Poll: Lightweight flywheel or stock?

7383 Views 75 Replies 24 Participants Last post by psjones13, Dec 27, 2012

psjones13

Discussion Starter · Nov 27, 2012 (Edited)

Ok guys, I need a new flywheel on my car. Here is a build thread so you can see what it is: http://www.d-series.org/forums/entertainment-area/165724-10-1-1-z6-forged-internals-build.html For those of you lazy guys, its a 10:1 z6, staying NA for a few months until after tax season, then a dsm small 16g converted to a 19c will be going on it.

My question is, I'm broke and I absolutely need a new flywheel. My Exedy one has been machined too much and it is now too thin to use. A new one is $220, but I have a stock one with a ton of meat on it just laying around that I could spend $30 on to get machined... I remember when I went from the stock one to the light one that it made a pretty noticeable difference in acceleration so I would really like to put a llightweight back on there. I'm just strapped for cash right now with christmas around the corner and I'm not sure if it's worth it. Let me know what you think.

Especially you guys running stock flywheels, I already know how great lightweight ones are, but I'm most interested in the opinions of people who have had both.

UPDATE: I did a comparison write-up on page 4.

21 - 40 of 76 Posts

psjones13

Discussion Starter · #21 · Nov 28, 2012

Cool. Thanks for everyone's input. Looks like i may stick with the stock one

Oh and Full Tilt, I do let off to shift because I have yet to wire up a clutch switch for full throttle shifts lol

xylocramer

· #22 · Nov 28, 2012 (Edited)

what's this fancy talk about switches and clutch pedals?? Just let the bitch bounce off the rev limiter a couple times between shifts. :1eye:

psjones13

Discussion Starter · #23 · Nov 28, 2012

xylocramer said:
what's this fancy talk about switches and clutch pedals?? Just let the bitch bounce of the rev limiter a couple times between shifts. :1eye:

haha seriously?

xylocramer

· #24 · Nov 28, 2012

no. but IIRC hondata and neptune both have flat foot shifting options

psjones13

Discussion Starter · #25 · Nov 28, 2012

yes they do, I use neptune. It has a full throttle shift option, but it requires the use of a clutch switch, which I have not installed, which is what I was saying before

xylocramer

· #26 · Nov 28, 2012

aaaah you have a 4th gen

psjones13

Discussion Starter · #27 · Nov 29, 2012

xylocramer said:
aaaah you have a 4th gen

That's correct. Damn car lol

Reactions: 1

Full_Tilt

· #28 · Nov 29, 2012 (Edited)

You dont need a clutch switch to flat-shift. You just need to do it close to the rev limiter and do it fast.
Ive never actually driven a car with no-lift-shift enabled with the clutch switch.

Here is a reeeally old datalog of Tw34k driving his Turbo, Vitara, I beam, D16Z6 '97 HX. This car has a disabled cluth switch, so definitely no flat-shifting enabled in the tune:

As you can see, the first shift he doesnt even let all the way out, the TPS is still reading quarter throttle, and the second shift he kept his foot flat on the floor. Even when partial throttle shifting the MAP sensor never read any vacuum, and when flat shifting the car stayed basically at full boost. That dip is tiny, and only lasted for a fraction of a second.

This log would look the same with a lightweight flywheel, only the shifts could have been even faster because of the rpms dropping faster, and the car would just be overall faster due to less rotating inertia.

See less See more

TheAssassin

· #29 · Nov 29, 2012

But what about for daily driving? He says that he drives the car a lot during the week in addition to drag racing. The amount the revs would drop would annoy me while stree driving. Also, any performance gains still need to be worth the $165 that he'd spend on the lightweight flywheel. What's the typical E.T. differences between lightweight and stock?

JaredKaragen

· #30 · Nov 30, 2012

I love my Fidanza aluminum. Swap a disc when u change the clutch, ultra snappy response on throttle for downshifts. A lot lighter on the synchros too.

40MPGd15b7

· #31 · Nov 30, 2012 (Edited)

TheAssassin said:
But what about for daily driving? He says that he drives the car a lot during the week in addition to drag racing. The amount the revs would drop would annoy me while stree driving. Also, any performance gains still need to be worth the $165 that he'd spend on the lightweight flywheel. What's the typical E.T. differences between lightweight and stock?

a 7lb flywheel for daily really isnt all that bad, either learn to shift quicker, or at higher rpm, or keep the throttle on just a tad. either way, it isnt annoying.

Reactions: 1

TheAssassin

· #32 · Nov 30, 2012

Thank you, I guess those are all good methods to deal with the "issues." It still isn't worth the $165 extra to me. To each his own.

