How to change tire size on LL8?

[dirt_track_racer_81]

How to do i change the tire size on these LL8's, cant find nothing for gear or tire changes in the software?

[ScarabEpic22]

First, make sure you have the latest version of EFLive Scan and Tune software (7.3.3).

What year LL8? I have an 02, and what you need to do is go into the Speedometer section and change B0205 and B0201. There isnt a calculator, so I dont know how you can figure out what to change them to, but the VSS part is directly related to the gears and tire size...

[dirt_track_racer_81]

First, make sure you have the latest version of EFLive Scan and Tune software (7.3.3).

What year LL8? I have an 02, and what you need to do is go into the Speedometer section and change B0205 and B0201. There isnt a calculator, so I dont know how you can figure out what to change them to, but the VSS part is directly related to the gears and tire size...i changed those..i used the calculator part by getting in just a regular tune that has it, just put in the tire size and gears

[ScarabEpic22]

OK, I think those are the only 2 tables regarding gears and tire size in EFILive now, so if those didnt change anything I think we are screwed unless someone wants to modify hex code.

[Whodunnit]

Hey folks! So have you guys had any luck doing speedo updates? The calculator tool looks very nifty but it doesn't seem to be working for me.

First off, when I dial in any tire size, the {H0104} value jumps from the original 2637.428850 to 1622.523953 regardless of the new tire size, so I'm immediately suspicious that I might be messing something up somewhere.

Using the Speedo Fine Tuning tab instead, the calculator updated {H0101} fine, but when I went to the Shift Point Correction sheet it didn't seem to be working right yet. It seemed that no matter what I entered, when I pressed "Apply" the percentage box went back to 0% and nothing had been changed. See here:
http://i157.photobucket.com/albums/t53/bretwylie/trailblazerstuff/speedoerror.png
and then I would get an error:
http://i157.photobucket.com/albums/t53/bretwylie/trailblazerstuff/speedoerror2.jpg
Does anyone know how to get around this?

Thanks in advance!

- bret

[goldbergv95]

First off, when I dial in any tire size, the {H0104} value jumps from the original 2637.428850 to 1622.523953 regardless of the new tire size, so I'm immediately suspicious that I might be messing something up somewhere.


You right I notice the same thing and i got myself thinking something is wrong. pcmforless does not even change or touch the H0104

[Whodunnit]

Ha, thanks for keeping this alive. I have to admit that I got frusted and gave up for a while. I guess it'd be worth downloading the latest versions and checking it out again. It'd sure be nice to have an accurate speedo again!
:help2:

[Whodunnit]

Hi folks, I finally decided to shake the bats out of the ol' efi tuner. (I have to take the car in for a smog and speed-sensor errors keep popping up:shock:)

I updated to v7.5.5 to see if this problems been resolved, but haven't had any luck with the Speedo Calculator (or at least lack confidence that it's/I'm doing it right) so I started to attempt the adjustment the old-fashion way, but I think the nomenclature has changed!:help2:.

With v7.5.5 does anyone know what values to adjust to correct for new tires, and by how much?

My speedo and VSS values are both reading 5.4% low. Intuitively I attempted to lower:
{H0101} "Vehicle Speed Sensor Pulses per Kilometer"
{H0104} "Trans Output Shaft Revs/Kilometer"
{B0205} "Vehicle Speed Sensor Pulses Per Mile On Data bus"
each by 5.4%, but that didn't seem to work. I don't see the {B0201} ScarabEpic22 mentioned anywhere?...

I tried changing just {H0101} and {B0205} a different time, but the adjustment didn't come out correct and the car just ran rough after coasting to a stop (hmm.... I'm wondering if H0104 needs to be linearly scaled with H0101 because the Description box states "It will normally be consistent with the equation: H0101=H0102*H0104.")

Do anyone happen to know if these values tend to be linearly scaled through zero (in a y=mx format) or is there an offset perhaps (such as y=mx+b)?

Any help will be GREATLY :welcome:!
Thanks in advance!

- bret

[Whodunnit]

FYI, I just tried using the Speedo Calculator tool again since I recently updated software and the FlashScan Firmware and Boot Block. I read somewhere that it helps to set Units and the Speedometer Segment in "Configuration Display Units" both to Imperial, so I did that too.

It looks bugged still though. My speedo readout went down, my computer readout went up (they no longer agreed), and worst of all the car insisted on lugging it in 4th at 900rpm. Basically the shifts were all over the place. Based on what I'm seeing, it seems multiple values must be labeled wrong for the LL8.

