Speedo Calculator issues...Help Please

[KAZ MotorSports]

Ok.

I am trying to get a 2000 T/A dialed in correctly. I have the tune spot on, but shift points and the speedo are off. Obviously I want to get the speedo sense and accuracy correct before I adjust shift points. The owner of the car installed 3.73 gears and a 3500RPM stall.

This is what is happening.

I am entering the tire size and gear ratio into the calculator.

275/40/17 and gear ratio of 3.73.

The calc wants to give values of:

TOS rev/mile = 2931.52
Pulse/mile of = 117261

The stock numbers are:

TOS rev/mile = 2615.3906
Pulse/mile of = 104612

The cars speedo shows 61 MPH and both my dyno and GPS says 54 MPH.

If I try to manually enter a number higher than 107239 it reverts back to 107239. It will accept the 2931.52 TOS value, but not the Pulse/mile speedo correction.

When I apply the numbers generated by the speedo calculator it holds the 107239 value and allows the TOS value.

The EFI-Live version of my V2 is V7.4.2 Build 622

Obviously the lower the Pulse/Mile value the faster the speedo will read over actual so how do I compensate without throwing the shaft revs per mile off?

Thanks much!
-Kenny
Your friendly Colorado Springs EfiLive cheerleader!!

[SSpdDmon]

I noticed a similar issue with this in my v.7.3.2 as well (still running flashscan v.1).

My '02 f-body (OS 12212156) had a max of 253436 VSS pulses/min. However, my friend's '00 f-body (OS 09381344) has a max of only 129759 VSS pulses/min. The problem is, that's not enough to cover the 132303 pulses/min his 4.10's need to report the speed accurately. Why is this limited so low when my '02 didn't have this restriction?


Sorry to hijack...

[eboggs_jkvl]

Yeah yeah, I know, I have the bastard 98 POS but I just tried your numbers

I entered

275 40 17
Clicked on recalculate

Entered final drive ratio of 3.73

TOS ia 2931.52 P/M = 49836

Clicked on "apply", "close"

Now I show
VSS 49835.9
TOS 2931.5242

When I do my setup 275 30 19 3.73 I get:
VSS = 50159.1
TOS = 2950.5366


Are we doing the same steps or is it the OS with a bug? My speedo is spot on for my setup. I'm running V2 V7.4

Elmer

[KAZ MotorSports]

I spoke with the kind folks at RedLine (Thank you Howard) and we tried entering the same numbers you said at 49835.9 (49836) and the same TOS. The speedo went to 60 or 70 MPH (I don't remember now) and the dyno showed 25MPH actual.

With the numbers the speedo calc is trying to generate for Pulse/mile and calculating actual MPH compared to displayed...the percentage is correct to send the Pulse/mile up to 117261 to get a proper speedo displayed to actual speed.

[Blacky]

Make sure you have entered the tire size correctly. Actually it would be better to measure the rolling circumference of the tire (the distance travelled -in inches - in one wheel revolution) and enter that in the circumference field in the speedo calculator.

The limit for H0101 (for 200 TA) is 230396, so ther eshould be no problem entering 117261, see attached screen shot.

Regards
Paul


Ok.

I am trying to get a 2000 T/A dialed in correctly. I have the tune spot on, but shift points and the speedo are off. Obviously I want to get the speedo sense and accuracy correct before I adjust shift points. The owner of the car installed 3.73 gears and a 3500RPM stall.

This is what is happening.

I am entering the tire size and gear ratio into the calculator.

275/40/17 and gear ratio of 3.73.

The calc wants to give values of:

TOS rev/mile = 2931.52
Pulse/mile of = 117261

The stock numbers are:

TOS rev/mile = 2615.3906
Pulse/mile of = 104612

The cars speedo shows 61 MPH and both my dyno and GPS says 54 MPH.

If I try to manually enter a number higher than 107239 it reverts back to 107239. It will accept the 2931.52 TOS value, but not the Pulse/mile speedo correction.

When I apply the numbers generated by the speedo calculator it holds the 107239 value and allows the TOS value.

The EFI-Live version of my V2 is V7.4.2 Build 622

Obviously the lower the Pulse/Mile value the faster the speedo will read over actual so how do I compensate without throwing the shaft revs per mile off?

Thanks much!
-Kenny
Your friendly Colorado Springs EfiLive cheerleader!!

[Blacky]

I believe H0105 or H0106 output drives the speedo (the other is for ABS I think), so you should be able to change one of those to alter the speedo needle without affecting the rest of the speedo calibrations

If you have a PCM pinout, lookup what the PCM pins are linked to:
H0105: J2-Pin 50
H0106: J2-Pin 49
If one of them is outputting to the speedo/cluster then try adjusting that.

Regards
Paul



Obviously the lower the Pulse/Mile value the faster the speedo will read over actual so how do I compensate without throwing the shaft revs per mile off?

Thanks much!
-Kenny
Your friendly Colorado Springs EfiLive cheerleader!!

[KAZ MotorSports]

Looking at mine it says the maximum is 66587 where you have yours highlighted.

I do not know how to take a screenshot to post like you showed sorry.

[Blacky]

Probably a difference between Auto and manual transmissions. 40 v's 17 teeth on the VSS pickup.

