I have an 2004.5 Duramax that I lifted and stuck 35s on, the speedometer and shifting is obviously way off and the 2.1.14 VCM Editor doesn't have the simple "enter New Tire size" option like to older Editor has, so I'm guessing I need to change the VSS ppm and VSS trans rev. per mile as well? Anything else that needs to be changed like Trans pulses/rev? Thanks
Last edited by Dmax; 11-15-2006 at 12:40 PM.
I noticed this the other day as well. I updated the tires for winter and went a bit larger and could not find the table to enter the new tire size, only the VSS.
Any word on an update?
Jon
2012 Ram 3500 6.7 Cummins with Banks CAI, intake tubes, intake horn, grid heater/EGR/DEF delete, 4" Straight pipe
Nothing yet...I've searched the site and haven't found anything... anyone have a link?
I changed the VSS ppm and VSS trans per mile and I'm throwing codes...so I'm doing something wrong. Any help would be appreciated.
........anyone??
Can you use this?? Of coruse your tire size and gear will be diffrent......
Originally Posted by EC_Tune
1st:
Check your roll-out in inches.
Mark the tire & the ground (at nomal tire temps after driving).
Rotate one or two revolutions (divide that value in inches by 2 if you do 2 revs). Then mark the ground where the tire mark makes it's 1st or 2nd revoltion. It should be ~88.18" If it's different, time to rescale.
Here's the math on how to do the speedo rescale:
Tire revolutions/mile = Inches per mile / Tire Circumference Inches
Tire Revolutions/mi = 63360 / 88.18 --- based on (28.07" tire * Pi)
Trans revolutions/mile = Tire revolutions/mile * Gear ratio
Your values:
(63360" per mile / 88.18" tire circumference) * 4.56 gear = 3276.33
Take that value and multiply by the Rev-Trans value (40 in *most* cases) to get the VSS Pulses/mile = 131053
Put your values in the appropriate places and your speedo's dead on. Check with a GPS if you have doubts.
EC
Last edited by DaGeorge2677; 11-17-2006 at 09:24 AM.
Thx for the help, I know the VSS ppm and trans pp/r, I just don't know if I changed everything correctly. I'm looking for the "appropriate places"....I thought I changed it right by changing VSS ppm to 87879, and the VSS trans rev/distance to 592.32 for the new tires (35-13.50-R20), but I'm throwing a VSS (SES) code..so I must be doing something wrong.
What is your rear end gear?
Assuming you have 4.10s and the exact tire diameter is exactly 35".... I get 2362.55 Trans revs/mile and 94502.02 Vss ppm.
ok im slightly lost, but how would i calbrate the speedo for 32" tall tires with 410 gears??
Tire rollout = 100.5310" (32" x pi)
Tire revs/mile = 63360/100.5310 = 630.2534
Trans revs/mile = 630.2534 x 4.10 = 2584.0388
VSS Pulses/mile = 2584.0388 x 40 = 103361.5502
To get closer you should actually measure the tire rollout.
Last edited by DaGeorge2677; 11-17-2006 at 08:08 PM.
I've got 373's in the truck....came stock that way
same problem on my 2004 GMC truck, I calculated all the no. but wasn't sure if I should change them or not. will changing only those two no#. work?
I had problems downloading my program also.
hi speed failed, lo speed worked but took 30 min. and forever to save the file.
is this common?
It used to download in 5-7 min.?
all good
Are ther any plans on putting the speed calculator back in?
all good
I am sure there isthis is almost always a sticky point on new software
Ellis
Speed Secrets
95 Z28 18* LTx
95 Z28 LSx converion
03 CCSB 4x4 D/A
the calculator is there, just not for Duramax or other vehicles that do not have enough information to calculate the tire or gear.
Chris...
I count sheep in hex...
Would this include allison trans?
when I try to read entire, it gets to 50% stops, and retry's gets to 76% and I get "unable to read TCM"
I did get it to read entire in slow mode, that seem to work fine, is there any problems with doing it that way?
Mark
all good
No problems. Just time consuming.I did get it to read entire in slow mode, that seem to work fine, is there any problems with doing it that way?
Mark
Always Support Our Troops!
i need to set hte speedo on a 01 duramax dually. they installed 410s with allision trans. stock height tire
i need to caluclate the speedo. stock gearing was 373. can someone help me out
Need some help - the only thing changed on the truck was to a 285/75/16 tire - what do i change and to what #?
thanks
+1Would this include allison trans?
when I try to read entire, it gets to 50% stops, and retry's gets to 76% and I get "unable to read TCM"
I did get it to read entire in slow mode, that seem to work fine, is there any problems with doing it that way?
Mark
Ellis
Speed Secrets
95 Z28 18* LTx
95 Z28 LSx converion
03 CCSB 4x4 D/A
what about the FDR? what is the meaning of the 2 different final drive ratio parameters? 3.72 (ratio) and 4.10 (trans), what is what?
Reply With Quote