Fuel consumption Speed sweet spot?

[Trued]

What Speed when cruising on highway is optimal?

[WHITEUNDERARM]

The faster the better! haha! But seriously...I would guess at around 100-110km/h.....I could be way off lol

[Wregie]

The speed that you don't get nicked for speeding at.

I do a fair bit of motorway driving and usually set cruise control to 80mph inefficient mode and return well over 30mpg on a long run.

I can get it under 20mpg caning it down a country lane

[dclowd9901]

In my sooby, the best point was right before turbo started spinning up (about 2800 rpm). In this car, it's hard to avoid a turbo, but my guess is that if you keep it around 2500 rpm, regardless of the speed, you'll be saving a lot on fuel.

[Trued]

Embrace yourselves... 43 miles/gallon - 6.5l / 100km ( car computer read 6,7)
- No passengers
- 14 Celcius
- Highway with speed held automatically at 80 km/h
- DCT in efficient
- 19" wheels with Michelin tires
- Calculated between gas fills
- Norwegian StatOil 98 Octane Premium Miles + Gasoline

Challenge me with measurements at a different speed.

[Wregie]

Originally Posted by Trued

Embrace yourselves... 43 miles/gallon - 6.5l / 100km ( car computer read 6,7)
- No passengers
- 14 Celcius
- Highway with speed held automatically at 80 km/h
- DCT in efficient
- 19" wheels with Michelin tires
- Calculated between gas fills
- Norwegian StatOil 98 Octane Premium Miles + Gasoline

Challenge me with measurements at a different speed.

Are you sure you aren't mixing up the average MPG with the average MPH??

[aperng]

The mileage on these cars aren't very good, but what do you expect. I get 17 city, 18 mixed, 19 highway. And the readings aren't accurate either on the trip computer - it reads 1 mpg better than reality. I divide the gallons it takes to fuel up at the pump by the miles traveled after each fill up - exact 1 mpg off.

The 6MT display always tells you to upshift REALLY early, like at 40 mph you should be going into 6th gear. If you want to get mileage, keep cruise control on at around 40-45 mph in top gear. But that ain't no fun.

[stressdoc]

19 highway? Must be some stop and go, A/C, and/or high speeds in that -- I consistently got 25 -32 mpg.

Originally Posted by aperng

The mileage on these cars aren't very good, but what do you expect. I get 17 city, 18 mixed, 19 highway. And the readings aren't accurate either on the trip computer - it reads 1 mpg better than reality. I divide the gallons it takes to fuel up at the pump by the miles traveled after each fill up - exact 1 mpg off.

The 6MT display always tells you to upshift REALLY early, like at 40 mph you should be going into 6th gear. If you want to get mileage, keep cruise control on at around 40-45 mph in top gear. But that ain't no fun.

[JoeFromPA]

Highway speed for cruising mileage is about 65-70. Below that you don't really get much better, and above that it starts to drop off noticeably once you approach 80 (but is still excellent).

With cruise control set at 72-73, A/C on, and just driving gently in sport mode, I achieved 30mpg over a 120 mile trip.

Normal highway driving with more cruising around 80-85, no cruise control, lots of braking and accelerating, etc....I get about 26mpg.

I've fidgeted alot with seeing what impacts MPG the most as I do alot of highway driving. It's not very speed sensitive at the end of the day, but it is very throttle sensitive. For example: If over 20 miles the computer reads 26mpg and you down to 3rd and redline in 3rd and 4th (very quick thing to do), you will lose .5mpg on your average for that ~10 second event.

[crashtestdummy81]

Don't know about ideal speeds but I do know if you want economy keep it out of sport!

When I picked up my car I drove it in sport all day just for the lovely exhaust note you get with the flaps open.
Heading home I noticed that the average mpg was 15.1, so looked back through the eco settings mpg history and it was very closely grouped around the 15.1 mpg average. Put it back to efficient for the last 5 minutes and the mpg was running between 24 & 40 straight way.

Must take a fair bit of fuel to just to keep them turbos pre-tensioned

(figures in UK mpg)

[tisme]

I'm getting just over 30mpg cruising at and around 70mph. Around towns, it's more like 15mph. I must admit to using economy most of the time, but flip it into sport mode for spirited driving and overtaking. I'm very pleased with mpg and performance.

[Trued]

My calculations is measured by two consecutive gas fills.
Anyone here having any BMW inside info on the Sweet-spot?
It is a turbo engine and my experience with previous Saab Turbos is that the high octane 98-99 makes the car to get significant better driving performance as well as lower fuel consumption.
I know You americans get pretty crappy gasoline so that could be a factor resulting inbad numbers.

[Powaup]

Drove from the bay to la and got just under 26 I was going 75 most of the time but here and there I would hit 100 just to wake myself up

[Powaup]

Originally Posted by Wregie

Are you sure you aren't mixing up the average MPG with the average MPH??

Seems like he is mentioning imperial mph and not US

[Viking123]

Originally Posted by Powaup

Seems like he is mentioning imperial mph and not US

Agreed, 6.5l/100km is 36 miles/gallon
http://calculator-converter.com/l_10...per_100_km.php

[Viking123]

Originally Posted by Trued

My calculations is measured by two consecutive gas fills.
Anyone here having any BMW inside info on the Sweet-spot?
It is a turbo engine and my experience with previous Saab Turbos is that the high octane 98-99 makes the car to get significant better driving performance as well as lower fuel consumption.
I know You americans get pretty crappy gasoline so that could be a factor resulting inbad numbers.

Not true... The octane of gas in the US is no different than in Europe... Just a different way to calculate:
http://rennlist.com/forums/993-forum...explained.html

[JeffM-Houston]

I'm making a 1200 mile round trip this weekend across I10 to Florida so will know more on Monday. But so far I've had several day trips of 180-200 miles out on 2 lane roads and we have averaged 26.6 on those, speeds between 55 and 75.

For this road trip I'll pretty much have to keep it down to 75, those Louisiana highway patrol guys love to write tickets to cars with Texas plates. I would expect maximum mileage to be around 65 mph, in my car that is just about 1800 rpm.

[ss134]

Originally Posted by Trued

What Speed when cruising on highway is optimal?

I find on the autobahn between 120mph and 165mph is optimal.......for my happiness