How Lightweight Flywheels Destroy Engines (LWFW part 2) 

1.25 speed is way better.

this video needs a lighter flywheel.

They don't. Lightweight flywheels are awesome. I've had one in my AE86 and my NA Miata, and the way they improve engine responsiveness is life changing. All the tolerances in the motor are already finely tuned, the dual mass shit they're putting in cars today is purely to make them easier to drive. Get a lightweight flywheel, learn to drive it well, and you will never want another boat anchor mounted to your rotating assembly again.

Go to options and view video at 1.25 x normal speed Just like a light weight brain Soooooo smooth

Just put a 12.7lb flywheel in my FRS (7.8lbs lighter than stock) best decision I ever made.

Are you sober ? :D

Automotive version of "Drunk History". Awesome!

I have put over 120k miles on a 12lb reduced flywheel (and replacement with same kit after turning the pressure plate into a flower ala leg day). A lot of these have been hard miles including club races, and there is no noticeable irregular wear at all, on anything. If there is any increased wear, it is only significant academically.

Crank, pistons, rod bolts, piston pins, clutch , trans input shaft, clutch pressure, bolts, etc, weigh about 130 pounds. Taking 10 pounds out of that equation and suggesting it does anything over 100,000 miles is a bit silly. Porsche put the dual mass flywheel there for the passenger, not the engine that is already balanced very closely via production controls. What you are missing by skipping the LW flywheel is the joy of shifting. Can't explain how it feels to you, you have to try it for yourself.

Flywheels don't cause issues at a measurable rate. Besides, you have a 3500lb flywheel the minute you let out the clutch.

Honda provided its new Civic Type R with (OEM) lightweight single mass flywheel. Engine warranty as usual.

"nicely smoother up some vibrations" professional explanations all over the time

Am having a DMFW installed on my 2000 base Boxster as we speak. The guy doing the work says that a lot of owners that went with the SMFW's for daily drivers complain about 'gear rattle'. I don't know what that is, but don't like the sound of it. And compared to most cars, the Boxster still has a very fast revving motor that drives like a lightened flywheel anyway.

First car I ever put a good bit of money into I upgraded the clutch after i torched it just trying to clean the tires off before a street race. Stage 2 competition clutch and an oem throw out bearing(never use the bearing in a clutch kit bc they are trash and never fit right.) Along with a 7.5 pound fidanza flywheel. Car picked up 2 tenths on the et from that flywheel alone not to mention a noticable seat of the pants feeling. Little 4 cylinder car was unbeat motor to motor. On the street. Was putting together a direct port nitrous setup for it with some godzilla sized nozzles when I wrecked the car on a rainy day. Car was prepped to make 550 whp with limited slip and slicks. Had a fender exit 4 into 1 header intake manifold coolant bypass, cold air intake. Colder plugs, limiter raised to 8600rpm with cams to take advantage of it. Solid mounts. Walbro 255 and a stand alone. Had the cam timing perfect had the ignition timing perfect on 93 and 110 with a table to pull timing as soon as nitrous was activated. Had the afr spot on at 11:2:1 off bottle and 10:8:1 on bottle. Wideband was in too of course. Car was scary. Lol

Had several LWF's. Neither were damaging nor notice any huge changes in driving. Just a slight acceleration in 1st and 2nd gear, which was the goal for Rally-x in my WRX. I think I lost maybe 1 mpg on the hwy but don't have enough data to confirm. I was against LWF's due to the extra mass needed for launching and MPG. I don't launch my WRX and 2nd gear is horribly long, and it already being on E85, a 1 MPG possible difference wasn't a deterrence for me.

