driving downhill - fuel consumption

I'll try that in my Xantia...

Please come to my funeral..

Mike P

He did say "...when it's safe and appropriate to do so". I think that covers him.

The risk is with people taking risks. Ans stupid people. It is safer not to coast imo. I still do sometimes though. I just don't give a shit.

When driving or idling, the oil is burnt. On the over run, the engine is still fuelling, but very little air is drawn in. Consequently, the mixture fails to ignite most of the time. If you had ever heard a Saab two stroke on the over run you would instantly know what I mean. They have a characteristic splutter as they burn the over rich mixture about one tenth of the time they should.

Chris

LOL:-) I know the feeling - all these effing idiots that want to control your life but prolly couldn't wire up a three pin plug to save their lives!

I've just had a thought, practically all the old conventional three speed automatic gearboxes have an overrunning clutch on low/first gear. I'm not up to speed with modern autoboxes though.

Julian.

Thus spake Julian ( snipped-for-privacy@supanet.com) unto the assembled multitudes:

This was true of two-stroke motorcycles too, until separate lubrication became the norm.

Are you speaking for the whole of humanity then?

Where have you cited anything from them?

It's Wikipedia. It's someone else's opinion, just like you and me. It also fails to mention that the effect it describes would not occur in independently lubricated two strokes.

I've experienced, and repaired many wrecked two stroke engines from seizure. I'm pretty certain they were all on full chat when failure occurred.

If you look on Saab enthusiast' web sites, the reason oft-quoted for continuing the free wheel on to the four stroke range was that owners loved the smooth drive it gave, and demanded it although it was totally unneeded.

Chris

Nope, when idling the oil tends to puddle at the bottom of the crankcase - hence the cloud of smoke when you blip the throttle.

On the over run, the engine is

Eh, you've now given an incorrect explanation of carburettor function - fuel is metered in proportion to air.

It's true that 50% of t'internet content is garbage!

Julian.

It does however on the 2-stroke Saab owners club - perhaps you know better than the Saab owners and the manufacturers?

And the reason why it was essential for the petroil cars is what - and why it was nice but not essential on the later oil injected engines?

Your explanations thus far have been pretty much pure bollocks - you'll have to do better if you want to convince anyone here I think!

Julian.

By what process is the oil magically separated from the petrol at that stage then?

And of course, those of us who were around in the fifties and sixties tinkering with those carbs know how wonderfully accurately they performed that function!

Indeed. The key is determining which 50%...

Chris

Was this not discussed at great length last week?

Ever seen an oily plug on a 2-stroke? Perhaps there's a little man in the cylinder that brushes neat oil on it with a brush.

Certainly good enough to put your daft theory to bed.

Indeed, we now have Saab owners, Vehicle manufacturers, Wiki (I know I know) and others here. You're the lone voice here I would suggest.

Julian.

Some sort of "gear lever" would seem to be appropriate, then.

It would be fun to take one in a car with a freewheel.

Ian

Illegal? Name the law. And explain how it covers cars with freewheels.

Ian

Good grief!

Ah, but if you listen to the shuffling stringbacks from the IAM they will tell you that it's "engine to go, brakes to slow". They are dead set against engine braking, and advocate /not/ changing down through the gears as you approach traffic lights. How 5th gear at 20mph is any more "under control" than neutral at 40mph is anyone's guess.

But hey, they look out for wheelie bins!

Ian

If I knew that would I have started this thread?

It is a surreal sight.

Which Saab owner, and which vehicle manufacturer, has voiced an opinion here then?

BTW, I'll leave you to explain how those two stroke engined cars that were fitted with free wheels that could be engaged or disengaged, ever managed to descend a hill without seizing!

Chris