98 trans am 2.73 to 3.42

[Eric]

Hi everybody, i have a question about changing the gear on my friends 98 ta , the gear is changed but drives wierd because the tune is seeing to many revs at the speed sensor i imagine , so my question is how do i go about this , i know i have to get into the speedometer parameters andca use the calculating table but not sure on the specifics ,can anyone clear this up for me , thank you eric

[joecar]

Hi Eric,

Goto the Speedometer segment, click Speedo Calculator, goto the Shift Point Correction tab, set original ratio to 2.73, set new ratio to 3.42, make sure all the mentioned tables are checkmarked, read the red warning, click Apply, save file, then flash it to PCM (calibration only flash).

[Eric]

Hi Joe , nice to here from you , thanks for the info , when you say mentioned tables do you mean the tables with the green checkmarks , they are all marked because i imagine they would all be influenced by a gear change , so i leave them all checkmarked , i hear you on the red warning , if clicked twice the change would be aplied x2, why is this alowed in the software, do i ignore tire size because there is none originally when i open speedo calculator , is this normal , one last question, my friend bought this ta two months ago and i dont know if the tune has ever been touched , is there any way of finding out if it is stock , will the history tab confirm this or does it just apply to my fresh start with the tune through the software, oh and when i open the tune with the software it warns me that this tune file can be harmfull if used on an ETC equiped vheicle , is that normal , his 98 TA is cable but it is linked to his cruise controle motor , thank you Joe, Eric

[joecar]

Hi Eric, good to hear from you, it's been a while :cheers:

Yes, with the green checkmarks, leave them all checkmarked.

Click once: good question, I don't know why it doesn't block subsequent clicking.

Your friend's tune file can be compared against the same OS stock file on www.holdencrazy.com (http://www.holdencrazy.com).

Yes, editing the ETC tables (red folder) incorrectly can brick the PCM; you don't need to touch those tables.

[Eric]

Your to fast Joe , thanks, yes i can compare it to a tune at holdencrazy with the same OS, lots to compare but the important stuff will tell me , my friends TA is not ETC but i guess its a warning incase i want to use this tune on a ETC equiped vehicle, oh by the way in the calibration window under segments there is only the operating system that is green checkmarked and engine and trans calibrations and diagnostics along with fuel system , system and speedometer are not green checkmarked , is this normal and the read did not pull up the vin# and no OSID and BCC is Z???, is all this dependent on the pcm and year , some can be retrieved and some not , thank you Joe, Eric , i am almost ashamed to tell you this but remember that long thread we had concerning installing v8 and updating firm ware and boot block so i can black box log , well would you believed i never got to it but i did save all that thread and plan on doing it very soon , you will know when i do it because i will probably get back to you while scratching my head and desperate for your help , your help is awsome and greatly apreciated

[Eric]

Hi Joe , i had asked you why i had no tire size or gear ratio when i opened the speedo calculator, of course it makes sence because this is all specific to the software and makes it easier for someone to ajust for gear and tire changes and can fine tune the speedometer , this can all be done by using the formula H0101 = PxDx1000000/(Txpi) but its more calculations and would take a bit of time for the speedo fine tuning , well i guess even using speedo calculator for speedo fine tuning can be trial and error till is almost perfect if you need it to be , am i on the right track here, oh wanted to ask , will disableling the egr on his 98 TA be done the same way as on my 2000 pickup, thank you Joe , Eric

[joecar]

Eric,

That's ok, take your time, read up, play/familiarize with the software.

No VIN and no OS ID... can you post the file.

[joecar]

Eric,

If you can measure vehicle speed independently of the PCM (i.e. using GPS or measured mile marker), then there is no need for trial-and-error...

in the Speedo Calculator goto the Speedo Fine Tuning tab, you enter your displayed speed and your actual speed and apply the correction.

[Eric]

Thanks Joe, yes i do have to catch up on all this , yes the best way is just to spend lots of time on it and be thankful for help from you guys , i did like you said and pulled up two tunes from holdencrazy with the same OS and as far as i can see compared to the two tunes the oil pressure on my friends tune on the upshifts are up by about 30% and that makes sence because i found that it was shifting hard for stock and i also noticed that the H0108 (etc speed govern shreshold) has been set to 0.0 and both the other stock tunes were set at 412 , does this mean that this etc has been diabled, i am confused about this etc obviously because i told you he did not have this on his car and you previosly told me not to touch the etc tables but it is ok to disable it , so this etc can actually cut the throttle mechanicly , does it work with the traction controle because i noticed while in his car that he had a switch that could dissable the traction controle or does the traction controle use an other method like torque limiting , thank you Joe, Eric

[joecar]

Even tho his car does not have ETC, the PCM is still able to control throtte via the TAC module (throttle cable wraps around it on its way to the throttle blade), this happens during traction control and cruise control...

I'm not sure, but those tables in the red ETC folders may come into play, and if the PCM thinks they are wrong it will brick itself.

[Eric]

Hi Joe , i sent you my friends file like you asked , like i said the H0108 is set to 0.0 and the stock tune from holdedcrazy is set to 412 and i also noticed that the holden tune does not have the vin# along with the OSID and BCC and the only the operating system under segments is checked just like my friends tune, all i want to do is recalibrate for his new 3:42 gear and remove torque management and redo the shift pressures because i find the car shifts to hard under light thortle and can take a bit more up high , i will reduce the shift times some , should i remove the abuse to get a faster peddle responce and so it doesnt kill torque from a dead stop kickdown, i can do all this but i dont want any problems with the ETC , when i was connected to the PCM to read his file i closed it and i reopened the file to make sure it was saved and that is when i got that warning about the danger of loading this tune into and ETC equiped Vehicle , this doesnt make sence to me because the tune is from his TA that has ETC , i hope you can clear this up for me , thank you Joe, Eric

[Eric]

Just thought it may be useful if i sent you the stock 98 TA tune from holdencrazy, thank you Joe

[Eric]

Wow first time i send a tune file to anybody , what scares you seems to dissapear as you move forward , thanks Eric

[joecar]

Set the VIN in the VIN box.

Use the Speedo Calculator to adjust the green checkmarked tables.

Set the shift times to 0.25s all across.

Set the torque reduction low cells to 30% and test drive for PT shift feel... if needed, set the first 5-6 cells to 45% and test again.

(I'd rather leave the shift pressures alone rather than decreasing them, unless shift kit has been installed).

Abuse mode kicks in when you move the gear lever from P/N to R or D... it reduces torque for a few moments while the RPM is high, you can leave it as is.

[Eric]

Thanks Joe , what should i do about the H0108, as you can see from his tune it is not stock but the only thing i see changed is the trans shift pressures and H0108 is set to 0.0 , what about the warning that doesnt make sence, Eric

[joecar]

I would leave H0108 as is.

[Eric]

Could it be that it came stock with a 0.0 setting , doesnt make sence because the other stock tunes are set to 412 , i will just leave it as is like you say , what is the difference from setting it at 0.0 or 412 , i will try and research it , do you think i could add a bit of timing without any problems or is that 98 tune already high , did gm set the timing table for 92 octane feul or just lower regular like they do with the trucks , that would leave me some play if we use premium fuel , thanks Joe