THSBXRX

I've been considering installing a lighter flywheel but here mixed reviews. I hear that the RPM drop off sucks. I drive a 130 mile a day commute. Any input or suggestions would be helpful.

draxcaliber

i have one in my tC. it takes some getting used to, but i stopped noticing a difference a long time ago. didn't bother me when i daily drove my tC.

ColonelSanders85

iTrader: (10)

I'm considering going the same direction......what do you mean it takes some getting used to? Like you have to rev it higher to get going? Do you lose low end torque or gain any top end acceleration? Does the gas mileage get any better or worse?

TrevorS

iTrader: (1)

I don't have one and am not interested in getting one, but it's pretty clear you can expect your engine to have less rotational momentum when engaging gears (including standing start -- more likely to stall). As with a lightweight crank pulley, you can expect better throttle response (and certainly more so), but no actual power is either added or lost, likewise MPG. So, if you need the engine to respond more strongly to throttle adjustments, then (presuming you've already done everything else to enhance throttle response), this is certainly a possibility !

Roller_Toaster

iTrader: (1)

I put one in my old bmw z3 1.9. Went from a 38 lb flywheel to a 12 lb. It was incredible, and felt like I had added 20whp to the car (I hadn't, I had just taken out a massive amount of rotational mass).

I LOVED it...until I drove on the highway. On off throttle deceleration, the flywheel chatter was horrible...it sounded like the transmission was about to fall apart. Unfortunately, I drove on the highway nearly ever day. If I hadn't I probably never would have noticed it.

I never had any problems with it at all, just typical flywheel chatter that I wasn't aware of until I installed it.

Since I still have to drive just as far, I won't be getting one for the xb2. I'm sure it will REALLY liven up the throttle, and make it feel much better though.

oreoremix42

I never took notice to the MPG but it will increase power to the ground. It honestly does not take any extra effort to not stall. It is more suitable for a turbo car as it will help spool the turbos faster. It does take adjusting as when you down ____ you really have nothing stopping you from slamming it into a gear. I think its much more fun to drive with and on ym old car the time was 15 years old never had a chatter ran just as smooth just clutch and tranny feel were a ton different. I would recommened getting one!!!

You had chatter? Are you sure thats not because of your car not the flywheel? I never had an issue when I ran one on my car. A flywheel should really only rattle if it is out of balance but I could be mistaken.

Roller_Toaster

iTrader: (1)

Every manufacturer of lightweight flywheels I've contacted (including the one specific to the bmw's) said that chatter is a standard by-product of a lightweight flywheel. Usually the lighter you go, the worse it gets. (thats what I've been told, at least)

I asked fidanza about their xb2 flywheel and they said that chatter is inevitable when lightening a fairly heavy flywheel.

oreoremix42

Hmm weird I had a fidanza never noticed it. Altho I had a lot of chatter period from a stripped down car. might not of noticed it.

NocturnalxRS6

Actually, turbo cars like heavier flywheels, easier to launch, bog less, builds boost a bit quicker and keeps more boost during shifts. Now N/A cars on the hand especially 4 bangers like lighter flywheels.

As far as clutch/flywheel chatter goes I have had the best luck with ACT but I dont know if they make anything for scion.

oreoremix42

It seems you are correct from what the internet says but it is also hard to find any true facts. I sent an email to a world renowned porsche builder. Has the 2nd fastest porsche in the world i believe. Hopefully I will hear back from them because I am hearing a wide variety of answer on this topic.

oreoremix42

In regards to a turbo car according to Markski@911tuning.com

"HI,
a LWFW will help a little with spool... worth the money? no.... its also causes the car to die sometimes at idle or cruising.. I do not recommend them anymore...
mark"


http://911tuning.com/

TrevorS

iTrader: (1)

As far as a lightweight flywheel delivering more power to the ground, that's only true in the same sense as a lightweight pulley, which is to say it only makes a difference while rpm is fairly quickly changing (like on a dyno). It makes no power, it just frees up some during transient conditions. It makes the car no faster at constant speed, and makes stalling more likely from a standing start. It will also effect rpm behavior at shift points, depending on ECU programming, it could drop more quickly, or could rev higher between gears.

NocturnalxRS6

"It causes the car to die sometimes at idle or while cruising" It can't die at idle, it wouldnt even be engaged.. LMAO!

