I just got my Edge EVO and installed it about an hour ago. Took a test ride and everything worked great on tune #2. Seems like it picked up about 15% on the bottom end. Anyway, I entered 87 for the octane and a tire size of 2550 per the formula in the manual. The tires are the stock Pirelli Scorpion tires that come with the 20" King Ranch rims. I was just wondering if anyone else has the 20" rims and the Scorpion tires and what value was used for them. I have not done the 3 rotation method yet in that I am at home by myself for a few days.

Another question I have is if anyone has done tune #2 with 91 octane? Does this significantly improve anything?

Thanks and sorry for the newbie questions.

 

I posted this in another thread, but you may want to use it to figure out what tire size your stock program is using.
Just program your truck to stock with the Edge and take drive. Run it up to 70 mph, play with the throttle a little untill you can tell what the RPM is for right when it hits 70 mph (use the mph on the Edge). My RPM was 1960 rpm.

My example:
Stock tire size in mm =

(mph/rpm X gear ratio X tranny ratio X mm/mile)/60

=(70/1960 X 3.73 X .7 X 1609344)/60

= 2501mm (stock setting for my truck)

Just substitute the 1960 for what ever your rpm is and the 3.73 to whatever your gear ratio is if it is different. The .7 will be the same, it is the gear ratio for 4th in the tranny. The 1609344 is just a conversion for how many mm in a mile. Everything in paranthesis is dived by 60, the 60 is just a conversion for how many minutes in an hour.

The values given in the Edge manual are just math applied to the tire size and the actual size varies by manufacturer (it will also change with wear). Mathmetically my tire size (circumference) is 2559mm, measured they are 2478mm and as you can see above the stock program used 2501mm.

Hope this helps.

 

Thanks FX4, I will try this method. I guess I was being a little lazy and checking to see if any other F150 KR owner had done this before. Always best to just do it yourself huh? Thanks again!

 

2550 per the formula in the manual?



I got:


2546.....

(I guess you rounded up)


If you do the roll test let me know what you get!

 

Haven't done the roll test yet. The Edge unit did the rounding for me, 2546 was not an option. However, my dash speedo and my Edge unit reflect the exact same mph reading so I must be close using the formula from the manual.