Needless to say, I flashed back to stock. Will the LL8 support ever come around? My old EEC-IV programming was not near this buggy. :bad:

[ScarabEpic22]

I changed the speedo settings but didnt bother to use the shift correction stuff. The likelihood of us getting any more P10 support is highly unlikely as it was only used in 1 platform for 4 years. I know there are a lot of TBs out there but when it comes down to tuning, they are a very small percentage of the total.

So go use the calculator for the speedo and odo correction then setup the shift points by themselves. I also changed TCC lockup to never occur under 45mph in 4th because my 02 would get into 4th lockup at 30mph and continually lock/unlock driving on flat roads because it would gradually speed up causing me to pull my foot off the gas= unlock then relock conditions.

[Whodunnit]

True, very true.

Hey any advice as to which values I need to change for my speedo, comp, and shift points to be right?... and by how much? Is it just a straight % of tire diameter change to each of these points or is there some sort of an offset at 0mph?

Thanks for your feedback!

[ScarabEpic22]

I used the calculator to adjust the speedo and odo. Shift points just start playing with them on the street, try bumping them up by 1mph at low speeds and 2-3mph at higher speeds. Honestly it took me probably 6 months to setup the shift points where I have them now and like it.

So yes its pretty much a %age value multiplied to the H0101, H0104, and B0205.

[Whodunnit]

Yeah that's what I was trying to do but it just made the computer read out and speedo read different and worse. I think I'm going to try to figure this out more scientifically now that I have some more time to play with it... first dialing in one parameter then the next... I'll report back here with what I learn.

thx.

[ScarabEpic22]

I was tuning a P10 tonight for bigger tires and ran across this same problem, the engine would choke to 600rpms and bog big time if I changed H0101 after I used the calculator to compute the theoretical proper values for the tires. Going to hand calc everything and see what happens in the next day or so and report back.

[Whodunnit]

Any luck?

I've run several combinations of +50% and -33% for H0101, H0104, and B0205 and still can't make heads or tails of what's going on. It looks like H0101 inversely affects my laptop reading but has no effect on the speedo itself. H0104 seems to have some effect sometimes, but I'm not sure if it's dependent on H0101 or not. I don't see any effects from B0205 whatsoever.

When I simply change all three or H010 and H0104 by say, +/-10%, the speedo stays the same but the laptop reading gets all out of whack.

Hmmm.....

[ScarabEpic22]

Its a customers truck so I havent seen it since I posted that last message but what you're talking about seems dead on to what happened for me. I would see the VSS output to the scan tool increase waaaay beyond what it should be while the guage readout would stay the same. I left it stock simply to make sure all the shift points didnt get thrown off big time.

Thursday looks like its going to be a testing/wash/clay/wax day for me so we'll see then. But I might have to by a license and start on my SS, cant wait to start playing with it!

[Whodunnit]

Hmmm... do you think this might be a software version issue? If so, is this the type of thing that can be resolved by loading a different software version or is that generally a bad idea?

[ScarabEpic22]

Has nothing to do with it Im afraid, Paul and Ross have both said that the speedo calculator is really only for the LS1 and its derivatives, there are so many ways to setup the speedo stuff they cant have a universal tool do it. Know it sucks big time but Im at a loss right now. Simply changing to an earlier software wont do anything, we've only gotten a few major revisions to the P10 files and the last one was back in Feb 08.

[Whodunnit]

Ha ha oops. I mispoke :doh2: I meant, would loading a different OS help... my OS is 12579357. I thought I read somewhere of folks flashing to a different OS somehow... or was that not with the LL8?

[ScarabEpic22]

Cant do it with EFILive (last I head HPT couldnt do it either), have to use a Tech II to change OSs then read the new stock tune out, copy tables over, then flash it back in. Doubt Full Flashing will ever be supported for the P10.

[Whodunnit]

Hmmm interesting... :gossip:
I think I may know a shop in a neighboring town with a Tech 2. I can check tomorrow. Is there an OS version you'd recommend that you think would fix my problem or is that just opening up doors to more trouble with other things?

Thanks Erik. I appreciate all the help you've given me. :cheers:

- b

[ScarabEpic22]

I havent had any greater success with different P10 OSs, its the way the speedo calculator works on the P10s thats the problem.

Anyone know the formula to hand calc the values for these tables?

Just curious, what OS are you running now? Im using 12575262, its the 2nd to last 2002 OS IIRC.

