2.73s to 3.42
2.73s to 3.42 I have 2.73s in my car now I got a differanty rear end with 3.42s. If I swap the rears how will the computer react will I be able to drive it or will the shift points be all messed up.
You should beable to drive it just fine until the tune. Just try to figure out how much your speedo is off. You could use one the online gear/speed calculators or go out with a friend and pace next to him at several different speeds. Not exact but you should be close enough to not get pulled over.
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You will probably be ok, although your speedo will be off. Your shift points will be fine until the tune, because although they will be off, your speedo will be off by the same %, so it all works out. You'll need the tune to correct your shift points as well as speedo though.
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hell yeah your speedo will be off, haha. i went from 3:23's to 3:42's and i was following my dad who was going 25 and my car said i was going 40, haha. i'll be getting mine tuned very soon, haha
The car should be driveable, but the shift points will be off (as well as speedometer). The higher gear ratio will make the PCM think the car is going faster than it really is, causing earlier shifts. At least that's how it is on my OBD2 Camaro, not sure about the OBD1's.
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From: Decatur, TN (N-W of Athens)
The car should be driveable, but the shift points will be off (as well as speedometer). The higher gear ratio will make the PCM think the car is going faster than it really is, causing earlier shifts. At least that's how it is on my OBD2 Camaro, not sure about the OBD1's.
For shift points to be screwed up they would have to be driven off the tailshaft speed but then the speed be driven off wheel speed like an old VW van( rear engine, rwd, front wheel speedo) or something, but that ios not the case it is all driven off the sensor in the tailshaft housing.
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From: Decatur, TN (N-W of Athens)
I'll assume you meant "shouldn't"
Both are with 245/50-16 tires factored in.
Here's A4's @ 5700RPMs (since that'll show the biggest change)
3.42s
RPM---1st----2nd---3rd----4th
5700---42----79----127----182
3.23s
RPM---1st----2nd---3rd----4th
5700---44----83----135----192
Here's M6 (95-97)
3.42s
RPM---1st----2nd---3rd----4th---5th----6th
5700---48-----71----98----127---172---254
3.23s
RPM---1st----2nd---3rd----4th---5th----6th
5700---51----76----104----135---182---269
Both are with 245/50-16 tires factored in.
Here's A4's @ 5700RPMs (since that'll show the biggest change)
3.42s
RPM---1st----2nd---3rd----4th
5700---42----79----127----182
3.23s
RPM---1st----2nd---3rd----4th
5700---44----83----135----192
Here's M6 (95-97)
3.42s
RPM---1st----2nd---3rd----4th---5th----6th
5700---48-----71----98----127---172---254
3.23s
RPM---1st----2nd---3rd----4th---5th----6th
5700---51----76----104----135---182---269
i forgot to mention that i was already off about 6 miles an hour ever since i bought the car. not sure why that is. i was just stating that it got worse when i did the gear change. sorry for the excitement in the thread, haha
As already said the shuift points will act the same as the speedo since they are interrelated. You are just overthinking this and convinced yourself there was more difference.
For shift points to be screwed up they would have to be driven off the tailshaft speed but then the speed be driven off wheel speed like an old VW van( rear engine, rwd, front wheel speedo) or something, but that ios not the case it is all driven off the sensor in the tailshaft housing.
For shift points to be screwed up they would have to be driven off the tailshaft speed but then the speed be driven off wheel speed like an old VW van( rear engine, rwd, front wheel speedo) or something, but that ios not the case it is all driven off the sensor in the tailshaft housing.
I too went from 2.73's to 3.42's and I noticed a few changes.....
First my speedo was off! But my car would shift the same way as when I had 2.73's. Although at WOT I would BOUNCE off the rev limiter EVERY time I got into the gas! But other than that I just noticed that I would be doing around 60 or so and my speedo/ Tach. would show 80 MPH @ 2000 RPM's (2.73 setup) But drove fine and just racked up a few more miles due to the fact that the speedo was showing I was traveling faster than I was actually going. But nevertheless it was perfectly OK to drive till I got it tuned!
Good Luck
James
First my speedo was off! But my car would shift the same way as when I had 2.73's. Although at WOT I would BOUNCE off the rev limiter EVERY time I got into the gas! But other than that I just noticed that I would be doing around 60 or so and my speedo/ Tach. would show 80 MPH @ 2000 RPM's (2.73 setup) But drove fine and just racked up a few more miles due to the fact that the speedo was showing I was traveling faster than I was actually going. But nevertheless it was perfectly OK to drive till I got it tuned!
Good Luck
James
