Effects of lightweight flywheel? [merged] light weight lightened aluminum ACT fidanza

[Fryguy]

All light weight flywheel newbie threads are merged here.

I'm looking for my car to be very fast at lower speeds; my main goal is very fast acceleration. Will a lightweight flywheel be beneficial to this? Or should I just save up all my money and drop a turbo on my 84k engine

 

[ChiGGz]

Yes, double clutching was something people did 40 years ago, but it doesn't benefit us now.

I'll try to explain what I mean by matching the RPM's.
When you ride a gear to 7K, and push the clutch in to shift, with a stock, heavy flywheel, the RPM's don't fall very fast at all. When you shift to the next gear and release the clutch, it grabs hard and pulls the RPM down hard to the bottom of the next gear. This can be hard on a clutch.

With a lightweight flywheel, it's different. When you ride the gear out and depress the clutch to shift, there is much less rotational mass and the RPM's begin to fall instantly. When you shift and release the clutch, the RPM's are right where they need to be. That makes for a very smooth shift and puts much less stress on the clutch.

Hopefully this makes some sense to you.

Awesome post made perfect sense

So now I'm thinking back to my ACT 2600 and remember that sometimes when I shift , it makes a CLUNK. Its hard to avoid and people who first drive my car almost always do it. I hope the lightened flywheel will help with that matter. I'm sure just dropping the clutch doesn't help, but having a lightened flywheel will make the clunk happen less often hopefully.

 

[99gst_racer]

I just wanted to clarify a few things regarding double clutching. In my most previous statement on the subject, I stated: "Yes, double clutching was something people did 40 years ago, but it doesn't benefit us now."

I just received a lovely negative rep. comment stating:
"double clutching is still benificiery with lots of vehicles. Even a stock trans DSM can benefit from double clutching. not everyone can have as much money as you to buy all these fancy expensive parts man. (jhondus)"

Now, because I can't reply in my profile, I'd like to reply to that here; to further explain my reasoning. Let's begin.

Double clutching is a driving procedure used for vehicles with unsynchronized manual transmissions. Before the introduction of synchronizers and automatic transmissions, double clutching was the only way to shift. Due to the difficulty involved in learning the technique, it has largely fallen into disuse. However, drivers of large trucks still use double clutching, as those vehicles are usually equipped with the older, more efficient, and more durable unsynchronized gearboxes.

The purpose of the double clutch is to match the speed of the rotating parts of the gearbox for the gear you wish to select to the speed of the input shaft being driven by the engine. Once the speeds are matched, the gear will engage smoothly. If the speeds are not matched, the gears will "crash" or grate as they come into mesh. A modern synchromesh gearbox accomplishes this automatically.

Here's the basic procedure to double clutch: Clutch - to neutral - release clutch - rev the motor - clutch- next gear - release.

There are similar/related procedures such as Heel-and-Toe, in which the brake and gas pedal are pressed by the right foot while the clutch pedal is pressed by the left foot. This is commonly used to RPM match while downshifting to avoid the unpleasant weight transfer accompanied when the RPM's aren't matched.

Some argue that double clutching can actually prolong the life of the syncros. This can be true in some rare instances, but typically the differences are unnoticeable across the lifespan of a transmission. When you upshift using a lightweight flywheel, all the tranny internals start to slow down as you shift (RPM drop), and the next highest gear will be spinning about the same speed as the output shaft by the time you engage. So, very little speed synchronization is usually needed for upshifts.


jhondus - Double clutching forcefully originated because the process was a necessity. The process of double clutching is now ancient history because of developments made to transmissions over the past 40 years. When you are using heel/toe, you can blip the throttle and shift smoothly while using the syncros for the purpose they are intended for. Heal to toe shifting (RPM matching) is the only thing even related to double clutching that we should be interested in.

I'm not sure exactly why you left the comment that you did, but I would very much be interested to hear "your side of the story". I think you might want to put more thought into your actions before you jump to leave comments claiming information to be unhelpful and inaccurate; especially on debatable topics.

As for your other comment about me having money and buying fancy expensive parts - I have this little secret that I will share with you; it's how I get all of my money......

I work for it and I work hard. I've been working since I was 13 and I built this car off of a grocery store salary, so please don't give me any crap because I manage my money better than some other people do.....

Thanks -Paul-


PS - Sorry for the short post. I would have given it my all, but I am currently at work, so my forum time is limited.

 

[dnhieu]

As for your other comment about me having money and buying fancy expensive parts - I have this little secret that I will share with you; it's how I get all of my money......

I work for it and I work hard. I've been working since I was 13 and I built this car off of a grocery store salary, so please don't give me any crap because I manage my money better than some other people do.....

