Lighten Flywheels - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Gismo R · 02-22-2002, 12:23 AM

I know all the technical issues about how it lowers the moment of inertia on the crank, thus improving throttle response. But how much of a HP gain should I expect to get. I've heard the 240 losses about 15% through the drivetrain. With a lighten flywheel, what will it drop to?
Also, is there anything I need to worry about with light weight flywheels??
-Thanks

tnord · 02-22-2002, 12:36 AM

i really don't know......but for timeliness reasons i'll respond, that and i'm bored......i would guess you would get around 5hp more than before to the wheels

drift freaq · 02-22-2002, 12:55 AM

well I can't give you HP figures but I can tell you that the lightened steel truck flywheel in my car made a big difference in the way the car accelerates. It pulls in fifth gear and revs up very quickly and smoothly I definitely feel it.

*Jeff240sx* · 02-22-2002, 01:00 AM

I dont think that a lightened flywheel will give you a change in horsepower, but more like a weight loss on the car.
Everyone knows that rotational mass is harder to get moving than a horizontal mass.  With this said, there is a mathematical function to realize how much exactly the loss in rotational weight will translate into as a function of horizontal weight.
Easily said... A general figure is 10lbs per 1 pound shaved off the flywheel.  Drop 10 lbs, your car will accelerate like it was 100lbs lighter... not more powerful.
-Jeff

tnord · 02-22-2002, 01:38 AM

jeff......you're on the right track, but not quite there
like you said, rotational mass is difficult to get moving, so in order to do so some amount of power must be used to turn it; hp if you will
no a lightened flywheel won't make more power at the crank, but it will reduce driveline losses, putting more power where it counts, to the wheels
5hp gained at the wheels is just as good if not better than 5 hp gained at the crank

AmericanBornSilvia · 02-22-2002, 01:44 AM

Basically, with all that said, it helps you rev faster. Also its real helpful with turbo applications.

*DSC* · 02-22-2002, 01:47 AM

here's what our very own James has to say about it...

Honestly, unless you're an autocrosser or have a turbo, I feel this upgrade is a waste of money. Yeah, it's does it's job, it makes the engine rev more free, but good drag launches seem harder to come by with this flywheel. An ECU upgrade would have made more of a difference. Basically, a flywheel wasn't as important as I thought it was.

DuffMan · 02-22-2002, 03:50 AM

In terms of power, it helps more in lower gears than higher. 1st and 2nd will be the only place you notice it. If you could provide specs for before and after weights, the physics arent that hard to work out.

97S14 · 02-22-2002, 09:42 AM

I don't know the formula, but this was actually calculated on a 97+ Prelude

I can't rember the exact numbers, but I'll give an estimate.  

The effect of the flywheel being lightened was like removing weight from the car and being directly related to gears ratios.

1st gear - 130 lbs
2nd gear - 100 lbs
3rd gear - 60 lbs
4th gear - 30 lbs
5 th gear - 15 lbs

Revs up faster, but loses revs quickly too.
In my opinion it is a worthwhile mod.

97S14 · 02-22-2002, 10:25 AM

In my opinion, the less rotational mass, the better (to a certain extent).

A nice set of lightweight rims (14,15lbs) would do wonders for your handling, braking, accelartion.

Ni5mo180SX · 02-22-2002, 12:41 PM

Yea I was talking to Mike (from JUN) at Area 51, says it'll make a big difference but seems kinda pricey.

Gismo R · 02-22-2002, 01:25 PM

I was talking about more power tramsfered to the wheels. I know that the HP at the flywheel will remain the same. And yeah I know it's be a bit pricey, considering flywheel~$300, not to mention installation. I was just wondering if it's worth the money.

Gismo R · 02-22-2002, 01:29 PM

Oh yeah, I've also heard that an averege of like 2.5 HP is gained for every lbs. taken off the crank. Not sure how much they weigh but I believe it's like 8 lbs. lighter. With those figures it seems like you should gain about 20hp. Not sure about how much truth is in that, but it's what I've heard.

Ni5mo180SX · 02-22-2002, 01:39 PM

Yea id say when its time to change the clutch you should change the flywheel out too since it seems like everything in the 240's drivetrain is a bit on the heavier side.

S13Grl · 02-22-2002, 04:45 PM

My boyfriend has an aluminum flywheel on his '96 240, and yes... it doesn't PRODUCE horsepower, but it allows more of it to the wheel. It DEFINITELY pulls a lot stronger through all gears, and not only first and second. This is definitely something I'll do on my car as well, whether it's turboed or not.

