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MG ZR ZS ZT Technical - Your to get 6 speed gearboxes!

Soon, don't know when but about time.
Mega
Mega

Courtesy of the boys at Qu**f*?
Syd Enever

Quaif have had them a while for the PG-1 box, originally created for the Elise boys.
m hammond

Well - there you go then.
Syd Enever

last time I heard Rog P thought they were about £2400 each....
David

That'd be the cheap version David. Quaife also retail a 6-speed sequential box that fits in the PG1 casting. But budget about 6 grand for that particular baby... :o(
Rob Bell

Nuffink new there then ..... back in the middle ages, well the 1960s/70s actually :O), me old MGB had 6 forward ratios. A nice H gate 4 speed gearbox with smooth switch operated overdrive on 3rd and 4th. The sliding switch located at the top of the gear lever knob. IIRC, this dropped the revs by about 1500 rpm with normal use so was useful. That action really was nice. I had two cars with these overdrives and both were a delight to use. Not driven any modern 5 or 6 speed box as nice as that was too use ..... and that includes my latest acquisition ... a new ZS which does have a nice box action I'm pleased to say.

However, still I still prefer to "creep about" in the old Monty turbos. I kid you not ... :)

.... anyway, anyone explain why we need six ratios on modern cars, except perhaps as a "gotta have the latest wotnot" sales hook ..?

JMcF
John McFeely

<< anyway, anyone explain why we need six ratios on modern cars >>
Suppose it could be useful if you've got a car that needs to be revved hard to get anything out of it.
JLD

6 six speed box/overdrive I would say is ok in large car, say a R75, as it would most likely give better MPG. As for a sporty saloon 5 speed is sufficent!

Kelvin
Kelvin

JLD

Do I detect a very subtle dig there? Nice one ! .... ;) LOL
John McFeely

Here's an interesting observation that few enthusiasts ever mention, and that includes the F1 TV professional commentators. Have you noticed how briefly the actual duration in each gear of F1 cars with their obligatory auto-gearboxes when under maximum acceleration say when entering the main straight?

It really is brief and although I've not put a stop watch on them, pretty difficult, say to measure how many gear changes in say five seconds, I suspect it's as little as one second in each gear. Now that's a NARROW power band! Hence the need for a multiplicity of ratios ... mere flesh and blood would not be able to cope with that level of gear change frequency ... hence the need for sequential auto boxes ... that's what I meant by obligatory ...

Me? Give me a nice wide power spread from an understressed lump every time ...... LOL

JMcF
John McFeely

>>.... anyway, anyone explain why we need six ratios on modern cars, except perhaps as a "gotta have the latest wotnot" sales hook ..?<<

Depends on your car, its weight, its power delivery and the way that you drive. In the most part, 6 speed gearboxes are a sales gimmick. However, on a 4 cylinder K-series, there is a good case to be made for the extra cog.

The standard ratios are spaced for optimal fuel economy - both at the constant speed, and the urban cycle. As a result, you find that the first 4 gears are reasonably tall, but are pretty closely stacked. 5th turns out to be something of an overdrive.

If you are on a race circuit, and change up at the red line in forth, the engine tends to fall off cam somewhat as you slot into fifth. Not ideal. :o(

The next option is to fit a close-ratio gearbox. Huge fun - you'll be swapping ratios the whole time, and you can readily keep the engine spinning in the 'sweet zone' for maximum grin factor. Terrific for a country B-road or track.

But an absolute nightmare for the motorway (one of the reasons why I'd be put off fitting one of these 'boxes).

So a 6-speed would be ideal: a close-ratio 5-speed with an over-drive 6th. :o) Perfect.
Rob Bell

This thread was discussed between 15/05/2003 and 03/06/2003

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