How to adjust tune for different tire size? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Akari · 01-19-2015, 06:28 PM

Hey all,

I'm running a slightly non-standard tire size that has my speedo off a couple percent throughout the rev range. I've looked and searched around but haven't yet found a place to change this in the tune.

Does anyone know if this is possible and if so what steps need to be taken? -I work in RomRaider with a OFT tune and definitions.

Thanks!

mad_sb · 01-19-2015, 06:35 PM

I don't think the speedo calibration is part of the engine ecu, which is what we have access too with the current tuning tools. Possibly one of the other ECU's though not sure.

steve99 · 01-19-2015, 06:45 PM

Im pretty sure what mad-sb said is correct, you can adjist gear display rpm thresholds to correct thge in dash display in ecu rom but not the speedometer correction.

However when i was messing with the toyota techstrem software i seem to remember a speedometer calibration adjustment in their. you can get software and adapter for about $40 on ebay seatch for techstream.

Akari · 01-19-2015, 07:35 PM

Thanks Steve, I'll explore that option and see if that leads anywhere.

Part of me wonders if this is possible in a tune but just not defined as a table/parameter yet?

Toyota John · 01-21-2015, 09:47 AM

Confirmed techstream works with tactrix op2 cable. I haven't looked into tire size re-calibration yet.

01-19-2015, 06:28 PM	#1
Akari Senior Member Join Date: Oct 2013 Drives: 2013 DGM BRZ Location: Auburn, WA Posts: 417 Thanks: 181 Thanked 149 Times in 97 Posts Mentioned: 11 Post(s) Tagged: 0 Thread(s)	How to adjust tune for different tire size? Hey all, I'm running a slightly non-standard tire size that has my speedo off a couple percent throughout the rev range. I've looked and searched around but haven't yet found a place to change this in the tune. Does anyone know if this is possible and if so what steps need to be taken? -I work in RomRaider with a OFT tune and definitions. Thanks!

01-19-2015, 06:35 PM	#2
mad_sb Senior Member Join Date: Jan 2013 Drives: 2013 Asphalt FR-S Location: Orange County Posts: 1,639 Thanks: 632 Thanked 982 Times in 537 Posts Mentioned: 100 Post(s) Tagged: 0 Thread(s)	I don't think the speedo calibration is part of the engine ecu, which is what we have access too with the current tuning tools. Possibly one of the other ECU's though not sure. __________________ ~Namaste~ 2013 Asphalt FRS

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01-19-2015, 06:45 PM	#3
steve99 Banned Join Date: Dec 2013 Drives: FT86 Location: Australia Posts: 7,996 Thanks: 1,035 Thanked 4,992 Times in 2,983 Posts Mentioned: 598 Post(s) Tagged: 2 Thread(s)	Im pretty sure what mad-sb said is correct, you can adjist gear display rpm thresholds to correct thge in dash display in ecu rom but not the speedometer correction. However when i was messing with the toyota techstrem software i seem to remember a speedometer calibration adjustment in their. you can get software and adapter for about $40 on ebay seatch for techstream.

01-19-2015, 07:35 PM	#4
Akari Senior Member Join Date: Oct 2013 Drives: 2013 DGM BRZ Location: Auburn, WA Posts: 417 Thanks: 181 Thanked 149 Times in 97 Posts Mentioned: 11 Post(s) Tagged: 0 Thread(s)	Thanks Steve, I'll explore that option and see if that leads anywhere. Part of me wonders if this is possible in a tune but just not defined as a table/parameter yet?

01-21-2015, 09:47 AM	#5
Toyota John Calle Atun Join Date: Sep 2013 Drives: 13 FRS, 93 Mr2, 85 ae86 Location: CT Posts: 158 Thanks: 12 Thanked 11 Times in 10 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Confirmed techstream works with tactrix op2 cable. I haven't looked into tire size re-calibration yet.

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