is a flywheel necessary?

"An Aluminum flywheel goes completely the other direction with almost no weight. This lets the engine rev up very quickly and allows the engine to work easier due to the reduced weight spinning around on the back of the crank. This is fine as long as you are at full throttle and wide open throttle all the time like in a Road Race or Drag Race only car. As soon as you let off the gas the engine RPM drops instantly and the car slows down. In a road car this causes surging and bucking at cruise speeds and poor driveability and clutch engagement."

Actually, I had a very mildly modified Infiniti G20 with a 9 lb aluminum flywheel, bucking/surging wasn't noticeable, unless you JUMPED off the throttle in first gear at higher speeds. Car drove perfectly, without any driveability issues, and clutch engagement was only a little tougher on hills in the rain with a lot of weight in the car - 5 people, 4 of which being over 170 lbs.

And I've never seen any loss of torque on a dyno from a flywheel... loss of torque, low-end, or acceleration is just false.
 
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Check this tread out I love mine:http://www.msprotege.com/vbb300/showthread.php?t=47247
All your questions on flywheels answered here: http://www.sakatamotorsport.com/srs/index.html

f9f1d723.jpg

Friction side OEM 14lbs vs. Aluminum 6lbs Flywheel
 
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and protegegarage.com has really light flywheels for those of you interested in really light weight units. Best price I've seen for unorthodox flywheels yet.
 
midnightracr said:
The only real advantage of a lightened flywheel would have to be that it helps a turbo spool faster. On a N/A car it's the last thing u would want it would take away a lot of your torque

I am only going to touch on this post...I will include the comments from some others too...

This is completely incorrect, at least the last part ;)...Torque is simply the force behind the twist outputted from the engine...The less weight bolted on to the crank, the more force behind the twist...Lighter flywheels WILL "free up" more torque and hp, albeit marginally...

The only energy stored within a rotating flywheel in relation to its weight is rotational inertia...the more weight and the farther away from the rotating origin (the middle, for anyone sitting in the slow seat :D) the more rotational inertia...with a super lightwieght unit, you have less inertia, which makes it easier to slow down...low throttle launches require more slippage because it is easier to slow the flywheel, and thus stall the engine...

Someone nailed the turbo issues with aluminum flywheels pretty well, so I won't get into that...They seem to be better reserved for NA apps in which the engine is kept boiling nearly all the time...the lightweight helps allow the engine rev faster in short gears at low rpms, which is when the engine is pretty far out of its powerband...So usually they help immensely with 1st and 2nd gear 0-60mph runs...But by third gear and taller ratios the benefits become unmeasurable...

They do not take away torque at all though...that is misleading...They simply create a slightly more difficult to launch vehicle because of the inertia issues...So some guys get pissed because they need to rev higher to get a good launch and return with "this stupid ass flywheel gutted my torque, I now have to rev 2 grand higher to do a burnout"...don't listen to them, their ignornace runs deep...
 
ill jump in, on a FWD car with STREET tires, a lightened flywheel is going to mean one thing...more wheelspin then the stock flywheel. My suggestion is if you plan on running street tires and thats it, leave the stock flywheel in or get it machined down a few lbs.
 
t3ase said:
Protege5Online also has the JDM MS flywheels for around $170.

i have this flywheel and have seen little gain if anything with it installed.
 
I agree with the above post. I have the Fidanza Flywheel and ACT in my car, and for 2 years, it has been great!
 
the main issue with a lightened flywheel ona turbo charged application comes in with the quick dropping revs. The idea of a boosted car is to stay in boost as much as possible. Sometimes with a lightened flywheel, the revs drop faster and you can fall out of boost fast. On the other hand however, you will be able to get into boost faster as well, but then there is the problem of wheelspin like everyone says. I say if you want good everyday quickness get it. If you are buildinga drag or 1/4 mile car, leave the stock one.

-B
 
there is also the jdm fylwheel which is only 15lbs, that might be a good option- chris
 
azian6er said:
the main issue with a lightened flywheel ona turbo charged application comes in with the quick dropping revs. The idea of a boosted car is to stay in boost as much as possible. Sometimes with a lightened flywheel, the revs drop faster and you can fall out of boost fast. On the other hand however, you will be able to get into boost faster as well, but then there is the problem of wheelspin like everyone says. I say if you want good everyday quickness get it. If you are buildinga drag or 1/4 mile car, leave the stock one.

-B

Some dudes illude to what may or may not be a myth about crank integrity though too. Some big time physics and material dynamics can be applied to a said crank in terms of harmonics...I will keep it simple though...Basically the more force you add to the reciprocating assembly, especially the crankshaft, while also decreasing rotational inertia effects, or "spun" weight from the ends of it...the more likely it is to crack; not crack as in fly apart but as in flectures that weaken the crank significantly...ultimately causing it to fly apart over time...I mention the myth thing only in that I know of at least a handfull of BP owners, who were running aluminum flywheels, underdrive pulley's and significant boost...who ran into this problem pretty quickly...

But that is a different engine, and no one with an FS has been combining very heavy boost with lightweight flywheels and/or pullies yet to see if this holds true for our crank as well...The math says maybe though, we have a similar rod ratio aspect as the BP (ours being a little higher)...which translates to similar amounts of piston speed in relation to crank revs...But a lot of the other variables including overall assembly balance are unkown to me...which are just as important in this problem...
 
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