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2.93 to 3.29 gear change tuning HPtuners

OH4CompG

OH4CompG

New member
Ok I know that you have to go into speedo and change the final drive from 3.29 to 3.69 for this and commit that change. My question is do I have to do a full write after this? I did this and did a partial write and my Tim King trans is shifting really hard like its in max adapt and maxing the line pressure. I can hear the pump whining too. This is the same thing that happened last time after I got it from him new. And eventually after a few thousand miles I had to send it back for repairs.
 


Just need to know that I changed the tune properly before I ask Tim for further advice or I just swap some 2.93 chains in there and be done with it
 


You don't change pulses per mile that I know of Matt. At least that's what the guys on HPtuners forums say
 
Found my answer! Need to do a full write on the tune after changing to 3.69 in the speedo section to reset all the trans adapts!
 
In case anyone needs it.

BillBoost37 said:
I had contacted Dave at TripleEdgePerformance on one of the other forums for his assistance in gear ratio changing. When Intense rebuilt my trans they recommended a different tooth count reluctor wheel (VSS) and a speedo recalibrator. Unfortunately as you tune etc the pcm is seeing the incorrect speed. This always bothered me and I noticed a few people doing it w/o the spoofs.

The below quotes are great info for anyone considering a gear change that has an HPT or can have the programming done.

Dave, I've heard alot about you and talked with many guys. Quick one for you hopefully. Car is a 97 Bonneville, may as well be a 99, I swapped the harness and pcm last week. Do you have the parameters for 3.29 gears with HPT? I have a couple different ones and am looking for the definitive sure thing. Trans was updated by Intense when done the first time around. Basically went with one of everything.

thanks
Bill
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Hi Bill, since you have HPT I am going to give the easiest sure-fire way that I use for 3.29s in place of 2.93s. First off make sure you have 100% STOCK 2.93 tables and numbers for everything trans related. Once that is verified go into the Speedo folder in the editor. You will see a handful of numbers but there is only ONE that you need to change and it works perfect every time. On the top of this menu there is "Tire size" and "Gear Ratio" You will need to re-enter the existing tire size but instead of 3.29 ratio that it has stock replace it with "3.69" . Leave the "Auto calculate" feature turned ON. click commit change and that is it! Its that simple. Many people calculate numbers are import numbers from 3.29 geared cars and it rarely works, dont ask why it just doesnt. You will know the method I gave you works because you will not recieve an incorrect gear ratio code and also in the scanner pull up Current Gear Ratio in the PID list. In 3rd gear it should read 1:1 and must be within a few hundredths or it will throw the code. So just change 3.29 to 3.69 and you are set. And just so you arent confused about why it already says 3.29 from the factory that is because the differential ratio is a 3.29. There is also a parameter for sprocket ratio and it will be 1.121 which after some math gives you the 2.93 overall ratio. Changing this to 1.00 does NOT fix the problem, just leave it as is and it will work fine. I hope this helps you out
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Click to expand...
 


Good info Bill. I already read that because it was posted up verbatim on the idahoclub3800 site. Just note, do a full PCM write after you change that gear ratio.
 
Yessir! It was Jared's doing. We miss Thomas. And we hate him for his year round racing ability in Arizona.... ;)
 


had similar problem in my 2000 daytona going from 293 to 329. i did put the heavy duty diff and learned the tune had to be at 369 gear ratio for the speed sensor. after doing this the code for incorrect gear ratio was gone and all is well. if the diff is the light duty then i would imagine u just flash 329 gear ratio and it should work
 
Gear ratio of 3.29 = gear ratio of 3.29 whether it's HD or not. However you won't ever go from 2.93 to 3.29 with a non-hd diff on purprose.
 
Sorry to revive this, but what would the input value be if you were changing from 2.93 to 3.05 gears? (Top swap with S/C bin purposes)
 
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