2.0 speed is still too slow, this guy needs a lighter flywheel

Very little here is understood by the presenter regarding torsional vibrations OR rev-match shifting, which is unfortunate. The better lightweight street flywheels currently available pose no additional problems for engine bearings. In fact, the argument could be made that the lower torsional resistance means the rod bearings might take less hammering. The crank main bearings will not notice the torsional difference at all (they don't "see" torsional excitation), although they will appreciate having less useless mass hanging off the back of the crankshaft due to the reduced bending moment. Also keep in mind that a "perfectly balanced" engine only compensates for 1st order torsional vibration of rotating components. 2nd, 3rd, etc., order torsionals cannot be compensated for without counter-balance shafts, which very few engines have (mostly inline 4-cylinders over 2.6L). Power pulse inputs are always unbalanced, as physics would have it. For shifting, rev matching on downshifts is significantly easier with a lighter flywheel, due to much less waiting for the engine speed to rise during throttle blip. A day or two after making the change, most drivers will become the most proficient that they have ever been at it. Getting back into a similar car with a heavy flywheel will now feel a bit pathetic and lazy. Lastly, the entire reason Porsche (pronounced "POR-sha" by Dr. Ferdinand and his family) and other manufacturers choose dual-mass flywheels (DMF) is missed. It is for noise/vibration/harshness (NVH) reasons -- not engine longevity! Very few street drivers would put up with a lot of rattle in a $100k plus car. A well-tuned DMF will eliminate the gear lash rattle the Porsche transmissions are well known for. Single mass flywheels have no means to damp the torsional pulses that excite the gears to bounce off each other, especially at idle with the A/C on. So, yes, one thing I've seen as a negative on Porsche's is a bit of gear rattle. This *can* be reduced by using a clutch disc with carefully selected hub springs (the factory Sachs/Porsche units have solid hubs), although it is nearly impossible to eliminate completely on these cars. That said, the noise is harmless other than slightly annoying to some. Overall, anyone intending to drive with any sort of sportiness or passion will definitely enjoy a lighter flywheel (within reason). Full race setups are far lighter, miserable to drive on the street and will wear out discs much more quickly. There is a huge difference, and anyone properly trained in modifying Porsches can correctly guide you towards an intelligent decision that is correct for your driving style. About 95% of the time, that won't be a DMF!

You can run a engine with no flywheel but getting the gearing low enough to get 5000lbs moving would be near impossible. 1000cc sportbike engine has no flywheel to speak of and will run for years. A 5 ton truck may have a 60 lb or more flywheel to get it moving from a stop. The mass of the flywheel is there to give inertia to get the mass of the car moving from a stop. The engine needs no more flywheel than is needed for it to start and idle. Dual mass units are for comfort and are often replaced with one piece units as replacements. No way it will ruin your engine ....A corvette with a 350 will not do a burnout with a 10 lb flywheel but will shift like lightning and the engine will run for 220kplus miles with no destruction. screw your calculations.

Been running one for over 3 years no issues drives awesome

The engine is moving the weight of the car from standstill, if it can handle the stress of this task, it's not.going to pack in because you've taken a few grams out of the flywheel

Very nice video explaining the pro and cons. To me it is surprising that car makers dont have a better way of damping the input energy, i dont have a better solution, but flywheels seem kinda "bad".

And this kids is why you don t do drugs

this is difficult to listen to. speed up the lesson to keep viewers.

Is this guy coming down from a gnarly acid trip?

Playback speed 1.25 makes him sound like he actually knows something about what he’s talking about.

I put 322k km's on my B18C1 with a lightweight flywheel. Then I rebuilt it and it's got another 60k km's on it.......with many a pull to 9,200 rpm. I daily it, and have never had ANY engine issues.

1.75x is so much easier to bear trust me

To compensate you can get a high quality harmonic balancer. That way you can have the lightened rotating mass while protecting your engine from the vibrations that it can allow.

The 997 (both .1 and .2) gt3 rs are PLAGUED by these problems. The solution for costumers was adding a ATI dampener. They do take more time then regular engines to blow, but it happens a lot.

Subscribed!! This video is great, I like the way you explain things. I do quite a bit of work on cars and I can tell you know a whole lot! Can't wait to learn more!

