Possible conspiracy??

I got my ScanGuage II in a few days ago and installed it right away. I am VERY pleased with it and find it very interesting to see how accelerating affects MPG...

But one thing I've noticed as well is that the MPH I get on the ScanGuage is about 3-4 MPH slower than the speedometer. I have also read this a lot around the forum from people with GPS units.

So, my question is this - is Toyota (and any other car manufacturer for that matter) giving the whole +/- 3 MPH (although all the claims I see has that on the plus (+) side) tolerance in the speedometer accuracy an attempt to get out of warranty claims early? Because, if I do the math correctly, a higher MPH will result in inaccurate odometer readings, reading higher than the "actual" mileage driven.

Just something I've been thinking about...........

 

Yep well my odometer is about 2 miles off slower i checked that on the gps of my cell phone....

 

Yep its true they are yet again cheating us. Thats why I installed my lift and tires so early on, less than 10,000 miles. Now all is good, well I am 2.7 mph faster now.

 

im about 3mph off oh well i cant even spell Conspear -acy lol

 

700 miles on my new '09 - ordered the new tires (285/75s) two days ago. They go on Monday!

 

hehe.... Take on The Man!

 

My scanguage speed is off from my speedometer BUT... If I look at the mileage it ends up matching the odometer exactly. I havn't compared it to a GPS's distance estimate but I'm sure it's darned close. (At least on my truck)

 

Oh, I have no doubt that it's a very small difference. However, multiply that out over 36000 miles and I bet you get a couple hundred miles or so...

Kinda like taking $.0001 from every bank account in a bank. No single person notices. But multiply that out to all the accounts in the bank and you have millions of dollars...

 

OR spring for the $250 speedo calibrator. (Which you should probably still do after the tires-cause your speed may be wrong the other way...)
Good luck finding a vechicle out there that doesn't have a bit or error built in.

 

My Speedometer is 2mph faster than the scangauge II. But when you compare the scangauge with the GPS - it's accurate. So - the speedometer needle isn't calibrated properly.

I also did a slow driving mile to compare with the GPS. Only did it once, but the Scangauge was only off by .02 of a mile.

 

It seems to me that the MPH and the distance traveled aren't really related. Even if the spedometer is off by +/- 3mph, that doesn't mean the odometer is off by that much. The real test would be to start your trip odometer when you pass an interstate mile-marker, and check to see that it rolls over every time you pass another one. After 20 or 50 miles, see how far off (if at all) you are.

If your tires are bigger than stock, then you'll actually be traveling further than your odometer records. Good for you... not so good for the Toyo warranty department.

I did the math... if you were to change your stock (16") tires for 17" tires when your odometer read zero miles, you could actually drive 38,250 miles before your odometer would read 36k miles. If you changed to 18" tires, you could drive 40.5k miles before your odometer read 36k.

 

aww hell My head hurts now.

 

I assume when you talk about 16", 17" and 18" tires, you mean "wheels"? And the wheel size doesn't change the diameter of your tire.

However, I know what you mean and get your point!

 

Auto manufacters are allowed 4% error in speedo/odo readings by law, anymore/less should not have made it through quality control, plus most manufacturers give a 1000 mile warranty grace period, so IMO it works out in the wash, in production extra accuracy equals extra time and money, personally I'm hoping tacomas dont go up anymore in price so I'll live with it

 

Damnit! You're right... In my hurry to post something I didn't think abou the difference b/w tire diameter and wheel diameter. Still... bigger tires means more distance traveled than odometer thinks.

 

MPH & distance traveled are related.

However - the speedo on your dash may or may not be calibrated to the actual readings from the computer.

That's where the Scangauge II comes in. The Scangauge takes the MPH and distance directly off the ECU (computer). I actually look more at my scangauge for MPH than I do my dash.

 

I'm with you. I pointed this out to the dealer, they double-checked my odo with their GPS, and then the service manager wrote me a letter extending the mileage for ny warrantee by 1500 miles. I have it in writing and it is in the dealer computer files.

Conspiracy defeated!

 

Score!