[Chevy366]

Go here and enter VIN info http://tis2web.xw.gm.com/tis2web , at least you can find out latest OS for your TB and what updates or fixes if anything .

[Whodunnit]

I'm running OS 12579357.

Yeah, if anyone had any tips as to what values might affect the speedo readout at all, I could work on figuring out the equation, but so far I haven't been able to generate any change whatsoever with H0101, H0104, H0105, or B0205. I've given up on the speedo calc tool and was just entering in values manually. As I mentioned before H0101 does inversely affect the VSS reading though.

I checked out the GM website... here's what I get:

Calibration History for: Speedometer
Part Number CVN Bulletin # Description
12580498 00008583 - Part number change only, same as prior calibration
12574176 00007291 - Speedometer calibration
Any idea what this means?

[Chevy366]

I'm running OS 12579357.

Yeah, if anyone had any tips as to what values might affect the speedo readout at all, I could work on figuring out the equation, but so far I haven't been able to generate any change whatsoever with H0101, H0104, H0105, or B0205. I've given up on the speedo calc tool and was just entering in values manually. As I mentioned before H0101 does inversely affect the VSS reading though.

I checked out the GM website... here's what I get:

Calibration History for: Speedometer
Part Number CVN Bulletin # Description
12580498 00008583 - Part number change only, same as prior calibration
12574176 00007291 - Speedometer calibration
Any idea what this means?
After looking at the data again , the website will show if there is a updated cal for a specific area of the PCM , if there is a update it will show in a repository (registry) style tree , last being newer first being older , but any ways if you open your tune file EFILive will show cals listed for you OS .
If OS number is different than yours it is newer , so you have to do a Tech II update to get that OS (sorry with P12 you can do a full falsh) .
But does not mean it will calibrate tire size any better , but would be nice to see if it helped .

[Whodunnit]

:)
Oh!... thanks for your help. It's finally starting to make sense now... at least the OS revisions are.

It looks like I'm up to date with the Speedo cals... but for the record here's what I have outstanding:
Calibration History for: Operating system
Part Number CVN Bulletin # Description
12588012 00000D5E - New software to improve idle stability

Calibration History for: Engine
Part Number CVN Bulletin # Description
12591968 00001D2F - New calibration with diagnostic enhancements for DTC P0130 and P0506. Also improvements to fuel trim and EVAP diagnostics.
12588569 000059A8 - New calibration to improve idle stability
12582726 0000AE66 - New calibration to correct problem occuring at the assembly plant. Does not address any service issues.

Calibration History for: Transmission
Part Number CVN Bulletin # Description
12588580 00000B26 - New calibration to correct cold start/shift problems
12583073 0000652D - New calibration to improve transmission shift quality

Calibration History for: System
Part Number CVN Bulletin # Description
12588589 00005A32 - Enhanced Calibration for Cooling Fan Noise Reduction
12581579 0000D550 - New calibration for improved fan control

:cucumber:

[Chevy366]

:)
Oh!... thanks for your help. It's finally starting to make sense now... at least the OS revisions are.

It looks like I'm up to date with the Speedo cals... but for the record here's what I have outstanding:
Calibration History for: Operating system
Part Number CVN Bulletin # Description
12588012 00000D5E - New software to improve idle stability

Calibration History for: Engine
Part Number CVN Bulletin # Description
12591968 00001D2F - New calibration with diagnostic enhancements for DTC P0130 and P0506. Also improvements to fuel trim and EVAP diagnostics.
12588569 000059A8 - New calibration to improve idle stability
12582726 0000AE66 - New calibration to correct problem occuring at the assembly plant. Does not address any service issues.

Calibration History for: Transmission
Part Number CVN Bulletin # Description
12588580 00000B26 - New calibration to correct cold start/shift problems
12583073 0000652D - New calibration to improve transmission shift quality

Calibration History for: System
Part Number CVN Bulletin # Description
12588589 00005A32 - Enhanced Calibration for Cooling Fan Noise Reduction
12581579 0000D550 - New calibration for improved fan control

:cucumber:

Looks like there are a couple of updates for your PCM cals , sorry I have not messed with the Speedo Calculator on a P10 , so can't help you there .

