Gears mystery.
Discussion
Morning,
Copied from another site:
I have a Vauxhall Corsa. In general, the higher the speed the higher the gear I can use. So I used to only go in 2nd or 3rd gear around the 10mph limit of the Titchfield site.
However, I've recently discovered that if I go into 4th then the car will take itself all round the site, without me even needing to touch the accelerator. Indeed, as its "natural" speed in 4th gear tends to drift up to about 12 or 13mph I sometimes need to brake to keep my speed down.
How can this be? How can a car travel in 4th gear without acceleration, whereas it would stall in lower gears? And is it ok to do this or might it not be good for the car? It just seems bizarre.
Any ideas? Thanks.
My first thought was dodgy clutch? Any other thoughts?
Copied from another site:
I have a Vauxhall Corsa. In general, the higher the speed the higher the gear I can use. So I used to only go in 2nd or 3rd gear around the 10mph limit of the Titchfield site.
However, I've recently discovered that if I go into 4th then the car will take itself all round the site, without me even needing to touch the accelerator. Indeed, as its "natural" speed in 4th gear tends to drift up to about 12 or 13mph I sometimes need to brake to keep my speed down.
How can this be? How can a car travel in 4th gear without acceleration, whereas it would stall in lower gears? And is it ok to do this or might it not be good for the car? It just seems bizarre.
Any ideas? Thanks.
My first thought was dodgy clutch? Any other thoughts?
Seriously? Have I mis-understood the question here?
currybum said:
Captain Muppet said:
I'm going to change my vote on the "How much does the average PHer really know about cars?" poll.
The ratio of people who actually know what they are talking about to people who think that know what they are talking about is about 1:20 form my experience. http://www.pistonheads.com/gassing/topic.asp?h=0&a...
davepoth said:
TBH it sounds like the quoted poster was doing a bit of industrial estate under 17 driving, so they might not know how the car works.
But the OP who quoted it seemed to think it was a dodgey clutch, rather than it just being how GM cars are calibrated (all the GM cars I've driven will maintain idle speed on zero throttle when in gear).Just to make it clear, as the 1st and 2nd attempt obviously didn't work.
I copied the following quote from another site (I'll add quotation amrks to make it clearer):
"I have a Vauxhall Corsa. In general, the higher the speed the higher the gear I can use. So I used to only go in 2nd or 3rd gear around the 10mph limit of the Titchfield site.
However, I've recently discovered that if I go into 4th then the car will take itself all round the site, without me even needing to touch the accelerator. Indeed, as its "natural" speed in 4th gear tends to drift up to about 12 or 13mph I sometimes need to brake to keep my speed down.
How can this be? How can a car travel in 4th gear without acceleration, whereas it would stall in lower gears? And is it ok to do this or might it not be good for the car? It just seems bizarre.
Any ideas? Thanks.
My first thought was dodgy clutch? Any other thoughts?"
The OP of the question is apparently a mid twenties something bloke who has owned previous cars.
I thought it was amusing - nevermind!
I copied the following quote from another site (I'll add quotation amrks to make it clearer):
"I have a Vauxhall Corsa. In general, the higher the speed the higher the gear I can use. So I used to only go in 2nd or 3rd gear around the 10mph limit of the Titchfield site.
However, I've recently discovered that if I go into 4th then the car will take itself all round the site, without me even needing to touch the accelerator. Indeed, as its "natural" speed in 4th gear tends to drift up to about 12 or 13mph I sometimes need to brake to keep my speed down.
How can this be? How can a car travel in 4th gear without acceleration, whereas it would stall in lower gears? And is it ok to do this or might it not be good for the car? It just seems bizarre.
Any ideas? Thanks.
My first thought was dodgy clutch? Any other thoughts?"
The OP of the question is apparently a mid twenties something bloke who has owned previous cars.
I thought it was amusing - nevermind!
Blayney said:
It's amazing how many people don't know cars can do this. I let the car idle in 2nd/3rd in slow moving traffic occasionally to give my foot a rest (always with my feet ready to go on the brake and clutch just incase).
+1.All cars are designed specifically to have a useful "crawling speed", ie. the idle speed must be a sensible-for-traffic roadspeed in 1st gear. That's one of the two main factors in deciding first-gear ratios - crawling speed, and the ability to launch up a steep incline at maximum towing capacity. For performance applications obviously you have to consider acceleration too, but even Ferrari are limited by keeping a reasonable crawling speed.
And yet people don't use it or even know it's there
hobbiniho said:
basically the ecu will not let the engine stall, it also depends if you are going up hill or not my tdi leon can idle in sixth in gear on flat ground but will stall when it comes to a relatively steep hill
not just ECU equipped cars, the Triumph will happily pull itself along at idle in all gears. Great for car parks.Gassing Station | General Gassing | Top of Page | What's New | My Stuff