Newb-ish tune question

cfitz · September 12, 2015

I have efi live installed on my 04 2500HD 6.0. My tuner and I have gone through it over and over again (he's a brilliant diesel guy) I feel like there's something stupid we're missing. I'm trying to figure out the off idle bog, and it absolutely refuses to do a brake stand. ALL trq management has been shut off and zero'd, timing tables are borderline aggressive (hi/low octane basically are the same) and made the trans shift a little firmer. It's fantastic 1700-6000, but when I floor it from a dead stop the timing goes from 30 advanced to 10 deg advanced, with no knock being seen by the ecu. I know I should just pay for a tune from Blackbear or someone who's done this enough to perfect it, but its really close to where I'm happy with it, and I've already spent the money for the initial tune. Any help would be appreciated, I can supply my file if someone would be interested in looking at it. Seeing my buddy with a hypertech blister the tires off while mine falls flat on its face is quite embarrassing... Thanks for any help!

Jennabear · September 14, 2015

First off, diesel and gas tuning are two completely different animals. So much so, we have partnered up with quite a few diesel shops, to provide gas tuning for them; gas tuning is more difficult with more "areas" to go wrong.

Are you tuning on the dyno, or on the street?

cfitz · September 15, 2015

Yeah I understand that diesels and gas tuning are completely different. The tuning is being done on the street in real life situations, making small adjustments along the way. The truck goes fantastic, its just the lack of a launch is really the only thing I was asking for help with. But if I can't get any info I'll just continue to try stuff, as after the latest flash its really close to where its a blast to drive, I cannot justify spending another $300 on a custom tune with it this close to being right.

Jennabear · September 17, 2015

Gotcha. Your biggest issue is that you have an 4L80e, which gives you a tall first gear ratio.

cfitz · September 18, 2015

That would explain some of it, but you can feel it hold back until around 1800 rpms or so, and it literally feels like you hit the nitrous button or something above that. I'm going to do some more data logging and see what everything is doing, its not pulling as much timing out as before, but the hesitation is noticeable. Thank you Jennabear for the feedback