oversized tires and speedo calibration / mpg's

My largest drop in mpgs was due to the TRD exhaust rather than tires.

Im a little more aggressive with the skinny pedal now. The novelty will wear off soon, as long as my son stops egging me on! Lo L

 

I've read about these. Was it hard to install?

 

Isn't the TRD exhaust supposed to help increase mpg?

 

Based on this my speedo is off anywhere between 5-10mph slower than my actual speed. Looks like I will be buying the Hypertech after all

 

Have you confirmed it with a gps? I tested it out last night and my truck is almost dead accurate now. That would be the best way to confirm how far off your truck is. However if you do purchase the hypertech, let us know how the install goes and how well it works

 

16lbs X 4

 

Yes, I checked it this morning on my way to work. Doing 65mph my gps states I am doing 74-75mph. It dropped to 73mph and jumped up to 76mph while going over several over passes. I had the cruise control on, so I can assume it was due to that.

 

It wasn't hard, but you have to research the wiring a bit. The instructions from Dakota are not specific to toyota. If I remember correctly, there was a very good write up on RST forum

here you go: http://www.rocksolidtoys.com/forum/showthread.php?t=191&highlight=dakota+digital

 

It's 16lbs total. 4lbs each

 

Wow, that is a decent difference. What size tires are you running

 

35s which are closer to 36s with the aggressive thread

 

Ah ok, that would make sense. Lol. I'm sure it looks sick though

 

There's pics on my profile and on my build thread if you'd like to see it

 

Careful with that one. The calculation using tire sizes is fine. The calculation using GPS speed and indicated speedometer speed is flawed. Most speedometers seem to be purposefully conservatively calibrated from the factory. Almost every car on the road today has a factory speedo that reads two or three MPH faster than they are actually traveling at highway speeds.

 

To add to steelhd's post : with oem tires, speedometer is off 2-3 mph, odometer is likely spot-on. Change tire size, and odometer is likely off, and speedometer may now be less or more error. Clear as mud?

 

Crystal as mud

 

This is true of my tacoma. When I was calibrating my Dakota unit, I found that I could calibrate either the speedo or the odometer, but the two could NOT be calibrated together. I opted to have a perfect odometer, since I have a Scangauge and GPS.

 

Did same as Badger on my Scangauge - zero odometer error.