How to drive an auto?

[hawk20]

Normally, leave in D and foot on brake.

But if stop looks longer then into N and keep foot on brake.

The benefit of N is that it allows engine to rev slightly higher and in very hot weather it moves the coolant around better reducing hot spots in the engine, and also allows alternator to charge better.


Do not like the idea of going into P at all !!!!!!!

Is this really what Advance Motorists say? It looks like self appointed 'experts' making life complicated just for its own sake, to me. I drive a Mercedes which is perfectly capable of cooling itself without such shenanigans. By the way the difference in revs from D to N is almost imperceptible -at least on mine.

As for the alternator charging better, I don't need it to. It does the job fine driving as the manual suggests.

I don't know if you have ever been shunted up the back, but sitting with your foot on the footbrake for long periods as you describe, may increase rear end shunts. When you are hit, the surprise and thump makes you let go of the brake. You then shoot forward and hit the one in front. You may well be deemed to be partially to blame as you should have applied the parking brake when stopping for longer periods or at the least gone into P as others describe.

Finally, as raised by others, on drive by wire accelerators and whether we can left-foot brake while the right foot does the accelerator, some say that the foot on the brake cuts off the accelerator. Well not on my S220 series. I can definitely use both together and I think it useful at times to have that facility.

 

[mike65]

Interesting thread I'm in an auto this weather and use D/foot-brake for brief halts and P for anything longer. When parking up I never use handbrake either.

When selecting a lower gear 'manualy' should it be done with the power being applied or with foot off the throttle? Or does even matter?

Mike.

 

[mlc]

Is this really what Advance Motorists say? It looks like self appointed 'experts' making life complicated just for its own sake, to me. I drive a Mercedes which is perfectly capable of cooling itself without such shenanigans. By the way the difference in revs from D to N is almost imperceptible -at least on mine.

As for the alternator charging better, I don't need it to. It does the job fine driving as the manual suggests.

I don't know if you have ever been shunted up the back, but sitting with your foot on the footbrake for long periods as you describe, may increase rear end shunts. When you are hit, the surprise and thump makes you let go of the brake. You then shoot forward and hit the one in front. You may well be deemed to be partially to blame as you should have applied the parking brake when stopping for longer periods or at the least gone into P as others describe.

Finally, as raised by others, on drive by wire accelerators and whether we can left-foot brake while the right foot does the accelerator, some say that the foot on the brake cuts off the accelerator. Well not on my S220 series. I can definitely use both together and I think it useful at times to have that facility.

Actually I dont think thats what the IAM says. The idea of leaving a gap is a standard defensive driving, however when I joined the IAM in 1990 the rule was to sit in traffic in drive and with the handbrake on, the reason being as you say that the jolt from a rear shunt would stop you applying the foot brake. I always select N for an extended stop because I think that saves wear in the gearbox.

Finally my S220 series does cut the accelerator at all times except when you are stationary, this is identical action to our 230SLK.

Mark.

 

[hawk20]

I always select N for an extended stop because I think that saves wear in the gearbox.

Mark.

Well here is a direct quote from an earlier posting by Television (Malcolm)
"You should get out of the habit you are just wearing it all out, read your handbook, your car engine is coupled up to a torque converter, at Idle min revs the torque converter can just about make the car creep, nothing is slipping, nothing wearing out, as soon as you raise the engine speed, the torque converter converts the power of the engine to the drive on the car.

Malcolm

 

[mlc]

Well here is a direct quote from an earlier posting by Television (Malcolm)
"You should get out of the habit you are just wearing it all out, read your handbook, your car engine is coupled up to a torque converter, at Idle min revs the torque converter can just about make the car creep, nothing is slipping, nothing wearing out, as soon as you raise the engine speed, the torque converter converts the power of the engine to the drive on the car.

Malcolm

Yes I understand this argument, just cant bring myself to believe it. If it is true then why do auto boxes wear qucker in city driving rather than motorway use?

Mark.

 

[Ultymate]

Holding the transmission in "D" will deffinately not cause any wear and or damage to the box and in reply to hawk20 further back up the thread there should be no difference in idle speed ie RPM in D or N as the idle is electronically controlled and should not vary, just my 2 cents

 

[television]

Holding the transmission in "D" will deffinately not cause any wear and or damage to the box and in reply to hawk20 further back up the thread there should be no difference in idle speed ie RPM in D or N as the idle is electronically controlled and should not vary, just my 2 cents

On some of the earlier cars there can be up to 600 RPM difference, air con can also speed up the engine by the same amount, did not have ECU in the earlier days.

Malcolm

 

[Ultymate]

Sorry Malcolm I thought we were talking relatively modern my mistake:Oops:

 

[Hibbo]

Yes I understand this argument, just cant bring myself to believe it. If it is true then why do auto boxes wear qucker in city driving rather than motorway use?

Mark.