Reactions: 1

BeerDrinkin

· #33 · Nov 30, 2012

A stock CX flywheel is 12lbs. Maybe find one of those used if possible.

Reactions: 1

Tw34k

· #34 · Nov 30, 2012

40MPGd15b7 said:
a 7lb flywheel for daily really isnt all that bad, either learn to shift quicker, or at higher rpm, or keep the throttle on just a tad. either way, it isnt annoying.

7lb flywheel centerforce clutch city driving - YouTube

Dat check engine light..

See less See more

40MPGd15b7

· #35 · Nov 30, 2012

Tw34k said:
Dat check engine light..

p28 ecu lol

Reactions: 1

patprimmer

· #36 · Nov 30, 2012

I find light flywheels shift great. The annoying part can be moving from a stop in low gear, especially up hill. It's rev the shit out of it and fry the clutch or spin the wheels or use less revs and stall or bog it.

It never worried me but it adds to the work, skill and concentration required.

Reactions: 1

maohonda

· #37 · Nov 30, 2012

The light weight flywheel dose take some skill to drive. You have to drive with the revs a little higher before you shift and don't let all the way off the pedal to match the revs with the gear. I have been driving with mine for about two years and have become fully accustom to it but pat is right going up a hill is a pain with little torque in a tank that I drive lol

Full_Tilt

· #38 · Nov 30, 2012 (Edited)

TheAssassin said:
But what about for daily driving? He says that he drives the car a lot during the week in addition to drag racing. The amount the revs would drop would annoy me while stree driving. Also, any performance gains still need to be worth the $165 that he'd spend on the lightweight flywheel. What's the typical E.T. differences between lightweight and stock?

I can totally understand preferring a heavier flywheel, especially on a street car.
But I do not agree that a heavier flywheel is going to be better for performance in any way. It is a matter of comfort and practicality, not performance.

Like I said, Im no drag racer, but Im almost certain that you can launch just as well with a light flywheel. It may be more difficult, and possibly too difficult for some people to master.

Ive always considered a light flywheel to be a very good bang-for-the-buck mod, and thats talking about typical flywheel prices, not the extraordinary low prices Honda guys pay. Even at $300 bucks its one hell of an improvement.
In "Chassis Engineering" by Herb Adams, he shows an example where 15 pounds removed from the driveline at engine speed (flywheel, crank, etc.) Resulted in an improvement in acceleration that would be equal to a 32 hp increase in power.

See less See more

Reactions: 2

TheAssassin

· #39 · Dec 1, 2012

Full_Tilt said:
I can totally understand preferring a heavier flywheel, especially on a street car.
But I do not agree that a heavier flywheel is going to be better for performance in any way. It is a matter of comfort and practicality, not performance.

Like I said, Im no drag racer, but Im almost certain that you can launch just as well with a light flywheel. It may be more difficult, and possibly too difficult for some people to master.

Ive always considered a light flywheel to be a very good bang-for-the-buck mod, and thats talking about typical flywheel prices, not the extraordinary low prices Honda guys pay. Even at $300 bucks its one hell of an improvement.
In "Chassis Engineering" by Herb Adams, he shows an example where 15 pounds removed from the driveline at engine speed (flywheel, crank, etc.) Resulted in an improvement in acceleration that would be equal to a 32 hp increase in power.

That's impressive. I always knew that rotating mass "counted" more than the non-rotating mass of the car. I guess the cost to worth ratio isn't quite as bad after considering this. I'd have to try it out and see what I think of it. I may turn it into a summer project (you guys aren't going anywhere lol.)

So for street, stock is better. For performance, lightweight is better. I could be equated, perhaps, to a very aggressive cam wherein the idle might be unstable (if that is the right term) and take some time to get used to, but for performance it may really help. For a drag car, poor idling may not be an issue, but with a street build (like mine) concessions must be made. My engine could handle a large amount of horsepower from a large turbo but that wouldn't be conducive for a street build, thus the use of a smaller turbo.

Sorry for the rambling lol

See less See more

CaliLegal

· #40 · Dec 1, 2012

TheAssassin said:
Just get a tungsten crankshaft:

http://www.d-series.org/forums/general-tech/163843-tungsten-crankshaft.html

Lol in all seriousness though, if you have a small turbo that doesn't take much to spool (plus you higher than average compression for a turbo build) then you may not need to worry too much about falling out of boost too much. I still vote for a stock flywheel for the cost to worth ration.

OMG NO!!!!! Dont bring that thread back up!

21 - 40 of 76 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.