A a heavy rotating mass is hard to slow down, so when your tires gain traction there is going to be a force against the flywheel to slow it down. Since it would be hard to slow down a stock flywheel your rpms will stay steady and climb up nice without any effort.
If the tires gain traction and force against a light flywheel, a light rotating mass is going to be TONS easier to slow down. So when the tires grab it will slow down the rpms and cause you to have to slip the clutch more than necessary.

A ligtened flywheel only seems to make sence if you are on a road course where the rpms are at a constant high.

Anyone agree?


[Modified by Aeka GSR, 7:14 PM 3/6/2003]

 

I definately agree.

 

nope.

once you get traction, then think about what you want to do.... you want to accelerate the car in the forward direction, which requires rotating the tires, wheels, clutch, crank pulley, flywheel, crank, tranny, axles, brake rotors and also pushing the rods/pistons up and down as well as powering the cams and thus the valvetrain as well.

So the flywheel is one easy place to reduce this huge mass of rotation... and a cost effective way as well since the light flywheels are getting cheaper every month!

 

well i dont see how that overcomes the problems you will face in the 60ft

edit: Launch is very critical, lightened flywheels may also negativly effect upshifts, I dont see benifits of acceleration overcoming the problems you will get at launch.
I was talking to somebody who actually lost .3 seconds in the 1/4th due to the flywheel.


[Modified by Aeka GSR, 9:00 PM 3/6/2003]

 

I agree with Aeka also. While you're staged your rotating mass isn't facing any resistance from the clutch and the rest of the drivetrain/wheels so it's easy to spin it to 5000RPM [or wherever your best launch RPM is].

Now, when you slip/side-step your clutch all that rotating mass is using it's extra inertial effects to help bring the drivetrain/wheels up to speed. It should be a big help in drag racing. Although, a lightened flywheel will help you on a race track/auto-x course.

Now I'm not an import/FWD guy myself, but can anyone explain something you guys do for me? Why use a carbon fiber hood to lighten the front end when that's where you need the weight for maximum traction? If you were going to do anything for weight reduction it should've been a CF hatch/trunk. I can totally appreciate a CF hood for road racing, but for drags it makes no sense at all. Us RWD guys move everything that we can off the front end to the back for more traction. Shouldn't you be moving weight to the front, or at least be removing it from the rear?

 

well, you do store less rotational energy with a lighter flywheel compared to a heavy one at the same rpm , but you can easily compensate by increasing the launch rpm.

Once you gain traction, it will take much less energy to rotate the flywheel, and that energy is transfered into accelerating the car.

lastly, I guess when you run out of things to remove from the back of the car, ie. spare, jack, sound deadening, ppl look to other places to reduce the overall weight of the car... plus, cf hood adds 30hp jo...

 

it just means you have to adjust your driving style. No big deal. a lightweight flywheel does make for a faster car, if you can drive to take advantage of it. Some people can't adjust thier styles, so it ends up negatively effecting thier times.


Nape: While you are correct, in that FWD drag racers would want the weight on the front wheels, most cars with carbon fiber hoods are street cars, and need to have a more balanced weight distribution if they want to avoid plow through corners. It's a FF, so it already has most of the weight on the front wheels. So the idea is just to get the overall weight down, and balance out the distro.

 

a lighten'd flywheel improved my times by a couple of tenths only when i wasnt using slicks.. but i was runniing a GSR I/H and some type R cams..

 

in a 92 hatch cx btw...

 

this is a good point, im just wondering if it really is that simple. I'll just stick with my turbo method of dealing with better acceleration

 

....at the cost of consistancy.

 

your spelling of 'sence' doesn't make sense to me.

 

I dropped between .15 & .2 in the 1/8 after my clutchmasters flywheel and thats from a type R flywheel. I would think you would drop even more if you changed from say an Si flywheel. My 60 ft. improved somewhat but most of the improvement came from 60-330ft. This is on street tires but on drag radials I had basically the same 60 ft so I'm guessing it wouldn't really help at all on slicks. it would prolly slow you down

 

I think you are not looking at the BIG picture... you are speaking as if the launch rpm is fixed during this short period of time that you are gathering traction....and as if the rpm cannot be changed at all during this timeframe. Of course it can be changed and raised if that is needed with alighter flywheel, so what... you will still get the power to the wheels and the next few seconds you will accelerate faster than a car with a stock, HEAVY flywheel.

*now I see some side effects... a light flywheel may make you eat thru clutches more often in a drag racing setup.
But I think since the driver control of engine rpm is easily maintained, that alight flywheel is a good solution for us 9000 rpm honda nutters.

 

Yes, it is. It's also just as hard to speed it up. (accelerate) Which do you do more of in drag race?