Hypertech Speedmeter Calibrator

[Ianborg]

I recently replaced my stock tires with LT275/65R20 KO2s. They look great but with increases diameter (31.9" to 34.1") and weight (39lbs to 57lbs) my performance, fuel economy, and shift points seem to be way out of way. Obviously I knew the increase in size and weight was going to affect performance and MPG but I didn't realize the tranny would feel that much different. My question is... with the Hypertech Speedometer Calibrator, when you adjust the speedo for tire size, does it affect the shift points of the tranny? I haven't been able to find a clear answer online so I was hoping someone on her has experience with this device.

 

Thanks in advance!

 

It's too bad it hit my performance so bad because they look sexy!

[Waaazooo]

I recently replaced my stock tires with LT275/65R20 KO2s. They look great but with increases diameter (31.9" to 34.1") and weight (39lbs to 57lbs) my performance, fuel economy, and shift points seem to be way out of way. Obviously I knew the increase in size and weight was going to affect performance and MPG but I didn't realize the tranny would feel that much different. My question is... with the Hypertech Speedometer Calibrator, when you adjust the speedo for tire size, does it affect the shift points of the tranny? I haven't been able to find a clear answer online so I was hoping someone on her has experience with this device.

 

Thanks in advance!

 

It's too bad it hit my performance so bad because they look sexy!

You know, I'm not 100% sure but I don't think the transmission really is calibrated by the speedometer alone. It has to do with speed, load on the engine and rpms. So while it will adjust the speed, i don't think you'll find much in the way of transmission fixes just by the speedometer. I think if you are looking to fix the loss of power from the bigger tires and to recalibrate the speedometer you should look at a device that will do recalibration on all the systems, engine, transmission and gauges.

 

Fuel economy isn't going to come back, you've added 20lbs per corner and a lot more rotational weight that sucks up torque like a sponge.

 

 

 

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[TJay74]

The transmission uses a table that is indexed by RPM and speed. So yes if you use the hypertech calibrator it will fix the issue.

[Ianborg]

The transmission uses a table that is indexed by RPM and speed. So yes if you use the hypertech calibrator it will fix the issue.

 

Have you done this personally TJay?

[Waaazooo]

The transmission uses a table that is indexed by RPM and speed. So yes if you use the hypertech calibrator it will fix the issue.

So regardless of the engine load my transmission will shift and run in particular gears based on my rpm and speed alone. Interesting

 

 

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[TJay74]

 

Have you done this personally TJay?

 

I use HP Tuners, so no I have not with the Hypertech programmer but yes using HPT. That is how I know how the transmission tables operate.

 

And yes on the load question. As long as the TCM knows what speed and RPM the engine is at it can reference the correct shift point in the shift tables.

[JRL1164]

I did the Hypertech speedometer calibration for my 275/70R18 KO2's and worked just fine. For the money most would say do a tune but I was content with that. Only funny thing is that the temperature will read 30 degrees for about 30 minutes then corrects itself after the flash.

[A.J. Curtis]

I recently replaced my stock tires with LT275/65R20 KO2s. They look great but with increases diameter (31.9" to 34.1") and weight (39lbs to 57lbs) my performance, fuel economy, and shift points seem to be way out of way. Obviously I knew the increase in size and weight was going to affect performance and MPG but I didn't realize the tranny would feel that much different. My question is... with the Hypertech Speedometer Calibrator, when you adjust the speedo for tire size, does it affect the shift points of the tranny? I haven't been able to find a clear answer online so I was hoping someone on her has experience with this device.

 

Thanks in advance!

 

It's too bad it hit my performance so bad because they look sexy!

If you live in Northern California you can swing by and try mine. I got one from my friend but I have not increased my tire height just the tire width and have not used it.