mikecronis

I'm at 7k feet altitude and my best octane is 91 here in Colorado.

If I choose the 91 Tune Diablo offers my idle is pretty satisfactory. If I choose the 93 Tune the idle is rather rough and the smell of fuel is a bit present, though it drives like a "Meatloaf album cover".

Does anyone at sea-level with the 93 Diablo Tune have a bit of a rough idle and/or fuel vapors? Also, do some of the 93 Tuners use 91 and to what result?

Mike@DiabloSport

The ONLY difference from the 91 to the 93 tune is commanded timing at WOT...

Is this an 05 LS2 car maybe?

mikecronis

There's definitely a difference at idle between the 91 and 93. The 93 lopes a bit and is an unsteady idle. There's some flat-spots under 3k rpms by-the-seat-of-my-pants. Bogs a bit until 4k.

I'm at 6800 feet elevation and can only get 91 octane. The folks at Diablo said the 93 tune would "be fine and others have used it with no problem in Colorado" but I've sat at idle quite a bit on both and it's a definite difference. The 93 tune makes the tachometer's idle bounce +/- about 200 rpm, the 91 does not. The stock setting is also stable in rpms on the tach.

I'm not sure if this was an altitude thing or an A/F ratio thing and just normal for everyone. I have a 2012 GS/manual LS3.

Mike@DiabloSport

I have honestly never heard of an idle issue on the LS3 cars, and I'm not really guessing, but telling you for a fact, that the 2 tunes are identical, except for commanded timing at WOT

Load the 93 tune then email me the tunes from the tunes folder on the intune drive and we'll check it out. mlitsch@diablosport.com


Thanks

corvetteflier

So, idle issue aside, what improvement would there be performance-wise at WOT with the 93 octane tune? I'm also at 7000' and have the 91 installed. I seem to recall your saying it was 2 degrees advance in timing. Would there be any real, noticeable improvement going to the 93?

tennblkc6

guess it depends on if you can feel the 2° of timing advance @ wot.

corvetteflier

Exactly. Is it enough to make a difference.

Mike@DiabloSport

I dont have any real world testing at altitude to say for sure, but based on traditional theory behind elevation tuning, the car should make slightly better power with the 93 tune, yes.

corvetteflier

Think I'll give it a try. At this altitude, you don't need as high an octane rating for the same knock prevention, that's why regular is only 85 here and premium 91. Will see if there is any idle funkiness. Easy enough to return it to 91.

ZYUL8r

Im in corpus christi tx, and the 93 tune is smooth on my LS3.

Twowheelin_wildman

In Illinois here and the 93 octane tune made a big difference, everything has a lot more response and a crisp feeling... though when I first started the car after the tune it lopped like a bitch then after a couple seconds smooth right out and has been all good since..

rednred

I'm in Denver area with 2008/auto/intake/full z06 exhaust. Tried 93 tune and idle was ok (and wot seemed ok) but at highway cruise it surged so bad I stopped and put 91 tune in. I've left the 91 in and idle is fine, cruise is fine and wot is fine.

Mike's LS3

Sounds like you are on the lean side. Have you data logged LTFT's? With the Z06 full exhaust, I would recommend a custom Diablew tune, your mods will benefit nicely.

rednred

Thanks for responding. I didn't log with the 93. Have just logged stock tune ... and (now that I think about it) before mods. Sounds like it might be worth logging with current mods and 93 tune just to see what's happening. I also don't remember what transmission setting was when it was surging.

06MonteSS

Yes, I can definitely get you hooked up with a custom tune and get things dialed in correctly....