I've got a D15b7 Eg and it's so much more fun to drive with a lightweight flywheel and heavy duty clutch, it's so slow but it's very very reliable, sounds good and always makes me happy to drive it

I listened until you used the term ‘take out your engine’ what exactly is it going to take out?

Did anyone else try wiping off the smudge behind him?

The Subaru crank pulley is NOT a harmonic balancer. That strip of rubber isn't what you think it is.

My 99 NB miata has a 13 lb flywheel - original is a 16 lb. It is fun although I recommend if you have a Miata and want onet then get a FM flywheel (Flyin Miata') as it will perform better than simple aftermarket one that is designed to work with it. My light weight flywheel is a CompClutch (same company FM uses to design their Flywheel - but not the same specs as mine). My clutch right now is an Exedy (slightly stronger than stock clutch not not made for forced induction applications). Great clutch however I think it would be more suited to a stock flywheel on my car as it has some vibration chirping noise issues that start happening later down the road. I am going to pull it and go with a FM clutch and flywheel (stage 1) even though I am not using any forced inductions. I'm not sure I agree with a lightweight flywheel shortening the engine life. If it does I don't think by much. It can be argued that it will actually extend the life of the engine - but of course this all depends on the driver and how well he decides to rev match it etc.

yo this video is great :) VERY well explained! thank you

just have you standard fly wheel balanced to your old DMFW plus most cars have a HB on the front to dampen abnormalities Porsches are an exception

You can avoid that with Fluidampr viscous silicone harmonic balancer... lessen vibrations and gearbox chatter

Would I bother using a light flywheel on a read car? No though have in the past. Racecar however [roadrace and speedway] they are essential and ideally you should also use a lighter balancer as well. As well as a smaller dia one. Or more importantly a smaller far lighter clutch. Centrifigual mass is a real issue, smaller mass the better the engine responds. Balance? IF the engine is balanced to suit there is no issues, even a 40lb nuetral balance clutch and flywheel can use one half that weight. Or speedway use just a small dia flywheel with a conical clutch.

Cool Story 📕 LIGHTWEIGHT FLYWHEEL *A L W A Y S*

I dont see why a light flywheel would hurt an engine, it just puts less load on everything. My car dosend have a dual mass wheel anyways

hello thanks for posting your video, I'd be glad to know if people around here have noticed a difference about the amount of vibration increase

You're actually explaining it wrong, the one you're showing is a boxer engine, a flat 6 is the same as a v6, but with an angle of 180 degrees (the opposing cylinders connect to 1 crankshaft pin)

I just want to say, that in theory you're 100% right and do agree with you, however, those vibrations on a daily/track car, how much do they really shorten the engine life compared to the use of the engine while the car is on a track. I am going to say that it's fine to use a lightened flywheel on a daily/track car and the engine life won't be significantly shortened in comparison to a daily/track car with a dual mass flywheel. That's fair to say right? People reading this should understand that if you are building a car to have fun on the streets, you don't need a lightweight flywheel since it won't make a difference and it's just a consumer mentality, however if you do go to a track and push your car to the limits then go ahead and buy a lightweight flywheel along with an aftermarket heavy duty clutch.

DMFs are nothing but a cash-grab. It replaces a never-fail part, that was easily replaceable if not serviceable, with a flimsy, un-reliable, and very expensive part. The reason why manufacturers are using them is because they reliably fail early, at around 100k mi, costing $3000.00+ in parts and labour, motivating customers to just buy a new car. The transmissions paired with DMF are also fragile pieces of crap that will break in short time if the DMF is replaced with a single-mass flywheel. DMFs are a regression in every single way. DMFs are nothing but anti-consumer business practices.

This niqqah tweaked out of his mind y0!

The replacement surface on my flywheel costs more than the factory replacement flywheel. I didn't put it in but I'm going back to factory

i had to make sure it wasnt .25 speed 💀

You didn’t explain that rev hang is also a con for heavier flywheel

Long time ago I was considering light flywheel for reason that about to spin out, off the gas and able to regain control because less inertia the engine immediately slows down. Now I don't care as car is just transportation.

