Speedometer Recalibration

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JBHorne

JBHorne

Joined
Aug 14, 2008
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Chandler, AZ
Has anyone done a speedometer recalibration for a 200-series yet? Can it be done at a dealership, or does it still require a TruSpeed device?

The problem is that without a correct speedometer reading, odometer mileage will be wrong and so will fuel economy readings.


It may not seem like much, but lets do the math:

Stock tire is 641 revs/mile.
Upgrade is 608 revs/mile.

(641/608) - 1 * 100 = 5.43% difference

That means that when the speedometer reads 60MPH, you are actually going:

60 + (60 * .0542) = 63.258 mph


When the odometer increase by 1000 miles, you have actually traveled:

1000 + (1000 * .0542) = 1054.2 miles


In turn, if your truck states that you are getting 12mpg after your upgrade, you are really getting:

12 + (12 * .0542) = 12.65 mpg


That's a pretty big difference, and even effects the scangauge's trip readings. I know you can do an offset from within the scangauge, but I want to do it with the truck instead. That way the SCII will pick up the correct signal from the OBD-II with no offset needed.


PS >> Not that I'm worried with almost 400HP, but the final drive ratio changed from 3.91 to 3.71, FYI.
 
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You might want to look over on Tundra Solutions, some of the guys there use something from Hypertech to recalibrate.

You could also find out if the 4.10 Tundra front diff gears would work, and Tundra or UZJ100 4.10 rears... IMO that would be the best way.
 
bjowett said:
You might want to look over on Tundra Solutions, some of the guys there use something from Hypertech to recalibrate.

You could also find out if the 4.10 Tundra front diff gears would work, and Tundra or UZJ100 4.10 rears... IMO that would be the best way.
Click to expand...

Hmm, might be something to think about when installing the front locker.

Can the ARB lockers accommodate different gear ratio parts?
 
JBHorne said:
Has anyone done a speedometer recalibration for a 200-series yet? Can it be done at a dealership, or does it still require a TruSpeed device?

The problem is that without a correct speedometer reading, odometer mileage will be wrong and so will fuel economy readings.

It may not seem like much, but lets do the math:

Stock tire is 641 revs/mile.
Upgrade is 608 revs/mile.

(641/608) - 1 * 100 = 5.43% difference

That means that when the speedometer reads 60MPH, you are actually going:

60 + (60 * .0542) = 63.258 mph


When the odometer increase by 1000 miles, you have actually traveled:

1000 + (1000 * .0542) = 1054.2 miles


In turn, if your truck states that you are getting 12mpg after your upgrade, you are really getting:

12 + (12 * .0542) = 12.65 mpg


That's a pretty big difference, and even effects the scangauge's trip readings. I know you can do an offset from within the scangauge, but I want to do it with the truck instead. That way the SCII will pick up the correct signal from the OBD-II with no offset needed.


PS >> Not that I'm worried with almost 400HP, but the final drive ratio changed from 3.91 to 3.71, FYI.
Click to expand...

Any luck on the re-calibration. Your right, getting that done is very important and leaves out the guess work on your end.
 
Mtnbike said:
Any luck on the re-calibration. Your right, getting that done is very important and leaves out the guess work on your end.
Click to expand...

Nope, nothing new. I've just calibrated my scangauge correctly. I've considered regearing, but its kind of a hassle.
 
JBHorne said:
Has anyone done a speedometer recalibration for a 200-series yet? Can it be done at a dealership, or does it still require a TruSpeed device?

The problem is that without a correct speedometer reading, odometer mileage will be wrong and so will fuel economy readings.

It may not seem like much, but lets do the math:

Stock tire is 641 revs/mile.
Upgrade is 608 revs/mile.

(641/608) - 1 * 100 = 5.43% difference

That means that when the speedometer reads 60MPH, you are actually going:

60 + (60 * .0542) = 63.258 mph


When the odometer increase by 1000 miles, you have actually traveled:

1000 + (1000 * .0542) = 1054.2 miles


In turn, if your truck states that you are getting 12mpg after your upgrade, you are really getting:

12 + (12 * .0542) = 12.65 mpg


That's a pretty big difference, and even effects the scangauge's trip readings. I know you can do an offset from within the scangauge, but I want to do it with the truck instead. That way the SCII will pick up the correct signal from the OBD-II with no offset needed.


PS >> Not that I'm worried with almost 400HP, but the final drive ratio changed from 3.91 to 3.71, FYI.
Click to expand...
You do realize that you're getting a 5.43% longer warranty (by mileage criterion)? ;)
 
WAIT...am I doing the math backwards??? I'm stupid...um...do you GAIN 5% or LOSE 5%???

When my vehicle say's I've traveled 1 mile, did I really go ~1.1 or ~0.9?

Think about it: The vehicle thinks you are going faster than you really are, so you are covering LESS distance in the same amount of time. (S=D/T --> D=S*T)

So did I do everything backwards? Are you really LOOSING 5.4% miles and 5.4% MPG?

For example: I set my scangauge's speed offset by -7 while holding a portable GPS. Now my scangauge is accurate, but the mileage reported is now LESS than my vehicle's reported mileage. Also my fuel economy is lower than what's on my info screen.

I think I may have been really stupid with the math and did it all backwards. Any math heads here???




Let's do the math again:

Stock tire is 641 revs/mile.
Upgrade is 608 revs/mile.

(1 - 641 / 608) * 100 = -5.43% difference

That means that when the speedometer reads 60MPH, you are actually going:

60 + (60 * -.0542) = 56.748 mph


When the odometer increase by 1000 miles, you have actually traveled:

1000 + (1000 * -.0542) = 945.8 miles


In turn, if your truck states that you are getting 12mpg after your upgrade, you are really getting:

12 + (12 * -.0542) = 11.35 mpg
 
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JBHorne said:
I just did a test at http://www.dakota-truck.net/CGI-BIN/TireCalc.cgi because they tell you the indicated and actual mileage and yeah, you are right, but then I don't get why my SGII mileage isn't correct?

Have to figure that out...
Click to expand...

Stupid question, but I am still going to ask. Have you noticed a big difference in fuel mileage since your upgrade? Does your tires pull when driving down the highway over 60mph?

Has anyone thought of re-gearing there cruiser to accommodate the bigger tires, so they don't loose fuel mileage?:wrench: I know it works for other vehicles, just didn't know if it's possible with the 200.:meh:
 
Old post resurrection here... has anyone successfully recalibrated their 200 series with anything? My specific application is an 08’ LX but I assume if it can be done with a LC then it can also be done to an LX.

Mark’s 4WD had this article... Digital / Electronic & Mechanical Speedo Correction Boxes
...but they seemed to only offer a solution for build date 08/15’ on.

P.S. I called Hypertech since they were mentioned with a Tundra solution but there tech support said “that hasn’t been tested” and were no further help to understand if their Tundra solution would work. Maybe someone here with both vehicles would be able to confirm?
 
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