, just out of curiousity, can you log the IDC on the 26's on spray before ya swap?
2.73 to 3.42s tuning w/ Hypertech -WTF?
2.73 to 3.42s tuning w/ Hypertech -WTF? So I'm as happy as a pig in sht. I got my 3.42s in and took it home to program. Go through my hypertech (until I get a 'real' program) and the only options are 2.73 and 3.15 gear ratios (C5, A4). I've read through the few posts and found out that's the only option I get... HOWEVER.. I'm thinking that I can adjust the wheel diameter.
See if this sounds right..
I've set the program to 3.15s and calculated the wheel diameter should be 24.4 dia. to make up the difference (although not sure this will work)
3.15 / 3.45 = 1.086
26.5" tire diameter / 1.086 = 24.4" tire diameter to log into hypertech.
According to my pee brain, that should make the correction factor.
Did I miss something?
See if this sounds right..
I've set the program to 3.15s and calculated the wheel diameter should be 24.4 dia. to make up the difference (although not sure this will work)
3.15 / 3.45 = 1.086
26.5" tire diameter / 1.086 = 24.4" tire diameter to log into hypertech.
According to my pee brain, that should make the correction factor.
Did I miss something?
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
Don't know if this helps but thought I'd post anyway. I have one of the first Predator tuners that came out and it wouldn't change my speedo for 2.73 to 3.42 gear swap and had to use this tire size change from a chart that used to be on RWTD's site:
2.73 to 3.42 - Factory tire size 275/40-17 to Actual tire size 275/30-14
Worked fine for me, checked it against one of the gear/rpm calculators.
2.73 to 3.42 - Factory tire size 275/40-17 to Actual tire size 275/30-14
Worked fine for me, checked it against one of the gear/rpm calculators.
I'll try and search out a calculator for it. I tried setting the wheel size now. Seems to work but have to get someone next to me to see how accurate my calculations are. So far, no codes.
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
To check mine this is the one I used - you can change final drive ratio, tire size, gears, etc. to your application and recalculate even though it's for F-bodies. www.f-body.org/gears/
When I went from a 2.73 to a 3.42, I contacted Hypertech because the transmission was confused as to when to shift. They had me send my PCM to them, and they changed it there (for free). It took a little while to get it back, but the speedo and the shift points were correct.
UPDATE:
Finally threw codes last night and shifted with the delicacy of a sledge hammer.
Ordered the HPtuner this morning and put the Hypertech on CF for sale. Dang that HPtuner program is intimidating. Oh well, one step at a time... right? LOL.
Finally threw codes last night and shifted with the delicacy of a sledge hammer.
Ordered the HPtuner this morning and put the Hypertech on CF for sale. Dang that HPtuner program is intimidating. Oh well, one step at a time... right? LOL.
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