Very informative. Thx!

Dual mass has no balance effect to the engine... thus a single mass will not cause more imbalance in any way. You are wrong and you need to stop smoking weed.

Im sure this guy is fun at parties haha I fell asleep less than a minute through the video 😪😂

Hi. I have something to throw in the mix. Besides lightweight single mass flywheel, how about a single mass flywheel conversion kit. Not lightened, but a oem replacement of the dual mass flywheel for daily drivers. I am looking to replacing my Dual mas, but the cost of a Harmonic balancer it a bit too a high cost to add with the conversion kit for a daily.

What about the old muscle cars? They didn't have dual mass flywheels back then. A lot of those cars went over 100,000 miles with no issues. And they was pounded on too. And some had flywheels that weight about 20 lbs too.

Sick tie shirt combo

Great info. Keep the videos coming!

balance the flywheel then u loose the vibrations

Great video!

He created this video because he cant control a lightweight flywheel. He prob destroyed his car and decided to make this video

Bla bla. All a flywheel is energy stored in a spining mass. Its how engine rpm drops to fast for road use or slow gear changes.

Thank you Burner sir! I was debating whether i should buy another factory clutch and flywheel for my audi a3 2.0t or a lwf. This video has answered whether or not to get one especially since ive heard that ill need to rev the car a little more to get off the line with a lwf or might stall (though i would expect it would just get some getting use to) as well as some other concerns. Anyways great vid!

The main point of dual mass flywheel is to dampen irregularities in engine revolutions - engine doesn't turn with constant speed - it accelerates and decelerates a little each revolution as the fuel ingnites etc. Dual mass flywheel is torsional spring and damper so on one side you can input variable rotation and with proper spingrates inside the flywheel you get constant rotation on the other side which is mainly percieved as less vibration, but yeah there is less force on the engine internals because of that. So that is the main function of the dual mass part, to stabilize the rotation.

i'm not trying to be mean but wouldn't take this guy's car advice but honestly I haven't been able to pay attention to his videos that long lol

I'm gonna go ahead and guess about why it's bad for the Porsche flat 6... Overrevv code being thrown and motor scattering not soon after? was I right?

well this saves me some money

The rest of this video is bla bla, one of the worst mods is a uprated clutch pressure plate. Then to gear fast means your kicking the hell out of the crank thrust/crank walk.

I think you make big things out of small things. Harmonic balancers have to do with torsional vibrations. Aand the longer the crankshaft the bigger the problems with torsional vibrations and stiffnes as it acts like a spring. A crankshaft from a flat six is short and it has a very good balance so not a big deal. A flywheel has to do with constant wheel speed. The lighter the wheel the less regular the spin of it. And so it has more vibrations at idle and gear noise. That's all it is. On the 911 RS who cares about noises. It's a race car.

F L A T P L A I N

Sit and listen to you talk for 10 minutes about things that are unrelated to lightweight flywheels. I think you like to just listen to yourself talk

I ve owned and own tercel 4wd 83-87. 22 years ago I lightened the flywheel I removed as much material as possible and had it balanced at a very hi-tech shop. that flywheel is on it s second motor and it s been resurfaced twice... it never broke a motor, nor did it vibrate but it is very rough on the flywheel s middle pilot bearing the one that bears the tip of the input shaft . there is only one PLUS for a lightened flywheel on such a small engine ( 1.45L ) and it should not be your daily confortable vehicule : on a slippery flat surface such as cold snow you get instant torque/;limiited rev , that s it. don t expect to go up hill easy , beware strong winds , forget smooth idle and in cold starts northern region (canadian shield ) hold the clutch pedal and massage it while shaking tranny s oil...

R you ok

Let's go to some nice trip, I'll be your pilot

I have a lightweight fly wheel on my BMW but its for racing (my car was being converted when we bought it)

No evidence of how a lightweight flywheel destroys engines.

