Airdam - suprise result!

[johnunit]

I'd hazard a guess that it will. However, seeing that you appear to be a driving instructor, it may well not see enough high-speed driving to show a difference.

[kingsway]

I still have to drive between customers - and pupils nearer the the test will certainly be driving at the national limit - 60 or 70 mph, depending on the road!

Just as a matter of interest - I've started making pupils aware of my Ultraguage. I show them the difference in consumption -which can be quite a lot - when using the correct gear. I also find DWB (Driving without brakes) is an excellent way to encourage planning and anticipation. They often drive and change gear much more smoothly....

[MetroMPG]

Out of curiosity: do you actively teach efficient driving techniques? (Meaning: is it specifically part of the curriculum?)

I taught driving part-time for a couple of years while I was a university student. Efficiency techniques were the focus of one of the 12 in-car sessions that made up the course, and it was part of the classroom section as well.

A ScanGauge/Ultragauge for that in-car lesson would have been a fantastic tool.

[skyking]

Originally Posted by kingsway

I still have to drive between customers - and pupils nearer the the test will certainly be driving at the national limit - 60 or 70 mph, depending on the road!

Just as a matter of interest - I've started making pupils aware of my Ultraguage. I show them the difference in consumption -which can be quite a lot - when using the correct gear. I also find DWB (Driving without brakes) is an excellent way to encourage planning and anticipation. They often drive and change gear much more smoothly....

No doubt. That was how I was raised by my dad, look far enough ahead to not need brakes.
For the last 25 years I have made a game out of it with my wife. My family is a 3 hour drive across the mountains, and she can sleep in the car. My big challenge is changing freeways and negotiating interchanges without waking her up.

[kingsway]

DWB is certainly a more relaxing way to drive!

'Ecodriving' with the emphasis on producing less CO2, is a small part of the syllabus here in the UK. But only a very small part.

I'm considering the idea of trying to offer some coaching sessions on how to be more fuel-efficient. Having immediate feedback on the dashboard is the key... Driving to a vacuum-gauge is much more boring, and you start to wonder if it's worth the trouble!

This would only be viable with my bigger car. With the little automatic, if I hypermile my brains out I can get a maximum of around 39mpg (imp) as against 36mpg (imp) normal driving...

However I did another coast down test from 50-40 today in the little car.
When the engine has just reached running temp, it takes 9 seconds to slow to the lower speed. When the car is thoroughly warmed-up, the time goes up to 15 seconds (today there was a headwind on both tests)

So the temperature of the transmission appears to make more difference than anything else! I looked for some fully synthetic ATF today. but could see only semi-synthetic... Might help a little?

[kingsway]

I've now done some slightly more valid test-runs. I found it very difficult, if the traffic is quiet, theirs too much wind or vice versa...etc etc !

Having discovered what a big difference in drag there is between a warm and a cold transmission, I pretty much convinced myself I was originally mistaken when I thought it was the airdam that seemed to be reducing drag.

I tried some coast-down tests today with the dam both on and off the car. I made sure both engine and transmission were properly warmed-up..

I'm not going to claim any great accuracy, but the airdam undoubtably has a quite noticeable effect!

The time to slow from 50 to 40 is, on average, about 3 to 5 seconds longer with the airdam in place.

The most suprising thing about this is the fact the dam is so flexible, it could only be folding back under the car to at least some extent under the influence of the oncoming airflow - so perhaps if the final version is more rigid the effect may be increased?

On my last tank-full I saw an average consumption of 43mpg (imp) - up from 36mpg previously. (P&G was the major reason for this)

When I get time, I'd like to try a full under-belly pan..

[allenh318]

Does anyone have any test data on a front air dam?

[RunningStrong]

Originally Posted by kingsway

I still have to drive between customers - and pupils nearer the the test will certainly be driving at the national limit - 60 or 70 mph, depending on the road!

Just a quick OT, do you tend to start learner off-street in car parks and such?

My first lesson involved driving on the street 10 minutes in and doing 60 mph on the way home.

[kingsway]

Originally Posted by RunningStrong

Just a quick OT, do you tend to start learner off-street in car parks and such?

My first lesson involved driving on the street 10 minutes in and doing 60 mph on the way home.

Where possible, yes. But it usually isn't possible *, so it's a matter of finding an area that's as quiet as possible - one of the challenges of being a Driving Instructor in this crowded little island! ( I have great sympathy for those ADI's who work in places like London....)

I do have the advantage of also having a little automatic car - so I usually start a novice off in that, and switch them to the 'manual' once they're a bit more confident with the basics of making it stop, start and go in the right direction.


* We are usually banned from most car-parks! The chances of a learner in a dual-controlled car, under the supervision of a qualified ADI, hitting a car in a car park are almost zero - but a customer will complain to the supermarket, who are then worried they might be liable if something did go wrong, so we get kicked out. Not sure where people think novices are supposed to learn... Most of my pupils can park a lot more safely and accurately than the general public! (Like all Instructors, BTW, I carry a couple of million Pounds worth of Public Liability Insurance)

[RunningStrong]

Ah the wonders of living near one of Thatcher's enterprise zones, an empty car park is never far away.