ls1 tuning?

[05lly2500hd]

Hey guys, Ive got a duramax tuned with efilive, but a buddy of mine has a 98 ls1, and wants a tune, he's goin up against a saleen soon. I don't have the foggiest idea where to start with his car. I was wondering if anyone can give me some pointers or tell me what tables to adjust. Any and all help is appreciated. Rignt now he has no major mods done, he's puttin slicks on, and thinking of 110 or nitrous.
Thanks.

[Bruce Melton]

I really think you would be better off not starting out with a rush learning curve with a Nitrous car. Might be regrettable move.

[SSpdDmon]

The power you usually get out of bolt-on cars usually comes from tweaking the AFR. So if you have a WBO2, then I'd say you could help him out pretty easily. If he's going to spray it, I'd take a couple degrees of timing out for the WOT cells on the spark tables. What mods does he have done?

[05lly2500hd]

nitrous is just a possibility, something he will consider. I think if I can get him a decent tune he won't spend the money on it. He has approxametly 3k miles on this motor, nothing aftermarket that I know of unless it's like an intake or exhaust or something. 98 Firebird. I have no idea what a WB02 is. Is is some kind of oxygen sensor for testing?? I figured AFR tables were the ticket, they just didn't seem familiar or helpful when I viewed them. And taking degrees out of timing.....same as "retarding" it?

I couldn't really tell which tables involved the AFR mixture, there's got to be more than one or two to adjust correctly to get the desired results, correct? I mean if I change one, I'll prolly have to change another 1 or 2 to make it work correctly??
Thanks guys I really appreciate it.
Jeromy

[SSpdDmon]

You say on "this" motor. What was that motor out of? Another '98 f-body, a different year car, or out of a crate? You really need a little more info before you dig in as the different head/cams from the different years can make a difference.

Assuming it's all '98 parts (motor, pcm, etc.) and given your rookie tuning status, I'd say leave spark alone if he's not using the bottle. For a quick tune, I'd log him driving around as well as during WOT. What you need to look for are positive long term fuel trims (LTFT's). This means the PCM is adding fuel while cruising around because the stock settings aren't rich enough. Positive LTFT's can be added to WOT runs. If you see any, you could add the highest percentage seen to the MAF (mass airflow sensor) table across the board. Since the motor is pretty much stock, you shouldn't have to add too much at all (3% tops???). Once that is done, I'd then set the entire PE vs. RPM table to an AFR of something like 12.5:1 across the board. That way, you'll have a safe N/A tune with a ~5% margin of error before you hit 13:1. Just make sure you pay attention to the units. If the table is asking for EQ, you'll need to type 1.17 since EQ=STOICH/AFR (1.17=14.63/12.5). Go out and log again...this time keeping an eye out for knock retard (KR). Assuming no KR is registering at WOT, I'd say keep it as is.

It's a quick, easy way to tackle some basics until you can get your hands on a WBO2 (wideband oxygen sensor) and read the tutorials/stickies at the different forums (that's how we all learned - read, read, read).

[05lly2500hd]

wow what a wealth of info, thanks. I'll make sure what it's out of. All I know is it was in this firebird when he bought it used. Thanks so much.

[joecar]

In the tune tool properties, make sure that the air:fuel units are either AFR or EQ and not Lambda.