What is your city vs. hwy mileage ?

[blueflame]

Warm up times vary according to ambient temps, speed, incline, load, vehicle type, coolant condition and ratio of water to glycol, driving technique......

I duct 100% intake air from the top of the exhaust manifold, reducing this ratio when climbing mountains in the height of summer. At the top of the mountain I pop the bonnet and change back to fully heated air.

Thanks almightybmw! regarding rev-matching.... I have only driven older auto trannys, mostly pre 95' Toyota diesels. Newer technology auto's must have varying performance characteristics.

Cd: maybe you should seek corroboration for your model of vehicle, and determine the level of engine braking (a rev counter showing high engine speeds with no throttle while moving means neutral will save gas), will guage what could be gained, by using neutral while moving.

That said, I usually flicked to neutral in my previous autos, but only when a neutral glide would be sustained for a reasonable amount of time and distance, which can occur descending even a minor incline.

[aerohead]

Originally Posted by jamesqf

Not necessarily so. Even in the winter, the Insight only takes about 10 miles (on level roads) to warm up to its normal operating temperature. Since it takes me longer than that to get into town, most of my city driving is with a warm engine.

jamesqf,the numbers I used are from SAE investigations by General Motors Research Labs.Their findings are,that for any car,at any given ambient condition,that car will not reach it's peak equilibrium temperature and peak efficiency for all fluids and lubes, until it has been driven continuously for 22-miles at 50 mph.Anything less yields higher viscosities , higher road loads,and higher fuel consumption.

[basjoos]

Its about 12 miles into town, so my car is somewhat warmed up by the time I get there, but on my city driving segments I’ve been able to average low 50’s (winter), high 50’s (summer) through the use of as much ICE-off time as I can manage.

On the highway its mid 70’s (summer), high 60’s (winter) at normal highway speeds, DWL when traffic density allows, and ICE-off on every coast-able downhill. Subtact 2 to 3 mpg for driving with the lights on. I don’t draft because it offers little to no MPG benefit for my car.

[TestDrive]

Originally Posted by basjoos

Subtact 2 to 3 mpg for driving with the lights on. I don’t draft because it offers little to no MPG benefit for my car.

Wow! That's way more than I'd have guessed. How do/did you determine?

[Formula413]

For highway MPGs I recently gathered some data and posted it here:

http://ecomodder.com/forum/showthrea...ting-6947.html

As for city mileage, when you say city I think of a fair amount of stop signs and red lights, my car is in the low 20's in these conditions, although of course it can and will vary greatly. My car is an automatic.

[jamesqf]

Originally Posted by aerohead

jamesqf,the numbers I used are from SAE investigations by General Motors Research Labs.

Might be a good average, but I'd be really surprised if the mostly aluminium 1000 cc engine in my Insight took the same time to warm up as a typical big-block GM V8.

[MetroMPG]

The engine warm-up isn't the only issue, though. The temp of the transmission fluid, tires, bearings all affect efficiency, and warm up much slower than the engine coolant.

I've seen this during testing. Repeated runs over the same stretch of road on cruise control, the segment MPG readings continue to climb for a surprising length time after the coolant temp stablizes (indicating the other components are still getting up to temp).

Haven't measured it for my car. I'd be a little surprised if it were as much as 22 mi., but it's certainly well past coolant max temp distances.

[blueflame]

Yep

I had a Citroen BX19 16v that was fitted with an oil temp and water temp gauge.

On the highway at about 13 degrees C, the oil temp took around 3 or 4 times longer to stabilize than coolant.

I would guess with that car about 10miles

[Formula413]

Originally Posted by MetroMPG

The engine warm-up isn't the only issue, though. The temp of the transmission fluid, tires, bearings all affect efficiency, and warm up much slower than the engine coolant.

I've seen this during testing. Repeated runs over the same stretch of road on cruise control, the segment MPG readings continue to climb for a surprising length time after the coolant temp stablizes (indicating the other components are still getting up to temp).

Haven't measured it for my car. I'd be a little surprised if it were as much as 22 mi., but it's certainly well past coolant max temp distances.

I can watch trans temp on the SGII in my Escort, and it definitely does take longer to reach operating temp than the coolant, and the lag varies depending on driving conditions.

[TestDrive]

No idea exactly how it relates to a car or light truck, but I use to operate 3 axle 19 ton curb weight trucks designed for seismic surveys for the oil industry. They were equipped with transmission oil temperature gauges (Alison 5 speed automatics). When moving from job site to job site we drove them on the highway (anywhere from 50 - 15000 miles). In cool/cold weather, it would usually take anywhere from 50 - 100 miles for transmission temperature to stabilize at a peak reading.