I wonder why they make light weight flywheels then. And why so many are sold... hmmm. I speak fom person experience on these things, fact is you'll probably never find a fact about it.

Bottom line is though, is that it's a Scion xb, It's a fwd wagon that will never be fast or sporty or handle good for the money. For my Scion I would never even think about doing a flywheel

My answer to the OP though is NO, dont waste your time with it.

NocturnalxRS6

Sorry if I'm being offensive lol but I'm going to add a couple more things for clarification.

Simply put. If you want to understand how a flywheel will basically feel take 30lb. wheels and put them on your car.. Then take 15lb. wheels and put them on your car.. How does it feel now? (taking pedal feel and sensitivity out of the equation)

Last thing, your car will never die while cruising with a light weight flywheel. Simply put. Havent we all push started a car? if you dropped the clutch going into 2nd while coasting at 800rpms or even with the engine stalled already it might bark the tires, but it won't die, I promise.

oreoremix42

No offense nocturnal but I would question you over that gentleman I quoted. You also have to keep in mind he is coming from heavy experience with porsches not a scion. So maybe yes with his LWFW setups it can cause the car to die. I don't know where that info comes from but his experience and knowledge heavily outweighs anyone on this forum next to maybe a few

Edit: gotta also remember his application will be completely different then ours.

NocturnalxRS6

Application has nothing to do with it, all flywheels work off of the same principle period.

I think you should e-mail Mark again and have him clarify some things for you so your not confusing people in this thread with misunderstood 3rd party information.

TrevorS

iTrader: (1)

Actually, when idling, the flywheel is engaged, it's part of the rotating assembly. With a lightweight flywheel, any significant roughness (or caminess) in the idle can result in the engine stalling. The OE flywheel provides much greater rotational momentum to overcome such idiosyncrosies.
I wouldn't expect it to die when actually cruising (engine engaged to drivetrain and vehicle moving) since vehicle momentum will offset loss of flywheel angular momentum, but coasting (which I do frequently) would be a different story.

However, with a stock 2AZ-FE, I can't easily imagine it dying at idle due to a lightweight flywheel. I just see greater likelihood of stalling when starting from a stop and possibly undesirable rpm behavior at shifts.

NocturnalxRS6

The flywheel is NOT engaged, it may be bolted to the crank but is not engaged with anything until your press it against the clutch disc with your foot, hence loading the engine down and moving the car. Edit: I guess if the car is in neutral then yeah.

Most caminess or rough idle will be due to an improperly machined/installed flywheel.

Most of the engines momentum/balance comes directly from the crank shaft, they are extremely heavy and weighted if you've never touched one before.

Did you know an engine can run without a flywheel? I believe some extreme race cars and boats do not use a flywheel, just a crank bolted to a drive shaft lol, I'm sure theres some diagrams out there but I'm to lazy to post a pic.

I'm also wondering if you've actually done a clutch job or if your just copy/pasting from the internet.

TrevorS

iTrader: (1)

As part of the rotating assembly and engine proper, the flywheel is always engaged, just as are the pistons, crank, connecting rods, camshafts, crank pulley, etc.

What changes when shifting out of idle, is the rotating assembly (obviously including the flywheel) is clutched (friction puck or hydraulic) to the transaxle and the rest of the drivetrain. The flywheel may be the transfer point of rotational energy to the rest of the drive train, but it remains part of the engine rotating assembly and therefore engaged -- if it wasn't, it would not be spinning whenever the engine is running.
I'm coming from the assumption that any part I purchase to install will be vetted for quality. Performance built engines tend to run in a syncopated or erratic fashion at idle -- however if there were issues with the engine or the idle were set too low, there could still be a problem.

Both are heavy, that isn't at issue.

Yes, of course an engine can possibly idle without a flywheel, it just depends on the setup. As I already said, it's unlikely the 2AZ-FE would have a problem idling with a lightweight flywheel.

No, I haven't done a clutch job, but why does that infer I'm copying and pasting? Everything I've said is 100% true and I'm not sitting here looking up things on Wikipedia.

NocturnalxRS6

For everyone out there, when flywheel and engaged are used in the same sentence we are talking about the flywheel being engaged to the clutch OR VISE VIRSA.

No one talks about the flywheel being engaged to the engine because that is already utterly obvious.

Edit: Personally I would call it installed, because in order for to be disengaged it has to be un-installed.