[Whodunnit]

Well I found a shop about 30minutes away that said they can do OS updates, but when asked if he had a Tech2 he said, "well, we have scanners...we can do it." I'm not real convinced that's going to solve my problem with EFI Live settings not having any affect, especially since the updates don't seem to directly hit on Speedo control, so at the tune of $150... benefits might not outweigh the risks.
:iamwithstupid:

Would anyone mind helping me approach this a different way? I was looking at tinkering with the rev limiters in park/neutral, but it seem whatever values I input, I still can only rev to about 2.2k in P/N, which is annoyingly gutless and low, and makes me suspect that something with the EFI Live - LL8 programming might be amiss across the whole OS. :wtf1:

Has anyone happened to notice if B1201, B1207, or B1208 has a direct 1:1 or any affect on their P/N Rev limits? I set mine as high as 10000, 9500, and 9200 respectively, but still no change; no dice! :bangin:

[goldbergv95]

My speedo and VSS values are both reading 5.4% low. Intuitively I attempted to lower:
{H0101} "Vehicle Speed Sensor Pulses per Kilometer"
{H0104} "Trans Output Shaft Revs/Kilometer"
{B0205} "Vehicle Speed Sensor Pulses Per Mile On Data bus"
each by 5.4%, but that didn't seem to work. I don't see the {B0201} ScarabEpic22 mentioned anywhere?...

I tried changing just {H0101} and {B0205} a different time, but the adjustment didn't come out correct and the car just ran rough after coasting to a stop (hmm.... I'm wondering if H0104 needs to be linearly scaled with H0101 because the Description box states "It will normally be consistent with the equation: H0101=H0102*H0104.")

Do anyone happen to know if these values tend to be linearly scaled through zero (in a y=mx format) or is there an offset perhaps (such as y=mx+b)?

Any help will be GREATLY :welcome:!
Thanks in advance!

- bret

i seem to found the problem, this may not have to do with the version of the efilive BUT rather the error of efilive using kilometers rather than meters measurement under H0104 when using the speedo calculator.

there was a reason gm, pcmforless and waitforme does not follow the speedo cal because it leaves speedo off balance. if you were to adjust the tires and gear ratio and click apply Ho104 would use the measurements under kilometers, which is a no no. But based on the stock, pcmforless, and waitforme's tune they use the meter measurement instead. Like this for example.

6804

try that and see how it works. mine seems to be fine since i havent gotten any speed camra tickets (knock on wood)...

[blown4pt3]

After searching both the Trailvoy and this forum, I haven't found a good mathematical explaination for the numbers here. It also seems that some of the calculations for H0104 and B0205 shown on my readout from my TB are off just bit, which could be why when I had the stock tires my speedo was a little off from my GPS. So, I tried to understand from a math standpoint what was going on, starting with H0101, which you should be then able to calculate H0104 and in theory, B0205.

Just some quick background info, my blazer is an 03 SWB, 4wd, 3.73 open diff and came with BFG Long Trail T/As from the factory.

The factory readout for my blazer shows H0101 = 65199.

Using the equation H0101 = P*D*1000000/(T*pi)

Where P = 40 (which seems to make sense, 40 pulses per revolution of the output shaft)
Where D = 3.73 (in my case, since it uses 3.73 gears)
1000000 = the number of milimeters in a kilometer
Where T = 727.656mm

Before I start, let me explain "T", as one might quickly point out that a 245/70/16 tire, measures 29.5" in diameter. That may be true in theory, however, if you look at the BFG website for the LongTrail T/A, you'll see that it is 704 revolutions per mile, which I as I understand is a measured distance with a given load on the tire.

So to find out "T",
Divide 5280 feet per mile, by 704 revolutions per mile. That gives you 1 revolution is equal to 7.5 feet.
5280/704 = 7.5

7.5 feet, times 12 inches per foot, gives you 90 inches per revolution.
7.5*12 = 90

Take 90 inches, divide by pi, and you get 28.6479 inches in diameter
90/3.1415926 = 28.6479

Multiply 28.6479 inches by 25.4mm per inch, and you get 727.656399mm
28.6479*25.4 = 727.656

I included the math for anyone that would like to check and ensure it was done correctly.

Now back to H0101
40*3.73*1000000/(T*pi) = 65266

I know, not quite the 65199 number, but close.
Rewriting the equation and solving for "T", using H0101 = 65199, I ended up with T being equal to 28.6776".

So, that is a difference of my calculated diameter of 28.6776" - 28.6479" (from above) = .0298" in diameter!
It would be safe to assume a little bit of rounding was used when BFG arrived at the 704 revolutions/mile number.

The reason for the math was to simply understand where the number of 65199 came from. And I figured that if I could indeed calculate it out, that I could then properly calculate H0104 and B0205.

Based on my math above, it is my belief that H0104 in the table listed in EFILive should not be labeled as "Trans Output Shaft Revs/Kilometer", but as in "Trans Output Shaft Revs/Mile".

