FTO AUSTRALIA

does anyone know much about engine balancing and the affect of lightened components? im thinking of getting a lightened flywheel except im unsure about stuffing up the balancing...

i know that if you stuff around with crank pulley weights etc, you can stuiff the balancing of the engine, but does the same thing happen with lightened flywheels? being on the other side of the engine, i would assume that it does have some effect but i cant find enough solid information on the net to support it...there are too many conflicting arguments out there

anyone got any ideas?

thanks

simon

having read your question several times I'm wondering what you really mean by balancing but here's my 2c anyway

engine balancing and lightening the flywheel are 2 different things in a way...

engine balancing is like a blueprinting process by which all reciprocal parts of the engine incl the crank, valvetrain, cylinders are 'balanced' (i can't think of a better word at the moment).

if you get lighter parts for the engine (ie: titanium conrods, valvesprings, forged pistons etc) which are much stronger, then you will have a bulletproof engine that will produce HP more reliably.

a lightened flywheel is usually matched to an appropriate performance clutch upgrade. If you get a lightened flywheel by itself and fit it onto the std clutch, you won't find much noticeable difference in terms of engine performance. You may feel a slight difference in drivability (easier to rev), but bear in mind that if an excessively lightened flywheel will make it easier to lose torque when climbing on a hill.

...so uh, does that help in any way?

umm yeah kinda...maybe i used the wrong term in "engine balancing"

ive read a lot of literature that indicates that if you use a lightened crank pulley, it can stuff up your engine harmonics....i was wondering if you use a lightened flywheel, wouldnt it change the balance on the crankshaft too? seeing as the flywheel is on the opposite side of the crankshaft as the crank pulley....

it just makes sense to me that if you lighten the crank pulley and that has a detrimental affect on the harmonics of the engine, then if you lighten the flywheel (which im guessing is on the other side of the crank shaft), wouldnt that also have a detrimental affect on the harmonics of the engine? im need someone to tell me i'm right or so wrong that i should be in a mental assylum before i continue considering doing a lightweight flywheel at the same time as an upgraded clutch...im going the heavy duty exedy too

Lightening the flywheel will cause the engine to loose torque,as it has less inertia.Lightening the flywheel wont cause any problems in itself so long as the flywheel is rebalanced after it has been machined.Personally i wouldnt lighten the flywheel as i doubt you would have any performance gain in fact by reducing the engines allready low torque output you might even reduce the cars performance!

Let me admit upfront that I don't know a lot about flywheels, but from the little I do understand I think it has trade offs.

I agree with Scracy's comments that a) it's probably not worthwhile doing (especially in relation to other performance gains for the same money) and b) it will reduce inertia.

But on this point of inertia (or the ability to keep the same motion without applying an external force) I think this would work both ways, and would primarily come into play when accelerating and changing gears.

Given that inertia relates to a change in motion, it would therefore suggest that a lightened flywheel will have no impact when driving at a constant speed, such as freeway driving. But it would appear that when it comes to accelerating that in theory, it would be slightly quicker, and likewise when decelerating it too would be slightly quicker. But here is the trade off, this would mean that although you can get the revs up faster, as soon as you put your foot on the clutch, they will also fall faster, making it harder to stay within the power-band rev-range, when changing gears. So unless you are lightning fast with your gear changes (even faster than what you can do now) your performance may be worse, as by the time you change into the next gear your revs will be lower.

While I could understand the advantages to this for a race car or drag car, where tiny changes in speed can mean the difference between winning and loosing, personally I would spend the dollars else where for a street car as I just don't think a lightened flywheel will be that noticeable.

when you get the heavy duty clutch from Exedy, there is no need to get a lightened flywheel... the existing flywheel are machined and balanced before the entire assembly is fitted back in.

and Scracy is right - the car in itself can do with more torque as is, not less torque... hehehe

GPXXX wrote:when you get the heavy duty clutch from Exedy, there is no need to get a lightened flywheel... the existing flywheel are machined and balanced before the entire assembly is fitted back in.

And of course if u in Vic u know where to get it done heeeheehehe

So Kev, is your mate going to look after all FTO owners in VIC, and does he do normal servicing too? I've got a 90KM service due in the next month or so. I like to find someone good and willing to offer a better deal

Yeah he do all kind of service, including tuning & upgrade on all Jap imports. Well except for dyno test, cause he sold it 2 his mate. He does compiles plate for four importers, plus he use to be a Porches Racing mechanic before he open up his own shop.

Anyway, let me know when u need your car to be service, & i ask him when he can book you in. I guarantee he look after you, & any other FTO members.

hmmm thanks for the info guys....

just on a side note, you mentioned mods that you would do with the extra 500-600 odd for a lightweight flywheel...what would you suggest?

i already have headers, exhaust, airbox/CAI, suspension mods, iridium sparkies, exedy clutch to come....the problem i see going forward is that even the tiniest performance gains are going to cost increasingly more and more money but hey...thats NA

what do you guys think about thinner head gaskets or porting and polishing? worth it? not worth it? it already has prety high compression so maybe a thinner head gasket wouldnt be very good bang for buck??

im thinking variable cam gears with some good tuning....

thanks again

simon

Hey mate,
Unique want to do a lightened flywheel i would recommend going and speaking to John there. as the test car i'm sure he'll do you a good deal.

They have already made lightened (and stronger) flywheel's for Skylines and 300's so they know what they are doing they just need the flywheel for a day or two to measure and make a prototype.