3.73lsd: 25.3mpg highway

[m3chaser]

Yep, I got 25.3mpg on the way up to Canada. I was travelling between 70-80mph with a couple bursts to 90-100mph and then back down again (maine is a looooong drive with noone on the roads ahahaha). Pretty darn good if you ask me for the 3.73lsd and that included about 200lbs of luggage and my wife.

Just thought I would share.

[GBimmer]

I hate you.

really.



I average 22 tops.

[Terry F.]

25.3? 80mph is 4000rpm. I get 16-17. Wow, that's remarkable, congrats!

Terry

[IslandS62]

was it all downhill?

[The ZED]

damn, the best I get is 22, but I have a wussy motor that doesn't go through gas like that.

[speedfreak81]

Damn Jon.....buzzing along aren't you! How loud was it inside the car?

[JWin]

Jeebus, I got 26 from Kentucky to Texas (with stock 3.15) generally obeying posted speed limits.

[m3chaser]

Originally Posted by speedfreak81

Damn Jon.....buzzing along aren't you! How loud was it inside the car?

Son of a beasting Brian, I just realized I never called you! I am really sorry bro. I was in the process of swapping out the diffs and I got down to the last bolt and it was stripped, so I ended up putting it all back together and keeping the 3.73lsd in for the trip. From there I got volunteered to help set up for a wedding and was there till 1am! I completely forgot to give you a call and I feel like an idiot. I do apologize.

The car is not very loud inside when cruising at those speeds. My wife slept soundly so the noise didn't bother her at all.

I was following my family and they were travelling around 70-80mph. I had my tire pressure at about 38psi and kept a steady throttle when I could. I also have a check engine light which I believe is an O2 sensor (just replaced the pre-cat sensors) so that may have hurt my mpg as well.

[speedfreak81]

Originally Posted by m3chaser

Son of a beasting Brian, I just realized I never called you! I am really sorry bro. I was in the process of swapping out the diffs and I got down to the last bolt and it was stripped, so I ended up putting it all back together and keeping the 3.73lsd in for the trip. From there I got volunteered to help set up for a wedding and was there till 1am! I completely forgot to give you a call and I feel like an idiot. I do apologize.

The car is not very loud inside when cruising at those speeds. My wife slept soundly so the noise didn't bother her at all.

I was following my family and they were travelling around 70-80mph. I had my tire pressure at about 38psi and kept a steady throttle when I could. I also have a check engine light which I believe is an O2 sensor (just replaced the pre-cat sensors) so that may have hurt my mpg as well.

No worries man, when are you coming back stateside? We'll set something up then.

[Rokomis]

I get about 27MPG if I keep it @ 70 with my 3.73. With the magnaflow it just kinda hums along nicely.

[m3chaser]

Originally Posted by speedfreak81

No worries man, when are you coming back stateside? We'll set something up then.

I should be back in VA by monday evening I believe. We will definitely get together soon!

Originally Posted by Rokomis

I get about 27MPG if I keep it @ 70 with my 3.73. With the magnaflow it just kinda hums along nicely.

Very nice. I wonder if the the M52 gets better mpg compared to the S52? I imagine I could get 1 or 2 mpg more if I didn't have all the extra luggage and it was just me and my wife.

[Rokomis]

Originally Posted by m3chaser

I should be back in VA by monday evening I believe. We will definitely get together soon!



Very nice. I wonder if the the M52 gets better mpg compared to the S52? I imagine I could get 1 or 2 mpg more if I didn't have all the extra luggage and it was just me and my wife.

Well another thing to consider is I have 400cc less of displacement too.

[mcoupemindy]

Originally Posted by m3chaser

Yep, I got 25.3mpg on the way up to Canada. I was travelling between 70-80mph with a couple bursts to 90-100mph and then back down again (maine is a looooong drive with noone on the roads ahahaha). Pretty darn good if you ask me for the 3.73lsd and that included about 200lbs of luggage and my wife.

Just thought I would share.

I couldn't get 25.3 mpg if I was rolling downhill with the engine shutoff. However, that's because of the gremlin under the hood.

For anyone wanting a set of 3.73's, I have some for super cheap.

[rf900rkw]

In the interest of doing my part for global oil consumption... it would appear that switching to a 3.73 will net me a 20% improvement. What is the current going rate from a E30 3.73 LSD?

[donald isaacson]

Last summer I went to ohio 600 mi. I was getting 32 mpg @ 70 with 92 octane no ethanol. Once I refueled with ethanol mix mpg dropped down to 28. No change in driving. 99 M Coupe s52 engine. I use as daily driver I get 25 in town with ocassional boosts of power. Stock diff.

[GBimmer]

Originally Posted by mcoupemindy

I couldn't get 25.3 mpg if I was rolling downhill with the engine shutoff. However, that's because of the gremlin under the hood.

I know you better than that. You're lucky if you get your MPG in the teens...

[The ZED]

I have a 3.73 for sale, just look in the for sale section!

[rf900rkw]

Originally Posted by The ZED

I have a 3.73 for sale, just look in the for sale section!

Thanks, I saw that after asking. A local shop owner has one he's been trying to get me to buy for some time for about the same money. I'm half way thinking of taking him up on it. And if it's gonna get me out of the teen's in MPG... it'll be a no brainer.

[LAWLence]

Maybe I should pull the 3.73 out of my E30 and put it in my coupe.. hmmm...

[JWin]

Originally Posted by LAWLence

Maybe I should pull the 3.73 out of my E30 and put it in my coupe.. hmmm...

Gonna say 3.46 would be better with the s54 because you should still be able to hit 60 in 2nd gear.

[LAWLence]

That is true. I have a 3.46 right now and it seems like an extremely good match for the motor. I'm getting 23mpg combined (as opposed to 21.5 with the 3.15), and there's a marked increase in performance.

[Z3speed4me]

I can't believe you get that type of mileage, that's really good! I hover around 22-23 myself, but that is on stock dif

I still don't think I would ever do a 3.73 unless I did a 6 speed swap, but that's just me...

[brm]

Originally Posted by m3chaser

I was following my family and they were travelling around 70-80mph. I had my tire pressure at about 38psi

...and his family was driving a full-size van, with him drafting a foot off the bumper... but seriously, the 38 psi will make a difference, too; it's substantially higher than the recommended pressures.

[2002Z3]

The OP's mileage seems reasonable to me considering the speed and extra weight, but the other replies seem off to me. I guess you M drivers have your foot really in it all of the time. Getting in the teens on the road is horrible! Maybe in town at a 1/4 mile at a time

With only 15 fewer HP than the S52, my 3.0i gets about 22/23 in town and 30+ on the highway. Stock ratios. I don't get all of the extra M goodies, but I do visit the pump a lot less. I don't drive like a granny either, but I keep it under 75 on the road. That may explain it. Maybe you M guys are doing over 80 most of the time?

[Z3speed4me]

I have never, nor do I expect my car will ever hit 30mpg, when even the epa on the cars original sticker says 19 city 26 highway, and thats with the car at like negative 10 mph in 5th gear.

I don't think 30 to the gallon is possible unless you are cruising at like 40-50.


As for guys with boost, I thought that actually made the car more efficient unless you romped on it, then you see the significant drop happen.