8.1L with Allison Tuning question

[383_Stroker]

Anyone know why the 8.1 trucks with the allison trans have this giant dead spot in the timing around idle/low rpm cruise?

I'm prepping a tune for a truck and i desperately want to smooth that sucker out there.





I want to smooth it out, but if i'm just going to get it to knocking down there and someone already has experience with this and can save me the trouble.. that'd be great..lol

[mrfister77]

That's very odd, it's almost like you could do for a cam.

[mm_n_p]

I had an 05 8.1/Allison and it had more timing down low and didn't have that weird dip in it like yours. I'm on my phone now but will post the stock file in the AM when I get back to the shop.

[mm_n_p]

Here is the tune that was in my 05... and it does look alot different down low than yours.

[383_Stroker]

Thanks man!.. I pulled one for an 05 from the repository and it had the dip... so.. i don't what the difference is here... hrm..

Anyway.. THANKS!

[97rs4life]

did you bump up that dip? I have the same dip in timing on an 01 2500HD 8.1 with the allison

[Rinkrat456]

Could it be a lazy form of pseudo-TQM? The easiest way to dog down an engine is to pull timing.

[LEDbetter]

I'm wondering if anyone has figured this out yet. I'm seeing it on an 01 2500HD as well.

[turboDave]

Almost Identical on the 8.1 Kodiak RV I'm tuning as well.