My table shows H0104 = 2637.4

Here is the math.

If H0101 = H0102*H0104,
then H0104 = H0101/H0102.

But 65199/40 = 1629.975, not the 2637.4 value shown in my table for H0104.

However, multiplying 1629.975 by 1.609344 (which is the number of kilometers in 1 mile) is equal to 2622.63. Hmm, so 2637 - 2622 = 15. This is a difference of 15 revolutions of the driveshaft in one mile, which is 600 pulses. 600 pulses in a mile seems like it would be a huge amount of error. We'll look at that issue in a moment.

15 revolutions of the driveshaft, divided by the 3.73 gear ratio, is 4 revolutions of the rear wheel. With a roll out distance of 7.5 feet per revolution of the rear wheel, this is equal to 30 feet. (7.5*4) in 1 mile.

So according to this, the percent error is 1/2%. I'm not going to show how to calculate percent error.

B0205 should also be able to be calculated the same way.

Taking the 65199 * 1.609344 = 104927, which should be a good value to use for the B0205. I believe that this math is what EFILive is using to calculate the numbers for what they call "TOS" for H0104 and B0205.

NOTE: This is all assuming that the transmission is using a 40 tooth reluctor, which is an assumption. I have not been able to confirm this, thats just what comes up when I do a search for replacement reluctors for the 4l60e trans.

Also note, to calculate the H0101 number, you need to start with the revolutions per mile from your tire manufacturer's website and calculate back the diameter.

This math also explains what goldbergv95 was showing in his chart with the circled numbers. I believe he means miles, not meters, otherwise the numbers would not match up.

If all of this has been explained before, sorry, I couldn't find it. Woohoo, post number 1 for me! :)

[joecar]

Hi blown4p3, welcome to the forum, excellent first post :cheers:

[ScarabEpic22]

Welcome to EFILive Dave, glad you made your way over from TrailVoy. Ive only half done the math before, Ill look at redoing it for my friends 04 P10 this week and see if I cant flash it tomorrow when Im borrowing his TB while he tints my SS.

[blown4pt3]

Thanks for the warm welcome guys!

Well, for the entertainment of it, I did toss the GPS into the TB tonight. With the stock tires, my speedometer would show about 2 mph faster than the GPS. Makes sense if the pulse count is greater than the actual calculated value. Not that it was be a bad thing. Now, the GPS is reading about 2 mph faster than the speedometer, or a net change of about 4 mph at 70/75. This is also fairly consistent with what the calculated difference would be between the stock 245/70/16s and the new 265/70/16s. A 5% difference at 60 mph in values equals about 3 mph.

However, the flashscan gave an error when trying to reprogram the computer. The first was the one about needing to be licensed to that vehicle. Ok, no problem, fixed that and tried again. It came up with a different error... but I didn't get a screen shot of it so I'll have to try again tomorrow.

[ScarabEpic22]

Did you get it working yet? Once it's licensed you shouldnt have any problems flashing it as long as there arent any aftermarket electronics on the databus.

[blown4pt3]

After sweating bullets last night when the PCM lost the base program and then finally getting it to recover with another laptop, I stopped working on it. Looks like I probably won't get a chance to try it again until the weekend. I'm committed to putting 4 new struts on our 13 year old Honda this weekend. Since it still has the factory ones on it, I'm sure I'll run into some problems that will have to be addressed before I can mess with the TB again.

I should mention that the TB is totally stock except for an Airaid filter/tube setup. Stock radio and all.

If it works, doesn't, or needs some other kind of tweak I'll post up what happens here.

[Taz]

Good post …. nice math !!!

In the past I had tried various approaches with speedometer calibrations - tire diameter (inches and millimetres) versus manufacturer’s revolutions per mile values.

I have found the software will make accurate changes to the speedometer calibration, based on tire diameter. If you input an accurate tire diameter, the software will recalculate tire circumference, tire revolutions per mile (this won’t match the manufacturer’s value), and VSS output pulses per mile.

The values in the Speedo Calculator will appear simultaneously in Imperial and Metric values - how this is displayed in the software will depend on the default settings you have chosen (Imperial versus Metric).

I would use a little caution in reverse engineering tire diameter from the manufacturer’s revolutions per mile figures - option for rounding and compounding errors to creep into the math equation.

I will generally confirm the tire diameter for the exact tire being used, and compare this value to the tire diameter of the same tire size from other manufacturers - to eliminate potential error.


Regards,
Taz