Falco78

I am looking into a new clutch and flywheel kit for my almost stock LS1 and have decided on a Monster Level 2 clutch kit with a new slave cylinder and Tick adjustable MC. My question is regarding the 18 vs 28lb. flywheels. Is there any gas mileage difference with the lighter flywheel and what are your guys thoughts on these for a DD?

BALLSS

My $02 is stay with a stock weight FW vs the lighter one for a DD car

You need to have the RPM's higher to run a light FW on take off as it does not have the inertia as a heavier one

They shine in auto x applications though if that is your primary use.

SNLPerformance

iTrader: (15)

I would recommend the 28lbs flywheel if your going to be daily driving it. As far as gas mileage goes you wont really notice a difference between the 18 and the 28.

HioSSilver

iTrader: (8)

This is almost complete bullshit except for the last sentence.

Go as light as you can afford to op. Last time I checked it takes MORE power to turn MORE weight. More power usually means more fuel, now in this situation it's probably unnoticeable. For those that maybe do not understand flywheels......they make ZERO power. Flywheels can only absorb and release power. Any tq being made is being made by your engine.

What up SNL

BALLSS

If you could elaborate beyond "bullshit"....

in addressing OP's ? regarding lightweight or standard for a DD. My point was same as SNL on that topic in that a heavier FW is better than a lightweight one

running a lightweight FW often requires slightly more RPM on clutch engagement starting from a stop. Yes driving technique adjustments can minimize that but a lighter FW simply has less inertia

does it take more effort for a motor to spin a heavier FW, yes...but there are +/- drivability issues with a lighter FW for a "DD". Auto X is a situation where a lightweight FW will benefit as motor can increase RPM's faster.

difference in gas mileage between the two, IMHO, would not be measureable if any. From a mechanical point would a motor spinning 18 lbs vs 28 lbs take less effort and thus use less gas...on paper one would assume so if that is your point.What that difference is I would argue would be so minimal that it would not be worth the trade off in drivability for a DD street car.....just my "thought" which is what OP is asking for.

If you are happy with a lighter FW on your car, great....but my response to that "opinion" would not be bullshit as each individual will find preference of one over the other for their own needs.

M4N14C

iTrader: (3)

Monster stage 3 w/18lb flywheel and Tick MC here and there is honestly little to no difference than that of the stock setup. Taking off from a dead stop is a bit trickier but I attribute that to the clutch not wanting to slip. Unless you live in a very hilly area with lots of stops there really isn't a reason you shouldn't go with a light flywheel.

As for mpg you'd probably see a bigger difference by eating a lager breakfast than switching flywheels...

chrysler kid

iTrader: (14)

I love low end torque you get with the heavy flywheel. If your car is a daily driver and you love getting pushed back into the seat from low end torque even at partial throttle go heavy.

If you have a weekend warrior you only want to redline regularly I would go with a light weight unit.

Neither is a bad choice I just love torque more than horsepower

I have stock weight with a stage 2 clutch. Never felt a need to go lighter for my daily driving style cruiser

HioSSilver

iTrader: (8)

Well snl is wrong and so are you if you want to agree with him. I explained in another thread to him there are several cars out there with 30-40~ clutch/fly combos stock(a 4cyl honda being one...a mustang the other. Does anyone complain about drivability with those?

There is absolutely no reason for these cars to have a 50-60+lb clutch/fly.

You said yourself a lighter clutch/fly allows rpm to increase faster. What do you think a heavy one does?....hhhmmmm Must increase rpm's slower. That equals slower acceleration. Is that what you want?
You sir have no clue whatsoever. According to this post if you took your heavy fly off and laid it on the floor it would start spinning all on it's own.

FLYWHEELS DO NOT MAKE ANY POWER. THEY CAN ONLY HOLD INERTIA FROM THE ENGINE SPINNING THEM.

Thus the engine is the only thing that pushes you in your seat. And unless you guys know something I don't if a lighter clutch/fly spins up faster than a heavy one. Which one will release power you in your seat harder?

redbird555

iTrader: (14)

I just made a thread about installing my rst/fidanza setup. Total wieghs 33lbs and has a much smaller MOI than a 12" clutch. A moster with a 18lb flywheel weighs roughly 46lbs or 56lbs with the 28 and stock is around 52lbs.

My mods are in sig and while my 3.90s help me I also have a cam which makes it a little more tricky...My car is NO more difficult to drive than it was stock clutch weight, I can still take off in 2nd and not even think about it. What has changed is how much more responsive the car is down low, with the stab of the throttle it will spin on command which never happened before and revs much faster

chrysler kid

iTrader: (14)

There is a difference between horsepower and torque. If all you care about is dyno numbers and peak horse power then by all means continue to post in all capital letters. There is a difference in rotational mass force when the flywheel contacts the clutch. Since the heavier weight is spinning with more force the engine requires less input when transmitting force to the back wheels.

Think before you post, this isn't just about peak power. The rotational mass of the heavier flywheel requires less load on the engine to transmit initial clutch release power. After the clutch and flywheel are released and mated the heavier flywheel will require more force to spin taking away horse power

HioSSilver

iTrader: (8)

Good post red. Most just don't realize the clutch/fly in these cars are to heavy for no real reason. The fact that Mustang clutch/fly has been around 40~lb for atleast the past 30yrs should give these guys a clue. I have never seen anyone complain about the streetablitly of those cars with a smaller engine and a lighter clutch/fly
Did you read what I said about the mustang clutches? THEN BY NOW YOU SHOULD HAVE A CLUE.

MAYBE YOU STILL DON"T. SO.....I will explain again. The hp or tq made by the engine is not effected by clutch/weight. It will still only make the amount of power it can. There for the flywheel can ONLY store energy......but the engine is required to reproduce the energy lost on clutch engagement. That means once you let the clutch out on both set-ups @1000- 1200 rpm for street driving the engine then has to over come the weight of the clutch to accelerate.

