Highest MPG anyone achieve?

[Stanley Rockafella]

With my 135/20/15's my OBC says I'm getting exactly 38mpg!

what means this?

[JenryKaly]

Thank you so much for the post. It's really useful.

[trackjunkie21]

I never got over 20mpg even with the m42, traffic around here is horrendous, I averaged about 20mpg on my way to my friends upstate with my nvm50, g240 and a 4.10s.

[p nut]

well, it was proably not totally, 100% bone stock though, right? tire size, engine wear (mostly injectors gumming up, or fuel vapor leaks), and any mods could affect the readout.

The same "mods" that could affect the readout, would also affect the MPG calculations. If the engine is running a little more inefficiently due to gummed up injectors or whatever, it would affect the readout as well as the manual MPG calculations. Same with tire size and engine wear.

I've also done this on other vehicles ( Honda and Toyota). Basically the same result. You can rely on the OBC to give you the warm fuzzies, but a more accurate MPG can be had via the fill up method.

[Stephen]

i got just under 29mpg on my roadtrip to cali with a reasealed 2.7i and a 2.93 diff ratio. twas nice.

[Ryann]

With my 135/20/15's my OBC says I'm getting exactly 38mpg!

[nando]

My experience was the OBC was always about 2mpg or close to 10% more optimistic than the fill up method (this was at 100% stock, down to the tire size). This was an average over several months (my commute was 90 miles). When I measured the miles with my GPS, it was even further off.

well, it was proably not totally, 100% bone stock though, right? tire size, engine wear (mostly injectors gumming up, or fuel vapor leaks), and any mods could affect the readout.

[Simon S]

318is – very ‘refreshed’ m42 car.. (all new fluids, filters, hoses, plugs, ICV, O2 sensor, etc.)
4 pintle injectors, COP, MarkD/91, 4.11lsd, AC & PS delete, iS lip, lowered on skinny cap wheels

30.2 mpg with mix of ~75mph freeway and city driving (miles/gallons calculated).

Got impression that if I were to drive at a very steady 60mph with a tail wind (in a dream world) – then I’d start seeing numbers flirting with 35+mpg.

[p nut]

There's nothing wrong with the OBC if you haven't monkeyed with anything

anyway, I got well over 26mpg with my auto 325ix on a trip over to Lake Chelan. I got an easy 30mpg in a total POS 318is.

My experience was the OBC was always about 2mpg or close to 10% more optimistic than the fill up method (this was at 100% stock, down to the tire size). This was an average over several months (my commute was 90 miles). When I measured the miles with my GPS, it was even further off.

[e30_325es]

When my ES was stock (+ebay chip), Id get 32mpg all the time on the highway cruise on at 70-75mph. When I put the cam and 4.10 gears it dropped to 24mpg, 80mph cruise. Now with built s50 (high comp forged pistons, vac stg 2 head and cams), zf trans, 2.93 gears, I still get 24mpg on the highway.

Now my 91 auto m20 I'm lucky to get 22 on the highway. Usually average 20mpg.

[5Toes]

If you REALLY pay attention you can save loads of gas. Such as coasting down from 30 to a 4 way stop from like 300 yards or more back... things like that

[bernzpeed]

40mpg is bs. even with an m42.

[TurboJake]

Best I've ever gotten is 78 mpg. 92 geo metro.

Best the E30 has gotten.
27mpg for 350 miles. 95 degree outside temps. Flat road. 72 mph.

30 is not out of the realm for an E30. You just have to be doing 45ish with no stops.

[goarmy]

In 2004 a buddy of mine used a mpg meter on a e30 m20 turboed at around 5 psi and made many miles runs after runs till he managed the sytem on low boost right and got 48 the key was to drive like a normal daily drive or like "Driving Miss Daisy" never runned it hard but consistant. Not bad but I drive hard at times.. not for me :(

[bastianshaw]

33mpg 89 325is chipped. 60mph cruise= economy+ morre time in your e30:-)