NA Flywheel Opinions

Big Tuna · 11-07-2007, 08:56 AM

I though I would give this a try on here and get Lukes, Dons and the other members opinions.

Originally Posted by liveforphysics

There are two sides to this game, both have a point.

Best Wishes,
-Luke

Here is my testing

2000lbs NA CRX 135whp/117 wtq
Stock flywheel 13.51 @98.1 w 1.74 60' on 22" MH slicks
7lbs flywheel 13.68 @ 98.7 w/ 1.80 60' Same slicks

My mph came up with the lighter flywheel but it did not have enough stored inertia to get the car to 60', if the I launched with the 2 step any higher it would spin or break axles and also I noticed a huge difference in preload. If I preloaded hard it would bog so I had to shock the driveline thus leading to more axle carnage. I had the lighter flywheel in for a month at 4 test n tunes. Replaced it with the stock flywheel, set 2 step at 6300 and bam first pass 1.76 and by the end of the night I had my best 60' and ET.
I have yet to try a 12 lb one. I did notice that my window for a good launch was greatly increased with the heavy flywheel. It was a ton more consistant, with the 7lb flywheel the smallest change would really effect the 60's.

Sometimes back to back runs would have way different 60's and the 2 step always needed little rpm changes throughout the night ect. With the heavy flywheel it was set it and forget it, I can pull it off the trailer and go mid 1.7's all night long.

I dont have the slips in front of me but on average the 1/8 mile mph was near identical with both flywheels. The 1/2 or so mph I gain with the lighter flywheel on showed up at the 1/4 mile traps. So the lighter flywheel did accellerate faster between the 1/8 and 1/4 mile but it wasnt enough to overcome the starting line 60' advantage the heavier flywheel gave me.

Per my experience drag racing with a NA car the 60' is the most important thing. I have to disagree on the "lighter flywheel made me accellerate faster". The heavier one allowed me to go 1320ft in less time, so I accellerated faster. The lighter took longer for me to go 1320ft but at the finish line I was going faster.

MPH doesnt equal accelleration in drag racing, ET does. I dont care how fast I am going at the finish line I just want to get there as fast as possible.

This is just my experience so I am going to stick with the heavy one for a while, I know there are a ton of guys alot smarter than me and have all the math and physics to prove lighter is better but I just dont see it in my real word testing on my car. I am not saying this is the flywheel gospel I am just saying in my case and my experience I wont use anything else but a stock flywheel.

Discuss....

Christopher_davis · 11-07-2007, 10:05 AM

From my own experience with flywheels. I have driven a few cars with with different flywheels. I am speaking from experience and what I noticed.

Take my car for example it is a 96 lx.
It cam with a 17lb flywheel. Launching with it always seemed to set you back in your seat a little more and you seemed to get nice solid shifts from it.

Solid shifts meaning 2nd to 3rd felt like it kept wanting to keep going. Keep in mind I say this because the stock lx tranny has a crappy 2nd to 3rd ratio.

Now I had it lightened to a little over 13lbs(thought it was a little over 12lbs, but I found my papers) With the lighter one it does seem to accelerate faster from a roll. Key word from a roll. I did sacrifice the that nice launch you get. If your spinning and then hook-up it wants to bog sometimes. With the stock one the weight of the flywheel seemed to carry the car through this rather than spin.

IMO with a more horsepower/torque the 13lb flywheel would benefit me more than it does now. I think a close ratio gear box should also be taken into account when selecting a flywheel. If your gears are further apart you should have a heavier flywheel to "bridge the gap" if you will. Think of each additional pound of the flywhees as a plank on a bridge.

Tuna, if you went with a 13lb flywheel I think it would have awsome benefits for you. You would still get a solid launch with solid shifting(more than me because of obvious power differences) and a little better mph in the 1/4.

Lets get some more opinions in here.

BoneSpec · 11-07-2007, 01:57 PM

I'm going with 15 lb to start, btu have a 11.4 and 12.5 to play with.

Lets not forget the clutch slippage as well.

YoungGuna267 · 11-07-2007, 02:06 PM

i was stupid and bought a fidanza 7lb flywheel........yeah i didnt look into it..its really not that bad and its my DD.........revs fast!!! thats about it...

kyle h. · 11-07-2007, 02:19 PM

I was always under the impression light flywheels were more for race cars that turn, and heavier flywheels always felt better on the street.

greasemonky89 · 11-07-2007, 08:35 PM

Originally Posted by kyle h.

I was always under the impression light flywheels were more for race cars that turn, and heavier flywheels always felt better on the street.

x2

gearhead98 · 11-08-2007, 12:43 PM

I think a slightly lightened flywheel would benefit most street cars rather than an extreme lightweight flywheel that so many people have. I under that yes because the flywheel is lighter on paper it should accelerate faster and yes it will rev faster BUT if the engine the flywheel is mounted to doesn't have the "balls" to keep that light flywheel spinning then there is really no point. With that heavier flywheel yes the car will rev slower but when you put a load on that engine the heavier weight will keep the revs higher to keep the car going instead of bogging down like with a lightweight flywheel because the engine rpms dropped out of the powerband and the engine has no stored interia to pull it out.

thats my thoughts on it.

also if you are going turbo especially don't get a lightweight flywheel, the turbo needs the load on the engine to spool and with that little bottle cap flywheel on it there is no load on the engine.

Christopher_davis · 11-08-2007, 05:02 PM

Originally Posted by gearhead98

I think a slightly lightened flywheel would benefit most street cars rather than an extreme lightweight flywheel that so many people have. I under that yes because the flywheel is lighter on paper it should accelerate faster and yes it will rev faster BUT if the engine the flywheel is mounted to doesn't have the "balls" to keep that light flywheel spinning then there is really no point. With that heavier flywheel yes the car will rev slower but when you put a load on that engine the heavier weight will keep the revs higher to keep the car going instead of bogging down like with a lightweight flywheel because the engine rpms dropped out of the powerband and the engine has no stored interia to pull it out.

thats my thoughts on it.

also if you are going turbo especially don't get a lightweight flywheel, the turbo needs the load on the engine to spool and with that little bottle cap flywheel on it there is no load on the engine.

That's exactly my thoughts on it as well. If you don't have the power then there's no way you should get an extremely light flywheel. I feel that 12-14lb flywheels would be most beneficial to our torqueless pea shooters

greasemonky89 · 11-09-2007, 12:08 AM

what about getting the stocker lightened maybe like 2 pounds. can you sorry i just went noob on you guys.

BoneSpec · 11-09-2007, 01:10 AM

the WHOLE combo matters GREATLY.

Why cut down a 18 lb stocker when you can get a 92-95 CX/VX at 15 pounds?

Also factor in clutch slip, slick size and bite along with launch rpms.

I had the PERFECT combo (PURE LUCK!) in 2002........but learned alot from it.