Here's the problem you have chrysler.......you listen to to many old schoolers.

Hell I'll give you another example......A typical stock honda clutch weighs in the low 30's. Does your car make less tq at idle than a honda? Mine don't.....lol

I have used clutches errywhere from stock to the current total weight of 17lb clutch/fly right now. Although I think a 22-26lb clutch/fly would be optimal with a low moi there is nothing unstreetable about a light clutch.

SNLPerformance

iTrader: (15)

LOL

chrysler kid

iTrader: (14)

We aren't talking about clutches we are talking about flywheels.

Hondas use heavier clutches because they need that extra rotational mass to overcome the weight of the vehicle since the smaller motor doesn't make power at lower rpms.

You contradicted yourself twice by saying the flywheel only stores energy, then you say it only over comes the mating to the clutch.

The flywheel stores the rotational energy which is why hondas need a heavy flywheel. You can run them on light ones but you would need to rev them high to get enough force to move the vehicle without stalling

On my personal vehicle I have found it much easier to control the launches at the drag strip with a heavier flywheel where as the lightened ones were very hit and miss on the launch. You either bogged heavily or just spun the tires, where as the heavier ones were easier to find a sweet spot

brigade24

+1

i have a lightened flywheel in my car which I autox regularly. Once the clutch is broken in, it will drive similar to stock however, driveability does suffer.

it begs the question, how much faster will you be when you make a car more difficult to drive.

brigade24

I can feel your love emanating from your words of wisdom...and you're approach, wow...simply exquisite...you somehow thought that it was a good idea to come on here and empower ppl...and i totally commend that. I encourage you to post the link to the thread you're referring to so we can all benefit from your virtual and/or apparent wealth of knowledge.

In passing, i'm not certain a flywheel/clutch setup for a honda or a mustang (what gen?) is a good comparison with respect to the F-body's setup. The last time i checked, LS1 is an aluminium piece which i'm sure has something to do with the 28lb flywheel selection. Now i'm not saying the GM engineers (accountants?) got it right...i'm simply stating that there is a reason.

but wait, hondas and mustangs also have aluminium blocks...geez, if only i had known.

i wait for your enlightenment....you wonderful wonderful...internet poster...dude

brigade24

No..there's no difference whatsoever in the MPGs. the 18lbs flywheel will require more revs to get the car moving smoothly until the clutch is broken in. the full stock clutch assembly and ML2 clutch assembly (with 18lbs flywheel) weigh almost the same...

if you don't plan on racing in any discipline, i would not encourage you to go with a lightened flywheel.

BALLSS

Hio

You obviously have an opinion and run a lighter clutch/FW set up so good for you.

Steve @ SNL, I would argue, has more knowledge of clutch components, their use and +/- on one set up over the other in specific applications. you infer you have greater knowledge than he....ah OK

To the Op's ? he asks if a lighter FW will benefit MPG....I, you and SNL don't have any credible data to show they do but certainly a mechanical point argument can be made that anything lighter attached to a engine should mean it takes less effort to spin it thus saving gas......but on the other hand a heavier FW will store more inertia so RPM's don't need to be as high to start the car moving....so in the end under practical use would a lighter FW save gas because the engine has to be revved higher each time to get the car moving...?

In practical use DD street cars and ones used also at 1/4 drag use benefit from a heavier (meaning stockish weight) FW than lighter ones as they are less prone to bogging on launch than cars with lighter FW's. It is the inertia that a heavier FW provides that benefits these two driving criteria.

You have your own opinions and feel your $ spent on the lighter set up you have is ideal for street, great but many do not share that opinion.

again auto x, drifting do benefit from lighter FW/clutch assemblies...but that was not the Op's ? nor are those 2 driving environments common for most street DD or 1/4 mi track cars

HioSSilver

iTrader: (8)

I did not contradict myself at all.....you simply don't understand the differences.

Last I checked the clutch/fly is a combo. It can have various styles and weights but one cannot really be used w/o the other. Hence why i use the clutch/fly designation.

You contradicted yourself by saying a heavy clutch/fly is easier to launch. You are releasing more power threw inertia with a heavy get up and it WILL take longer for the engine to react with a heavy clutch/fly making a "bog". I'm sure if you would have spent the time on the lighter clutch/fly to get it to launch is would have been fine.......after all......ALL the record cars use a significantly lighter than stock clutch/fly.

You also may have comprehension issues as I said honda's have LIGHTER clutche/flys.
The bold makes sense.

As I said.....If you can drive a stock honda as many do then you can drive a v8 with a light clutch/fly
WTF are you talking about blocks for? Enlighten me with your wonderful internet wisdom.

HioSSilver

iTrader: (8)

yep Steve has more experience on the clutch components......and he is also wanting to sell a part that he has no complaints on so he can make money. I've been yakkin at him for years to make a 25~ clutch with various materials to offer the engagement characteristics that people would want.

I have made my own clutch set-up work.....so I am not dumb or necessarily in experienced on the subject . A 5.5 tilton triple to be exact. It weighs far less than most peoples clutch and the myths of light clutch/flys being hard to drive increasingly astound me. It is simply ignorance as I have posted cars that come with much lighter clutch/flys and no one complains about their drivability ......YET.....everyone will agree that a lighter clutch/fly will accelerate better.

It makes no sense what so ever that a larger engine should need a heavier clutch/fly to take off.....none....zero

SNLPerformance

iTrader: (15)

I do have more knowledge, but, at the end of the day it is personal preference.

We can argue this point day in and day out, most people do not want what you're feeding them and when they buy in to what you're saying I wind up getting the angry phone calls.

I still love you though.