LT4 tune need help
Pro
Joined: Feb 2003
Posts: 745
Likes: 136
From: Detroit MI
Greg, I watched your LS tuning videos from back in the day, and they were the most helpful and informative videos on proper speed density tuning. I know that the LTx is a completely different beast, and decided to get it professionally tuned. However, none of the shops around here actually have a load bearing dyno. Well, one did, had the eddy current brake, but said he doesn't use it while tuning. (???)
I eventually ended up taking my C7 to a shop that has reputably done several C7s in the past, and had them do it, and the driveability tune seems fine, but I worry that by only doing WOT tuning on his dyno, I've got compromised closed loop tuning. It seems to drive fine, though, no surging or anything...
Thoughts?
I eventually ended up taking my C7 to a shop that has reputably done several C7s in the past, and had them do it, and the driveability tune seems fine, but I worry that by only doing WOT tuning on his dyno, I've got compromised closed loop tuning. It seems to drive fine, though, no surging or anything...
Thoughts?
Simply put, if they "tuned" your GenV engine without using a loaded dyno in steady state, it wasn't tuned properly. PERIOD. The only remaining question becomes: "How far off is it?" A lot of people either don't notice or don't understand the connection between this calibration approach and how it manifests in shift quality, tip-in behavior, etc. It's not something you can go back in and "smooth out the driveability" on later. It has to be right from the start with the fundamentals when you start working with the torque models.
Burning Brakes
Joined: Dec 2015
Posts: 1,096
Likes: 322
From: Denver Colorado
^Thanks, that's great news, I look forward to the GenV video, and the day that I can just rent loaded dyno time and really nail in my tune myself. (I may even try to convince the guys at the shop that having you out for private training is worth it, if you still do that.)
In regards to the no-dyno driveability tune, can it be effectively done with road tuning with a wideband? I know it's not ideal, and will take a lot longer to gather the various load/rpm af values, but can one decently tune using this data?
In regards to the no-dyno driveability tune, can it be effectively done with road tuning with a wideband? I know it's not ideal, and will take a lot longer to gather the various load/rpm af values, but can one decently tune using this data?
Pro
Joined: Feb 2003
Posts: 745
Likes: 136
From: Detroit MI
It's painful, frustrating, takes four times as long and yields less accurate results, but it's theoretically possible. I'm not a fan of wasting my time and resources to do something half-assed.
