Maximum acceleration in an auto?

[M80]

That's correct, max revs doesn't mean max power or torque.

But going beyond max power is say 2nd will mean 3rd is closer to max power when it's selected, less of a roller coaster in power delivery.

I'm with the rest on this select S, floor it and the car will give you the best output.
In truth when flooring it I'm not sure there is a difference between C and S as the car will rev to the limit in both.

 

[V6Matty]

In truth when flooring it I'm not sure there is a difference between C and S as the car will rev to the limit in both.

yep the car adapts to throttle position, so it you push it to the floor is selects 1st and rev's to the limit

 

[star]

But going beyond max power is say 2nd will mean 3rd is closer to max power when it's selected, less of a roller coaster in power delivery.

I'm with the rest on this select S, floor it and the car will give you the best output.
In truth when flooring it I'm not sure there is a difference between C and S as the car will rev to the limit in both.

That depends on the power curve and fast it drops off and how close the ratios are or not, and if a gear change is needed to reach the desired speed.

 

[Essel]

I'll lose my licence if I try this

 

[Frontstep]

Drive off cliff, terminal velocity can be reached without wasting too much fuel.

 

[M80]

Drive off cliff, terminal velocity can be reached without wasting too much fuel.

Only with an empty tank.

 

[television]

Only with an empty tank.

That would spoil it, with a full tank it could send you back up again

 

[Rory]

If you manually select a gear then the gearbox will select lower gears if required or remain in that gear even once the rev limiter is reached.

I appeciate mine is diesel and the OP's car is probably petrol, but mine doesn't hold a manually selected gear on full acceleration - it still changes up, and it does it quite early at not much over 4K RPM.

 

[whitenemesis]

Pretty sure only AMGs will hold a gear at the red line using the rev limiter with the pedal floored but then only in M mode.

 

[television]

I appeciate mine is diesel and the OP's car is probably petrol, but mine doesn't hold a manually selected gear on full acceleration - it still changes up, and it does it quite early at not much over 4K RPM.

Are you sure about that, the cars have hold for descending hills etc, if you select say hold 2nd, it will not change up at all.

 

[EmilysDad]

Are you sure about that, the cars have hold for descending hills etc, if you select say hold 2nd, it will not change up at all.

I'll check, but I'm sure mine will if you keep your foot planted

 

[ajlsl600]

i have a clk320.auto avanteguarde for 10 yr now i find it best to use tiptronic and drop it one or two gears if i am in a hurry or short of space to overtake.its slighly quicker otherwise i leave it in auto and let the box do the work. sometimes the only clue to the gear change is a drop in rpm . 103,000 miles now, never truely thrashed.

 

[whitenemesis]

I'll check, but I'm sure mine will if you keep your foot planted

There's the difference, one doesn't keep the pedal to the floor when using the gears to descend steep hills. Counter productive!

 

[EmilysDad]

There's the difference, one doesn't keep the pedal to the floor when using the gears to descend steep hills. Counter productive!

:lol: :lol: OK .... maybe not going down hill then.

 

[whitenemesis]

LOL... What I mean is the box won't shift up if there isn't the demand from the throttle? So, coasting downhill with the shift range restricted by nudging the selector results in the box holding the gear.
That said if the revs try and rise above the red line because engine braking can't slow the car, it must shift up? Unless the car auto-applies the brakes, which some models can do if the speed limiter is employed?

 

[television]

There are times when I have used the paddles to change down and the car changes down 2 gears, when ready to go back to normal I have lifted the paddle just once to upshift and the car will stay in that gear, its only when I have looked at the rev counter that I have twigged it. The box will stay in that gear till I upshift again, no matter if going uphill or down.

 

[M80]

Unless the car auto-applies the brakes, which some models can do if the speed limiter is employed?

and with cruise control in use.

 

[brandwooddixon]

I'm pretty sure that I've hit the rev limiter in my CL500 and previous E430 when overtaking without the car changing up a gear when I've manually selected lower gears.

Perhaps if you keep the kickdown switch depressed it behaves differently.

 

[Rory]

LOL... What I mean is the box won't shift up if there isn't the demand from the throttle? So, coasting downhill with the shift range restricted by nudging the selector results in the box holding the gear.
That said if the revs try and rise above the red line because engine braking can't slow the car, it must shift up? Unless the car auto-applies the brakes, which some models can do if the speed limiter is employed?

I would imagine it will hold a manually selected gear when engine braking down hill, but you'd have to be pretty bonkers to be hitting the red line.

Certainly threw me first time that it changes up on acceleration though - I use a flowing single carriageway A road quite a bit and I'll generally select a lower gear if I'm behind a truck and I can see an overtake opportunity coming up. I'd rather it held the gear until I was clean past but it doesn't - it changes up, and, as mentioned earlier, at a surprisingly low amount of revs.

 

[television]

None of my cars will change up under any conditions if locked to a lower gear, that is the idea of it all.