Discussion in 'Chassis - Suspension - Wheels and Tires' started by NitroChemist, Sep 17, 2017.
Wow, that sucks. Sometimes I wish there were limits!!
Can the dealer program 245/70R16 into the ECM? Or do tire size 30"? Another trans flash wouldn't be to expensive. The ECM is learning the new tires. I notice it shifts differently. RPMs are down. It will take a few tanks to see mileage is affected. For now, I'm using a +2.4% difference between stock and new tire sizes.
I bet there won't be difference. While you may have slightly better mileage on HWY, any acceleration will be worse due to "heavier" gear.
There are only 3 tire size options that a dealer can program into the computers. P225/75R16, P235/65R17, and P245/50R20.
Of the 3, the 20" has the largest diameter at 29.65”.
I don't think they need to be programmed. Circumferences are almost identical for all 3 tires. (within 1-2% what is less than the resolution of the speedometer)
Programming should be advanced to install any tire size we wanted. EPA
The torque converter is very loose. It's bad. I've driven all kinds of vehicles and this one has it the worst. A tighter converter would help but some people wouldn't like it. I had a GMC Jimmy programmed to lock the converter above 45 MPH instead of 50+. It gained 1 MPG in the city. The Nitro has similar weight. The main differences are first gear and 3.42 (GMC) vs 3.73 gears (Nitro). If I ever replace the trans, I'll definitely look for a better converter.
Do you have 42RLE or NAG1?
42RLE. It was flashed shortly after I bought it. One udpate was added. It make a nice difference. Shifts were better and firmer. Once in a while it will bang the gears hard on WOT.
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