How Heavy is the flywheel?

[jouslee]

Hey guys I was just wondering how heavy the stock flywheel is for our Yaris'

Thanks
-Josh

[Yaris TTE JWRC]

Hey guys I was just wondering how heavy the stock flywheel is for our Yaris'

Thanks
-Josh

18-20lbs

[jouslee]

mmm... isn't that a bit heavy for a small car like ours?

[Yaris TTE JWRC]

negitive- the old echo's flywheels weights about 18lbs.

[jouslee]

I donno man.. My buddies stock weight on his VW Corrado (200ish HP) is about 18 lbs.

This may be the cause of our cars having a sticky feeling...

[bugnuts]

The heavier a flywheel the better the idle, If you lighten a flywheel sometimes the engine wants to stall...Then again if you lighten it it will also rev faster and give better racing performance, So it is a draw between racing and everyday driving.

[jouslee]

bad idle? Really? I thought having a lighter flywheel is going to make it hard to drive not because of rough idle but because there is less inertia on the flywheel therefore the flywheel is more prone to stop moving when the clutch is applied (Which causes a stall).

Anyways, the stickiness i was talking about is when you rev your engine the rpm stay at the same level for a second when you release the gas.

I'm thinking that this stickiness is due to a heavy flywheel.


Any opinions? Anyone with a light flywheel?

[Doc Zaius]

I think there are rumours about that the "sticking" is due to the drive-by-wire throttle system. I was also hoping that lightening the flywheel would get rid of this, but would probably only be a partial solution.

[heylookitsjames]

light flywheels have the potential to do exactly what both of you described.

[ItsMyDaily]

Lighter is going to help greatly in acceleration. I had a 8lbder on my S and it improved the car all around nicely. never stalled, but on occassion would see the rpms drop low while stopping.

[Moose]

The "throttle stick" is the "lag" in the electronic throttle (drive by wire). The computer takes measuresments from the vacuum system before making throttle adjustments- after you let off of the throttle, there is still "excess" air cycling into the intake manifold via the EGR valve (exhaust being rerouted into "fresh" air for emissions requirements). Once the "over idle" exhaust gas is pushed into the intake and the computer senses an idle-quality amount of exhaust gases coming from the EGR, the throttle lets off. Basically, the throttle "sticks" to allow all exhaust gases to be expelled.

As far lightened flywheels go, lighter flywheel = quicker engine response at the expense of torque. You will have better high end power, but less "grunt" off the line. The same principle works with lightened underdrive pulleys- they allow for higher revs and less parasitic draw, but lose their "underdriving" power- this is why your lights will dim under hard acceleration/high revs- the alternator is not working at peak efficiency.

[jouslee]

oh okay, that explains a lot. but EGR didn't seem to effect my Rx-7 it does in this car... Dang... Is there anyway to disable the EGR system electronically?

[Moose]

oh okay, that explains a lot. but EGR didn't seem to effect my Rx-7 it does in this car... Dang... Is there anyway to disable the EGR system electronically?

Nope- the EGR system is simply a tube from the exhaust manifold/downpipe leading to a mechanical valve in the intake manifold. Removing the system will cause your vehicle to sound like it has an exhaust leak, trip a CEL, and make the car run a little crappy (you would lose some pep).

It's just one of those things you're gonna have to live with. Thanks CARB!