Wheel Speed

[GWADD]

I don't understand why the logged wheel speeds on my car are inaccurate.

I know the Circumference and Number of Wheel Teeth are correct.

Tks very much.

Grant

[RickS]

Hi Grant,

Can I have a few details on how you are logging etc? Are you sending the data out from the ACD and logging in the internal logging on the ACD or are you using a datalogger etc. Which vcersions of ACD and ECU are you using? Is it a Lancer 9?

Thanks
Ed

[GWADD]

Hi Ed,

I have an EVO 8 with v1.03 software in the ACD.
Logging the data directly to PC and playing back via DLOG.

Any ideas ?

Grant

[RickS]

Hi Grant,

Have you downloaded the latest GWv4 from the website? there was a bug fix similar to this a couple of weeks ago which is up now i believe. When you display the wheel speeds as parameters are they correct. What are you verifying your speed with? did you measure the rolling circumference of the wheel? i know these are obvious questions but i have to check.

Thanks
Ed

[GWADD]

Hi Ed,

The data was logged with an older version, but I am not sure which one. (Older than v5 anyway).

Circumference is correct and wheel speed does play back with a maximum of about 70 kph in the particular data that I logged.

The actual road speed was at least twice this value.

How do you change the default units to mph ?

Is it necessary to relog with the latest version of GWv4?

Cheers Grant

[RickS]

Hi,

Ok, I thought you were pc logging directly from the ACD but it appears you are doing it from the ECU as the Road speed is ECU derived with the Evo acd v1.03. There should be an Option in the ECU options list called Road speed M. This is a road speed multiplier. If you half this you should have a good road speed.

Depending on what version of ECU you have depends on whether you can chnge the units you see. In GWv4 go to the configure Menu and select units. If there is a speed unit shown there you should be able to select Miles per hour. If not you will have to add it as a maths channel in the DLOG software i'm afraid as we haven't added maths channel parameters to GWv4 yet. Multiply Kilometers per hour by 0.621371 to obtain miles per hour. Adding a maths channel is in the DLOG manual and is as simple as click Maths > Create and saving your libary.

Hope this helps
Ed

[GWADD]

Hi Ed,

I am logging directly connected to the GEMS ACD computer ?

[RickS]

Hi,

Yes you do need to re-log the Data with the new version of GWv4.

Hope this helps
Ed