2003 Silverado 2500HD 6.0 to 5.3 Swap - Kept 4L80

[ZMBKLN]

Hey guys...

Need a quick bit of advice.

I recently purchased a 2003 Silverado 2500HD... Which would have originally come equipped with a 6.0 and 4L80 Combo obviously.

However... The previous owner swapped the 6.0 short block for a 5.3 short block and left the 4L80... Erroneously thinking it would improve fuel mileage.

He left the stock 6.0 and 4L80 Tuning in the ECM...

I'm trying to figure out the most "correct" way to get the tune corrected for the 5.3...

Am I better off copying the Engine Parameters from a 5.3 1500 Truck to the original ECM... Or should I grab an ECM from a 1500 with 5.3 and segment swap for the 4L80?

Let me know what you guys would suggest.

Thanks!

-David

[5FDP]

Either can work.

I think it would be easier to just change over the different tables from the 5.3 and add them to the 6.0 computer. See how it runs and adjust anything else that you see fit.

[ZMBKLN]

Well... I copied all the engine parameters over from a 2003 5.3 Powered Silverado and Left all the Transmission stuff alone.

Seems to be running considerably better.

Now to work on the tune itself... Jesus the 4L80 sure is a power hog... Because this thing is a turd.

[5FDP]

It's going to feel that way without more mods to the engine.

The 6.0 has alot more torque at different rpm's than the 5.3 and that's where you feel the difference.

[ZMBKLN]

Yeah... But I've driven plenty of 5.3 / 4L60 trucks and this thing just feels like a total turd in comparison.

I'm hoping I can find another LQ4 at some point to swap back into it...

Thanks for the help!

[5FDP]

Also remember that the 2500hd is a heavy truck, with a 14 bolt rear and takes more power to turn it. Depending on cab config it could be over 1,000lbs heavier.

Without seeing the tune file you have, it's hard to comment on what other changes can be made to help it out.

[Montecarlodrag]

Even on a light truck, if you swap in a 4L80E it will feel a lot slower than it was with the same engine and the 4L60E.
That's completely normal because the 60E has a ratio of 3.06 1st vs 2.48 on the 80E along with a heavier rotating mass. It feels like a dog until 3500 rpm when the 5.3 starts picking up power.

I suggest you install 3.73 gears or even 4.10 if the tires are big. It will feel much better, the 5.3 just doesn't have the torque a 6.0 has. Keep the 4L80E, it is a great transmission and it will give you a long service life.

[ZMBKLN]

Oh I agree guys...

Don't get me wrong... I know where the power is going... Parasitic loss.

And I love the 80... I just wish it weren't such a power hog or had a lower first gear.

Thanks for the input guys...

I'll attach my tune file though so you guys can tell me what you think of the changes I've made already... Nothing but correcting for the 5.3, some emissions stuff, and Trans / TM Reductions...

But let me know if something stands out as completely wrong...

6L to 5.3L CorrectionDMRBase.hpt

[5FDP]

Looks alright at a quick glance.

You can always adjust some of the Power enrichment settings to help it get up and go a little better. Lower the throttle pedal enable from 90% to 60% as an example. Change the RPM delay from 5,000 rpm to 2,000 and take away the 2 second delay as well. Also because you changed much of the TM settings, I normally set the enable torque from 100% to 80%. Past that you could lean it out some in PE because they do run a richer calibration but a wideband is something handy there. These are just small changes that can help.

[ZMBKLN]

Yep... Next step is to get the Wideband in and start making fueling and spark changes...

Probably won't do much with spark since I enjoy being able to run crap gas in this turd...

Thanks for the input though!

-David