After putting a lightweight flywheel in my little fwd hot hatch and seeing how much more quickly the engine revved and how much easier it was to rev match....it has become a "must have" upgrade for me.
A heavier flywheel is helpful when drag racing cars that have low torque, like a rotary engine. The reason is that a heavier flywheel will store a bunch of energy before the green light, artificially improving the launch and 60 foot times. Beyond that, the lighter the better when it comes to ET's. For almost all cars, the better launch (if traction is available) is negated by the inertial losses, especially in the lower gears. This is both from a scientific standpoint, simulation and years of track testing.
Marvin Eghan he literally just gave the answer before tou asked the question A heavier flywheel will get you better launched in a low torque car... Just stick with stock if youre not going around a race track or need to rev match often
Lightweight flywheel helps my Mustang GT launch better with about 310 ft lbs of torque. With the stock one I wouldn’t stop burning rubber until 3rd gear when I clutch dump. Now she hooks up faster.
Yes. What you have to learn is to rev your engine on take off. In most cases the engagement point will actually pull the car with out throttle. If you do that with a LW flywheel. You’ll literally hear and feel flywheel chatter. If you don’t already.
Had a lightweight flywheel in my accord ages ago. Made the motor rev happy, and was able to raise and drop revs at a moment's notice however when driving uphill without the lighter flywheel I only had to drop to 4th or maybe 3rd gear to make it up the hill. But with the lighter flywheel I had to drop to 3rd, or even second gear due to less rotational mass helping the engine push the gearing. Went from a nearly 23lb stock flywheel to a 17.5lb fidanza.
The factory put heavy flywheels on to allow a smoother and easier driving experience. Yes the rotational mass is beneficial as a vibrational dampener but means it takes more torque to initiate the rotation but once it is rotating it will continue by itself for longer. Stored energy. A lightened flywheel is beneficial in many ways. From Launch to acceleration to deceleration and stopping. If you buy a cheap one then you will be disappointed as it will be out of balance which will increase the harmonics inside the engine that has the potential to break things and cause alot of rotational resistance slowing down the engine and causing power loss. (Torque) I would advise that regardless of what brand you get get it balanced and skimmed that way you are certain of its specs. I use an excedy lightened flywheel on my rb25det. It was skimmed and balanced before installing it. It was out of balance and out of square out if the box. I have spent in excess of 25k in the engine bay alone so an out of balance flywheel on it for how it is tuned for hight rpm and other things would cause vibrations that could easily turn my 25k into a boat anchor. So the 100$ for machine saves me alot in the ling run. .
The trans does not slow the engine down. The engine slows to idle when you put the clutch pedal in because because your also lifting off throttle. And the benefit of a lighter flywheel is lower inertia so the engine rpms drop/climb faster. Making rev matching up or down faster. The engine is mechanically disconnected when you push the clutch "in".
Don’t forget that when you disengage the clutch and the motor is spinning freely the flywheel weight is what helps prevent sudden drop in RPM as it’s rotating mass decreases the decceleration effect of passive compression in the engine. So a short shifter to quicken your shifts and even double clutching can keep revs steady and get through gears easily whether up shifting or downshifting. So if you’re driving the twisties a standard weight flywheel is fine considering you have a clutch and a gear shift to stay in the peak HP range. On modern cars a lightweight flywheel is a great way to generate phantom misfires and trick your car into limp mode which isn’t going to add performance that’s for sure. Downshifts and gear rattle can be harsh with lightweight flywheel because the tranny is spinning so much faster than the engine as the flywheel doesn’t keep the engine rotating at a matching RPM which can be pretty hard on tranny parts and the low end of the engine. Lots better ways to gain performance without compromising the reliability of you’re looking to improve a car that you also daily drive or want to be reliable
@@nobodynoone2500 02 WRX with EJ205 with complete rebuild with OEM components other than ARP head studs, ACL race bearings, GSC stainless steel exhaust valves. Threw misfire code with downshifting under braking and hard acceleration over 4500rpm w/ lightweight flywheel. Swapped in the stock one and misfire went away and has never come back. Shifts are much smoother as well.
