I was looking thru a buyers giude and saw a lighter rotors kit. Some one I knew said that the S4s had more torgue because the rotors were heavier. I am still new, so my question is what is the advantage to using this kit? And what applications? N/A, Bridgeport N/A, Turbo, or best for a Turbo Bridgeport. Or any other kind of porting. I apologize for my noobness.

 

No, S4s do not have more torque due to having slightly heavier rotors than S5+ engines. S4 & S5 NAs both have ~138 ft. lbs. peak. Lower rotating mass means less parasitic loss, which means some power gains. This will be true regardless or induction or porting. There's a reason companies like Racingbeat can sell lightened rotors for $2400 and still find buyers.

 

lighter rotating assembly equals quicker response to throttle inputs, less power spent on inertial forces. the advantages can be applied to any port-type and engine. the actual difference (quantitative) will vary though.

i've read that the heavier rotors do provide better torque, and i suppose i see the reasoning, but a part of me is still a tad skeptical. perhaps, it merely allows for better torque at lower RPM, that makes more sense to me than "more torque". what i will say the only fair comparison would be swapping rotors in the same engine and i don't see the hassle being worth it to the average person.


EDIT: i didn't refresh the page before i sent my response. RotaryRocket88 beat me to it.

 

Hello Skaterking. Heavier rotors can only provide more inertia for the already moving assembly. Persue a better understanding of Newton's laws first, and the reasoning behind a lightened flywheel will become clear as well. Please think about trying to catch baseball line-drive to short stop. Not so hard with a good eye and glove. Now try to catch the same size ball moving at the same speed, but made of steel. It will break your arm and/or hand! There is more energy in the steel ball's mass than in the wound string and leather baseball. It takes more energy to get a heavier object to speed, and conversely more effort to reduce that object's speed. Now can you see how a lighter rotor will scroll up faster, and the heavier rotor will be harder to slow down? "O"

 

LOL, wow I feel like I just went to bill nye's science lab. Ya I get it. Understood, and thank you all. lol

 

I have used them all in my 13b. Stock S3, S5 TII, S4 TII and S6 rotors. S6 rev'd quicker, for sure. S4 along with the heavier s4 flywheel does not rev as quick but is awesome at cruise and low rpm throttle input and makes for a great launch. All depends on where you want your power and what your combo is. For a stockport daily driver, the heavier rotors are great. For a ported turbo set up or high reving bridgeported n/a, the lighter the better.

 

Oh wow... now that helps. I feel more confident in putting those in my project now. Thank you.