Mileage from a 6 speed install

[Skarkull]

I currently have a '05 GT with a saleen twin-screw on it. Pushing 9.5 lbs of boost and a GT500 fuel pump, some cams, etc. Currently when cruising on the highway at 70 mph, I average 20-22 mpg. That is with the stock 3650, and 3.55 rear gears. I'm looking to install a T56 Magnum, and was looking to see what kind of mileage improvement I could be seeing. With a .50 6th gear, and 4.10's I'd still have a 400 rpm decrease at 70 mph, anyone know how that will effect my mileage?

Thanks for any help you can provide.

-James

 

[skwerl]

Considering how easily I can skew my mileage with just a couple hard throttle pulls, I don't even bother keeping track. It does appear that my mileage has slightly increased since my T56 install but that could simply be a result of me not getting on the throttle as much due to higher temps. I also don't do much highway driving with it as it sucks as a highway vehicle (my 2002 F150 Lariat is much more comfortable on road trips). My overall mileage consisting of mostly urban driving is about 13.5-14. If I wanted a gas saver I would have bought a Civic.

 

[05yellowgt]

I gained a good 2mpg gong from the stock 3650with 3.55's to a t56 with 0.50 6th gear and 4.30 rear gears. I was NA at the time and saw an honest 28mpg by computer readout and hand calculation. You will probably see a bit less being supercharged.

 

[BruceH]

I currently have a '05 GT with a saleen twin-screw on it. Pushing 9.5 lbs of boost and a GT500 fuel pump, some cams, etc. Currently when cruising on the highway at 70 mph, I average 20-22 mpg. That is with the stock 3650, and 3.55 rear gears. I'm looking to install a T56 Magnum, and was looking to see what kind of mileage improvement I could be seeing. With a .50 6th gear, and 4.10's I'd still have a 400 rpm decrease at 70 mph, anyone know how that will effect my mileage?

Thanks for any help you can provide.

-James

Use whatever it takes to justify the purchase, lol.

 

[weather man]

I currently have a '05 GT with a saleen twin-screw on it. Pushing 9.5 lbs of boost and a GT500 fuel pump, some cams, etc. Currently when cruising on the highway at 70 mph, I average 20-22 mpg. That is with the stock 3650, and 3.55 rear gears. I'm looking to install a T56 Magnum, and was looking to see what kind of mileage improvement I could be seeing. With a .50 6th gear, and 4.10's I'd still have a 400 rpm decrease at 70 mph, anyone know how that will effect my mileage?

Thanks for any help you can provide.

-James

Good gooby de doo James! You got your audiences mixed up! You tell the wife your looking to drop a wad of cash to increase MPG. Tell us your tired of a shitty stock shifting TR 3650!

 

[hamish]

I expected to see better fuel economy going from 4.10's with the 3650, to a tr6060 with .50 6th gear.

In reality there hasn't been anything I can conclusively say other than I am getting about 17mpg.

I used to sit at roughly 2300rpm going 60mph, now it's 1600rpm.
I'm finding that I just drive faster!!
Haven't missed a 2nd to 3rd shift yet, I love that.

 

[Skarkull]

Good gooby de doo James! You got your audiences mixed up! You tell the wife your looking to drop a wad of cash to increase MPG. Tell us your tired of a shitty stock shifting TR 3650!

My 3650 shifts fine, but I also have a MGW shifter on it. I actually care about the gas mileage because I want better mileage to justify driving my car 1K miles one way to go see the family in it. Other wise, I should just take the wife's Intrepid. It gets about the same mileage, but doesn't need premium gas.

 

[BruceH]

My 3650 shifts fine, but I also have a MGW shifter on it. I actually care about the gas mileage because I want better mileage to justify driving my car 1K miles one way to go see the family in it. Other wise, I should just take the wife's Intrepid. It gets about the same mileage, but doesn't need premium gas.

Once you have the new transmission you will realize how bad the 3650 is, even with the MGW. Been there.

 

[jodadejss06gt]

I love my the magnum. Its much better than the 3650 and I had 0 issues with mine. I also have the .50 6th gear and I am still on 3.55. I def need to switch to maybe 3.73 or 4.10 to gain a little more omph in 1st.

 

[Skarkull]

I love my the magnum. Its much better than the 3650 and I had 0 issues with mine. I also have the .50 6th gear and I am still on 3.55. I def need to switch to maybe 3.73 or 4.10 to gain a little more omph in 1st.

What happened to your gas mileage in your swap?

 

[hamish]

just went for a drive today and found the flattest road I could.
Went both directions and averaged 23.5mpg @ 60mph .50 6th gear and 4.10's

 

[v8venomgt]

I love my the magnum. Its much better than the 3650 and I had 0 issues with mine. I also have the .50 6th gear and I am still on 3.55. I def need to switch to maybe 3.73 or 4.10 to gain a little more omph in 1st.

what do you have now, 3.31 or 3.55?

 

[jodadejss06gt]

I'm still on 3.55. My millage went up a little bit, but as others said.....with 400+ hp it doesn't take much throttle input to muck up a whole tank worth of easy cruising. This past weekend I got around 22 cruising decently fast on the interstate with an r32 and v70. After I filled up and took it easy home the gauge showed 25. I'd say 1-2mpg increase over the 3650, but its hard to really tell.