You hit the nail on the head ... If one has a 5 hp Briggs Engine that was turning a 500.lbs flywheel versus a 5.lbs flywheel, whitch of the two flywheels would have the most torque while spinning ?
Um I'm not sure if changing the weight would change the tourque much in consistent clutch engagement, but if you were revving and then dumping the clutch then the 500lb flywheel would have more energy stored for the clutch to absorb
IF the engine is under load, the 5lb flywheel would have more torque due to the fact it requires more energy to spin up a heavier flywheel. That extra energy used = loss of power and torque. However when you come off the throttle with a heavy flywheel, the momentum is going to continue to transfer more torque and the car will roll longer. If you're slipping the clutch to launch with a heavier flywheel, the extra inertia can potentially make the launch feel faster. To sum it up , OEM flywheels are heavy to make the car easier to drive and smoothen out the power pulses of the engine . Lightweight flywheels are better for performance but only in the hands of an experienced driver
If you want a light weight flywheel and you also want to drag race, get a set of adjustable cam gears and short headers/intake manifold. The idea is that you are moving the power curb to lower RPMs. The cam gear can be set to give you power at low RPMs. This is ideal for a light weight car like the civics that can hook and go without moving so much weight.
Great explanation. For drag racing (and acceleration in general) you Most Definitely want to reduce rotational inertia as much as possible: the car accelerates faster in short gears. It is less noticeable in high gears only because the engine acceleration is less than in short gears but it never hurts. However, since there is less kinetic energy available during launch, the drivers must adapt their launch technique, typically rev the engine quicker to compensate. There is nothing wrong with launching from the rev limiter if the clutch can take it, the car on my avatar is a 300hp 4-cyl 2.0L N/A with a 5" clutch and it launches at 8,500 RPM :-)
I have a volvo 850 t5, I dynod the car with stock fly wheel then changed the flywheel for a lightened one and made more power to the wheels with the lightened flywheel than I did to the crank with stock 👍 lightened flywheel all the way
Right on; I have two T-5Rs and wanted to put in lightweight flywheels, but am worried about drivability afterward. How are the street manners with your flywheel?
@@unicornsqueezins7906 in all honesty matey you don’t notice the differance day to day, the throttle becomes a little more responsive and the only downside is because you go from a dual mass to a single mass the throwout bearing will make a small amount of noise when the clutch pedal is depressed 👌
exactly. the engagement of a larger flywheel is probably more jarring so it gives the impression of momentum when shifting but it makes up for it when your climbing up the RPM range. If anything the light weight flywheel is probably just slightly quicker. However the main benefit is like the guy said, rev happy engine that is more responsive and better for spirited driving.
I find that upshifts are easier to do quickly with a heavier flywheel, and down shifts are easier to do quickly with a lighter one. The maintained rotational inertia of a heavier flywheel seems to keep the engine spinning faster, making the upshift engagement easier on the gearbox as the synchros seem to prefer higher rpms.
I have a lightweight flywheel on my LS swap. ACT prolite. The gear is machined into the wheel, so unlike the aluminum ones, there's no chance of the gear becoming un-rivited. Just some hot-rodder advice: A heavy flywheel is more likely to grenade your diff under hard launches and wheel hop.
@@Shakshuka69 "..keep the engine spinning faster..." bad english expression. Only saying this because it clouds your intended meaning, it keeps the engine revs spinning (due to the extra rotational mass inertia). Upshift engagement is going to happen no matter what, the real trade-off is the higher engine stall speed on clutch engagement and I feel this is a momentary enough inertia window to not be a serious concern over the vehicle rolling mass which, after all, is powered by the engine regardless of flywheel rotating mass differences.
