Lightened Flywheel - Is It Worth It?

[mspek]

Just after peoples experiences with the Exedy lightened flywheel 6.2kg. Is it really worth it?

My end aim is about 260kw-280kw, I am looking at getting the following clutch:

http://www.skylinesaustralia.com/forums/ip...roducts_id%2F27

Rev210 swears by a lightened flywheel, saying 0.5 seconds can be shaved off his quarter mile. Yet other people keep telling me the lightened flywheel really doesnt make a great deal of peformance difference?

Can people please validate with real world experiences. I dont want to throw money at something, just for the sake of it, (bear in mind my end goal).

thankyou

[SKYPER]

Lightened flywheel affects engine acceleration or how fast a engine revs.

It can help to reduce the time it takes for engine to reach rpm's where

full boost is for turbo.

The benefits for dragracing would be when the revs drop as your changing gear

and need to get the engine revs back to where peak power, torque are in the

rev range.

Read this link about how a lightened flywheel works -

http://www.uucmotorwerks.com/flywheel/how_...wheel_works.htm

From reading the link above, it seems a very light flywheel affects top speed.

Nismo or Excedy flywheels seem to be the best compromise between extra

engine acceleration and able to reach top speed.

Edited April 21, 2008 by SKYPER

[mspek]

Thanks for this, the theory makes sense.

I really want to hear about peoples experiences with and without it on (and with similar spec't skylines).

Lightened flywheel affects engine acceleration or how fast a engine revs.

It can help to reduce the time it takes for engine to reach rpm's where

full boost is for turbo.

The benefits for dragracing would be when the revs drop as your changing gear

and need to get the engine revs back to where peak power, torque are in the

rev range.

Read this link about how a lightened flywheel works -

http://www.uucmotorwerks.com/flywheel/how_...wheel_works.htm

From reading the link above, it seems a very light flywheel affects top speed.

Nismo or Excedy flywheels seem to be the best compromise between extra

engine acceleration and able to reach top speed.

[SKYPER]

You're welcome.

I think this is the link with torque output, etc -

http://www.uucmotorwerks.com/flywheel/ther...torque_loss.htm

Edited April 21, 2008 by SKYPER

[R338OY]

I asked the same question before. The responses i got turned me away from it. Seems to only give serious improvement in certain conditions. I'd say if you're either big into motorsport/into heavy mods then it's necessary. For a daily driver it'll make tottering around town worse because the factory flywheel works well for low rpm gear changes due to its extra weight/momentum.

A lightened flywheel won't be the same. It needs rpms to get going (not much i'd imagine) but once it does will provide much less restriction on how fast you hit redline.

That's what i was told from memory. Cheers.

[mspek]

Yep, I suspected what you are saying..

There are quite a few people using Exedy in the community, so lets wait and see what other people have to say.

I asked the same question before. The responses i got turned me away from it. Seems to only give serious improvement in certain conditions. I'd say if you're either big into motorsport/into heavy mods then it's necessary. For a daily driver it'll make tottering around town worse because the factory flywheel works well for low rpm gear changes due to its extra weight/momentum.

A lightened flywheel won't be the same. It needs rpms to get going (not much i'd imagine) but once it does will provide much less restriction on how fast you hit redline.

That's what i was told from memory. Cheers.

[sl33py]

I had (and recently sold) an Xtreme light flywheel. It was about 6kgs. Stock is 14kgs if memory serves. I do 90% of my driving in stop/start traffic, the rest is cruisy 80-100kph stuff, and it was a complete pain in the a55hole. Yes, the engine revved through the range quicker, but if ever want to drive the car lazily (ie not slamming it between gears in 1 millisecond), then there were always massive jerks. Makes you feel like you're learning manual all over again..... possibly for months. I couldn't get used to it and went back to stock. I can't express how relieving it is to be able to change gears as fast/slow as I want, based on the conditions at hand, not the car's requirements. Also, on the track (Wakefield) I couldn't change gears smooth enough for my driving instructor, no matter how quickly I shifted the stick and how smoothly/slowly I let out the clutch. I can tell I'll be way smoother when I go back (and smoothness is what you want on circuit). I guess it depends on what you want, and how dedicated you are to it

[(B1) MR_fanny]

ive got the exedy flywheel and I'm quite happy with it. Yes it is noisier down at super low revs, its tricky in the car park and yes it does take a while to get used to, whether its the combination of both the cushion button clutch and flywheel. Strangely I find that it takes less revs to get going as once its engaged it just wants to go. Accel is alot smoother but at the same time if you'r not used to it it can become quite rough. I dont have any issues with gear change, that may be due to the short shifter and my driving style which is cruzy. I don't flog the car and smash gears. Rev matching is alot easier. Along with a slight tune it was a completely diff car to drive.

If your really concerned about a smooth comfy ride then stick with the stocker, I personally think its a good mod, just dont go super light as its uncessesary, thats why I got myself the exedy one instead of a super light one. There's no real major draw backs to make me want to go back to stock.

[mspek]

Interesting comments. MR_fanny I assume you have the 6.68kg exedy flywheel.

I will leave my judgement on this till the end of next week. Bit disappointed I thought there would be more comments by now.

Silence to me indicates its just not a good bang for buck mod that people can be bothered with. Having said this, itpuzzles me, as whilst doing the clutch, it would make sense to put a light weight exedy flywheel (if you have the coin).

I've pm'd a few known heads, lets see if they contribute.

ive got the exedy flywheel and I'm quite happy with it. Yes it is noisier down at super low revs, its tricky in the car park and yes it does take a while to get used to, whether its the combination of both the cushion button clutch and flywheel. Strangely I find that it takes less revs to get going as once its engaged it just wants to go. Accel is alot smoother but at the same time if you'r not used to it it can become quite rough. I dont have any issues with gear change, that may be due to the short shifter and my driving style which is cruzy. I don't flog the car and smash gears. Rev matching is alot easier. Along with a slight tune it was a completely diff car to drive.

