9 replies to this topic

[Minisniper]

Hiya
I have a question for those of you who have a 998cc Automatic.
I'm trying to work out from my rev counter and speedo what speed I should be doing to what revs on a flat road, example 50mph = 3000rpm which to me seems a little high, I would be interested to hear from those of you who have a 998cc Automatic.

Looking forward to your replies.

[Ethel]

You can use a computer gear calculator Guessworks, Winsu etc. Just tap in your tyre size and diff ratio (3.27:1?)

[Ouster]

In my 998cc manual, I'm doing 4000 revs at 70.

[mini mark]

ye mines a little under 4000 at 70 .

[Guess-Works.com]

Auto's are strange beasties which have odd final drives, but also, because there is no direct drive between the crank and the gearbox ( there's a fluid torque convertor in the way ) there will never be a direct comparison between what your right foot is doing to the engine RPM and the speed of the vehicle.

The auto's also had a number of final drives, not only the 3.2, but also a 2.7 on the "E"conomy models and a 2.6 on the some of the 1275 units.

[Minisniper]

In my 998cc manual, I'm doing 4000 revs at 70.

ye mines a little under 4000 at 70 .

Hiya
Thanks for the replies but mines an auto as I said in my post and from what I can gather what you get in your manuals doesn't necessary follow with an automatic as the ratios in a manual gearbox and an automatic gearbox are different.

Looking forward to more replies.

[Minisniper]

Auto's are strange beasties which have odd final drives, but also, because there is no direct drive between the crank and the gearbox ( there's a fluid torque convertor in the way ) there will never be a direct comparison between what your right foot is doing to the engine RPM and the speed of the vehicle.

The auto's also had a number of final drives, not only the 3.2, but also a 2.7 on the "E"conomy models and a 2.6 on the some of the 1275 units.

Thank you for your reply Guessworks however what you have put here all sounds very good and complicated and to be honest has just gone straight over my head. What I am trying to find out is if I'm doing 50mph on a flat road at around 3000rpm in a 998cc auto with only 15,000 miles on the clock would this seem to be normal/reasonable?
I wish I had as much knowledge as you do or as you seem to have on this site

[Bristolboy]

about 85mph @ around 4300rpm, but mine is a 998 manual

Bb

[Guess-Works.com]

What I am trying to find out is if I'm doing 50mph on a flat road at around 3000rpm in a 998cc auto with only 15,000 miles on the clock would this seem to be normal/reasonable?

Yes

But the point about there is no hard physical connection between the crank and the gearbox in a Mini auto is an important one... unlike a manual where there is being the clutch. This why you can 'coast' along for a while in an auto at an absurdly low rpm and going down hill, but when you come to go up a hill, the engine has to 'over-run' the gearbox to get up...

I'm trying to think of an easy to understand analogy for the torque converter but it's difficult... something like a water wheel comes to mind but an example escapes me

[Minisniper]

What I am trying to find out is if I'm doing 50mph on a flat road at around 3000rpm in a 998cc auto with only 15,000 miles on the clock would this seem to be normal/reasonable?

Yes

But the point about there is no hard physical connection between the crank and the gearbox in a Mini auto is an important one... unlike a manual where there is being the clutch. This why you can 'coast' along for a while in an auto at an absurdly low rpm and going down hill, but when you come to go up a hill, the engine has to 'over-run' the gearbox to get up...

I'm trying to think of an easy to understand analogy for the torque converter but it's difficult... something like a water wheel comes to mind but an example escapes me

Hiya Guessworks.
thanks for the reply, my partner has an automatic pajero and he's just replaced his torque converter so I know what they look like and you're right they do look like a water wheel and I do understand abit about being no physical contact between the engine and the gearbox so thanks again for your help.