Thank you. Great video. What if the car will be used on a short circuit arranged by cones? Slalom on a parking lot, with very short straights (less than 15 metres) and sharp corner (90/ 180 degrees). Lighter flywheel or heavy?
Hi Griffin, Thanks for your great video, I installed a lightened flywheel on my car around 5 years ago, it worked great for 5 years, now the clutch slips under heavy acceleration. Is it possible the lightened flywheel could be warped causing the clutch to slip and require replacement? Is there anyway I can test for this without pulling the flywheel out? Thanks
I'm taking the lightweight flywheel OFF my C5 Corvette. It completely ruined the car. RPMs crash and sometimes stall out the engine when I push the clutch in at speed or between shifts. If it doesn't stall, the RPMs bounce around until it stabilizes which is really annoying. Really sucks in stop and go traffic. Yes this is after an expensive dyno tune to try to fix it.
Aside from the performance aspects, there's also the street drive ability aspects to think about. With a lighter flywheel, you'll need to rev the car WAY more to take off from every stop sign , red light etc. You'll also get a lot more noise coming from the transmission and will make the car sound like a dump truck.
I have heard that a lighter flywheel gives more vibration/rattle in the cabin, for a street car does this affect the driveability of car and how annoying is this ? Good Video - Thank u
of course as the engine is balanced on the factory so the stock flywheel is dynamically balanced to all the other rotating parts of the engine as to not produce any unwanted vibrations in the useable rpm range basically changing the flywheel mass moves this resonant frequency
adding weight makes no sense, horse power comes down to speed. the faster you can accelerate, the faster you will get to where you are going, that is not to say that using certain light weight parts in your car will not adversely affect it...you are correct about having more weight in motion tends to slow down more slowly HOWEVER first you have to get that weight "in motion" and guess what? the heavier an object is that you have to move, the longer it will take!!! that's a fact. if you take 2 identical cars and add more weight to one and then race them witch one would you bet on your house on if you had to??? with that said, i have to disagree with you on that part.
@@darioavendano369 a light flywheel in a low torque car will make it easier to stall because the engine itself will have to do more work when you let down the clutch. It also loses revs much quicker and thus, you will have to learn to shift faster, although that's kind of a secondary concern.
Screw that. Get the lightest piece you can, under one condition. The gear must be machined into the flywheel material, so chromoly flywheels are generally better than aluminum ones. The button clutches that attach to automatic flexplates are bananas!
Would this also apply to vehicles with a dual mass flywheel? Would one be able to shave a stock flywheel down or would one need to buy a specific lightened flywheel?
Mclaren F1, Carrera CT both have NO fly wheel. The revs drop tremendously during gear changes so it makes for a less "smooth" drive BUT for road racing it is superior if an experienced driver is on board. A weighted flywheel just helps keep the revs up during changes for those that don't have the skills to change up or down rapidly.
its not all about revs the flywheel smoothens out the power delivery for a more comfortable ride
2 года назад
Is it correct to say that ITBs will give you the same benefits of a lighter flywheel (faster throttle response), but without the disadvantages? Thanks for the video
My question is unrelated to this video, but what transmission are you running in your truck? I've got my own build going and I'm using a lsx 454 engine for sure but I'm wanting going to with a turbo 400 and a overdrive unit, but then there's also the newer 4L70's or 85 that'll do the job without the overdrive unit. Any feedback will help, thanks!
John TerBeek no worries man! If I were you I wouldn't go anything smaller than a 4l80e. It's basically a th400 with an overdrive. If you want to get fancy the 6l90s are even stronger with 2 additional gears so you can have your cake and eat it too!
Griffin Steinfeld Thanks for the reply. It's looking like the 4L80 then, the final resting place is in a 68 GM A-Body. Those 6L's look mighty big to fit in the tranny tunnel without a little metal massaging lol.
