24v swap miles per tank - make no sense.

[416stroker]

Ya but:the s50 does have bigger injectors more displacement than a m20 and more agressive cams so its not bad if you ask me.

I think you care to much about MPG. If your worried about 4mpg.

I used to get about 28-9 if I babied my M50 car. My newst m20 shit it gets horrible not even 20.

[Matt-B]

27 mpg here, m50 NV 410LSd

12.5 gallon tank

[rThor432]

Weird.. I averaged 32mpg with my S52/G260/2.93 @ 2,450lbs. With the ZF I averaged 29mpg. My E36 M3 averages 27mpg with the overdrive 6-speed doing mixed driving. I usually do 375 miles per tank with the E36 before filling up. Can't remember how far I'd get with the E30..

[nrubenstein]

it's like 500lbs heavier than an average E30 (~2700 vs ~3200). how is that not meaningful?

it doesn't make sense when guys with stock M20's are getting 20-27.

*shrug* a fully loaded swap car is closer to 2900. My '95 M3 was 3150 with no lightening. At speed, a few hundred pounds doesn't really matter.

That said, I'd love to know how people achieve close to 30mpg. I can't get past 25 cruising at reasonable speeds.

[roaddigitydogg]

People here need go to take some basic physics classes....

It's like what nrubenstein has been saying: if you are maintaining a constant speed for the most part, aerodynamics are the most important factor. a large majority of the fuel you burn is because you are simply pushing air out of the way. being that e30's have a .38 drag coefficient (horrible), in theory you should get worse gas mileage than an e36 while maintaining constant speeds.

extra weight will cost you more fuel to accelerate the vehicle, so you may see some savings from an e36 s50 to an e30 s50 when driving around in town. decreased weight will also decrease frictional drag from your bearings, tires, etc too. since air drag increases exponentially with speed though, it easily starts to become the dominant force in slowing your vehicle.

on the highway, the extra weight is barely going to affect you in terms of air drag. even if you can't maintain a constant speed, the extra energy (gas) it takes to accelerate a heavier vehicle is conserved when you coast by coasting longer. as long as you aren't using the brakes it doesn't matter.

[roaddigitydogg]

I can't get past 25 cruising at reasonable speeds.

Same. I think 30 mpg would be achievable at 45mph in 5th gear with a 2.79 final drive ratio. Calculating gas mileage is so simple, yet people still seem to fuck it up. Or they 'lie' to themselves by remembering their best fuel economy (the one were you drive from 15,000 feet elevation to sea level on the same tank of gas) and spread the lies online

[roaddigitydogg]

oooooo my favorite one is this: stating the fuel economy that the OBC reads after changing to larger injectors. i was talking to a mechanic and he said he was getting 53mpg with a supercharged m20 and 550-600cc injectors. So I asked him "so you get about 800 miles on a tank, huh?" and he said yeah. ahahahhaha

[roaddigitydogg]

Bottom line is I just dont get it. When I had an M20 I would get 25 avg, I get now 21 avg driving somewhat chill and its an engine that doesnt have to work as hard and more "efficient."

Ironically, working engines harder generally makes them more efficient. And I don't mean working an engine harder doesn't waste more fuel than the same engine working less hard. I mean it makes more power with less fuel burned.

By 'working' an engine harder, you are opening the throttle valve more which creates less of a pumping loss. Think about it? If you had to move a set amount of air over a certain amount of time, would you rather do it through a tube with a almost closed throttle valve or a fully open one?

It gets significantly more complicated than that, but you get the idea. One of the reasons why you get better gas mileage when switching to longer gear ratios is NOT PRIMARILY because your engine is spinning slower. long gear ratios decrease the torque available at the wheels, so you are forced to compensate and open the throttle more to maintain the same speed and therefore decrease your pumping loss.

[A_Whelan]

I get about 21 mpg but I drive like an asshole....

Ahahahhahahahah that was golden! Sigged.

[mo diesil]

27 mpg here, m50 NV 410LSd

12.5 gallon tank

idk i have a NV and a couple things done to it and a tune i get more like 22ish
im a early model though 87 coupe

[e30austin]

I'm averaging 25 MPG. Mixed driving. I drive the shit out of my car. '89 325 sedan, M50TU and S3.73 final drive.

[agustingig]

same here haha.. m52

x3 M50NV/G260/3.91ESAB

[scottinAZ]

getting just a hair under 22mpg with my M50TU/G260/4.10 combo in the cabrio (no ac yet)

doesnt seem to make a meaningful difference if I drive like an asshole or not, I get within 10 miles range on a tank of gas

I want (need) taller gears in the ass end, the 4.10 is way too much (first gear is useless, E30's dont need a granny)

Wanting to go with a 3.46 or maybe 3.73, as this should ease up on the freeway revs (4K at 80)