Diablosport Forums

I have a silverado with the 6.2L and 6 speed.
I have read through all the different posts but there is a lot of contradicting information.

I already have the diablo tune installed. My street MPG went up, and my highway MPG dropped about 2mpg.
Street mpg is about 11.5-12 and highway is 13-14. i used to get 16+

Am I supposed to log in 5th or 6th gear for cruise?
I know im supposed to be between 1800-2000rpm.
in 6th gear, at about 1850 rpm im at about 71mph.

How do I get a good data log for cruise and for WOT.

Here in socal, there are barely any freeways that are nice/straight/flat. And traffic makes it impossible to get anything over 5 minutes for a log. You are bound to run into a group of slow cars.

Any help with this logging stuff would be great.
If i cant get better hightway mileage, im thinking of taking the tune out and just keeping the tranny tuned.

Lew says that 5-10 minutes is all he needs on a cruise log to do custom LFTF tuning for cruise. If you can get in 6th and maintain 1,850 rpm you're doing that part right. If you're tuning off of DSLogredux then you need to dial in cruise first and once that says there are no adjustments needed you can go into WOT logging. That is as simple as getting the truck up to operating temp and then flooring it from a dead stop through as many gears as safely and legal possible, on ramps work well (what you do beyond the law is up to you). Do not do back to back WOT logs as it gets everything hot and skews the logs from then on. Then use the DSLogredux software to adjust your timing and repeat.

Okay so a lot of my assumptions were good.
For WOT tuning. Is it okay if I end logging once I start slowing or am I supposed to end it as I'm still accelerating.
I don't want it to pickup any data that is going to flaw the log.
I still think my main problem is getting an open stretch of highway to maintain constant speed.
Yes I am using dslogredux.
My first log I did in 5th and got ltft's of 4 and 2.
It said to adjust down -4.
Guess I gotta redo it in 6th.
Now if I'm adjusting fuel slope down -4%. Is that adding more fuel or taking fuel out. I imagine adding more fuel would give me worse mileage right?

bump...
too much spam on site.

For the WOT, just run it from a dead stop through a 2nd and/or 3rd and when it's safe you can stop it any time after you let off. Lew prefers the top gear for cruise tuning unless it isn't feasable then he will tune it in 5th. I did most of my tuning running down about 4 minutes of a 65 mph road and would turn around get up to speed the other way and then stop at the end giving me about 7-8 minutes and Lew had no problems with that. Anything over 10 minutes is just to much data for him to process but I'm sure DSLogredux would be fine since its pulling numbers from the log.