cluster swap
Senior Member
Joined: Oct 2005
Posts: 3,579
Likes: 1
From: Wilmington DE
Most likely,,your MPHs is off because of your big wheels!
I have 2 different tunes to correct my speedo.1 for when I'm running my stock 16"s and 1 for when I'm running my 23"s
You can fix it with custom tuning.
Phil
I have 2 different tunes to correct my speedo.1 for when I'm running my stock 16"s and 1 for when I'm running my 23"s
You can fix it with custom tuning.
Phil
Last edited by phil6608; Jan 6, 2009 at 12:43 AM.
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Member
Joined: Mar 2007
Posts: 39
Likes: 0
From: FORT WORTH
i trade my 24's for some harley davidson 20's and still my mph are off
Senior Member
Joined: Oct 2005
Posts: 3,579
Likes: 1
From: Wilmington DE
let me know what all the dealer tells ya.
I'm getting ready to put a Lightning cluster in my truck and could use any info.
Thanks
Phil
Technical Article Contributor
Joined: Jun 2002
Posts: 10,511
Likes: 10
From: Under the flightpath of old ORD 22R
Was it correct prior to the cluster swap ?
The PCM is what is modified for adjusting the wheel ratio.
The factory tire for a '03 XLT is 255/70-16, which would have a rev per mile of 671
If you change to a 20" wheel and put 275/45ZR20 tires on it, the rev per mile is now 678.
My 2001 was off by about 4 MPH with the factory tires on it, and I put on L wheels with 285/60R18 ( I think that is the size), which put it close to correct, at 640 RPM.
The other info, did you switch the gears on the truck ?
The PCM is what is modified for adjusting the wheel ratio.
The factory tire for a '03 XLT is 255/70-16, which would have a rev per mile of 671
If you change to a 20" wheel and put 275/45ZR20 tires on it, the rev per mile is now 678.
My 2001 was off by about 4 MPH with the factory tires on it, and I put on L wheels with 285/60R18 ( I think that is the size), which put it close to correct, at 640 RPM.
The other info, did you switch the gears on the truck ?