I have been wondering for a while and cant seem to figure it out. I used to have a dmf on my car, and accelerating quickly from a stop was easy. I put a lwf at 13 lbs in my car and it feels slower off the line than before. It also feels like it has less torque than my car with the dmf (even though I know thats not the case). Once I get going to normal traffic speed and then want to punch it, the lwf does feel quicker than the dmf would be. So why does my car feel so sluggish off the line with a lwf?

Good video! Only what I hear is that a SMF does more wear to your gearbox instead of the engine itself... I have a tuned petrol turbo car and I'm considering replacing my current (almost worn out) DMF for a LWSMF... Doubts doubts doubts :-P

You look like that crazy dude from prison brake so1 :D

Very well said. Thanks.

Hey ben, how long did it take you to complete this clutch job, and where did you get your IMS bearing from and about how much did it cost? Thanks!

I still don’t understand how it would damage the engine to have less rotational mass if there is s harmonic balance shaft already doing that in the engine and I’ve actually got a Mazdaspeed6 where every single person with one swears that removal of the 20lb balance shaft extends engine life in its case by keeping the oil Chanel clear please explain in more detail y it would damage an engine and how and by how much

I started looking for a LWFW but quickly changed my mind, exactly because of what you thoroughly described. All GT3 and RS engines have LWFWs, but then the entire powertrains of these cars are built to a higher spec thus reducing the need and potential damage caused by not having external/intermediate balancing. Thanks for the videos, I appreciate that you justify your claims.

nothing a good tune and appropriate engine bearings couldn't fix.

This guy has no clue and in one of the comments he admits not even trying them! Yes you can fit a lightweight flywheel, add a harmonic damper just in case and your golden. The end.

Did this dude really slow this video by nearly 2x to extend run time? Or is he just *that* slow?😳

Tell that to my k20 a3 engine with 150k on it with single mass flywheel 😂

Wait so your saying if I drive my rotary engine at 6k+ rpm it will be as ballenced at it would be at idol with a stock flywheel...okay Il.just drive it on the interstate in 3erd gear like I normally do anyways ahaha

Word of advice to Mitsubishi 4g63 turbo Owners: do not get a light weight flywheel. 1.The inertia of the heavier one will help your launches. 2. The lighter flywheel will not combat vibrations effectively leading to increased likelihood of crank walk. I would even go as far as to say any car that's awd your also going to be disappointed in launches if you go to a lighter flywheel.

So wrong if you put time and money in engine change pistons and other things they last and they can take this. Sont tell shit if you dont know

muy buenos los videos gracias

Excellent.

Thanx , You are awesome

did he just say Subaru flat six?? I WANT ONE !!!

Your logic is flawed. If you put a noise cancelling muffs, does the noise cease to exist? And yes... you are using only logic and no actual math or facts in your opinion.

...Outstanding!...

Really enjoying the content here. Well done from a 2.7 986 owner. Great cars eh? Must look up the flywheel spec of the magnificent V10 Porsche GT... From the reported legendary clutch sharpness, i am guessing its single mass........

I see you had to get "ready" to make this video. 🤣🤣 🍺🥃🍸🍷

Claims to have done the math to prove his point but then shows no calculations whatsoever. Fail. I have never seen or heard of a single piece of motoring literature that claims DMFs are for the benefit of engine life. They are there for NVH reduction in the passenger compartment, nothing else. You are not "increasing the vibrations" of anything by removing it, just removing a filter between the engine and trans. How and why this would have any effect on engine life either way is nonsensical.

okey and if i put the single mass flywheel but with almost the same weight than dual mass? i also dont like light flywheel for daily driving, but I also dont want to change it each 80.000kms and pay like 400€ more when just the clutch kit is like 140€ euros..

having a problem rev matching with my porsche 2002 turbo that has the lighten flywheel ..I am thinking of take it out should i keep clutch masters FX350 CLUTCH in and go back to the factory flywheel??? or put it all back to factory