Silverado 5.3l questions.

[tonym]

Ended up buying an 05 Silverado Z71 Crew Cab on the GMS sale. Found out after the fact it is the 295hp version........ (Those window stickers used to state HP numbers....)

Anyway, I haven't scanned it yet, but wondered how close the factory tunes on the trucks are?

Definately need to look into the shifting, it's pretty sloppy and seems to shift frequently when at speed just to shift up again due to the 3.73's I think.

Anyway, any tips or experiences would be appreciated.

Thanks,

Tony

[GMPX]

If there is one thing that makes doing your own tuning great, it's the ability to make the trans shift just how YOU like it, some people like it to kick down earlier, some like the TCC to kick in later etc, etc.
Personally, I altered my 'power' mode trans settings so it hangs onto 1st gear even with only 15% throttle. That way you can take off from the lights and the engine will hold at say 2500 - 3000 RPM at moderate throttle, then if you want to floor it there is no need for it to kick down, it's really cool.
I think drive your new truck for a while and find what parts of the trans shifts you don't like then have a mess around with it.
As for the engine tune, I am not sure about the 05 trucks, but generally GM don't tune them to be right on the edge, they always have alot of 'safety' margin.

Cheers,
Ross

[tonym]

Thanks for the info.

Yeah, my 04 C5 was running SUPER Rich before I got it fixed up. stock tuning it was running at 11.2:1 AFR on a Dynojet.

After I get the truck broken in I'm going to go through it, just wanted to see what to expect with the trucks.

Thanks again,

-Tony

[SinisterSS]

WOT is pretty rich, timing is pretty tame and the transmission settings are made to be as smooth as possible.

Basically do the normal tweaks to it like any other vehicle. :D

[dfe1]

On my 02 Silverado, I found that light throttle shift speeds were way too high. Why GM thinks the transmission should stay in first gear until vehicle speed is ridiculously high is beyond me. Fuel economy is improved and so is drivability by bringing shift speeds down a bit. As Ross says, drive your truck for a bit and see what you think needs to be changed. Also, play with DFCO. You can squeeze a bit more fuel economy by getting more aggressive with DFCO enable/disable speeds.