BMW Accelerator jam car hits 135mph

On Mon, 13 Mar 2006 12:21:13 +0000, Alex Heney waffled on about something:

What was he thinking?

That's easy "Bloody BMW drivers!"

Dodgy

-BMW driver :o)

1) He may have imagined the actual figure over 130. The indicated speed might well have been 130+

2) This incident did take place. Or are you suggesting it is an elaborate hoax?

DAS

For direct contact replace nospam with schmetterling

I have quite good knowledge of industrial applications [it is part of my business] and the only difference in many applications is the stall speed and terminology. I am thinking specifically of ZF transaxles which had an option of with or without fluid flywheel aka low stall speed torque converter. On engines with a maximum rated speed of 2200 these things more or less lock up at 1100erpm which is a high idle. The primary purpose is to reduce wear on the primary dry traction clutch.

The reason that there is no way you can define a torque converter as a clutch is that it does not actually 'clutch' or 'declutch'. Substitute 'grab' for the word 'clutch' and you should see what I mean; grab or degrab.

Huw

Easy. He's from Portsmouth.

Huw, with all respect, you need to do a bit of research. The construction of a fluid flywheel and torque convertor *is* different. Google will come up with the answer.

I'm no expert on industrial equipment - this is a car group. But I've owned car autos with both fluid flywheels and torque convertors, and the big difference is the FF acts more or less like a normal dry clutch in that it has effectively no action once the car is moving. A TC is obviously in action in all but the highest engine speeds. Of course many autos lock it out under some circumstances since it's not the most efficient way to provide torque multiplication.

A Lanchester?

and torque convertors, and the

Yes, that type of coupling is certainly more of a clutch than a torque converter.

A TC is

Almost all torque converters fitted to modern cars have a lock-out mechanism which, surprise-surprise, requires a CLUTCH to work.

LOL.

Huw

Close. The first one was actually a BSA - but of course with a pre-selector box, not auto.

Rolls Royce didn't use torque convertor autos until something like '68. They had fluid flywheels. As did Mercedes.

But your definition of a clutch is like a light switch? ;-)

But not an on/off switch. ;-)

BTW, the Borg-Warner DG box fitted to things like late '50s Rovers and Jaguars had a TC lock out clutch which only operated in top gear.

Didn't realise you were an AOL customer.

Well yes actually. It is either engaged or disengaged with, in most cases, a degree of softeness to the actuation or 'soft modulation' designed in.

Even these had an actual CLUTCH to lock the torque converter then.

Huw

So what? It still didn't operate like an on off switch. It modulated the speed of lockup - same as you do with the clutch on a manual transmission when starting from rest.

As does a clutch, a clutch act as a torque convertor. A torque convertor is just a posh word for a clutch, cars with automatic transmissions are bought buy posh people who are impressed with posh sounding words, clutch sounds so common.

Yep. It modulates between the on and off position, neither of which is possible with a torque converter without a separate clutch to facilitate.

Huw

"Emperor's New Widescreen" wrote

Actually it says that the stator contains a one way clutch, a sprag in fact. All cars have a number of clutches. This does not mean that the car is a big clutch any more than it means that just because a converter contains a clutch or two, that it is actually a clutch in itself.

For Dave, the first sentence defining a converter describes it as a fluid coupling device that also acts as a torque multiplier during initial acceleration.

Never any mention of a converter being a clutch, which of course it is not and if a converter allied to a conventional synchromesh gearbox there must be an actual clutch in the driveline to allow disconnection during a gearchange. While synchro boxes in conjunction with torque convertors are not common in cars they are not uncommon per-se. In an automatic or power-shift gearbox, there is of course no need to disconnect drive to achieve a ratio change because the clutch is integral to the gearbox in that it replaces a synchro unit in effect, whether in a constant mesh or planetary unit. From this it should be obvious that it does not matter which side of the converter a clutch is fitted, either on the input shaft or the output.

Please do try again your widescreenness :-)

Huw