Reprograming Computer for 285s

[LLY DMAX]

Hey all!

 

After 3 years of being a DMax Fan I just ordered one. The New LLY motor was just too tempting to pass up. My build week will be March 1st.

 

I want to get a set of 16 by 8 inch wheels and install 285 75 16s.

I would like to get the computer reflashed to recognise the tire change. It would be nice to have acurate MPG numbers.

Is there any problem with getting that done on the Allison??

I have been told that the dealer can reflash for the 265s because the 3500s have that tire size stock.

Can they do the 285s though??

Or should I just get the the 265 program and call it close enough?

 

Are there any changes to the new LLY Computer that would cause problems??

 

Thanks for the help!

[Wingnut]

OK, I don't know much about the Ally, as I don't own (and never have owned) an HD.

 

I can tell you that the stealer cannot reprogram for 285s on the 1/2 tons, so I doubt they can on the HDs.

 

You will have to go with an aftermarket programmer, or chip in order to get the correct speedo reading....Upshot to spending a little is get more power too.

[Wingnut]

Welcome to the forums, by the way

[silverado3500]

Wingnut's right. The tallest tire size the dealer can program for is a 265 (that is unless you own a hummer) that goes for all trucks...1500s, 2500(HD)s, and 3500s.

 

IMO, Your best bet would be to wait until Wester's comes out with a tune for your truck.

[LLY DMAX]

Thanks for the help guys!

 

The only thing I worry about an aftermarket Programer is that I have heard of dealers Flagging your Truck as a Warranty Void if you have used one.

I wonder how likely it would really be, But it is too expensive of a chance to take.

 

I am planning on getting the Edge Attitude, wich doesn't flash the computer.

It has a readout that corrects for 285s, But I wanted the DIC to be correct in its calculations.

 

I will get the 265 reflash so it will be closer to correct.

 

Thank you again for the help.

[tmf6902]

When I used to have my superchips, i just put the stock program back on the computer when it went to the dealer....they asked me once if I reprogrammed for the larger tires....I told em I just did it in my head while I was driving. I had no warrenty problems.....that's if you ignore my lift

[bigdogs]

Will that dealer reflash also handle the TCM as well or just the speedo basically?

[LLY DMAX]

I don.t know about that. I didn't know there was a differance.

 

Wouldn't they be able to program everything for the 265s since the 3500s come with them?

[bigdogs]

I just called my dealer and he told me they are not allowed to reprogram the truck for 265 tires.

[conradv]

Yep - my dealer told me that GM WILL NOT program for bigger tires, not even the ABS system.

 

I told them that other people had theirs done, and they told me "not any more"

 

p.s. - I have 255's, which are about the same size as the 285's

[JimWilson]

The only thing I worry about an aftermarket Programer is that I have heard of dealers Flagging your Truck as a Warranty Void if you have used one.

There is no method of diagnostics that can lead them to a PCM upgrade -- it's entirely transparent to them and their equipment (except for their right foot, of course ).

[03GMC2500HD]

I have a HPPIII to recalibrate for the 285's on my HD. I remove the program any time the truck goes to the dealership and I even keep it in the glove box just incase I get stranded and it has to get towed in I can remove it. Even if they don't have a reason to reflash you it can happen and then you are left with a useless programmer! When I went to the 285's I noticed MAYBE 1 mph difference in the speedo. Where the difference was is the acceleration. Taller tires made it a little sluggish. The HPIII took care of that just fine too.

[Woody1]

unless something has changed, you can repro. your puter on engine, but on an Allison, you cant get to it with the same programmer. I have an Allison, and 285's. Hypertech repro puter but Allison stays the same. At 72-73 MPH, my GPS says I do 75-76 MPH.