Just like the title says, what is the function of the flexplate, other than to connect the crank to the torque converter, and to provide a place for the starter gear to engage? Why do automatic trans cars have a flexplate, and manual trans cars have a flywheel? Does a flexplate truly "flex"? Reason I ask is that I have found somebody who is making replacement flexplates from a billet. Obviously this won't flex, and it weighs much more than stock, much more like a flywheel. Will this work? If so, why didn't the mfr do it that way to begin with? Thanks in advance for educating a green-horn!!!!o No: Keith
they do flex when the convertor is bolted up it is much thiner and lighter then a flywheel and dont have a clutch plate heating it up a billet would be solid and would neet to be shimmed for the convertor distance and balanced as part of the engine
The other thing to keep in mind is the flywheel is the "friction surface" where the clutch disk rubs (for a manual trans vehicle). The flexplate in an automatic doesn't need to have that function. As far as thickness/billet etc, there is an age old debate as to whether it is better for it to be lightweight, so it can spin up quickly, or better to be heavy, so that once it is spun up it is resistant to change (ie, more rotational inertia). Two schools of thought on that one. K
Interesting - I've never heard of any "pros" for a heavier flexplate/flywheel. For better acceleration of the reciprocating assembly (drag racing), the lighter the better. Regarding the question as to why the OEMs didn't use billet flexplates to begin with, it's simply a matter of cost. Stamped low carbon steel is cheap and works fine. Devon
The flexplate has to flex on an automatic trans vehicle. The torque converter "grows" as the rpm increases. Also, the crankshaft has endplay and the flexplate handles this. Excessive endplay will crack out the center of the flexplate. Shims(between the crank and flexplate) are available to take up excess clearance. An auto trans with a rebuilt front pump will also cause excess clearance because the front pump was machined in the rebuilding process.
Can someone 'splain how that sheet metal flexplate can handle 300 plus horsepower without ripping the center out?o No: Frank
Doesn't seem too surprising to me, maybe I don't understand the question. The relatively thin stock does fine with the auto trans application, as there's little "shock" due to sudden acceleration/deceleration such as what's seen dumping the clutch on a manual trans setup. Your drum brakes aren't much different if you think about it...thin wall steel at the hub, big torque and stresses seen during heavy braking. Devon
if you think about it when take off a stock convertor stalls around 1400-1800 not making big hp there and when it is at peak the hp is transfered to the trans easily because the car is in motion already ,not as much stress
