19 replies to this topic

[coopdog]

for some reason my mini struggles to get anywhere over 80.

been in my mates standard 998 and it goes off the clock!!!!


i think its because its a 2.9 FD and his was 3.1 i think.


and its not even like my car is slow or lacking power.

its a 998 which has 64 bhp and 64 torque.

goes up to 70mph  in 3rd fine then change into 4th and game over


toruqe problem?

 

[minirage]

im struggling to hit 40 and its a 1275 my old 998 was flat out off the clock to, check your engine number on final drive plus timing and fuel mixture to rule them out

[lrostoke]

make sure your getting full travel on the pedal and its opening the carb fully.

 

My 998 with same 2.9FD goes over 80 easy enough

[coopdog]

well the engine is sound

full re build

mini city e so 2.9 fd

998cc+60
12G295 head
mg metro cam
28/36 carb

fully rolling roaded

just **** in the higher end  :/
 

[iwatkins]

Indeed, check that putting the pedal to the floor is fully opening the throttle via the cable.

Mine had slipped at the end and was only giving just over 50% throttle. Was like it when we got and I changed all sorts trying to get some speed. Then someone mentioned the throttle pedal was a bit low and went to the carpet. And there was me really reaching to try and heal & toe as well. Doh!

Goes like stink now

Cheers

Ian

[coopdog]

Indeed, check that putting the pedal to the floor is fully opening the throttle via the cable.

Mine had slipped at the end and was only giving just over 50% throttle. Was like it when we got and I changed all sorts trying to get some speed. Then someone mentioned the throttle pedal was a bit low and went to the carpet. And there was me really reaching to try and heal & toe as well. Doh!

Goes like stink now

Cheers

Ian

im pretty sure its fine,
but i will check,

but the only gear its bad in is 4th

[coopdog]

Where's cooperman when you need him?!

[iwatkins]

Clutch slip?

Brakes binding a bit?

[coopdog]

Nah everything is good :/

Just sonething that's happening on the road that didn't on the rolling road and all I can think of is air resistance which lead me to believe that ther is a torque problem :L

[Twincam]

Maybe it's all that muscle on your body weighing you down ;)

Seriously though, in 1-3rd, you're able to get full power and go right through the rev range? Wonder if the mixture is getting weak towards the end. And you've deff got full travel on the throttle yeah?

[coopdog]

Yeah like you said 1-3 smashes right through the rev range 4th kills it :/

[coopdog]

When it was rolling roaded he said it was a bit rich at second jet so I got the next small one down,

It's just weird always been the same, even before the rebuild

[Cooperman]

The problem is the final drive ratio.

To pull a very high final drive, like a 2.9:1 requires an engine with a very wide and mainly mid-range torque curve. It is not so much a question of the peak power as without the torque you cannot pull up to the revs in 4th where the power will be effective. The shape of the car which causes the high aerodynamic drag means that you need a lot of torque to pull the car into the higher speed range.

Remember, the original 998 Cooper, which had a reasonably mild cam and 295 head had a 3.76:1 FDR and yours, Coopdog, has a 'hotter' cam and a Weber carb.

You could try a 3.44:1 FDR which would probably be a good compromise. That is what the original 1275 Cooper 'S' had.

With a 998 don't be afraid to rev it. Cruising at over 4500 rpm is fine.

In fact I've just been out in my Inno 1274 which has the 3.44:1 and it is great, even at 5000 rpm.

[Craig914]

Indeed, check that putting the pedal to the floor is fully opening the throttle via the cable.

Mine had slipped at the end and was only giving just over 50% throttle. Was like it when we got and I changed all sorts trying to get some speed. Then someone mentioned the throttle pedal was a bit low and went to the carpet. And there was me really reaching to try and heal & toe as well. Doh!

Goes like stink now

Cheers

Ian

I think mine has this problem, it should have plenty more reach. . My speed depends on how far I want to put my foot though the firewall. How do you sort it? New throttle cable? Or cutting carpet away?

Also mine is a 1275 as standard and its sounds like its about to go pop at 85. No good for the motorway atall.

Edited by Craig914, 06 May 2013 - 11:28 AM.

[coopdog]

The problem is the final drive ratio.
To pull a very high final drive, like a 2.9:1 requires an engine with a very wide and mainly mid-range torque curve. It is not so much a question of the peak power as without the torque you cannot pull up to the revs in 4th where the power will be effective. The shape of the car which causes the high aerodynamic drag means that you need a lot of torque to pull the car into the higher speed range.
Remember, the original 998 Cooper, which had a reasonably mild cam and 295 head had a 3.76:1 FDR and yours, Coopdog, has a 'hotter' cam and a Weber carb.
You could try a 3.44:1 FDR which would probably be a good compromise. That is what the original 1275 Cooper 'S' had.
With a 998 don't be afraid to rev it. Cruising at over 4500 rpm is fine.
In fact I've just been out in my Inno 1274 which has the 3.44:1 and it is great, even at 5000 rpm.

Exactly what I thought it was :L

Thanks cooperman


Can you change final drive with the engine intact?