Gear Change Question?

[wa04compg]

Hey guys I have a 04 Comp G with the 3.29 gears would like to switch to the 2.93 gears to help increase my MPG's...other then the sprockets would I be able to tune for the diff gears and tapshift still work normally? People switch to 3.29's all the time but they aren't usually Tapshift cars. Anyone have thoughts on this not working?

[Fivefingerdeathpunch]

Sounds like a question Dave at TEP might know more about.

Otherwise adding timing to the cruise tables and driving 65 instead of 70+ will help alot.

[wa04compg]

Yeah I already have added timing in the cruise tables best I have done was 26mpg...my trans is getting weak so when I do a rebuild was hoping to change the gears for a couple more mpg

[SlowNA06]

Thought dudes were saying they got better mpg when they switched to 3.29's anyway.

[BillBoost37]

I would do it the reverse of what I posted that Dave said about 3.29's.

Start with the stock 3.29 Comp Table, I'd expect it says 3.69 gears. Plug in 3.29 and the tire size then commit with the auto scale on. Poof...

[wa04compg]

Thought dudes were saying they got better mpg when they switched to 3.29's anyway.

Best I get is around 26mpg highway...my buddy with 2.93 gears gets 28-30

[wa04compg]

I would do it the reverse of what I posted that Dave said about 3.29's.

Start with the stock 3.29 Comp Table, I'd expect it says 3.69 gears. Plug in 3.29 and the tire size then commit with the auto scale on. Poof...

I just pulled my stock Comp Table and it still says 3.29 for calculated gear....so would I have to plugin 2.93 after the gear change? This may be more of a pain then its worth

[Fivefingerdeathpunch]

Im curious as to what your tables look like, 26 is pretty low for highway mpgs.

[wa04compg]

Im curious as to what your tables look like, 26 is pretty low for highway mpgs.

Timing ranges from 35 to 45 degrees from the 1st column to 0.36 cyl air mass....rpm range is 1200 to 2400...as I remember last time I went on the freeway was seeing High 30's Timing...was told to not go over 40

[OH4CompG]

I would do it the reverse of what I posted that Dave said about 3.29's.

Start with the stock 3.29 Comp Table, I'd expect it says 3.69 gears. Plug in 3.29 and the tire size then commit with the auto scale on. Poof...

Comp G tables have the correct sprocket ratio of 1:1 and 3.29 FDR. Should just be able to do the opposite of what the 2.93 guys do and just put in 2.93 and click commit.

[wa04compg]

Did you notice a mpg drop when you put 3.29's in your regal? Wondering if its really worth the hassle...maybe I just need more cruise timing

[SlowNA06]

Maybe you're burning coolant instead of a healthy AFR. Got an aluminum LIM?

[BillBoost37]

There are definately trans tables we can't see that effect things. If you did it, you might be able to get away with correcting the sprocket ratio to 1.21

[wa04compg]

That is a possibility...I'm in the middle of changing to alum ones waiting for the parts to show up but yes the plastic ones looked like the where starting to come apart

[wa04compg]

Thanx for your input bill! At this point I think ill put my gaskets back in do some more tuning for freeway and see if it helps at all...if not then ill try the 2.93's

[SlowNA06]

Stray coolant will definitely lower your mileage.

[wa04compg]

Ok we'll hopefully that is the issue...what mpg do people usually get with 3.29's

[WolvesSoulZ]

With my Comp-G last time I did a little road trip I had 28-30mpg the whole trip(About 300 miles with about 100 of hills.). Gets about 20-24mpg city driving with a careful foot.
My L67 + 3.29 GT gets about 26-28mpg, but it's heavier. (Hitch, two subs, all my tools were often in my trunk.)

[wa04compg]

Yeah mine gets 24 to 26 highway and about 16 to 19 in town

[OH4CompG]

That's about right. My regal did about the same after I 3.29 swapped when I got the trans.