Irena

Ni5mo180SX · 02-22-2002, 04:55 PM

Hey S13grl what do you think of my new avatar?? *wink wink** lol

S13Grl · 02-22-2002, 04:56 PM

Ni5mo180SX · 02-22-2002, 05:50 PM

Tuck&Poke · 02-22-2002, 06:33 PM

w/e she meant its not good.  the flywheel is a good mod even if  your not an auto x racer.  it just gives you a more responsive engine and more power to the wheels.  im definatly gonna do it......when i get the money

S13Grl · 02-22-2002, 06:41 PM

it's :cool:

whateverjames · 02-22-2002, 08:15 PM

Honestly, unless you're an autocrosser or have a turbo....oh yeah...thanks DSC :biggrin: of course it's an upgrade that's going to perform, but i really do think an ECU would be better. the flywheel, was almost as good as taking of my power steering and mech. fan. except it COST me 425 which is good compared to the  525 i've been seeing. i made good money when i purchased that flywheel, so i was like most people that want one, just another upgrade. my car does rev up fast as #### though, i do good against modded turbo eclipses (GST/GSX). the eclipses will jump ahead, with less than a foot between our cars, then they stop pulling! it's like their rate of accelleration is the same as my car, except they get that jump (also waiting for them to spool up the turbo to the right RPM and letting them get a .1 second jump). but still, that doesn't make up for the RS non turbo eclipse that beat me only because he didn't have a speed limiter, my rev limter kicked in twice before he passed me. but oh well. one day i'll have an ECU and i'll praise both mods.

*Jeff240sx* · 02-23-2002, 01:53 AM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from Gismo R on 3:29 pm on Feb. 22, 2002
Oh yeah, I've also heard that an averege of like 2.5 HP is gained for every lbs. taken off the crank. Not sure how much they weigh but I believe it's like 8 lbs. lighter. With those figures it seems like you should gain about 20hp. Not sure about how much truth is in that, but it's what I've heard.
</td></tr></table><span id='postcolor'>

Not at all 2.5hp per pound.  I believe the stock weighs 18 and a Fidanza weighs 8 lbs.  This would be a 25 horsepower increase according to that math!?!  I'm kinda sure that the entire drivetrain doesn't lose that much power, and you're gonna get all it back and then some with a flywheel that has been established to lessen losses and NOT create power.
I believe that the increase in wheel power would be minute on a dyno.  Possibly let another 2 or 3hp back there.
This is why I said the weight loss from the car is a better way to look at it.  Not adding power, yet going faster.  Also.  What would you rather pay $400 for?  A couple ponies, or 100# weightloss.
-Jeff

240sxtreme · 02-23-2002, 04:41 AM

I have the fidanza flywheel on my 240...it feels way way faster.  does it add HP?  does anything really?  intake, headers, exhaust don't "add"....they free up....same concept with the flywheel...it frees up HP to the wheels...I'm not sure about 5th gear...but it does help every gear...even without my CAI extension on and the silencer for my N1 is still on...it basically feels like I have all that stuff on/off.  my friends used to say "it motors"....now they say "dayum, it goes to 100 real quick."  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>  if you ever have to change your clutch...you might as well get this flywheel.  resurfacing the stock flywheel (from what I'm getting) is around 80-150 bucks.  I got the flywheel for 320.  so far...the only people I've heard say that it isn't worth the money is people who actually don't have it.

02-22-2002, 12:23 AM	#1
Gismo R Zilvia Member Join Date: Feb 2002 Posts: 167 Trader Rating: (0) Feedback Score: 0 reviews	I know all the technical issues about how it lowers the moment of inertia on the crank, thus improving throttle response. But how much of a HP gain should I expect to get. I've heard the 240 losses about 15% through the drivetrain. With a lighten flywheel, what will it drop to? Also, is there anything I need to worry about with light weight flywheels?? -Thanks

02-22-2002, 12:36 AM	#2
tnord Nissanaholic! Join Date: Dec 2001 Posts: 1,975 Trader Rating: (0) Feedback Score: 0 reviews	i really don't know......but for timeliness reasons i'll respond, that and i'm bored......i would guess you would get around 5hp more than before to the wheels

02-22-2002, 12:55 AM	#3
drift freaq R.I.P. Aya, always love Join Date: Nov 2001 Location: Los Feliz/Hollywood Posts: 18,564 Trader Rating: (215) Rides Gallery: drift freaq Feedback Score: 215 reviews	well I can't give you HP figures but I can tell you that the lightened steel truck flywheel in my car made a big difference in the way the car accelerates. It pulls in fifth gear and revs up very quickly and smoothly I definitely feel it.

