any 6sp's that bolt to m42?

[briansol]

my problem, back to page 1 here, is gearing. i cruise 85+ mph on the highway because i have a long as hell commute. r's are over 4k most the way into work.

it's not that i'm flooring it, in fact, i'd say most of my ride is under 10% throttle.
around town, i actually get slighly better mileage... 25-26. on the highway, 24-25.
it's all backwards.

but, around town, i'm just crusing around and the car rarely sees 4k in any gear around town.

so, i point my finger directly at gearing. it's just winding out for no good reason.

my active has an lsd on it already. not sure what the fdr is on it.

[yoda]

Originally Posted by briansol

my problem, back to page 1 here, is gearing. i cruise 85+ mph on the highway because i have a long as hell commute. r's are over 4k most the way into work.

it's not that i'm flooring it, in fact, i'd say most of my ride is under 10% throttle.
around town, i actually get slighly better mileage... 25-26. on the highway, 24-25.
it's all backwards.

but, around town, i'm just crusing around and the car rarely sees 4k in any gear around town.

so, i point my finger directly at gearing. it's just winding out for no good reason.

my active has an lsd on it already. not sure what the fdr is on it.

Then you have answered your own question... you are in fact cruising at 85+... there is NO fuel Efficiency in that, no matter what car or engine... the 1.9 ltr 4 cyl engine is not made for that, not enough torque to push the car through and maintain the speed without undue stress on the little engine. In fact you're getting great MPG's if that's how you're treating it... try it on the M3 at those speeds and you wont get 16 MPG!... If you want to keep the car at lower RPM's simply swap the diff... you probably have a 3.45 if it's a manual... raise the rear end of the car and take a look at the plate on the differential, it'll tell you the FD... and if it is an LSD it'll say S3.45XXX if not it'll say 3.45XXX... you can look on ebay for e30 lsd's and you can go with a 2.93 if you're going to continue with the 85+ MPH commute... the whole swap will cost you about $400 (LSD, Half shafts)... other than that... move closer to work!... lol

[briansol]

i have a 95 it's a 1.8 and yes, its manual.

i actually get my best mpg in the m3 in the mid 80s. 60mph, i see 22-23. at 80-85 i can do 24 ish mpg. around town, i see 18-20.


Here's the kicker though.

i did do a test at 70mph for a whole day. (110 miles) my mpg was still 24. 70 or 85, i'm getting the same crap mileage.
going 70 adds 20 min or so to my commute over going 85.
so, it may be using less gas per minute, but its on for many more minutes.

[spidertri]

Just wondering, did you reset your mpg gauge before trying this? I commute 50 miles a day and I keep it at 70mph and see ~32mpg from the obc.

[briansol]

yes, i reset it.

[Swap_File]

This might be a stupid question, but has anyone ever looked into swapping gears inside the transmission?

I know with many older Honda transmissions you can combine two transmissions to get the ratios you want. Take 5th gear from another transmission to give you a nice cruise RPM, then take 1st - 4th from another for nice acceleration.

Does anyone know how the guts of a Getrag 250 and a Getrag 260 compare?

I am keeping an eye out for a Getrag 260 at the junkyard, but I doubt I will find one any time soon.

[J!m]

Swapping gears is also done in some Range Rover transmissions to get better cruising RPM's as well.

I personally don't like the idea, but I know it is possible.

My friend Mike had a 4-speed in his 101 Forward Control with a very tall fourth- he said it was like "Gear 1, 2, 3, and 5- no 4!"

Diff gear changes make a bit more sense, particularly with a six speed.

Also, altering tire height can fine tune final drive ratios as well...

[spidertri]

Originally Posted by Swap_File

This might be a stupid question, but has anyone ever looked into swapping gears inside the transmission?

This is a pretty common mod for the VW TDIs. The euro versions had a taller 5th gear that could be swapped in to the US transmissions. I think with the BMWs it just came down to the diffs being easier to swap and more readily available. The euro 6speeds have pretty much the same gearing for 1-5, they just tack 6th on, not much help when you want to swap gears into a 5spd.

Try looking for 260s on E30tech, I've seen them pop up on there occasionally.

[96cali]

g260's are all over in the e28 community. check out my e28.com

[Swap_File]

Yeah, I know if I really want a Getrag 260 I can pay for one and get it, but my goal is to find it cheap at the local junkyard.

They have flat rate pricing, so every transmission is $100, diffs are $50. Prices are half on Wild Wednesday.

And if I get it cheap, I won't care as much if I manage to damage it while experimenting.

[95EurOLoVin318ti]

i usde the cheapest tire and i cant keep the pedal off the floor soo i wudnt know the gas milage and i think my meter is broken cuz my temp is always reading neg 20

[z6crx]

I agree the Ti's need a longer 5th or a 6th gear.

finding a 6 speed would be pretty hard and expensive so I'm probably going to look out for a rear diff with LSD , must have with the hills and ice/snow here.

[Mad-Machine]

Originally Posted by briansol

i have a 95

i did do a test at 70mph for a whole day. (110 miles) my mpg was still 24. 70 or 85, i'm getting the same crap mileage.

Sorry to bring this back.. but there is your problem. At 70MPH I get low mid30s in my Ti.. something is wrong with your car. My car is also lowered and running M3 rims and tyres.. 235/45/17s all around... Potenza re050as too.. so wide AND sticky

[kalimot]

Originally Posted by CirrusSR22

I don't think you should do either a transmission swap or a diff swap. My car is an automatic (4.44 stock diff) and I put in a manual diff (3.45) to try for better fuel economy. Engine RPM on the freeway dropped from 3,000 RPM @ 70 MPH to 2,400 RPM @ 70MPH. Fuel economy has not changed at all. I have 15,000 miles on the 3.45 diff and 63,000 miles on the 4.44 diff, so I would have seen the change.

Maybe it'll help at 80 mph, but I doubt it'll be more than 2 mpg.

On a steady freeway cruise at 65 mph, my car will routinely get 32 mpg at a minimum. But, I consider 35 mpg to be routine on a long, steady cruise in the 60-65 mph range during the summer months. Winter is a bit less. Slowing down is you only choice IMO

Was the 3.45 diff a direct swap? I'm thinking going this route as well to improve my gas mileage. How's acceleration compared to the 4.44? I'm only getting around 27 mpg freeway on my automatic ti I've done all tune ups and I'm pretty light on the pedal. I was hoping to get 30+mpg when I first got my ti, help is appreciated! Thanks!

[J!m]

The manual diff is a direct swap.

Your acceleration will be really poor with that diff. The car will feel like it is loaded down with tons of cargo...

But it is a direct swap, yes.

I personally do not believe it will make a significant average fuel economy increase because you will be harder on the pedal to get going, even though you will be easier on it once you are going.