Do you need to have your chip burned specifically for a smaller than stock tire diameter? I'm wondering if performance is comprimized if you use a 26" slick or DR and just have a chip that does not take that into consideration... Anyone know if 1/4 times are affected? thanks Jeff

 

The only issue is that the speedo will be off. The tuners can fix that if you care. The motor will not care a bit. It only cares about load and RPM.

Hope this helps

Andy

 

What year is your L ??? I have a 00 that I put 3:73's in and went to the 26" tire,you may have a problem banging the rev limiter.It can be fixed with the proper chip.If you have a 01 I doubt you'll have a problem.
J MAN

 

What you did was reduce the load slightly and now the motor is changing rpm so quickly with the lower gears and smaller tires and is not starting the shift sequence soon enough. You would have gotten the same result with the old gears and tires driving full power down hill.

Andy

 

Thanks guys...I have an 01 and I don't care about the speedo being off at the track. I just wanted to make sure that the pcm was not doing some weird stuff with the smaller diameter tire... Jeff

 

Jeff, didn't someone state that the PCM can affect vehicle performance when a smaller/larger tire diameter is used? Some respectable top tuner said something about it at one time and gave a reason for why it could.

Now don't everyone wig out over what I just said. I'm only relaying something that was told and I could have it completely out of context. Personally, I don't think it can affect performance.

BfB

 

Well maybe we need a tuner or one of the diehard drag guys to give us an opinon...

 

ttt

 

Jeffs Lightning,

1/4 mile times are affected. Your computer cares about tire speed. Best to either get a flip chip or a race program for the 26" tires.

Jim

 

Jeff, I have tuned trucks doing it both ways. Some chips were corrected for short tires, some were not. Our testing has shown that NOT correcting for the 26" tires resulted in the same ET, but higher mph. If you change gears, you need to correct for that, but for the tires, it's not needed. Also, with the 2001s, you cannot access the rear end ratio part of the PCM anyway, so no gear or tire change correction can be made on an 01.

 

Sal,
If I'm reading you correctly, you're saying you cannot put 4;10 rear gears in an 01.
noelvm

Wonder if you could put an 00 pcm in an 01. Probably not and it would probably be illegal anyway.

 

Noel, you can put any gears you want in an 01, you just can't correct for it with a chip. I have not hooked my NGS up to my 01 to see if the 4.10s are selectable with Ford equiptment though.

 

Well, that was my point. When you change gears if you don't correct with a chip the thing is vertually undriveable. If you can't correct an 01 gear change with a chip how else could you do it?
noelvm

 

Not required, As Sal explained above. I have seen no gain in correcting for tire height. But gear changes do need to corrected for. IMO You'll be fine

 

Why with Gears but not with Tires... aren't shorter tires exactly the same as putting in gears??