So I just got my Aasco lightweight flywheel installed and it is said that the flywheel is about 13lbs. I have been driving it for about 1,000 miles now. From the seat of the pants, my car def. feel like it accelerate much quicker than before. I must say I feel a significant difference. Currently I have GHL muffler / header and K&N intake. I felt almost no gains from the intake / header / exhaust mod but it does add a very nice more sporty tone to the car. I feel that a 996 with a lightweight flywheel can out accelerate a stock 996.

However, the nosie / chatter is quite noticable from outside the car. It sounds like a rattle like bb's in a can or a diesel tractor while in idle. If I am in my car with the windows up, I wouldn't be able to hear it unless I really really pay attention. But with the windows down and with either a curb or another car next to me, its LOUD. I don't know if this is normal or not but I am going to ask around.

Does anyone in SoCal have the Aasco flywheel that I can listen to? Btw, I am on stock clutch.

Aside from that, the car revs up and down very quickly and it did stall a lot at first but I believe that the ECU adapt to it and it haven't stalled in a while.

*another thing came to my mind, since there are less stress on my engine, would I see any increase in mpg? That would be a bonus.

 

What you gain is the torque required to increase the rotational speed of the flywheel, is reduced by the ratio of the difference in the mass of the flywheels: What this means that a 13 lb flywheel will spool up quicker with the same applied torque than the dual-mass flywheel. With the torque output of your engine more or less constant and the required torque to spool up the flywheel has now been lessened, there is a net gain of torque applied to the transmission and the wheels on the street.
T (mN·m) = J aJ = Inertia in g·m² (g = mass in grams)
a = Acceleration in radians/sec radian = 2 Pi/360 deg of rotation
With the light weight flywheel, there is less rotational energy stored in the flywheel, that is why you were stalling the engine. Your foot finally compensated for the change, not the engine software.

You will also see a gain be the overall reduction in the weight of the vehicle because Force = mass x acceleration F=mA or A=F/m
What this means is the torque/min (horse power) is constant, the weight is reduced, the net acceleration is increased. So remember, to increase the acceleration of you 996, the most cost effective way would be a lwfw and remove all the unneeded weight (mass) you can. Oh, a supercharger will help a lot to.
Have fun and let us know how long you can put up with the extra noise.
J. Greer

 

I've driven a couple of 996 cars with that flywheel and the noise is totally normal. Despite the noise when it's time my car will be getting the LWFW too. Just can't justify it yet.

Andy

 

Does anyone know the weight to the stock flywheel? Is there an option between the AASCO weight and stock?

 

Thanks J. Greer, this is a very educational read for me but as of my stalling, here is what happen or happened.
When driving in lets say 3rd gear at 40mph while coming to a stop red light, I usually let off the gas first and when I almost stop, I engage the clutch. After installing the flywheel, I still drive with this same habit but when I engage the clutch pedal, the RPM dropped much quicker resulting in stalling. Now, I still drive with the same style but it doesn't stall anymore. I am not sure how my driving style (gas pedal) would adjust to this as my foot is not on the throttle while coming to a stop. Maybe I am stepping on the clutch differently? Whatever reason it is, I am glad it doesn't stall anymore.

As far as the noise, I don't know if my chattering is on the same level as others with lwfw. I have been in a car with a lwfw before but it wasn't nearly as loud as my 996. I have gotten used to the noise for the most part but for those people who doesn't know cars very well, they ask me what is wrong with my car since it was so loud. Maybe I can come up with a sound clip for you guys to check out.

 

I will weight the stock one this evening but the thing is HEAVY! I am guessing close to 30lbs.

 

With the LWF the sachs spring hub disc (the stock is ridged) will cut the chatter at least by 50% and should noise be an issue this clutch disc which will take a bit of the harshness upon engagement should be contemplated.

regards

 

Hey nine9six, I'd like to check out your new LWFW sometime. Let me know if we can set something up.

 

racing 97 - will the Sach spring hub disc help the noise that I hear while idle?

slaaw - Yes we can definetly set something up. Please pm me. Also, what kind of wheels do you have?

 

I would stick with the stock flywheel. You're not any faster. You're just getting that post mod placebo effect.

 

Ben - I'm curious why you don't think a lwfw would help acceleration on a 996. I had been considering one for when my clutch needs to be replaced. I've always accepted that the lwfw improves acceleration due to the reduction of weight between the engine and drive wheels.

 

you don't get a lightweight flywheel to get more power to the ground. anyone getting a lightweight flywheel for more power is outright silly.

you get it for a "freer" revving tranny/engine. you end up having to rev up a bit more from the get-go since the flywheel is lighter and you have to shift faster since the revs fall faster.

it's a bunch of gives/gets and it's never been a compelling package for me since you also get all that extra noise with it. power is a non-factor here. we're supposed to get more power with a freer flowing exhaust as well... haha good luck with that too for those that believe that.

 

[quote=nine9six;1905427]racing 97 - will the Sach spring hub disc help the noise that I hear while idle?

Yes it will help the noise at Idle.

regards

 

It works in a similar manner to lightweight wheels Ben. You won't put more power to the wheels, but you are decreasing rotational forces so you actually will accelerate more quickly. If you have two absolutely identical cars and you install a LWFW in one, it will out accelerate the other.

 

Instead of internet yapping away about these lightweight gains, would love to see someone post up some youtube vids comparing the real world results of such mods.