4.10 Diff cross country

[atmobenzin]

lolwut I've driven my m20 car with 4.27 for hours at 110kmh+. The high revs(3000-4500rpm) do get annoying considering the low speed, but other than that never experienced any problems due to diff being too short. Stop being whiny bitches.

The car was built for autobahn yo

[flyboyx]

^tru dat!

if it were me, i would go find a 528e and grab an open/lsd 3.23 for this trip. check it out really good, put synthetic oil in it, live happily ever after.


/thread

[e30construction]

I can actually lick my elbow. Just sayin'

I call bs..pic or no u can't

[lolcantturn]

You are going coast to coast and your diff is what you are most worried about?

LOLCANTUNDERSTAND
Get a 2.93 and get better mpg, it is a no brainer.

My car is pretty meticulously OCD maintained, I drive it up and down the Jersey coast 250+ miles every weekend for school, driven it up and down to Vermont/Canadian border 3 times in 2 months, with no problems, and other shit, so yes, the only thing I'm worried about is my diff. It'll be the longest continuous trip I've done so I'm just making sure. Silly unfunny elitist.

Changed the trip around, instead of taking just interstates, I'll be driving US routes in the day and interstates in the night (Nothing to see in the night anyways really). So not much high-rpm continuous driving. Diff fluid has been changed for the trip though :)

[nando]

So now if you have a brain and can think critically, you're an elitest?

Nice.

Maybe i should go grind all the paint off my car, then i could get some respect! :p




..lighten up....

[phreshkid]

I call bs..pic or no u can't

Don't tempt me boy

[Holland]

You are going coast to coast and your diff is what you are most worried about?

LOLCANTUNDERSTAND
Get a 2.93 and get better mpg, it is a no brainer.

I'm going to call this out a bit. There is no way he will get even marginally better MPG with this. His revs will definitely be lower but that M42 produces no torque. His foot will be too buried.

I'm thinking anything less than a 3.73 or a 3.64 will be poor economy.

[Dj Buttchug]

I'm going to call this out a bit. There is no way he will get even marginally better MPG with this. His revs will definitely be lower but that M42 produces no torque. His foot will be too buried.

I'm thinking anything less than a 3.73 or a 3.64 will be poor economy.

gonna chime in here. This is a false statement. I know from experience.

First off op, you will not be buried in the throttle at all with a 2.93 especially freeway driving. you may have to downshift to take on hills ect but the mileage of an m42 is GREATLY increased with a 2.93 rear end.

I have two NA m42 cars right now consistently getting 36 mpg on the freeway with this setup.

[Holland]

gonna chime in here. This is a false statement. I know from experience.

First off op, you will not be buried in the throttle at all with a 2.93 especially freeway driving. you may have to downshift to take on hills ect but the mileage of an m42 is GREATLY increased with a 2.93 rear end.

I have two NA m42 cars right now consistently getting 36 mpg on the freeway with this setup.

Well shut me up. I still find it a bit hard to believe though.

[Dj Buttchug]

A m42 turning 3600 to 4000 r3v at 80mph uses more fuel. I was in the same boat as you holland before I started messing with gear ratios. I wanted to lower my freeway revs cause my car was annoying to drive such long distances at such high engine speeds. I drive almost 500 miles at a time so the higher ratio just wasnt cutting it.

After I swapped in a 2.93 the pep of the m42 was no longer noticeable, at least until you shift down about two gears. At 65mph on the freeway the m42 is great with 4.10 the only problem is your going 65 and you are constantly avoiding being run over by semi trucks ect. I saw a steady 9mpg increase with a 2.93 and it makes cruising at 85+ mph so much more desirable. with a 2.93 out back and the g240 trans the m42 turns about 2700 revs at 80-85 mph

Ive also found that other things come into play when trying to squeeze the most miles per gallon out of m42 cars. Obviously weight is a huge factor and so is wind resistance. A lowered car gets about 1-2mpg better. A car that has less air turbulence underneath it cuts through the air better. blah blah blah.


To stay on topic the answer to the question is yes. The m42 can handle the high revs for an extensive period of time provided it has been maintained properly and is in running well. Have fun driving it turning 4k for hours on end trying to listen to music and or hear yourself think over the constant buzzing. If you have exhaust or an intake it makes the noise significantly more annoying. expect somewhere between 27-30 mpg at best with a tailwind. As stated above the diff shouldnt be your biggest worry driving that far in an e30 anyways.

pic to prove im not full of shit. yes I know my gas gauge is broken. this is pushing it but you still see the mpg indicator which gives you a ballpark idea of what you are getting at that exact time at that rate of speed. This is on flat road, no wind bout 40% throttle if I had to guess.

[lolcantturn]

A m42 turning 3600 to 4000 r3v at 80mph uses more fuel. I was in the same boat as you holland before I started messing with gear ratios. I wanted to lower my freeway revs cause my car was annoying to drive such long distances at such high engine speeds. I drive almost 500 miles at a time so the higher ratio just wasnt cutting it.

After I swapped in a 2.93 the pep of the m42 was no longer noticeable, at least until you shift down about two gears. At 65mph on the freeway the m42 is great with 4.10 the only problem is your going 65 and you are constantly avoiding being run over by semi trucks ect. I saw a steady 9mpg increase with a 2.93 and it makes cruising at 85+ mph so much more desirable. with a 2.93 out back and the g240 trans the m42 turns about 2700 revs at 80-85 mph

That's insane! 9mpg? Really? Because I got 38mpg at best with my E30 at a constant 70mph. Can't imagine 9mpg more....

Though a 2.93 around the rockys with a passenger and load will be....literally impossible.

[Dj Buttchug]

That's insane! 9mpg? Really? Because I got 38mpg at best with my E30 at a constant 70mph. Can't imagine 9mpg more....

Though a 2.93 around the rockys with a passenger and load will be....literally impossible.

yea but the faster you go the less less efficient you are. at 65-70 i have never gotten 38 mpg with a 4.10. EVER. shit I cant even get that good with a 2.93. theres no way thats right

[lolcantturn]

yea but the faster you go the less less efficient you are. at 65-70 i have never gotten 38 mpg with a 4.10. EVER. shit I cant even get that good with a 2.93. theres no way thats right

Honestly, it is. Didn't pull it out of my ass. Filled up at my town, drove to Killington Vermont, filled it back up. 38mpg. VERY light foot.

[Wschnitz]

I call BS,

But yes, 2.93 is nice, I get 33ish highway in my seta, and that's having fun dropping gears and scaring Prius drivers too.

[3vilE30]

2.93 lsd on my super eta with a 4 speed auto, 4th gear has a .73 ratio paired to the 2.93 lsd I'm at about 70-73ish @ 2k rpm in 4th getting some pretty good mpg numbers. Obc says 40-50mpg range