dsadsdaiouser

Has anyone used one? We have a 2012 GMC Sierra 1500 5.3 and replaced the factory 17" wheels and tires with 20". Only used a factory Texas Edition size so we didn't go crazy. Immediately the gas mileage, acceleration and "seat of the pants" feel went south. I'm sure it's because of the additional weight and size of the wheel. I don't want to go with a dyno tune for a couple reasons:

1. I like the monitoring capabilities of the handheld.

2. I'd like to be able to return it back to a factory tune and remove it in case of warranty work.

3. We tow and according to Bully Dog there is a program specifically for that.

4. We get a racer's discount at Summit so the price will be less than a dyno tune.

5. I want to try the 87 and 93 octane tunes and see if there is a difference in power and mileage.

I know their stuff is first class for diesels and they make a TON of power but haven't heard much on their gas tuners. Anyone use one? These new wheels look good but the acceleration, lack of power and gas mileage is annoying now.

Scott

LSX Power Tuning

iTrader: (4)

I have seen more handhelds corrupt the ECM and TCM on 08+ than I have seen do any good. Im not a 100% on the model your asking about but a lot of the handhelds do NOT actually return the ECM and TCM back to stock even if they claim they do. I get atleast a call a week about re-tuning a 08 or newer truck that someone put a handheld on and now it doesnt run right even after returning back to "stock". Just do your homework if your going to use a handheld.

spawne32

iTrader: (2)

Stay away from handhelds, they are gimmicks. Alot of the handheld tuners with their octane based tunes, all they really do is take the stock high octane table and overlay it to the low octane table to make them match so that the car constantly runs the high octane timing numbers regardless or they add 1 or 2 degrees of additional timing overall. You won't find a handheld tuner that removes things like torque management or any of the redundant "safety" features that OEM's put into the tunes on ECU's that you can only remove with a program like hptuners. Alot of times the tuners that allow you to adjust for mods just add percentages of fueling to your VE tables to allow for these things, but they are by no means accurate at all because every car is different. They rely on closed loop correcting **** poor tuned one size fits all fuel tables and are typically either very rich or very lean on WOT. The tv shows might showcase alot of good products, and might have some helpful tips, but not all of it is true.

scout2000

I'm probably overlooking something obvious, but if I were in your shoes, I would first consider install some lower gears (numerically higher) to compensate for your 17"->20" tire size enlargement.

At least that would get you back to square one.

I wouldn't personally start looking for aftermarket power till I restored my stock performance.

How is it the axle ratio (to compensate for the larger tires) isn't the first thing on your list? 3" of new wheel/tire size, plus the added weight is definitely something you would want to account for.

dsadsdaiouser

The old wheel/tire combination was 245/70/17 and the new is 275/55/20 which is a factory size on all Texas Edition trucks. The difference in diameter is only 1.4". With so many GM trucks being equipped with that size I can't believe they all run so "poorly"; it has to have a different tune (shift points, etc.) than ours.

Thanks guys for the advice. I feared that would be the case. So would a new custom dyno tune help with power feel, mpg, shift points, acceleration, etc? I'm not trying to rotate the Earth here; just wanting to get rid of the lazy feeling that came with the tires. Any advice on a quality tuner in the East Texas area?

After some research we have a 3.42 gear which should be sufficient and not anything that needs changed. That might be something I do down the road with a CAI, exhaust, etc. but for now I think a tune might be in order.

Scott

LSX Power Tuning

iTrader: (4)

You dont need a dyno tune in your application, a good street tune would take care of it. In the 5.3 1500's you wouldnt believe the difference wheels and tires make on driveability and fuel mileage. I have a local custom with a 2012 silverado who tracks his fuel mileage every tank (hand calculated) and has had 3 different sets of factory wheels with non factory tires and the fuel mileage difference was 3mpg between them.

Mike@Diablosport

iTrader: (2)

If you are interested in a good, safe tune, that can be restored to stock anytime, we offer the intune or Trinity.
Trinity might be what you are after as it has the built in monitor, virtual drag strip, LED warning lights, etc, in addition to the tuning. It also works on lots of Ford and Chrysler applications in addition to 99-15 GM trucks and cars.

I cant speak to corrupted pcms or not restoring the stock tune, those are not issues I see to be common with our tools and we always read the pcm first and restore whatever we read on any GM application.

Let me know if you have any questions.

Thanks