Lightweight Fly really not good for drag racing?
 

I was really excited about picking up a lightweight fly, because I read everywhere that it made the engine rev more quickly (I come from sport bikes, I love that quick rev) and that it'll help when at an autox. However, then I read that it really hurts you when you're at the dragstrip, that made me pause a bit. As it stands now, I've been drag racing more than I have autoxing, though I hope that may change later. In any case, I've searched for a good 2 hours or so and can't really draw much a conclusion. Could the people with lightweight flywheels who drag chime in? Did the lightweight fly really hinder your 1/4 or 1/8 mile times?

from what i understand about lightweight flywheels is that they have less inertia due to the reduced weight. this is good for auto-x and the like, because you're constantly changing throttle input. however, with drag racing you want that greater inertia because it gets the car moving and keeps in moving.

A light flywheel only makes it hard to launch, especially when combined with an aggresive clutch.

There is allot less margin between engaging too hard too fast and burning out, and bogging down off the line.

After the car has left the line the light flywheel becomes and advantage.

+^^
 

i agree.
only hard to start off the line.
but can be just as good if you rev it right before droping the clutch.

edit

Lightweight flywheels are an absolute advantage when you want acceleration. Street, track, autox, drag, it's a performance advantage.

The trick is that you need to be good at launching with it or your 60' times will get worse.

The downside for street driving is that the lighter the flywheel the less easily it will engage.

Dave

well then, i'll just shut up :uhh:

The power of the engine goes into spinning the flywheel and drivetrain and pushing the car forward. The less energy spent getting the drivetrain moving, the more energy that gets put to the wheels.

Once you let off the throttle and coast, yes the stored energy of a spinning flywheel will sustain the rolling of the car longer. This makes a heavier flywheel more streetable. But in drag racing you are accelerating all the way from the start to finish and this doesn't apply.

Dave

In simpler terms, energy here = hp ;) I love quoting the following findings whenever this discussion comes up to help fully illustrate just how much difference a light flywheel makes hp-wise!

From back in '03 (https://www.rx7club.com/showthread.p...7&page=2&pp=15)

50hp TO THE WHEELS in 1st, and 16 in 2nd!!!

~Ramy

Most people stick with the stock flywheel or actually heavier if your using forced induction. As you shift on the dragstrip with a lightweight flywheel you can fall out of boost. Lupe;Viking War Hammer (Eric) can be a reference to this situation.

MOVING to drag racing forum

Right, but I'm still on the stock twins, so I wouldn't think falling out of boost would be much of a problem for me. I just basically didn't want to not be able to launch at all. From what I've been reading, I'll have to drop it at around 5k now instead. The problem with that on other cars would be that they have much more powering, making launching at that RPM very hard. I'm hoping since I'll only have bolt-ons, that dropping that high won't be as hard for me since I won't be having to deal with as much power. I just hope the ACT S/S clutch can handle dropping it that high.

ha! i knew i wasn't completely off.

Unless you have a large turbo, you don't really have to worry about the lighter flywheel being that big of a deal.

Option 1. If you are going for all drag, use a stock flywheel.
Option 2. If you want a little of both, use a lightened flywheel, just not superlight.

The idea is that you can potentially fall out of boost (RPM) easier on launch and in-between shifts with a lighter flywheel due to the fact you don't have as much rotational mass keeping the RPM up due to inertia of the heavier part. IF you have a larger turbo this could pose a concern because the problem is magnified. If your on stock twins, go for option 2, you will be happier. :icon_tup:

Option two it is, now I'm just wondering if I should get the Prolite or the Streetlite.

Streetlite = Best of Both worlds...think about it.

Oops, guess we'll have to see how the prolite goes as it's already been ordered. :D

I had a light one and went back to stock.. nicer to drive etc etc. better for drag racing in my exp... plus does anyone know of any proven dyno runs to show more power??? yes it revs faster but i liked the stock mucho..
Greg

Greg, reading is your friend... ;) https://www.rx7club.com/showpost.php...47&postcount=9

~Ramy

and your my hero.... :)

and i have also spoke to a few people who have dynoed cars close as it can be back to back and no difference..