considering a gear change, what kind of 1/4 mile improvement should i see? What kind of top speed decrease should i see. Will it kill my gas milage

 

typically 2-3 tenths are seen with a good driver, top speed wont be a problem because you will still be able to go 150+, and it will kill your gas mileage about 4-5 mpg, depending on how you drive it too of course, could be 1 mpg decrease. although i have noticed an increase in city by 2 mpgs in mine but huge decrease in highway

 

I got 4.10s and still get around 22-25mpg driving like I do (WOT once a day). If you plan on keeping it around or near stock (as in no H/C) then I'd go for the 3.73s. My 4.10s feel real good, but I feel that as my car is currently (just about stock) then 3.73s would've helped it more. But get the gears, you'll love 'em.

 

I love the 3.73's in my A4. I have known a few people who have dropped .5 in there et swithcing to 3.73's with good tires and practice. Some people it may slow a tad bit due to poor tires and poor throttle control. I gained several car lengths over my buddys mustang after I dropped mine in.

 

4.10's are fun

 

i have 4.10s in my A4 and i love em. youll notice a huge gain in the city mpg cause it takes strain off the engine from getting the car moving (shorter gears now), but will notice a big drop in highway mpg. hope that helps!

 

I love my 3.73's and my 3200 stall. They are the best mods I have done.

 

in an OBDI car should you or do you need a tune for gears?

 

in the 93 cars you need to change out the speedo gear?? in the tailshaft,in the 94 and up cars the computer can be retuned for the gears

 

is a retune needed to run right? even with a 6 speed?

 

^Yes.

Its very simple. The PCM needs to know what ratio the gear is, so it can align the shift points correctly.

A local speed shop should be able to do it, and even some fix-it garages.
If you know someone with the Hypertech III Hand-held, they can plug it in and switch the gear ratio right there.
You don't need to run the crappy performance tune that it has ( im pretty sure ), you just need it to plug in and switch the ratio.

No, a special tune isnt needed, but it does need to be changed".
I think you can drive around, but you wont get as much performance.

 

what about a 6 speed car?

 

Get a MadZ28 tune computer and tell them you have 3.73's in it. They will program it and send it to you already done that way. They are a good upgrade anyway.~Cole~

 

sad to say its not that easy with the M28 or M29... they have a different setup i believe... so you just have to go with a dakota or SLP recalibration box... the dakota is far better anyways...