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Putting the G8 away for the winter so I picked up a 2003 Tahoe Z71 5.3 with the 3.73 rear.
She's at 140k miles, but according to the 2 inch thick bible of maintenance receipts I'm fairly sure it was well taken care of.
Anything worth looking at in the bin file for either passing performance or highway mileage?
I did some poking around and the trans tables a lot simpler than the new A6's. ;)
Attachment 47080
Lots of stuff can be done.
I'd recommend you spend 20 bucks on a corvette servo from Oregon performance, some of the best money you'll ever spend. Make the shifts quicker aswell as they are super slow. I like to go around .350 down to like .260 as the the torque gets higher. (look at the table and you'll understand)
They run really rich from the factory as always, you can raise it up some without a wideband and still know you are safe. Shoot for low 12's, they run low 11's down to about 10.9 I think in 1 spot.
The ETC MAX TPS under torque mngt stops some throttle feel and stuff, setting that to 100% for all cells is a good idea. It just allows for full throttle blade movement without TM kicking in.
PE delay is set to 5,000 rpms, set it alot lower and the ramp in rate for fuel is very slow. I up that to like 1.5.
If you change the engine TM "max torque" and maximum torque vs rpm to higher than 350 ft lbs, set the enable tq under PE to like 75% or 50% so it still does it job.
I don't have my trucks tune on this computer, but it's basically 98% stock with most of these things done along with a full VE and MAF tune with a wideband. It woke it up alot and is more fun to drive for now. I also only added a few degrees timing for when on the freeway and I've gotten 22-23 freeway with it, but I am 2wd.
Cool man thanks for the info. Few questions though:
Ramp in Rate, are you referring to the PE delay in seconds? Its right below the PE Delay - RPM, which is set to 5,000rpm on my stock bin file. I'm thinking 3,000rpm for PE Delay. As for delay is seconds, its currently at 2.0
Also, do these trucks even use Performance tables for the trans or only Normal? This is my current shift times:
Attachment 47089
If you could share a similar bin or take a look at mine I'd appreciate it.
Ramp in rate is the rate at which fuel comes on, it goes from 0-4.
I set the time delay in seconds to zero, then just keep it based off a MAP number and or a RPM. So say 75 kpa and 3,000 rpms in your case.
The "performance" is tow/haul mode, which you'll likely never use. I just set up the normal shifts to what I want it will always go to that.
Why increase the PE Enable for MAP? Wouldn't I decrease it? Currently its 55 kpa.Quote:
Originally Posted by 5FDP
Also, when you originally talking about the "ramp in" were you referring to Enrichment Ramp In? Its pretty low right now at 0.0195
I believe he is telling you to raise the kpa so it does not come in to earl as you will zero the time delay and yes the PE ramp in.
Yeah PE ramp in, sorry I wasnt super clear.
But pretty much what he ^^ said about the KPA, you wouldnt want to lower it because then if you were at just say 2500 rpms and at 40 kpa with enough throttle % you'd be in PE when you really don't need to and thats just kinda like wasting fuel.
So I like to set it slightly higher because you'd normally only be at that KPA when you are trying to get up the speed with your foot down.
Does that kinda make sense??
Yep got it, thanks!
Lower rpm, raise kpa.
I'm used to wasting fuel with the G8, just gotta change how I think about tuning with the Tahoe.
Your DFCO is different than mine but worth tooling with if you don't tow a lot with it. Mine you can set how many crank reference pulses until it begins cutting fuel instead of having to screw with blending %. I picked up a lot of MPG on a 4cyl using higher trans pressures and optimizing the DFCO.
These tips should work with a 04 suburban with a 5.3 right?
Yeah, pretty much exactly the same.