I NEED ANSWERS...QUICK!!!

Waitin2Drag · August 7, 2003

Aight...I just put my 3.90's in today as apposed to my 3.42's. Got on the interstate and got beyhind a buddy doing 60mph. My speedo said I was doing 68-70. So theres a 8-10 mph difference on my speedo than my actual speed. I went to 2 dealerships today and one said "it cant be done"...the other said..."you have to wait until monday." Heres the thing, I'm going to the track Sunday and want my speedo corrected so I can't reprogram my truck with my superchips programmer. And I am leaving town monday morn for a 4 hour roadtrip and will be gone for a couple days. What can i do? What exactly does it take to correct my speedo with new gears? A buddy of mine said there is something from Jeggs that I could plug in or something like that? I really need help quick! Any advice MUCH appreciated!!

Thanks,

Chris

AZ-Z71 · August 7, 2003

Not sure maybe some can give a definate but doesn't the HPIII adjust for gear changes? I don't have one but I thought that they could.

Waitin2Drag · August 7, 2003

Opps...I forgot to mention that. I have the superchips programmer and it only adjusts for 3.42, 3.73, and 4.10. So, that doesnt help me..I even called superchips and asked if they could reflash my programmer and they said it wasnt possible

Professor · August 7, 2003

Adjust it for the 3.73 and smaller tires or 4.10 and taller tires. Even if you leave the tire programing stock, you will only be off 1-1.5 %. Likely it was off more than that to start with. Find a GPS to get an accurate speed. Your buddy's is likely off as well.

Shaners · August 8, 2003

Adjust it for the 3.73 and smaller tires or 4.10 and taller tires. Even if you leave the tire programing stock, you will only be off 1-1.5 %. Likely it was off more than that to start with. Find a GPS to get an accurate speed. Your buddy's is likely off as well.

The professor has a great idea!!!!

265 tires and 4.10 gear combo should give something pretty close I would think... I went from 245's and 4.10's to 265's and I estimated that my estimated rear gear would be more like a 3.90 than a 4.10 because of the larger tires... Dbl checking it with a GPS would be a geat idea too!!!

Waitin2Drag · August 8, 2003

thats a kickass idea bud. After i posted this topic i called a speed shop and he said do the same thing with the 4.10 and tire ratio, but i never thought of the GPS. come to think of it..my buddy has a gps transmitter that will be perfect. sweeet.....THANKS

Chris

Waitin2Drag · August 8, 2003

Got another problem...I think? I got my buddies GPS unit...I just took a drive with it and i noticed as my speed increased on my speedo...the difference between my actual speed and my speedo grew also--->the faster I go, the bigger the difference. Whats that all about?

Shaners · August 8, 2003

If you are off 5 MPH at 30 MPH (indicated), then you would be off 10 @ 60 MPH and 15 @ 90MPH...

Waitin2Drag · August 8, 2003

No More Worries. I just got back from making a few insterstate and frontage road runs calculating my speedo with my GPS. First I programmed the 3.73's in. Then drove a mile or so and noted how much i was still off. Then after 3 or 4 stops and re-programming at each stop, I finally found the right tire height and I may only be like 1/4mph off now!! Thanks for all the help guys! can't wait to get to the track Sunday.

Chris