02-22-2002, 01:00 AM	#4
Jeff240sx I hate you too... Join Date: Jul 2001 Location: Tampa, FL Age: 42 Posts: 5,828 Trader Rating: (0) Rides Gallery: Jeff240sx Feedback Score: 0 reviews	I dont think that a lightened flywheel will give you a change in horsepower, but more like a weight loss on the car. Everyone knows that rotational mass is harder to get moving than a horizontal mass.  With this said, there is a mathematical function to realize how much exactly the loss in rotational weight will translate into as a function of horizontal weight. Easily said... A general figure is 10lbs per 1 pound shaved off the flywheel.  Drop 10 lbs, your car will accelerate like it was 100lbs lighter... not more powerful. -Jeff

02-22-2002, 01:38 AM	#5
tnord Nissanaholic! Join Date: Dec 2001 Posts: 1,975 Trader Rating: (0) Feedback Score: 0 reviews	jeff......you're on the right track, but not quite there like you said, rotational mass is difficult to get moving, so in order to do so some amount of power must be used to turn it; hp if you will no a lightened flywheel won't make more power at the crank, but it will reduce driveline losses, putting more power where it counts, to the wheels 5hp gained at the wheels is just as good if not better than 5 hp gained at the crank

02-22-2002, 01:44 AM	#6
AmericanBornSilvia Leaky Injector Join Date: Jul 2001 Posts: 101 Trader Rating: (0) Feedback Score: 0 reviews	Basically, with all that said, it helps you rev faster. Also its real helpful with turbo applications.

02-22-2002, 01:47 AM	#7
DSC New Title Join Date: Aug 2001 Location: VA Posts: 3,454 Trader Rating: (0) Feedback Score: 0 reviews	here's what our very own James has to say about it... Honestly, unless you're an autocrosser or have a turbo, I feel this upgrade is a waste of money. Yeah, it's does it's job, it makes the engine rev more free, but good drag launches seem harder to come by with this flywheel. An ECU upgrade would have made more of a difference. Basically, a flywheel wasn't as important as I thought it was.

02-22-2002, 03:50 AM	#8
DuffMan Post Whore! Join Date: Oct 2001 Location: in a cardboard box Posts: 2,517 Trader Rating: (0) Feedback Score: 0 reviews	In terms of power, it helps more in lower gears than higher. 1st and 2nd will be the only place you notice it. If you could provide specs for before and after weights, the physics arent that hard to work out.

02-22-2002, 09:42 AM	#9
97S14 Join Date: Feb 2002 Posts: 36 Trader Rating: (0) Feedback Score: 0 reviews	I don't know the formula, but this was actually calculated on a 97+ Prelude I can't rember the exact numbers, but I'll give an estimate.   The effect of the flywheel being lightened was like removing weight from the car and being directly related to gears ratios. 1st gear - 130 lbs 2nd gear - 100 lbs 3rd gear - 60 lbs 4th gear - 30 lbs 5 th gear - 15 lbs Revs up faster, but loses revs quickly too. In my opinion it is a worthwhile mod.

02-22-2002, 10:25 AM	#10
97S14 Join Date: Feb 2002 Posts: 36 Trader Rating: (0) Feedback Score: 0 reviews	In my opinion, the less rotational mass, the better (to a certain extent). A nice set of lightweight rims (14,15lbs) would do wonders for your handling, braking, accelartion.

02-22-2002, 12:41 PM	#11
Ni5mo180SX Zilvia Junkie Join Date: Dec 2001 Location: Orange County Posts: 423 Trader Rating: (0) Feedback Score: 0 reviews	Yea I was talking to Mike (from JUN) at Area 51, says it'll make a big difference but seems kinda pricey.

02-22-2002, 01:25 PM	#12
Gismo R Zilvia Member Join Date: Feb 2002 Posts: 167 Trader Rating: (0) Feedback Score: 0 reviews	I was talking about more power tramsfered to the wheels. I know that the HP at the flywheel will remain the same. And yeah I know it's be a bit pricey, considering flywheel~$300, not to mention installation. I was just wondering if it's worth the money.

02-22-2002, 01:29 PM	#13
Gismo R Zilvia Member Join Date: Feb 2002 Posts: 167 Trader Rating: (0) Feedback Score: 0 reviews	Oh yeah, I've also heard that an averege of like 2.5 HP is gained for every lbs. taken off the crank. Not sure how much they weigh but I believe it's like 8 lbs. lighter. With those figures it seems like you should gain about 20hp. Not sure about how much truth is in that, but it's what I've heard.

02-22-2002, 01:39 PM	#14
Ni5mo180SX Zilvia Junkie Join Date: Dec 2001 Location: Orange County Posts: 423 Trader Rating: (0) Feedback Score: 0 reviews	Yea id say when its time to change the clutch you should change the flywheel out too since it seems like everything in the 240's drivetrain is a bit on the heavier side.

