Manual trans final drive ratios.

[thaharlequin]

After breaking into the 40mpg range, well, 39.9mpg, but it's close enough, by having a route where I could pulse and glide, I'm pretty certain that an OD change could put me well into the 40mpg range, or likely the low 50mpg range at about 60mph. Now, the problem is that even with 265/75R15s, if they fit, I'm only at ~1600rpm, and I need to turn around 1200rpm to see decent (~50mpg@60mph) efficiency. My question is, are there any final drives around 3:1, instead of ~4:1 I see in all the E153/E51/etc...? Or, is there enough room in the case to fit a .5:1 fifth gear set in a manual?

[thaharlequin]

What about the diff/pinion shaft from a C-series transmission? Could that swap over?

[Eye8Pussies]

I think that people have asked the same question...and all the answers point to no....


and I personally would have thought that hte e153 would have a better final drive ratio...I was surprised when it cruises at about 400rpms higher than the auto did after I did the swap at 140kph

I had htought it'd cruise about hte same, thus giving better gas mileage, but I was wrong. higher rpms but less load = same mpg

[thaharlequin]

Yup... I doubt the diff from a C-trans would bolt up, so all I have left is cutting up a spare trans I have and using the 1.94:1 2nd in reverse for a .515 5th. I think it's doable as long as there's already enough room, or I could make enough room, in the transmission case cover. The gear set would be a bit trickier, since I would need to turn down the original 5th and hollow out the 2nd from the spare so that the 5th goes in the 2nd, and the tines on the gear line up with the grooves on the clutch hub, and do the same for the driven gear. Then weld 'em up good while making sure run-out is minimized and I should be golden. I can even check to see if this is viable next time I find a E-series trans at the j-yard by pulling off/measuring the trans case cover, provided I don't find someone who already has done so or convince someone to measure it. That, with a set of 265/75R15s and a 3.944 diff ratio should put me at ~1300rpm@60mph comapred to ~2100rpm now. Although I'm sure 235/75R15s would be fine. I should be able to get into the 50mpg range while having better off the line acceleration thanks to the other four gears. Eat that hybrid owners. OH YEAH I USED MAH BRIAN!!!1

I am so smart! I am so smart! S-M-R-T! I mean, S-M-A-R-T!

P.S. I'm so never gonna do this.

Edited cuz ah used mah brian.

[thaharlequin]

Ohhh, and I gotta measure the run-out of the stock setup compared to the modded setup to avoid problems with uneven loading.