Question From a Novice

Hello

    I have a question and was seeking some input. I have a 2003 Avalanche Z-71 5.3L. The vehicle was purchased used and the previous owner had switched the stock Rims from 17" to 20" American Racing Rims. The tire size is 275/60/20 All-Terrain.
  My question is how much has the tire and rim package affected the engine ( IE shift points, RPM, Gas Milage.) I have nothing to compare the current performance with since I have never driven it stock.  I wondering how much benefit a Handheld Programmer  would make?
Thanks
Mcklain

There are tons of links dealing with this on the search button... The larger tires have moved to a 32.99" diameter from the stock 31.6" diameter (265/70/17).

That has added a 4.2% difference in your outer tire diameter and reduced your 60 mph speed on the speedometer to 57.4 mph which is 4.409% too slow.....

Your rev per mile parameter needs to be changed from a 658.2 to a 630.4, if it has not already been recalibrated by the previous owner....

Hope this helps...

I got the Predator which is fine for a mostly stock motor. If you get into forced induction and stuff you will need something better. The Predator will let you change tire size and such. I noticed some decent picked up after using there program for 91 octane gas. I know there is more stuff that can be changed, but I am not experienced enough to try changing other points.

Use the search feature..you will find many topics on this.

FlaBouy said:

There are tons of links dealing with this on the search button... The larger tires have moved to a 32.99" diameter from the stock 31.6" diameter (265/70/17).

That has added a 4.2% difference in your outer tire diameter and reduced your 60 mph speed on the speedometer to 57.4 mph which is 4.409% too slow.....

Your rev per mile parameter needs to be changed from a 658.2 to a 630.4, if it has not already been recalibrated by the previous owner....

Hope this helps...

Click to expand...

Now that is a lot of good information.  A bargain at twice the price.  I expected a good answer from FlaBouy but this impressed the h-e-double-hockey-sticks out of me.

(hush, I am not kissing up)

I pay him to follow me around and clean up the mess I leave.....

Hey Guys



? ?Thanks for the information !!
                                                          Mcklain