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Not ready to jump in the delete club, but would like to get a programmer to fix tire size/speedo issues. Shift point are off and it's driving me nuts on the back roads. If I pick up some small HP/torque/economy great, don't need it though in this truck. What are my options?
I am not a fan of the delete club myself. To each his own though. Get in touch with Mike at 5 Star Tuning. You can get just a transmission tune, or for the same price get a daily tow tune. You will not be disappointed. Just did it with mine and it was worth it for the transmission performance alone. The fact that I picked up 40 HP and 80 ft. lbs. at the rear wheels was just an added bonus for me. Have you tried daily driving in the tow / haul mode?
I have checked with many tuner people. No one that I have come across can program for tires larger than what come stock with the 20" wheel option, 34.4" or close. I have 37's and it makes my shift points off too. I hope someone knows something I don't.
With my tuner, I just changed the rear gear ratio in the system from 3.55 to 3.31 to get me close. The tallest tire option I could select was 34" on my tuner, which was what was already there.
With my tuner, I just changed the rear gear ratio in the system from 3.55 to 3.31 to get me close. The tallest tire option I could select was 34" on my tuner, which was what was already there.
Did this affect any of the abs/stability/traction control systems?
Going with 3.31 and a tire size of 32.2 should net/mimic a 34.5 with 3.55 similar 33.9 w/3.31 is close to 37 with 3.55
So I am curious if this logic will create problems with individual wheel speed sensors as they are tone ring type I believe.
I tried the tow haul mode on the way home tonight, felt alot more like I thought it should, engine brake surprised me a couple times on the sharper turns and stops.
Been looking online and all these programmers claim to be able to change tire size. I had the SCT for my old 6.0, so was looking at them a little harder and am leaning towards the SCT X4. Less than $400 on a couple sites. Anyone familiar with it on the 6.7s? I guess an email to them or one of the vendors might shine some light if it'll do 35s.
The SCT X4 tire size limit is 34" (as I assume all of the tuners are limited to for the 6.7s). I sent them an email a while back asking if they would ever be able to update this and allow larger sizes. Their reply was they could not, due to a size limitation being built into the Ford software (or something to that effect).
The SCT X4 tire size limit is 34" (as I assume all of the tuners are limited to for the 6.7s). I sent them an email a while back asking if they would ever be able to update this and allow larger sizes. Their reply was they could not, due to a size limitation being built into the Ford software (or something to that effect).
this is what I was told by SCT as well, limitation on ford's side
Well. We will see if I have a normal drive tomorrow or make a system mad
I am expecting it to get mad and have to reprogram back to 34 and 3.55, unless each wheel speed sensor is relative one another and doesn't look at vss on diff
Last edited by cangim; Feb 9, 2017 at 07:36 PM.
Reason: making image smaller
My new tires are 295/65/20's. My factory tires were the 34.5" as you had. Since my tuner would allow reprogramming for factory available sizes only, I couldn't get it any larger than it already was. I lied to my computer and told it I had changed the rear diff to 3.31. I have had no issues with this new configuration, and the speedo appears to be more accurate.