Thanks -Paul-

this is a very good point. i am considered a very cheap person. i just like to save my money to do other things, like build my car.

anyways back on topic. is it better to rev match or not? i tend to do it alot driving around town and after reading this tread im confused on if its good to do it or not? i would think it would be excess wear beacause instead of just putting it in nutral and coasting you instead run through the gears causing excess wear on the syncros (correct me if im wrong)

thanks
david

 

[99gst_racer]

this is a very good point. i am considered a very cheap person. i just like to save my money to do other things, like build my car.

anyways back on topic. is it better to rev match or not? i tend to do it alot driving around town and after reading this tread im confused on if its good to do it or not? i would think it would be excess wear beacause instead of just putting it in nutral and coasting you instead run through the gears causing excess wear on the syncros (correct me if im wrong)

thanks
david

Yes, it is better to rev match; It makes for a smoother ride. I also found it easier to rev match with the lightened flywheel as apposed to the stocker.

 

[dnhieu]

thanks man

 

[ChiGGz]

this is a very good point. i am considered a very cheap person. i just like to save my money to do other things, like build my car.

anyways back on topic. is it better to rev match or not? i tend to do it alot driving around town and after reading this tread im confused on if its good to do it or not? i would think it would be excess wear beacause instead of just putting it in nutral and coasting you instead run through the gears causing excess wear on the syncros (correct me if im wrong)

thanks

Yes, it is better to rev match; It makes for a smoother ride. I also found it easier to rev match with the lightened flywheel as apposed to the stocker.

Sounds to me like he was talking about riding the car in neutral as opposed to downshifting and riding out the clutch -> repeat till < 5 mph in which case it comes down to this, what costs more to replace, your worn clutch from excessive clutch deceleration or your brakes? 99gst_racer seems to be talking about revmatching while upshifting.

Correct me if im wrong, these two posts have me a little confused.

 

[SethA]

I agree that there are two different instances here.

It is not necessary to rev match and row though every gear when you are coming to a stop (like at a stop light). In fact this is just extra wear and tear on the clutch and syncros. Slip the tranny in neutral or depress the clutch and use your breaks to stop, that is what they are for.

99 is talking about the case where you are slowing down and will need to accelerate again in a lower gear (like when you are turning onto another road with out stopping). In this case, heal/toeing from say 4th to 2nd can make you a smoother driver and be fun. Race car drivers do this to prevent upsetting the balance of their car (as 99 alluded to).

I do find that double clutching into 1st is helpful sometimes but does seem pointless in other gears. My luck always leaves me rolling up to a red light when it changes to green going too slow for 2nd but still faster than the 1st gear syncros want.

Seth

 

[drivemusicnow]

There is one thing that hasn't been brought up. As many of you may know, Brake rotors are better when they are larger, and thicker, due to better heat absorbtion and rejection. A flywheel and clutch is, in a few ways, similar to a brake rotor and pad.

When you slip your clutch, it heats up the flywheel. the more material there, the better it is at handling that heat. If you're using a GOOD/high friction clutch, as in, not a street disk and heavy pressure plate, you are creating a fair amount of heat, just like more agressive brake pads make more heat.

When drag racing, this heat doesn't accumulate because for the most part, it heats up, and then has time to cool down before you do it again. When road racing, specifically when not rev matching on downshifts and using the clutch to slip power to the wheels, you create A LOT of heat... enough to quickly destroy some cheaper aftermarket flywheels. this can create a dangerous situation of "oops, my clutch/flywheel just tore the bell housing and half of the engine bay apart"

Which ever product you do use, make sure that it is in good shape and use it appropriately.

 

[drivemusicnow]

I agree that there are two different instances here.

It is not necessary to rev match and row though every gear when you are coming to a stop (like at a stop light). In fact this is just extra wear and tear on the clutch and syncros. Slip the tranny in neutral or depress the clutch and use your breaks to stop, that is what they are for.

99 is talking about the case where you are slowing down and will need to accelerate again in a lower gear (like when you are turning onto another road with out stopping). In this case, heal/toeing from say 4th to 2nd can make you a smoother driver and be fun. Race car drivers do this to prevent upsetting the balance of their car (as 99 alluded to).

I do find that double clutching into 1st is helpful sometimes but does seem pointless in other gears. My luck always leaves me rolling up to a red light when it changes to green going too slow for 2nd but still faster than the 1st gear syncros want.

Seth

As a quick safety reminder, whenever you are slowing down for a stop light, you SHOULD have the car in gear, and preferably engine brake to slow down. While this may add a slight bit of wear to the syncros and clutch (SLIGHT) if for instance, you are about to be rear ended, having it in the correct gear with the clutchout makes getting out of the way a much easier process...

It pains me to see people at stoplights let the clutch out, shifter in nuetral, and put the E-brake on. So much to do before you'd be able to move. Not everyone will agree with this, however not everyone avoids getting rear ended either.

