stuff (http://moates.net/) and the customer service is outstanding. Based on your budget / what you want to do, you can spend just over $100 to around $400.

 

bye bye L98 anything you don't like about that book?

 

Hmmm...not a lot or replies on this one. Looks like the fact that the 96 went to ODBii limits your choices. Looks like either tunercats (now sold to Jet) and LT1 Edit are the only choices. Anyone using either of these?

 

You can swap to the 94-95 PCM and get the 94-95 software cheaper than buying the 96-97 software. Can't do that if you're in a state that tests your emissions by plugging into the OBD2 though.

Start here:
http://forums.corvetteforum.com/showthread.php?t=202488

The FAQ itself isn't all that great, but some good sites are linked from it.

If you google "LT1 tuning" or "gm efi tuning" or variants on those, you will find quite a few sites describing how the system works and how to modify it.

 

I have that book. It gives you a good overview of how the system works, and can help answer some esoteric questions that pop up here and on C4 tech, but it has very little relevance to the actual tuning process.

If you don't know anything about GM EFI and want to understand it better, get the book, but if you just want to tune the car, it would be a waste of money.

 

Fully agreed! (sorry for the delayed response).

I don't know of any tuning specific book out there that gives you detailed tuning instructions. I spent a LOT of time over at http://www.thirdgen.org/techboard/diy-prom/ reading the stickies and just about every relevant MAF thread I could. I know you've got a '96, but the principals of fueling, timing, and engine management still apply. I learned a lot of what I know now by trial and error.