RE: Driven: Porsche Boxster S
Discussion
Overstier said:
It's the coast function I don't quite understand.
If you are going down hill in gear clutch engaged, throttle closed then no fuel is required, the momentum of the car turns the engine.
However if you do the same but disconnect drive and coast then fuel will be required to turn the engine, even if it is only turning at idle speed.
Or am I missing something??
Indeed, most people who put the car into neutral on a descent thinking it will save fuel know nothing about how a modern car works and actually backing off the accelerator with the car in gear will save more fuel.If you are going down hill in gear clutch engaged, throttle closed then no fuel is required, the momentum of the car turns the engine.
However if you do the same but disconnect drive and coast then fuel will be required to turn the engine, even if it is only turning at idle speed.
Or am I missing something??
The coast function is designed to not go into neutral as you described but drop down to idle speed to preserve fuel but not drop the speed as if you were to take your foot off the throttle.
Disappointed the S only has 315hp, the spyder had 320hp.
Also, those wheels are comically stupid. I hate the way the average consumer perceives big wheels on cars these days. I know everyone will option them because they look flash. This st makes me lose my faith in humanity.
Otherwise looks great!
Also, those wheels are comically stupid. I hate the way the average consumer perceives big wheels on cars these days. I know everyone will option them because they look flash. This st makes me lose my faith in humanity.
Otherwise looks great!
That was kind of my point. It's not possible to go to idle speed when going downhill without either disconnecting the drive, which can only be done by disengaging the clutch and/or putting the gearbox into neutral or slowing the car to a speed that corresponds to idle speed in that gear.
So when the engine us at idle fuel has to be added to keep the engine turning, but when going down hill with a closed throttle no fuel is being used regardless of engine speed.
Closed throttle I think = no fuel
Idle I think = idle air control valve open fuel added
So when the engine us at idle fuel has to be added to keep the engine turning, but when going down hill with a closed throttle no fuel is being used regardless of engine speed.
Closed throttle I think = no fuel
Idle I think = idle air control valve open fuel added
vimfuegoturbo said:
some bright spark suggested melding the words 'boxer' and 'roadster', to be met by simultaneous back slapping and nodding of heads.
Technically , it's a fusion of Boxer and Speedster, it being a Porsche after all. But I get your point!Love the car, love the wheels, love the fact that it's deliberately been moved away from the 911. Bring out a 981 Spyder and I'm all over it like the proverbial rash.
Overstier said:
That was kind of my point. It's not possible to go to idle speed when going downhill without either disconnecting the drive, which can only be done by disengaging the clutch and/or putting the gearbox into neutral or slowing the car to a speed that corresponds to idle speed in that gear.
So when the engine us at idle fuel has to be added to keep the engine turning, but when going down hill with a closed throttle no fuel is being used regardless of engine speed.
Closed throttle I think = no fuel
Idle I think = idle air control valve open fuel added
Someone did the calculations to say that the added friction of turning the engine over faster uses more fuel in total over declutching and idling the engine.So when the engine us at idle fuel has to be added to keep the engine turning, but when going down hill with a closed throttle no fuel is being used regardless of engine speed.
Closed throttle I think = no fuel
Idle I think = idle air control valve open fuel added
It is quite rare to completely cut fuel even on extended over run as it messes up the catalysts.
Overstier said:
It's the coast function I don't quite understand.
If you are going down hill in gear clutch engaged, throttle closed then no fuel is required, the momentum of the car turns the engine.
However if you do the same but disconnect drive and coast then fuel will be required to turn the engine, even if it is only turning at idle speed.
Or am I missing something??
Yeh, that's my thinking too! What's the point? If you are going down hill in gear clutch engaged, throttle closed then no fuel is required, the momentum of the car turns the engine.
However if you do the same but disconnect drive and coast then fuel will be required to turn the engine, even if it is only turning at idle speed.
Or am I missing something??
juansolo said:
Oddly these days I think lower powered cars with less grip are more fun to drive than higher powered grippier ones. This reads like it has way too much grip rather than not enough power...
couldn't agree more. What is better on paper isn't always the case.Edited by juansolo on Saturday 10th March 08:47
it is pretty though. well, except for the headlights
veevee said:
Me too, can someone explain the coast thing? Can't be no engine braking, but it does sound like it.
No, but I've read some bumf from Porsche on it, they admit that an engine on over run shuts down the fuel but the coast system enables a car to "sail" thus over a given distance it consumes less petrol than simply lifting off the loud pedal as it travels further as there is no engine braking.(well they said something like that)
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