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dthompson
Gear Head
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Joined: Tue Jan 21, 2014 9:02 pm

Speedometer and BE dont agree, VSBAR and a trans swap

Post by dthompson » Sun Sep 12, 2021 7:55 pm

After a recent t56 magnum swap, my speedometer was way off. There does not appear to be any settings in GSALC related to the VSS. I purchased one of the Dakota digital boxes with bluetooth and installed it. I am intercepting the signal before it goes to the EEC and the Gauge. The box I purchased has a handy little test feature that lets you output a few different frequencies from an app on your phone. If I start a log in BE, and then send a test signal, I get a different reading on my gauge compared to the log. For example, when I send the 133hz test signal, the gauge reads 44mph compared to the datalog shows 30mph.

I dont understand why these wouldnt match?. Im not sure if something is wrong with my speedo? It seems like they should show the same speed given a certain frequency. I tried changing the rear gear ratio and tire size in the vehicle info section of BE, but it didnt change anything with the log.

I can drive the car the way it is, but it makes it a little odd trying to read through the logs and make sense of things when the actual speed is a lot higher than the data log. Its also a little weird on the dashpot tuning.

Thanks for any help and suggestions.
89 Thunderbird SC
427 SBF Twin PTE 6266s, T56 Magnum XL
9.5:1, AFR 205cc, 222/227cam, TFS R intake, FID 1600cc, 93 Pump Gas
EEC=L1C (92 5.0 Tbird), BE/QH, GSALC

jsa
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Re: Speedometer and BE dont agree, VSBAR and a trans swap

Post by jsa » Mon Sep 13, 2021 3:52 am

Get a gps app on your phone that displays speed. Use that as a benchmark.

Speedo and VSS could be wrong after your changes.
Cheers

John

95 Escort RS Cosworth - CARD QUIK COSY ANTI / GHAJ0
Moates QH & BE
ForDiag

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EDS50
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Re: Speedometer and BE dont agree, VSBAR and a trans swap

Post by EDS50 » Mon Sep 13, 2021 7:15 am

There is a provision under the datalog tab called speed correction on the bottom right you can use to correct any speed discrepancy between your displayed speed on your speedometer and the BE dashboard/gauge.
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 333 on Meth, Lentech Trans, TRZ Backhalf, A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

dthompson
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Posts: 16
Joined: Tue Jan 21, 2014 9:02 pm

Re: Speedometer and BE dont agree, VSBAR and a trans swap

Post by dthompson » Mon Sep 13, 2021 5:46 pm

EDS50 wrote: Mon Sep 13, 2021 7:15 am There is a provision under the datalog tab called speed correction on the bottom right you can use to correct any speed discrepancy between your displayed speed on your speedometer and the BE dashboard/gauge.
Cool, I never noticed that was there. If I change it there, does it just fix the BE gauge/datalog or will the EEC use the corrected speed as it relates to things like DASMPH for the dashpot mph for declutch?

For example, I currently have DASMPH set to 20MPH. I can get my actual speedometer to display 20mph accurately using the dakota box. BE was showing 10mph, but I use a speed correction of 2 in order to correct for the difference. Say I'm driving 25mph and declutch, will the EEC "realize" that I'm going 25 or will it "think" that I'm only going 12mph and start depleting dashpot from the mon clip as soon as I declutch?
89 Thunderbird SC
427 SBF Twin PTE 6266s, T56 Magnum XL
9.5:1, AFR 205cc, 222/227cam, TFS R intake, FID 1600cc, 93 Pump Gas
EEC=L1C (92 5.0 Tbird), BE/QH, GSALC

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EDS50
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Re: Speedometer and BE dont agree, VSBAR and a trans swap

Post by EDS50 » Mon Sep 13, 2021 6:11 pm

Changing the speedo correction will only change the display on BE to match your physical speedometer in the car. I have my apeed correction set at 1.05 to correct the transmission gear/speedo gear combination which was off by a few mph over 35 or so mph. Experiment with it.
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 333 on Meth, Lentech Trans, TRZ Backhalf, A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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