02-22-2002, 04:45 PM	#15
S13Grl Married to the Mob Join Date: Dec 2000 Age: 44 Posts: 3,670 Trader Rating: (0) Feedback Score: 0 reviews	My boyfriend has an aluminum flywheel on his '96 240, and yes... it doesn't PRODUCE horsepower, but it allows more of it to the wheel. It DEFINITELY pulls a lot stronger through all gears, and not only first and second. This is definitely something I'll do on my car as well, whether it's turboed or not. Irena

02-22-2002, 04:55 PM	#16
Ni5mo180SX Zilvia Junkie Join Date: Dec 2001 Location: Orange County Posts: 423 Trader Rating: (0) Feedback Score: 0 reviews	Hey S13grl what do you think of my new avatar?? wink wink* lol

02-22-2002, 04:56 PM	#17
S13Grl Married to the Mob Join Date: Dec 2000 Age: 44 Posts: 3,670 Trader Rating: (0) Feedback Score: 0 reviews

02-22-2002, 05:50 PM	#18
Ni5mo180SX Zilvia Junkie Join Date: Dec 2001 Location: Orange County Posts: 423 Trader Rating: (0) Feedback Score: 0 reviews	?

02-22-2002, 06:33 PM	#19
Tuck&Poke Zilvia FREAK! Join Date: Aug 2001 Location: MIA Age: 38 Posts: 1,046 Trader Rating: (0) Feedback Score: 0 reviews	w/e she meant its not good.  the flywheel is a good mod even if  your not an auto x racer.  it just gives you a more responsive engine and more power to the wheels.  im definatly gonna do it......when i get the money

02-22-2002, 06:41 PM	#20
S13Grl Married to the Mob Join Date: Dec 2000 Age: 44 Posts: 3,670 Trader Rating: (0) Feedback Score: 0 reviews	it's :cool:

02-22-2002, 08:15 PM	#21
whateverjames Nissanaholic! Join Date: Jul 2001 Location: St. Louis Age: 45 Posts: 2,263 Trader Rating: (0) Feedback Score: 0 reviews	Honestly, unless you're an autocrosser or have a turbo....oh yeah...thanks DSC :biggrin: of course it's an upgrade that's going to perform, but i really do think an ECU would be better. the flywheel, was almost as good as taking of my power steering and mech. fan. except it COST me 425 which is good compared to the  525 i've been seeing. i made good money when i purchased that flywheel, so i was like most people that want one, just another upgrade. my car does rev up fast as #### though, i do good against modded turbo eclipses (GST/GSX). the eclipses will jump ahead, with less than a foot between our cars, then they stop pulling! it's like their rate of accelleration is the same as my car, except they get that jump (also waiting for them to spool up the turbo to the right RPM and letting them get a .1 second jump). but still, that doesn't make up for the RS non turbo eclipse that beat me only because he didn't have a speed limiter, my rev limter kicked in twice before he passed me. but oh well. one day i'll have an ECU and i'll praise both mods.

02-23-2002, 01:53 AM	#22
Jeff240sx I hate you too... Join Date: Jul 2001 Location: Tampa, FL Age: 42 Posts: 5,828 Trader Rating: (0) Rides Gallery: Jeff240sx Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from Gismo R on 3:29 pm on Feb. 22, 2002 Oh yeah, I've also heard that an averege of like 2.5 HP is gained for every lbs. taken off the crank. Not sure how much they weigh but I believe it's like 8 lbs. lighter. With those figures it seems like you should gain about 20hp. Not sure about how much truth is in that, but it's what I've heard. </td></tr></table><span id='postcolor'> Not at all 2.5hp per pound.  I believe the stock weighs 18 and a Fidanza weighs 8 lbs.  This would be a 25 horsepower increase according to that math!?!  I'm kinda sure that the entire drivetrain doesn't lose that much power, and you're gonna get all it back and then some with a flywheel that has been established to lessen losses and NOT create power. I believe that the increase in wheel power would be minute on a dyno.  Possibly let another 2 or 3hp back there. This is why I said the weight loss from the car is a better way to look at it.  Not adding power, yet going faster.  Also.  What would you rather pay $400 for?  A couple ponies, or 100# weightloss. -Jeff

02-23-2002, 04:41 AM	#23
240sxtreme Zilvia Junkie Join Date: Oct 2001 Location: Portland, OR Age: 48 Posts: 386 Trader Rating: (0) Feedback Score: 0 reviews	I have the fidanza flywheel on my 240...it feels way way faster.  does it add HP?  does anything really?  intake, headers, exhaust don't "add"....they free up....same concept with the flywheel...it frees up HP to the wheels...I'm not sure about 5th gear...but it does help every gear...even without my CAI extension on and the silencer for my N1 is still on...it basically feels like I have all that stuff on/off.  my friends used to say "it motors"....now they say "dayum, it goes to 100 real quick."  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>  if you ever have to change your clutch...you might as well get this flywheel.  resurfacing the stock flywheel (from what I'm getting) is around 80-150 bucks.  I got the flywheel for 320.  so far...the only people I've heard say that it isn't worth the money is people who actually don't have it.