For those with light flywheels

[Sideways Danny]

I fitted Dans Fidanza, Lovely bit of kit, shame I was lying on Gravel while bolting it on or i might have been in a better mood

[200sxer]

I fitted Dans Fidanza, Lovely bit of kit, shame I was lying on Gravel while bolting it on or i might have been in a better mood

Does this mean you won't fit mine anymore...

... what if I brought a blow up bed

[Busky2k]

Oh yeah, also giving you easier gear shifts with a lightweight flywheel is rubbish. A lighter friction plate will, but not a flywheel/pressure plate.

Anyways yeah with the Fidanza, constant cruising is no different from stock. I love it because the engine revs up alot quicker, which is perfect for gearing down during mountainous driving.

[Roo]

I've got a HKS lightened flywheel in my S14a. It was fitted at the same time as there super-happy-clappy-clutch. I'm very happy with the results. Car feels more urgent with a much more immediate response to the throttle. I have stalled it a few times but I blame the puck clutch plate for that, not the flywheel. Can't say I've noticed any change in engine braking and I've not had any problems holding a constant speed (70mph, officer ). Definitely a recommended mod.

[paul]

Have to agree with Roo on this one. Get one, you wont regret it.
But have it fitted on its own, not with other mods, then you can come tell us what you think


Paul

[Daniel Gard]

Whats the weight of the Fidanza one? and the HKS piece..
Ive got the Nismo SuperCooper mix clutch/pressureplate/flywheel and Its the bomb.. Jesus it feels good.. and revs up fast. Not that Iv'e had any chance of really testing it out since its winter her but Im eager to give it a blast as soon as the snow dissapears.

[stu658]

I fitted my Jun flywheel at same time as Exedy paddle clutch. The car spins up quicker and feels great. As already stated seems to come of the revs quicker and it tries to stall sometimes revs go right down but it soon settles down again. No regrets wot so ever, get it fitted

[paul]

Fidenza is quoted as 4.9kg. As a comparison it is nearly 5kg lighter than standard

[Busky2k]

Actually I think the Fidanza was rated at 4.3kg. Its light as, i couldnt believe the difference when I was comparing it to stock.

[Jon]

I think we're at cross purposes here.

THEORY
An engine, on a laboratory stand, spinning at 5000rpm, will drop to idle within one second when the throttle is closed. This is because there isn't the weight of a car or flywheel to prevent it.

The engine is slowing the flywheel during braking

Nope, the brakes are slowing the flywheel (via the prop and gearbox).

as you are changing to lower gears so the engine speed needs to drop to sensible levels after down shifts.

Nope, the engine speed needs to rise to sensible levels.

The more resistance the engine gives to this (i.e. the heavy flywheel) then the more the engine forces will go through the tranmission and try to slow the car down. This causes the rear (on RWD) to slide and try to lock up, this won't happen so much with a lightened flywheel.

At the moment I'm still thinking that a lighter flywheel allows more engine braking, and is more likely to lock the wheels.

If we ignore other things like brakes, gears, the weight of the car, and grip.

A 200SX accelerates from 40 to 80 mph.
It should accelerate quicker with a lighter flywheel, because the engine has less flywheel mass to spin.
If you let off the throttle, inducing engine braking, a light flywheel is will slow down more easily too.


A heavy flywheel will try harder to continue spinning, and propelling the car along the road, hence less engine braking.

[BBB]

Jon, that seems to make the most sense so far.

It reads like the benefit of a lighter flywheel is faster spin up (due to less mass) and so improved acceleration, with a potential downside of irregular idling and tendency to stall. This is exactly what I used to have on an old 1.9 205 GTi, which had a light flywheel.

[Grim]

don't forget there are effectively two sorts of engine braking.

1/ you are driving along and you take your foot off the throttle. in this case a heavy flywheel will keep then engine spinning and you don't get much deceleration. If you have a lighter flywheel, then you will notice reduced engine braking.

2/ you drop the clutch, change down, but don't blip the throttle. the engine is now doing say 2000, but needs to be doing 5000 when you release the clutch. A heavy fly wheel will give you more engine braking in this case.
this is when the back end can step out.

either way a lighter flywheel reduces fuel consuption, 0-60 etc.

[duskinas]

don't forget there are effectively two sorts of engine braking.

1/ you are driving along and you take your foot off the throttle. in this case a heavy flywheel will keep then engine spinning and you don't get much deceleration. If you have a lighter flywheel, then you will notice reduced engine braking.

2/ you drop the clutch, change down, but don't blip the throttle. the engine is now doing say 2000, but needs to be doing 5000 when you release the clutch. A heavy fly wheel will give you more engine braking in this case.
this is when the back end can step out.

either way a lighter flywheel reduces fuel consuption, 0-60 etc.

But after you downshift and still want to engine brake, you will have to take your foot off the throttle. And here goes engine braking no 1/
imho

[GrahamB]

Ok then here is the first down side then

If you have a turbo timer and you pull up take the key out (so the turbo timer is still running the car) then lock the steering, the idle will be all over the place

I initially thought the stupid revs were due to something else, but it only does it when there is a load on the power steering motor (If I leave the steering lock off or I pull up with the wheel in the correct position to lock then I don't get this issue).

Oh and your car will rev while you move the steering wheel (not in gear)

[Hates_]

Whats the weight of the standard flywheel?

[GrahamB]

10kg

[formula]

don't forget there are effectively two sorts of engine braking.

1/ you are driving along and you take your foot off the throttle. in this case a heavy flywheel will keep then engine spinning and you don't get much deceleration. If you have a lighter flywheel, then you will notice reduced engine braking.

2/ you drop the clutch, change down, but don't blip the throttle. the engine is now doing say 2000, but needs to be doing 5000 when you release the clutch. A heavy fly wheel will give you more engine braking in this case.
this is when the back end can step out.

either way a lighter flywheel reduces fuel consuption, 0-60 etc.

spot on...

but in the last sentence under case number 1, i think you mean lighter flywheel will mean increased engine braking rather than decreased.. no?

james

[David Reid]

A heavier flywheel will give more engine braking.

The reason for this is that during deceleration you are trying to accelerate the engine (through gear change).
The heavier the flywheel the more mass that is attached to the engine and hence the slower it will accelerate.

The lighter you make the flywheel the easier it is to accelerate the engine, hence it will accelerate faster, but engine the braking effect will decrease.

I fitted a super light weight racing flywheel and back plate to my mini years ago, and this affect was very apparent, it would also stall easily with lots of electrical load on.

[PhatBob]

The most effective engine braking I've ever come across was in a Capri with a high compression 3.1 V6. Taking your foot off the accelerator felt like you had stepped on the brakes.

A lightened flywheel will allow greater acceleration for the same force (Force = Mass x Acceleration), but the flywheel is attached to a large air pump.

Rob

[dunc]

Jon, the heavy flywheel provides more engine braking because it takes more effort for the transmission to alter its revs. Plain and simply, sorry if I confused you by trying to state it in more simplistic terms. Its all down to the momentum of the flywheel, the heavier one has more momentum therefore more effect during engine braking.

If the internals and flywheel were zero weight when you dropped down a gear the engine would just alter its revs without causing any engine braking because there would be no momentium to stop it doing this.

I believe the Jun superlight flywheel is in the region of 4Kgs.

Dunc.