Hey Griffin, question for you. I have a 65 mustang I am rebuilding. I have a 351Windsor and using a T5 Manual Trans. I'm NOT drag racing. Just a Daily driver. I'm looking for Flywheel info. Whats your thoughts on which one I should use? Thanks
Nice video. I have some mods on my accord 2.4 mt. 165kws 250nm. Replacing the clutch. Adding a 3.5kg flywheel. Do you have experience with this build, I'm uncertain about problems that may arise.
Love the video man ! really help in not buying the flywheel ! I was about to purchase one, but thanks to your video, i will not now.. i'll stick with the stock and just order new clutch ! Do you recommend Stage 2 Clutch on stock Flywheel ? Thanks
wait a second... if it frees few bhp, for example 4-5 hp... how does that momentum in engine still makes you loose at drag race? what about racing from 20mph or from a dig? Does it changes only when you are out of gear(while you try to get into another) or in gear?
Leo E36 like I stated in the video, an object in motion will stay in motion unless acted upon. With that being said, more mass (heavier flywheel) will be harder to slow down than a light weight fly wheel. When you up shift, the clutch/ trans is fighting to drag the engine down so if you put more mass on the rotating assembly it will feel like it's hitting the next gear harder due to the fact the engine doesn't want to slow down as easily
because in drag racing you can clutch dump this means you can rotate the heavier flywheel to some x rpm then dumping the clutch and it will pull alot harder and faster because of the stored energy vs a lighter flywheel. but in any other case example going out a curve the lighter flywheel will win as it will rev faster and you dont clutch dump anywhere else except launching
so the deal is you gain horsepower (at the wheels) and by extension torque with a lighter flywheel but you lose inertia (the energy stored in the flywheel from the mass that's spinning)... so now you need more torque to get those wheels moving. It's like you're swinging a bag full of quarters around and hit it into your friends chest and knock him off his feet. Now you have a half full bag and hit him swinging it around at the same speed as before. Now you just make him stumble. With the half full bag you have to spin it faster than before you hit him to knock him off his feet again (you have half the mass so you need to up the speed to achieve the same amount of force as before). The extra mass in the heavier flywheel can be used to help the car start from a stop better. You may not accelerate as fast after that as if you had the lightened flywheel, but if it's a relatively short distance then it may not matter. There's probably an optimal flywheel weight for any given distance where it balances out for the fastest drag time. A stock flywheel is probably a lot closer to that number for drag races.
@@RBoysMedia I have the same flywheel ACT prolite. It's the best flywheel on the market. The gear is machined into the flywheel, so there's no way it will un-rivet itself.
Good day & good evening Griffin just having one new energy drinks in snack but taste is not good I miss all of you alot 😁😁😁😁😁😁🥤 making some very beautiful and sweet memories ....how about you how things are going 😁 cheers 🥤🍺🍵
With a light flywheel, you need a super good clutch. I have a 9.5 exedy and it won't grab. I can feel it slip at high rpms when I'm slamming to the gears. It is better for mountains. It climbs with ease that's what I notice. I'm still not sure what people are talking about being rough chatter for everyday driving. People not must know how to drive.
You have a Miata too I'm guessing. Does the light flywheel really make it harder to engage gears with a stock clutch? I'm trying to figure out if I should upgrade the clutch with the flywheel. I'm on stock power and don't intend on changing that, so I figured the stock clutch would just be nicer to live with.
AD1 it feels no different from a stock car. The only time you will feel a difference is from a heavy duty clutch from how hard it is too push down on the clutch. I would recommend a heavy duty clutch with a light flywheel. The only time chatter happens is when the flywheel is warp like brake rotors. Just think of it like brake rotors, it will only chatter if it warp. People must stall a lot to get the chatter which then warp the flywheel then they complain of chatter. It does not change how it engages. The only difference I felt with a heavy duty clutch is how hard you have push on the clutch and when you release it, it will spring back faster and actually hit your feet before you release it. It took a minute from getting used too and it's rough for everyday driving like in out of bumper to bumper traffic. It's stiff as fuck.
