Lightweight flywheel.

[jdflyer]

So I’m trying to make a decision on my motor and would like some input. Just FYI it’s an s14 sr20de vvl rwd conversion

It will be used for mostly on the street with some spirited driving.

The motor has Manley Rods, CP pistons and N1 cams. Machine shop will be removing about a pound of weight from the crank to match the weight loss on the pistons and rods. I was thinking of also adding a lightweight flywheel but am concerned about it’s daily drivability if I do so. I would love to solicit this forums opinion.

This is the package I’m considering.
https://www.ebay.com/itm/EXEDY-OE-CL...f41e%7Ciid%3A1

The other option is the stock flywheel rebalanced with all the internals

[S14rebuild]

That clutch will not hold very much power as its rated for oe motor setup.

But that flywheel will work..

[Allen2688]

In my opinion, if your mostly street driving the car as like a daily, it comes to personal preference of how much comfort you want. I'm personally a big fan of lightweight flywheels as the engine revs out faster, shifts quicker, and has better throttle response. It all adds up to better output at the wheels. The downside being you will have harsher shifting, and a less forgiving clutch engagement. If you plan on ever tracking the car, I would definitely go for lightweight.
If your still really on the fence, I'd try finding someone with one that would offer a ride along.

[jdflyer]

Originally Posted by S14rebuild

That clutch will not hold very much power as its rated for oe motor setup.

But that flywheel will work..

My goal is 200-210 whp since it’s a NA build. I was thinking a turbo OEM clutch would be fine.

[S14rebuild]

Oh then yea, that setup is solid for what your going for

[SidewaySSS]

Light weight all the way for me.
I almost never notice much difference in how the car drives & behaves, all positives in my view. Every motor I’ve built for myself has had drastic flywheel weight reduction either by billet steel or aluminum.
I currently have two motors running, one (NA L22) with a 4,5kg aluminum flywheel & one (SR20DET) with a 5.3kg steel flywheel, no driving drawbacks at all.

[Wookie384]

Don't go too light on the flywheel. I personally hate Fidanza flywheels as they tend to be lighter than 10 lbs and usually that causes dive ability issues, I LOVED my Toda flywheel on my SR20DE and I regret removing it and I really want to reinstall it!

[jdflyer]

Would the Nismo RS521 be a better choice? I think it’s heavier then the Fidanza.

[TheRealSy90]

There's a couple NA sr20 builds I follow from Japan that all seem to run really light weight flywheels. One guy even runs a tiny 5.5" clutch.

[S14rebuild]

What driveability issuses would one see from a lighten flywheel?


Ive only been told before on an sr20 application that is u run a 1 peice light front pulley aka balancer, that u cant run a lighten flywheel too...idk thought it was bs

[SidewaySSS]

Originally Posted by S14rebuild

What driveability issuses would one see from a lighten flywheel?


Ive only been told before on an sr20 application that is u run a 1 peice light front pulley aka balancer, that u cant run a lighten flywheel too...idk thought it was bs

I’ve built numerous motors with flywheels from 11lbs down to 8lbs some on turbo setups with mild cams or stock cams, some on na setups with 300 + cams.
The only drivability issues & “this is really nitpicking now” is in the NA setups with big cams & race ports, I have seen that you might need to give a little more throttle & clutch action on take off if on an incline.
Now if you’ve driven a stock motor with a 20lbs flywheel for years and love how easy it is to get away & that you can leave the clutch it’ll just roll on idle & you expect to do that with a 9lbs flywheel & big cams, then there might be an issue.
Maybe I’ve just been driving on really light flywheels for too long to find fault but everything I build has either aluminum or billet steel with cutouts everywhere to get it as light as possible.

[mechanicalmoron]

If you are not a beginning driver and can handle a normal manual transmission car, you don't have a crazy race clutch or engine, and you don't want to drift, put the absolute lightest flywheel you can cheaply find.

If you have drivability troubles, you need to learn better clutch manipulation, because the weight of your flywheel has nothing to do with the way the friction surfaces behave.

[jedi03]

its basically more gas on take off w/lighter flywheel, can affect highway economy but otherwise revs faster

[mechanicalmoron]

Originally Posted by jedi03

its basically more gas on take off w/lighter flywheel, can affect highway economy but otherwise revs faster

No, it's less damping effect, so you must actually control the slip of the clutch, instead of drop it and let the mush handle your stoplight experience.

If you can't do it, all you need to remember is one two three, ARE, ENN, DEE and mash the go-button.

[Wookie384]

When I mentioned driveability issues I should have been more clearer by saying that in a daily driven car, or in a square or oversquare motor, it can be annoying. The drop off of RPM's between shifts with a too light of a flywheel could cause the engine RPM to be out of your powerband band when the clutch engages again, this is of course dependent on how/where your engine makes power (take your gearing also into account). I hate the fact when I've driven buddy's cars and they stall/sputter/struggle to idle when I drive their car on the street, That loss of inertia from the flywheel being too light can cause that, also I personally believe that most of our "street engines" could stand to benefit from some inertia which is why the factories design weight into the flywheel, and some engine builders take into account the weight of the clutch and flywheel assembly when building motors, so if the engine is mostly stock or isn't built and is daily driven I strongly recommend against a too light of a flywheel, Now if it's a race car, or you're too cool to care about the above mentioned stuff go right ahead. I personally have a Toda flywheel waiting to go back into my track car.

[jdflyer]

Thanks guys. So I’ve gone ahead and ordered the NISMO lightweight flywheel since it’s a little bit heavier then the Fidanza (~4lbs) but still less than the original. I use the stock pressure plate and exedy clutch with it. I’m still waiting on my pistons to come back from swain and rods from WPC before I send out the crank to be balanced and lightened