 

[ChiGGz]

As a quick safety reminder, whenever you are slowing down for a stop light, you SHOULD have the car in gear, and preferably engine brake to slow down. While this may add a slight bit of wear to the syncros and clutch (SLIGHT) if for instance, you are about to be rear ended, having it in the correct gear with the clutchout makes getting out of the way a much easier process...

It pains me to see people at stoplights let the clutch out, shifter in nuetral, and put the E-brake on. So much to do before you'd be able to move. Not everyone will agree with this, however not everyone avoids getting rear ended either.

E-braking might not be a good idea esp if there is no one at a full stop behind you yet, however, I do agree with at least putting the car in neutral and using your brakes. I wouldnt want to put excess pressure on the crank for a whole two minutes while waiting for the light to turn. Multiply this for every Red light you encounter in a day

 

[99gst_racer]

Sounds to me like he was talking about riding the car in neutral as opposed to downshifting and riding out the clutch -> repeat till < 5 mph in which case it comes down to this, what costs more to replace, your worn clutch from excessive clutch deceleration or your brakes? 99gst_racer seems to be talking about revmatching while upshifting.

Correct me if im wrong, these two posts have me a little confused.

Rev matching helps for upshifting and downshifting. Even though rev matching while downshifting does put much less wear and tear on the clutch disc, I still perfer using my brakes to do most of the deceleration. But if I had to simply downshift from 4th to 2nd for a speed limit change, I always rev match.

I assure you - One month driving on a lightweight flywheel, you'll find yourself doing it out of habit just because it feels healthier.

99 is talking about the case where you are slowing down and will need to accelerate again in a lower gear (like when you are turning onto another road with out stopping). In this case, heal/toeing from say 4th to 2nd can make you a smoother driver and be fun. Race car drivers do this to prevent upsetting the balance of their car (as 99 alluded to).

Exactly.

 

[nightstocker99]

Last night I was reading an issue of Super Street and came across an ad for Nippon Power and in the ad there was a picture of a Fidanza Flywheel that listed all the reasons to buy the flywheel. One of the reasons was that it increased your horse power. Now for as much as I know about flywheels (I am going to go buy one today) I found nothing about them increasing the HP. So either Nippon Power is false advertising or I just learned something new.

So just give me some input on what you guys know!

Thanks

 

[nightstocker99]

nipponpower.com is either out of business or they are making a new website so you can't visit the website sorry I just found that out!

 

[Splitpi]

I wouldn't say they "make" horsepower. But I would say they free up weight on the rotating assembly of your engine, thus saving horsepower. How much? I don't know I would think it all depends on your setup. Could be none, could be a couple or dozen.

 

[my98GST]

its kind of in a sense the same as a better clutch. It frees up more power and makes it more possible to put it down to the ground

 

[95blackGsTurbo]

Flywheels can add horsepower. They do this by making the flywheel lighter so it is easier for the crank to turn. Less rotating mass means it doesn't take as much effort to spin it and if it doesn't take as much effort to spin it, it will spin faster with the same amount of effort. Taking 3-4 pounds off of a rotating assembly will help out tremendously. I could feel the difference when I went from my stock flywheel to lightened ACT one.

 

[xveganxcowboyx]

"making" horse power is kind of misleading. Your engine itself should be producing the exact same power output. You will see a horse power increase to the wheels, because less is used turning a heavy flywheel.

 

[95blackGsTurbo]

No it is actually making more power. Just like when we use SCAT lightwieght cranks in some race motors. On the a engine dyno one of those is worth 33hp. Just using one that is 8lbs. lighter too. It is using the same amount of effort but it netting more power because of the lightness of the rotating assembly.

 

[nightstocker99]

Very interesting keep it coming!

Ok so lets say that your car is running 200 HP at the fly about how much would it be at the WHP, would it be like 200 WHP or less.

 

[larsenracing]

If you are running 200hp at the fly then you will be running less to the wheels.

 

[95blackGsTurbo]

I'll edit my previous post quick by saying it free's up power. And if you are putting 200 to the flywheel on a FWD it is probably 190ish to the ground and 175-180 on an AWD. Have to factor in drivetrain loss.

 

[nightstocker99]

OK I see now, so it doesn't really give you more more it just taps into power that was there but not used, and it lets you use it.

Right?

 

[Corpssnare]

Basically you'll have the same horsepower at the crank, but a little more at the wheels with a lighter flywheel.

 

[SkyLineGtR-R34]

Basically you'll have the same horsepower at the crank, but a little more at the wheels with a lighter flywheel.

I agreee
lighter flywheel will also help you rev up faster

 

[Matrixhunter]

Hey doing 5-speed swap almost got all the parts just need a flywheel what it the benefit of going with a fidanza flywheel over stock? other than being lighter. Thanks