V8 and lightweight flywheel for road use?

[fiju]

I've got a V8 with a 6 speed that will be used for road and track days.

Has anyone got experience with lightweight flywheels?
I hear it becomes a bit jerky at low rpm due to less inertia, but unsure on what engines people are using. A V8 should be smoother than a 4 cylinder and I imagine would succumb less to this phenomenon. In theory I should be able to go very light and retain civility.

[GreenV8S]

I think you'll find that engine tractibility and clutch behaviour make a big difference - plus how tolerant you are of the need to drive around driveline shunt issues and balance clutch/throttle accurately when you've moving off.

If you like how it drives at the moment, don't make any big changes.

[fiju]

A V8 with a 6 speed is not a factory option so I have no idea how it drives as it's not even built yet! Probably should have mentioned that.

The gearbox is off an engine with a V6. That has a 12kg flywheel. Obviously that would behave like an oe application.
I have the option to specify flywheel weight. The clutch will be a bespoke uprated item.

Having no experience with lightweight flywheels, I can't comment on drive line shunt etc. So I'm trying to gauge from others opinions.

[Boosted LS1]

12 kgs is par for the course. I'd go with a tad lighter and see how you like it. Maybe 10 kgs should do it.

[fiju]

It would be nice to have a way of testing different weights to find the sweet spot...

[Boosted LS1]

If you have the time you could add heavy metal to a lightened flywheel but really it's not that important on a road car. There are differences to be felt but on a road going v8 almost anything 'factory' will be acceptable. A 7" race flywheel would work but you may not like it. i'd aim for the 12 kgs as a starter or listen to feedback from others.

[fiju]

There is no feedback from others as it's not a common conversion. Most stick with an auto box.

It uses a 240mm flywheel.
I know of one guy who runs a 12kg solid flywheel and says it's fine. But I'd like to know just how light I can go within reason.

[Zener]

Also depends how light the car is etc I use a 6.6kg FW on a road car V8 no regrets although it depends what your driving style is , I would agree with others however 10 / 12kg a good compromise

[fiju]

I'd say the car will end up somewhere around 1300kg. Driving style depends on the mood I'm in lol.

What car is that in? How does it feel to drive? Do you get any gear rattle?

[DVandrews]

A V8 has a lot of rotational momentum so reducing the flywheel weight shouldnt create too many problems getting off the line, the engine should feel more responsive and acceleration will improve marginally, especially in the lower gears, one possible side effect is roll over noise from the gearbox as the crank excitations are not so well damped.

Dave

[Kokkolanpoika]

My 5.2l V8 SD1 weight 1700kg inc driver. I have got Eales steel billet flywheel witch weight approx 7kg. 1 gear ratio 2.95.
No issues at all. Drives like stock car with throttle bodies. Only issue is tyre grip..

[Zener]

DVandrews said:

A V8 has a lot of rotational momentum so reducing the flywheel weight shouldnt create too many problems getting off the line, the engine should feel more responsive and acceleration will improve marginally, especially in the lower gears, one possible side effect is roll over noise from the gearbox as the crank excitations are not so well damped.

Dave

Realistic outcome above ^ agreed