If your really concerned about a smooth comfy ride then stick with the stocker, I personally think its a good mod, just dont go super light as its uncessesary, thats why I got myself the exedy one instead of a super light one. There's no real major draw backs to make me want to go back to stock.

[djr81]

Well I can't speak of a GTS-T. But I have one in my Gt-R. A HKS unit, but the prinicple is the same.

IMHO the bottom line is:

1. It is noticeable that there is less inertia in the motor, particularly at low revs.

2. It means you have to be a tiny bit more careful when driving, but if you cant drive it properly you shouldn't have a licence.

3. It does make it a bit easier to smash through the gears.

4. It makes acceleration in the lower gears slightly quicker - but only if you have traction.

5. It is a gain (however small) and if you are serious about a time then do it.

6. Other than the cost there really isn't a down side.

[r33cruiser]

just got a exedy twin installed with a lightened ventilated flywheel.

FIRST thing u will notice is u NEED revs on take off. i launch at 3000 and if i just drop it it will bog down to around 1000rpm. thats the MAJOR problem i have found. i know accelleration increases etc. however i havent really found that.

i have to do more testing i suppose

*edit...however i used to be able to cruze comfortably in 5th at 60km/h.

now it likes it better to be stuck in 4th. so i guess u could say it likes its revvs now

Edited April 24, 2008 by r33cruiser

[mspek]

Thanks for the comments. Interesting you have to launch at 3000 everytime?

just got a exedy twin installed with a lightened ventilated flywheel.

FIRST thing u will notice is u NEED revs on take off. i launch at 3000 and if i just drop it it will bog down to around 1000rpm. thats the MAJOR problem i have found. i know accelleration increases etc. however i havent really found that.

i have to do more testing i suppose

*edit...however i used to be able to cruze comfortably in 5th at 60km/h.

now it likes it better to be stuck in 4th. so i guess u could say it likes its revvs now

[(B1) MR_fanny]

a twin clutch would probably be reason for the 3000 launch.

I can get off with as low as 1000rpms. literally engage and go pretty much. Have never needed to take it over 1200-1300 to get off the line unless im on a slope. That was the first thing I noticed after a couple days driving though it did take a while to get used to. The first couple days it was rough as guts breaking in the new clutch.

You might say because the cushion button clutch grabs better and theres less mass in the flywheel than before is the reason why my car feels like theres less effort needed to get it off the line. chances are I dont know what Im talking about...haha.

[rev210]

A good chrome molly flywheel is the go. It's stronger than cast iron and light. I had an excellent experience with the Ogura 4.8kg unit on the Rb25.

The Ogura units are very well balanced. As they are fairly light the type of clutch also comes into the equation for drivabillity. A big mistake I see plenty of Skyline owners make is going for a pressure plate with too much clamping force. If you get one of those ceramic/metal sprung 9 puck units, then a standard pressure plate will have them hooking up very well. Even on a fairly grunty motor by virtue of the clutch plate being far more bitey than the organic stocker.

Multi-plate clutch kits often come with a light weight flywheel too.

[**RB2530**]

From an acceleration point of view lightening the flywheel has a similar effect to lightening your car...It reduces the rotational inertia of your engine. lightening your car reduces the mass of the car and therefore inertia will reduce..therefore faster acceleration...effect from flywheel lightening is more pronounced in lower gears as previosuly stated..

Have used the stock flywheel and now have a 6kg FW and the 6kg definately more responsive...BUT

+1 on the driveability comments...carparks etc are trickier but in my mind a small price to pay...

[sh@un]

May as well come late to the party.

I can confirm what a lot have said- When i had my R32 GT-R equipped with a lighter, 700hp twin-plate Exedy clutch, the car became noticeably more tiresome to drive in traffic due to the sharp on-off throttle nature (clutch dip often required to smooth the transition) and the increased sensitivity around the take-up point (engine loses revs more easily).

That said, the response was awesome, and the engagement was super quick during fast driving.

Just avoid uphill traffic jams...

[STATUS]

i prefer to use complete clutch flywheel assys, not mix and match.

like the hyper series from EXEDY / ORC / NISMO etc i do prefer to use the ORC from a driveability point of view. If your only a full daily driver dont bother as some people just cant come to grips with the differrent pickup feel.... 9 times out of ten though a quick adjustment of the pick up point will fix any unwanted driveabilty issues.

[nigs]

another +1 to what everyone has said so far about driveability.

I've had lighten flywheel in both my previous cars with heavy clutches.

Traffic was a bloody pain in the ass. Alot of clutch dipping and riding needed

Response and pick up is awesome. Loved having the cars rev out so fast.

My 32 GTR on the other hand is practically stock and it's the easiest thing to drive. Not a single problem in heavy traffic.

Creeping foward in stop/start traffic just requires me to let the clutch out (without accelerating). No stupid jerking motions. The car isn't sensitive to throttle inputs either.

It's nice to have a car that doesn't make a fuss when u need to move @ 10km/hr

I guess it comes down to how often do you drive in traffic?

[Busky2k]

I think a lot of people buy new heavier/less streetable clutches at the same time as getting a lightweight FW so it doesn't help the cause. I like lightweight FWs, I'd go them every time. Quicker rev matching and better low rpm/gear response is worth it IMO.

[PLYNX]

And thanks sl33py for that flywheel ! Its going on my 3ltr and will do just fine.

Used ligthened flywheels on a lot of engines over the years, right up to a full aluminium one. Basically you get used to them as you go along. Its true about their ability to improve the speed of the recipricating mass of the engine. The faster it revs the faster it spools !