Going from D to N and then back to D will cause wear to the autobox, as it is disengaging and reengaging. It is the engaging of the gears that causes wear - that's why they wear quicker with town driving.
Sat stationary in D, nothing is moving, no wear is taking place. The torque convertor is splipping as it should, allowing the engine to turn but NOT the gearbox.

 

[television]

Sorry Malcolm I thought we were talking relatively modern my mistake:Oops:

No :Oops: please, its so easy to forget things as our cars span some 30 years, I do it all of the time.

Malcolm

 

[hawk20]

No :Oops: please, its so easy to forget things as our cars span some 30 years, I do it all of the time.

Malcolm

Help! Malcolm or any who know, please. Some have said Mercs with drive by wire accelerators cut out the accelerator if you apply the brake. I said my S220 series does not do that. (It is 1st registered December 2005). I can sit on a hill holding with left foot on main brake and accelerate away with right foot. Someone else (mlc ) said his S220 only cut out when moving. I went straight out and drove mine. You can definitely brake and accelerate at the same time on mine even when moving.

Question: - does this mean I have a fault?
or does the other S220 series has one (mlc's)?
or have Mercedes changed what they do from year to year?
And lastly, what is the point of making it cut throttle off when foot on brake? It can be useful.

 

[television]

Help! Malcolm or any who know, please. Some have said Mercs with drive by wire accelerators cut out the accelerator if you apply the brake. I said my S220 series does not do that. (It is 1st registered December 2005). I can sit on a hill holding with left foot on main brake and accelerate away with right foot. Someone else (mlc ) said his S220 only cut out when moving. I went straight out and drove mine. You can definitely brake and accelerate at the same time on mine even when moving.

Question: - does this mean I have a fault?
or does the other S220 series has one (mlc's)?
or have Mercedes changed what they do from year to year?
And lastly, what is the point of making it cut throttle off when foot on brake? It can be useful.

Hello Hawk, this maybe a petrol-diesel thing, I will ring my friend with his new diesel S class its only one week old. Its something that I knew nothing about until a few weeks ago, I am sure that everyone who has said that their car does it is petrol.

Malcolm

 

[hawk20]

Thanks Malcolm. I await the news.

 

[Ultymate]

It's common practice on most modern cars not just M/B, that have full engine management systems be they diesel or petrol to cease or minimise fuelling on the overrun, as one of several ways of maximising economy. I would think though that as soon as you apply throttle normal fuelling will resume irrespective of whether you are on the brake as well

 

[mlc]

I had not thought of it being a difference between petrol and diesel, mine is a 2001 S320 petrol, and the 2003 SLk230 is of course petrol.

Mark

 

[hawk20]

I had not thought of it being a difference between petrol and diesel, mine is a 2001 S320 petrol, and the 2003 SLk230 is of course petrol.

Mark

So perhaps it is. Tell me, if you drive along at say 25 mph on a clear road, and very gently apply the brake with the left foot, and then press accelerator with right foot -- are you saying that it won't accelerate, that the throttle is cut out by the brake.

On mine you can still accelerate even though main brake is on with left foot.

 

[mlc]

So perhaps it is. Tell me, if you drive along at say 25 mph on a clear road, and very gently apply the brake with the left foot, and then press accelerator with right foot -- are you saying that it won't accelerate, that the throttle is cut out by the brake.

On mine you can still accelerate even though main brake is on with left foot.

Yes that is exactly what it does, and I find it a pain. I have always used two feet in an auto, a good example is reversing onto our drive which is very steep initially from the road. I would also have used both pedals when parking for more control. When we bought the SLK I actually thought it was a fault as our earlier SLK worked as expected.

Interestingly MrsC uses the handbrake reversing up the drive, but then the S class doesnt have one of those either!

Mark.

 

[hawk20]

Yes that is exactly what it does, and I find it a pain. I have always used two feet in an auto, a good example is reversing onto our drive which is very steep initially from the road. I would also have used both pedals when parking for more control. When we bought the SLK I actually thought it was a fault as our earlier SLK worked as expected.

Interestingly MrsC uses the handbrake reversing up the drive, but then the S class doesnt have one of those either!

Mark.

Can't wait for one of the more technical people to tell us why Merc removed this useful feature. And since it is the natural way for an auto to be -and the way they have always been- it must have been a conscious decision to deprive us of what we like --presumably for some good reason. I can understand cutting fuel off when you take foot off accelerator, but find it hard to see why they stop you accelerating if you want to while other foot on main brake.
BTW I really like the foot operated parking brake and hope it never goes (for autos which is most Mercs) and like the way it frees up the central area fpr storage/armrest etc.

 

[mlc]

BTW I really like the foot operated parking brake and hope it never goes (for autos which is most Mercs) and like the way it frees up the central area fpr storage/armrest etc.

Makes handbrake turns a little difficult though dont you think, or should I just grow up and behave like an adult

 

[television]

should I just grow up and behave like an adult

Cant see any advantage in that.

Malcolm