@@Dr_Xyzt I ended up going with www.fidanza.com/collections/1997-honda-car-civic-all-models-all-sizes/products/aluminum-flywheel-191161?variant=11936587022379 i have had it in my civic for about a year. any experience with these? i love mine personally but its the first time with a light mass
@@orozcocris93 Fidanza is known to be a good aluminum flywheel, and was a big name in the 90's to late 2000's. I tend to get ACT prolite because the whole thing is made of Chromoly steel, so it's impossible for the starter gear to become disconnected from the flywheel, and friction surfaces don't have to be added to the wheel. 4340 Chromoly has a fatigue strength of 53,000 PSI, where good 6061 aluminum is 15,000 psi. The aluminum requires 3.5 times as much material. 490lb/FT^3 for steel, 170lb/FT^3 for aluminum, ergo, 600 lb/ft^3 structurally corrected mass for aluminum. Yes, the aluminum ends up being heavier than good steel. But, a lower grade of steel can shift the situation in favor of aluminum. RAM flywheels weigh more than ACT.
@@Dr_Xyzt that is good information! I got a light mass flywheel because I wanted more of the engine power to go to the wheels. for my particular scenario, I am more focused on gas mileage rather than speed or torque so it made sense. I love that you have done your research and are willing to share thought. Thank you!
Kevlar, and yeah maybe. I hear Kevlar is highly friction/abrasive resistant and impact/shock resistant. Not so much tensile/compressive strength, very stiff. Maybe it'd make a clutch plate instead?
Wow The Comments people really?? If you care about performance and racing of any kind GET A LIGHTWEIGHT FLYWHEEL, zero people in racing use a heavy flywheel THOUSANDS of dollars spent making race cars lighter you really think they have the stock 20+lb wheel spinning in there? No it’s the lightest one they can find, and at constant high rpm aka drag racing rotational inertia isn’t as important.
I have a question: I drive a MK7 Fiesta ST. And when I‘m driving fast, I change gears also too fast for the car(It can’t slow down the rpm as much as it should) So it also would be better in both directions...? So it would benefit me in increasing the speed of the rpm climbing up and also of getting the rpm faster down? I hope you understand what I‘m trying to ask. (English is not my motherlanguage😅)
Geile Potsau technically yes it would accomplish that but you’ll transfer that load into the crank bearings. You’re better off getting a short throw shifter.
in 1:30 he's talking bullshitts. With clutch pressed into the floor (between the gears), flywheel is disconnected from the gearbox. The only mass which will be bonded to transmission (input shaft ) is clutch friction plate. The lighter it is - the less effort synchro rings needs to slow the input shaft down whilst clutch pedal is down. Lighter flywheel, apart from less resistance to engine when it increases its RPM, in the traffic environment (1-2-3, stop, 1-2-3 and so on) will also result in less fuel consumption. We've proven it empirically at UNI, verified on Ricardo Wave simulation SW and finally proof in real life vehicle.Simply, an engine requires to waste some torque to speed up heavy flywheel from n1 to n2, instead of transmitting this torque to your wheels. Also, heavy flywheel limits engine max RPM as some energy is needed to keep heavy mass at constant angular velocity. Simple exercise form young years - a moped with 2 stroke engine, after just removing totally flywheel, disintegrating flywheel to remove just a cam (for operating contact points - non-electronic ignition), installing just a cam for its own, was driving faster than with OEM heavy flywheel.No other mods been performed.
No, you dont get it (krisbham). You are right that the flywheel is disconnected from the wheels when shifting, and that's the whole point. When you shift up, the engine RPM has to drop. If the flywheel is heavier, then when you engage the clutch at a higher gear, and the engine is still spinning faster than the gearbox, it will be harder for the gearbox to slow down the engine (That's what he says). And guess where that energy goes that the gearbox takes away from slowing down the engine. To the wheels.
