Change final drive ratio...

So whats that then? As others have pointed out, you're looking at around 100MPH.

Why do you need to find graphs? I said "average".

Exactly. And not only that, is the engine really going to be generating enough power at 2500-3000rpm to keep the car going at 100mph?

If you make that 90, then it equates to 20 mph/1000. Not unreasonable for a medium sized engine in a heavy car.

That's in the ballpark. Maybe it's not unreasonable, but I don't like it!

Maybe I just need to wait till I can afford a 6 speed :-(

I bet that, if you sat down with a pen and paper, and actually worked out, taking into account the drag coefficient, mass of the car etc., the amount of power needed to maintain a constant speed of 90mph on a flat surface, then the chances are the 2 litre engine wouldn't be producing enough power at the lower revs you'd quite like. If it's only going be coping at those revs on a downhill stretch then you won't save any fuel as it'll be at a much smaller throttle opening anyway, or possible on the overrun (i.e. no fuel being pumped through at all), and obviously on any upwards gradient you'd be wanting to drop down a gear, so it'd spend a *lot* less time in 5th gear anyway. You want either a TD or a V6/V8 somethingorother! But you're not going to get a low mileage one of them for £300, so just be happy with what you've got :-)

Or you could try a Metro GTi, to see what low gearing *really* is.

For cruising, we're talking torque. Peak torque on most petrol engines comes at around 2300-2800 revs, which is where I'd like to be at 85-90.

In practice, it's running at 4000-4500 which is irritating.

Oops finger trouble..

Alright, I give in, they've geared it just right, I'm being unreasonable. Although the 2.0 Zetec does have 80% of it's peak torque from practically nothing right to 5800rpm or so, it's surprised me like that.

Unlike the small Rovers which seem to have a torque band about 300 revs wide...

Perhaps not, but if the gearing was higher you'd probably find you'd be forever changing gear on a motorway.

Not on most 16 valve designs.

The thing is, torque gets you there, but power (product of torque and revs) keeps you there.

Where did you nick that from? - I know it's not yours 'cos you're a mechanical numpty :-P

No sadly just something wrong with the OP. It was a troll and he wasn't talking about 70 mph at 4500 rpm. So he's blocked for wasting everyone's time and if he ever does have a serious question it won't be getting answered.

-- Dave Baker

Indeed. With the cruise control set well under 90, my 2.0 turbo is nearly on boost even on the flat at 3000 RPM.

Cheers,

Colin.

Oh dear.

And is smack in the middle of the powerband - where it wants to be.

Err no, I think you will find peak torque for your Mondeo petrol is at or around 4000rpm. You dont mention which engine you have though..

If the gearing is too high the engine will have insufficient torque or less than ideal torque to propel the vehicle at that speed and mpg will be worse due to a wider throttle opening being needed.

tim..

No!

Tim,,