MPG and Gears question.

[Mark42]

Plans are to put in 3.73 gears and a True Trac LSD (torsen) in my 98 Bird. Right now with the 3.08 gears I average 27 mpg doing a lot of highway commuting. The car is stock with an automatic trans.

Wondering how the 3.73's will affect the mpg?

Can you guys post your MPG and gears? (and I don't mean mpg while drifting :mrgreen:)

Thanks!

[LTb1ow]

Like 10-12.... 3.73s/3400 stall. LOL

[Anti_Rice_Guy]

3.23s, not even a full bolton lt1 A4

18-23 but never seen a full tank of highway

[Mark42]

Hmmm. Something tells me you guys don't do much highway. I would also gander that you got a heavy right foot. :grin:

Any commuters out there that eat up some highway?

[sweetbmxrider]

how do you have 3.08's?

[Mark42]

how do you have 3.08's?
Thats what came in the Firebird Coupe in 98 without any performance handling options.

[sweetbmxrider]

not to wander off topic too much but, 2.73's, 3.23's, and 3.42's were the f-body gear choices from the factory

[deadtrend1]

I know that my 91 305/T5 bird had 3.08's.

Maybe since he has a V6, they put 3.08s in them?

[sweetbmxrider]

i dono, i dono anything really anymore :-?

[Jersey Mike]

subbing. I'm getting about 18mpg city/highway with a bolt-on LS1 & 2.73s.. thinking of upping to 3.73s. Wonder how the tank will take it.

[LTb1ow]

I think its more of your stall that will kill your MPG than gears. If you don't nail it off every line that is.

[Anti_Rice_Guy]

Hmmm. Something tells me you guys don't do much highway. I would also gander that you got a heavy right foot. :grin:

What's a highway? :mrgreen:

The 24 was on like 2/3 of a tank of highway, but that included some messing around as well, plus the rest was around my area with hills and such.

[Mark42]

Don't you commute to school? Ya know that wide road near your house that is always under construction? (I think they call it RT80??) :D

My 96 Camaro w/5 spd averaged high 20's if I remember right. Hope the 3.73's don't kill it much.

[Anti_Rice_Guy]

Don't you commute to school? Ya know that wide road near your house that is always under construction? (I think they call it RT80??) :D

My 96 Camaro w/5 spd averaged high 20's if I remember right. Hope the 3.73's don't kill it much.

That I do, but I rarely take Rt. 80, between traffic and construction it could take as little as 45 min or as much as 2.5 hours. I stick with backroads through Morristown, then Rt. 510 right to Seton Hall. And besides, Camaro has never been to school, only the Explorer...

[Tru2Chevy]

Can't speak from personal experience, but from what I have seen on the v6 forums and with friends with 3.8 F-bodies, the 3.73s will likely hurt your highway mileage a bit, but as long as you keep your foot off the skinny pedal, you should see an increase in around town mileage.


how do you have 3.08's?

3.08s were factory gears for a 3.8 / A4 without the performance package (which added 3.42s and a posi for auto cars, and just a posi to the stock 3.23s for M5 cars, as well as dual exhaust tips).

not to wander off topic too much but, 2.73's, 3.23's, and 3.42's were the f-body gear choices from the factory

These are the only 4th gen v8 gears offered from the factory.....v6s (and 3rd gens) got different options.

- Justin

[sweetbmxrider]

yeah i didn't notice it was a v6 till it was mentioned

[V]

'01 SS(decently modded...cammed, bolt ons)... 29 mpg highway(M6).... 3.42s

I can easily go 350 miles highway, upstate NY to NJ, on a full tank and have some left over for the next day.

[Pampered-Z]

I'll guess you are going to loose about 5 MPG on the highway.

With my heads/cam LT1 = With 3:23 I was about 24MPG on long runs, with 3:42s I pickeed up a bit, around 26. With 3:73s I dropped to 20.

[maroman88]

ls1, intake, TB and catback, A4, went from 2:73's and no tune, swapped to 3:42's and a tune and now i get 15mpg with a very heavy foot and no highway, previously was in the 13mpg range with 2:73's and no tune :)

my old LT1 was in the 15mpg range with the 2:73's and a tune wen i didnt push it to hard