20 replies to this topic

[babsbrown]

Hey guys

I have a 1098+40 3.1FD
It has a verto A+ flywheel and clutch assembly. I do have to rev it quite a bit to give it the best acceleration. But it does fly when the revs are at the right amount.

I was contemplating a lightened flywheel, but... as the 1098 has typically more torque will I be sacrificing the torque at the expense of better revs low down?

My logic is thinking the weight of the standard flywheel would have more inertia which may be better for torque than a lightened one?

I'd love to get a 3.7 FD but I don't really want to split the engine and box again.

Any advice is much appreciated,

Cheers, Babs


Cheers

[Ethel]

You can, in theory, change the final drive without splitting the the box & engine.

 

The benefit of a lightweight flywheel is it absorbs less energy spinning up, leaving more to put on the road. That's the same as what you'd want from a torquey engine.

 

To store energy the flywheel has to already be spinning faster, so you can only recover it in situations where the engines is being slowed down. Starting to climb a hill or changing up gear.

 

....or revving it up & dropping the clutch 

[babsbrown]

You can, in theory, change the final drive without splitting the the box & engine.

The benefit of a lightweight flywheel is it absorbs less energy spinning up, leaving more to put on the road. That's the same as what you'd want from a torquey engine.

To store energy the flywheel has to already be spinning faster, so you can only recover it in situations where the engines is being slowed down. Starting to climb a hill or changing up gear.

....or revving it up & dropping the clutch

Thanks Ethel, definitely seems like a worthwhile investment then.

Ah yes makes sense actually I could access the diff through the back and just remove the speedo housing and remove the pinion there.
Although I imagine not a job really sensibly done with the engine in situ. 😂

[Cooperman]

I think you would find the 3.44:1 FDR the best for your engine.

A lightened flywheel will not reduce the available torque as that's defined by the engine capacity, camshaft, compression ratio and gas-flowing of the induction and exhaust systems.

A lighter flywheel translates to better acceleration and usually a slightly lumpier tick-over, although that is often the result of a 'hotter' camshaft. Yes, you will have to rev it a bit more to get it 'off the line' due to the lower stored energy in the flywheel, but once moving it makes no difference to the torque.

You don't say which camshaft you are using and for your engine an MG Metro or Kent 266 would be good, or the Mini Spares Evo001.

As you have to remove the engine and gearbox to change the diff ratio, it requires little extra work to take the engine off the box which makes the diff change easier, and check such things as bearings, oil pump. timing chain, etc. You can change the cam at the same time if you so wish.

General advice with a 1098 engine is to have it all balanced and not to rev it regularly at much over 6200 rpm. I once had a 1098 with a 295 head, twin HS2's, a flowed head and a 731 cam. It had a 3.76:1 FDR and it was a bit low geared really. I intended on changing it to a 3.44, but I sold it and got a MK.1 Cooper which had been fitted with a 1275 'S' engine & 'box'.

A 3.44:1 will give around 16.5 mph per 1000 rpm in top gear.

[whistler]

Hey guys

I have a 1098+40 3.1FD
It has a verto A+ flywheel and clutch assembly. I do have to rev it quite a bit to give it the best acceleration. But it does fly when the revs are at the right amount.

I was contemplating a lightened flywheel, but... as the 1098 has typically more torque will I be sacrificing the torque at the expense of better revs low down?

My logic is thinking the weight of the standard flywheel would have more inertia which may be better for torque than a lightened one?

I'd love to get a 3.7 FD but I don't really want to split the engine and box again.

Any advice is much appreciated,

Cheers, Babs


Cheers

I have an overbored 1098 with a minispares ultra-light flywheel. Final Drive of 3.4:1. Engine produces 80ftlbs of torque and it's quick. 

[Shooter63]

My personal view is that I wouldn't bother with a light flywheel, you can't get that much out of a verto set up, you are no doubt aware that the advantage degrades with each gear, if I remember right you haven't got alot of compression, again personally I would spend the money on skimming the head to get the compression up into the high nines/ early tens, more compression equals more torque.

Shooter

[babsbrown]

I think you would find the 3.44:1 FDR the best for your engine.
A lightened flywheel will not reduce the available torque as that's defined by the engine capacity, camshaft, compression ratio and gas-flowing of the induction and exhaust systems.
A lighter flywheel translates to better acceleration and usually a slightly lumpier tick-over, although that is often the result of a 'hotter' camshaft. Yes, you will have to rev it a bit more to get it 'off the line' due to the lower stored energy in the flywheel, but once moving it makes no difference to the torque.
You don't say which camshaft you are using and for your engine an MG Metro or Kent 266 would be good, or the Mini Spares Evo001.
As you have to remove the engine and gearbox to change the diff ratio, it requires little extra work to take the engine off the box which makes the diff change easier, and check such things as bearings, oil pump. timing chain, etc. You can change the cam at the same time if you so wish.
General advice with a 1098 engine is to have it all balanced and not to rev it regularly at much over 6200 rpm. I once had a 1098 with a 295 head, twin HS2's, a flowed head and a 731 cam. It had a 3.76:1 FDR and it was a bit low geared really. I intended on changing it to a 3.44, but I sold it and got a MK.1 Cooper which had been fitted with a 1275 'S' engine & 'box'.
A 3.44:1 will give around 16.5 mph per 1000 rpm in top gear.

Hi Cooperman,

I have indeed got an evo001 camshaft which I find very nice to live with. Its funny you mention that set up. I do also have a 12g295 and twin hs2s. Both unfortunately needing a tefurb. The head has recessed inlet valves unfortunately. Maybe one day I will invest in getting it sorted with either inserts or oversized valves.