Regards
Paul


Yeah yeah, I know, I have the bastard 98 POS but I just tried your numbers

I entered

275 40 17
Clicked on recalculate

Entered final drive ratio of 3.73

TOS ia 2931.52 P/M = 49836

Clicked on "apply", "close"

Now I show
VSS 49835.9
TOS 2931.5242

When I do my setup 275 30 19 3.73 I get:
VSS = 50159.1
TOS = 2950.5366


Are we doing the same steps or is it the OS with a bug? My speedo is spot on for my setup. I'm running V2 V7.4

Elmer

[Blacky]

Email me your *.tun file to paul@efilive.com
I'll take a close look.
Paul


Looking at mine it says the maximum is 66587 where you have yours highlighted.

I do not know how to take a screenshot to post like you showed sorry.

[KAZ MotorSports]

I just "measured" the tire circ and with a line wrapped around the tire and then with a tape measure it was 81". The calculator shows 80.62" so I would say that is close enough.

*edit* Paul I just sent you the file.

-Kenny

[Blacky]

Hi Kenny,

I received your email, thanks.

My mistake, the image I posted was from a 2000 LS1, but I had upgraded the PCM to a 2002 operating system. So the limit you see in the image is from a later OS.

The "physical" PCM limit for the 2000 LS1 is 0 to 131,070 however, we have found that setting the speedo values to their absolute min (0) or max (131,070) values can cause the speedo calculations in the PCM to get a "divide by zero" error. To prevent that, we artificially limit the speedo settings in EFILive to 100..90% of maximum.

In the 2000 LS1 operating system 90% of 131,070 is 117,963. Unfortunately, it looks like that is not high enough to allow certain combinations of tires/diffs. In the next release, I will set the limits to 100..98% which will give the 2000 LS1 a range of: 100..128,448

Unfortunately there is no simple workaround for this problem right now.
The only option would be to upgrade the PCM's operating system to 2001/2002. But that is not trivial and the calibrations cannot be easily copied to the new OS.

An updated version of the software will be available in a day or two.
Please subscribe to this thread to receive notification when it is available.
http://forum.efilive.com/showthread.php?t=4442

Regards
Paul Blackmore
EFILive Limited

[KAZ MotorSports]

The wheels and tires are stock size on this car. So changing the gear ratio from 3.23 to 3.73 is that radical of a change to walk it out of it's limits? Bummer.

I will let my client know it will be a few days before we get things correct. He absolutely loves the way his car is now compared to his PCMforless tune was...but the speedo issue is a thorn in his side which I can fully agree with. The .tun file I sent you if for your eyes only and not to be published please.

I TRULY APPRECIATE YOUR HELP PAUL!!

I am eagerly awaiting the update.

Thank you for your help,
-Kenny

[Blacky]

The wheels and tires are stock size on this car. So changing the gear ratio from 3.23 to 3.73 is that radical of a change to walk it out of it's limits? Bummer.
No, it's not a radical change. The PCM can support your setup no problem - just as soon as I raise the upper limit.

We can cause our test PCMs to lock up if/when H0101 is set too high (or too low). The exact number varies between different PCMs, so we took a conservative approach and set the maximum for ALL PCMs to 90% of the actual maximum limit. Unfortunately the conservative approach was too conservative.

We figured it was better to have a PCM with a speedo that is (temporarily) wrong, than to have a dead PCM.

Regards
Paul

[Redline Motorsports]

Paul,

Chad and I saw this problem this weekend. We got around it but its in Chad's head!

Howard

[Black02SS]

:lol: I will get it all in an email and send it to Paul tomorrow.

[KAZ MotorSports]

No worries Paul. I hope you did not take my statement as a jab at the software. I absolutely enjoy the software and feel you guys have outdone yourselves in how effective the software is for tuning...especially compared to other software packages I have test driven.

Thanks again to you Howard for spending time with me on the phone today trying to get this straightened up. I look forward to meeting you in June for the EFI-Live class!

[KAZ MotorSports]

Thank you Paul! It worked perfectly.

-Kenny

[Blacky]

No worries Paul. I hope you did not take my statement as a jab at the software.

No offense taken :cheers: We need (and actively encourage) people to report any and all problems. That's how 90% of them get fixed.

Regards
Paul

[Spdfrk1990]

How exactly does this work I have the stock tire size and speedo settings. I entered the tire size anyway to see if it changed and the diameter/cir/revs did but when I hit apply it changed H0104 from 805.1953 to 2687.8238??? Also H0101 from 47020 to 45693 that part seems normal tho. Should I just leave the stock setting alone or whats going on.
Using v7.4

[Blacky]

I presume you have a manual gearbox.
As the description for H0104 says:
For manual vehicles, it is not used and is often set incorrectly.
For automatic vehicles, it is used by the PCM to determine the transmission shift speeds.
805 is wrong, 2687 is correct. However, it doesn't matter if you have a manual trans, that value is ignored.

I should add another piece of text:
For manual vehicles, it is not used and is often set incorrectly (by the factory).
For automatic vehicles, it is used by the PCM to determine the transmission shift speeds.

Regards
Paul


How exactly does this work I have the stock tire size and speedo settings. I entered the tire size anyway to see if it changed and the diameter/cir/revs did but when I hit apply it changed H0104 from 805.1953 to 2687.8238??? Also H0101 from 47020 to 45693 that part seems normal tho. Should I just leave the stock setting alone or whats going on.
Using v7.4

[Spdfrk1990]

Doh thanks