Absolutely agree with the 6k rpm, especially with the more fragile longer crank. although I can't imagine myself ever pushing that. It seems to have an abundance of power in the 4k mark. The thought of pushing it to 6k scares me hehe.

Edited by babsbrown, Yesterday, 06:40 PM.

[babsbrown]

Hey guys

I have a 1098+40 3.1FD
It has a verto A+ flywheel and clutch assembly. I do have to rev it quite a bit to give it the best acceleration. But it does fly when the revs are at the right amount.

I was contemplating a lightened flywheel, but... as the 1098 has typically more torque will I be sacrificing the torque at the expense of better revs low down?

My logic is thinking the weight of the standard flywheel would have more inertia which may be better for torque than a lightened one?

I'd love to get a 3.7 FD but I don't really want to split the engine and box again.

Any advice is much appreciated,

Cheers, Babs


Cheers

I have an overbored 1098 with a minispares ultra-light flywheel. Final Drive of 3.4:1. Engine produces 80ftlbs of torque and it's quick.

Wow that's impressive. Am I right in thinking yours is the +100 flat top calver st pistons build?

[whistler]

 

 

Hey guys

I have a 1098+40 3.1FD
It has a verto A+ flywheel and clutch assembly. I do have to rev it quite a bit to give it the best acceleration. But it does fly when the revs are at the right amount.

I was contemplating a lightened flywheel, but... as the 1098 has typically more torque will I be sacrificing the torque at the expense of better revs low down?

My logic is thinking the weight of the standard flywheel would have more inertia which may be better for torque than a lightened one?

I'd love to get a 3.7 FD but I don't really want to split the engine and box again.

Any advice is much appreciated,

Cheers, Babs


Cheers

I have an overbored 1098 with a minispares ultra-light flywheel. Final Drive of 3.4:1. Engine produces 80ftlbs of torque and it's quick.

Wow that's impressive. Am I right in thinking yours is the +100 flat top calver st pistons build?

 

Yes.

[babsbrown]

My personal view is that I wouldn't bother with a light flywheel, you can't get that much out of a verto set up, you are no doubt aware that the advantage degrades with each gear, if I remember right you haven't got alot of compression, again personally I would spend the money on skimming the head to get the compression up into the high nines/ early tens, more compression equals more torque.

Shooter

Thanks shooter yes we'll remembered. It has 9.2CR at the moment. Another 40thou off the head would take it to 9.6

I think I'm at the point where I've built the engine and it runs great. But now I'm like
what next? ..... . Think I should be perhaps happy, especially for my first build but I know there's always improvements that can be made.

by the way shooter, do you have a YouTube channel?

Cheers

[Shooter63]

My personal view is that I wouldn't bother with a light flywheel, you can't get that much out of a verto set up, you are no doubt aware that the advantage degrades with each gear, if I remember right you haven't got alot of compression, again personally I would spend the money on skimming the head to get the compression up into the high nines/ early tens, more compression equals more torque.

Shooter

Thanks shooter yes we'll remembered. It has 9.2CR at the moment. Another 40thou off the head would take it to 9.6

I think I'm at the point where I've built the engine and it runs great. But now I'm like
what next? ..... . Think I should be perhaps happy, especially for my first build but I know there's always improvements that can be made.

by the way shooter, do you have a YouTube channel?

Cheers

I've got an OnlyFans site if that's any good to you:)

There will be a YouTube channel coming but it won't be anything to do with automotive, I've decided to retire soon and will need something to stop me going insane ( or more insane as my Mrs would say )

Shooter

[babsbrown]

My personal view is that I wouldn't bother with a light flywheel, you can't get that much out of a verto set up, you are no doubt aware that the advantage degrades with each gear, if I remember right you haven't got alot of compression, again personally I would spend the money on skimming the head to get the compression up into the high nines/ early tens, more compression equals more torque.

Shooter

Thanks shooter yes we'll remembered. It has 9.2CR at the moment. Another 40thou off the head would take it to 9.6

I think I'm at the point where I've built the engine and it runs great. But now I'm like
what next? ..... . Think I should be perhaps happy, especially for my first build but I know there's always improvements that can be made.

by the way shooter, do you have a YouTube channel?

Cheers

I've got an OnlyFans site if that's any good to you:)

There will be a YouTube channel coming but it won't be anything to do with automotive, I've decided to retire soon and will need something to stop me going insane ( or more insane as my Mrs would say )

Shooter

Hahahaha is that we're you show your mini?
Ah I thought I saw a mini guru with a similar username on YouTube thought it could be you.
Absolutely, It so good to keep the mind busy isn't it!!

[Spider]

With a 3.1 FD, you won't get a lot of benefit from a lightened flywheel. Since you are considering a lightened flywheel, I'd suggest swapping out to a pre-Verto clutch set up, right off the bat they are lighter.

 

You definitely can swap out the FD gears without splitting the engine off the gearbox.

[Cooperman]

I am sure lightened pre-Verto is the way to go combined with a 3.44 fdr.
If you know that the bottom end bearings and oil pump are good, then it’s easy to change the diff with the engine on the box. Just remove the end cover and diff cover. A cross pin diff is a good idea as well.

[timmy850]

My 1098 has 3.44 diff and a lightened pre-verto flywheel. 

 

If I was going to change the diff ratio either way I'd go for something longer like a 3.1, or in-between 3.44 and 3.1 using some different drop gears. 

 

However, with standard ratio gears, a low final drive ratio (like 3.1) and using less than 6000rpm you'd have a big RPM drop between each gear and it'd feel flat when you change gear and drop back in rpm

 

What's your timing curve like at 2000rpm?

 

Mine happily revs well past 6000rpm, I currently have an rpm limiter on at 6000rpm to keep it under control.

https://youtube.com/shorts/yCJE_DkMf8s