djr81

I have a couple of them. They are in good condition.... http://www.skylinesaustralia.com/forums/in...howtopic=178971

No I was pretty much resigned to having to cough up for some 18" LM's or similar. Just trying to figure out a way of buying some F50 callipers & matching them to some rotors without having to pay stupid money for Brembo rotors. It looks like Stoptech will work as well as Biot. I just need some calliper bracket drawings to make some progress.

Well sort of. But the aftermarket caliper is held on by a bracket which determines its offset. Logically this will be paired with the particular hat to put the centreline of the rotor the same as the caliper. I guess what I am saying is there is not necessarilly a guarantee that Biot use the same centreline as, say Brembo or anyone else. I just don't want to be caught with a wrongly offset calliper bracket. Does that make sense?

More talking about this sort of thing. See how the centreline for the new larger rotor is different to that of the old. 98_647_2470_01.pdf

Well it is a bit of a punt without having the drawings. The second problem is that the offset of the rotor may be different between the brands. Which would mean your brackets are then useless aswell. Why can't they just provide all of the information like the kindly folk at AP Racing do? cp5555_1cd.pdf

My basic worry is this: You usually only find out you have a cracked rotor less than a week before an event because you are too damned lazy to do your preventative maintenance and/or servicing in time. Which makes it hard to get a replacement rotor ex Japan. I guess my preference is for local & cheap (yeah, no chance) Secondly I have some issues with trying to translate the website. Babelfish gives you the literal translation, but whilst it looks like English I have NFI what much of it is trying to say. But yes the rear lined hats look the shit. Stuffed if I can figure out what they cost, however. Nor what half the options are. Still how much do you use your handbrake?

Bought locally, good sized Brembo gear 14" by 1.25" rotor, F50 calliper is on the not so fun side of $5k. On the upside the Stoptech range of rotors appears to be a nearly exact match for the Brembos. The hats even appear to be the same. http://www.stoptech.com/products/img/0605A...orDataSheet.pdf

Sent you a PM about the rears. Are they still available???

The filter you are referring to (the Ryco Z145A or equivalent) is off an RB30 motor, so VL Commodores & R31 Skylines. It is larger that the "proper" Nissan item, but if you have had a good look at the Nissan item (I have a spare at home) you end up thinking "Yuck, not going to use that". Or similar sounding words. The larger filter is better in that it can hold more filth before it degrades in performance. Downside is that they are a pain in the arse to fit past the HICAS unit. Just about every filter you can buy has an anti drain back valve. It is just a bit of rubber that stops the oil draining out fron the filter. In any case filters are basically just paper/cardboard so I can't for the life of me figure out what all the fuss is about.

Can you post a photo of the rears? Also are you willing to split them as I am only after a rear pair. If so how much?

Thanks for the offer, Baron. I have some thinking to do... The first question question is F40's on a 332 rotor, or the F50 on a 355 rotor? Then which handbag should I get the hats to match?

Well my point was that, for me, I get wheelspin (see the ragged blue line on the data log) on corner exit in third. So the lighter flywheel isn't helping here & in anycase doesn't make much of a difference in the higher gears. The 100kg is nominal & as I said is not relevant for me because in the second or so (Based on a 0 to 100km/h time of 4 seconds) the car is in first barely any of it is with traction at the wheels. Maybe we can agree on some motherhood statements. A heavier flywheel will store more energy than its lighter equivalent. A lighter flywheel will make in gear acceleration slightly quicker, but only if you have traction - otherwise it is irrelevent. The benefit of a lighter flywheel is more substantial in lower gears. The relationship is proprtional to the square of the gear ratios. You get the stored energy from the flywheel back when you change up a gear. A heavier flywheel makes the car easier to drive. A lighter flywheel makes the motor more responsive when the clutch is depressed. A heavier or a lighter flywheel MAKES ABSOLUTELY NO DIFFERENCE to the amount of torque and horsepower your car produces. If you have the choice, the cash & can live with the slight driveability losses then get one. Calculations are both fun & tell you things about the real world where you would otherwise have to rely on peoples opinions. As can be seen from this thread there are as many opinions as people. Given that everyone disagrees on nearly everything you have to accept that most people are wrong. The hard part is figuring out who...

Well personally I blame McLarens short wheelbase. Really. Works like this. Short wheelbase means more load taken by the front wheels (relative so a longer version). Which in turn requires more front downforce. Hence more chance of front tyre dmamge... As an aside it also means your front wing design needs to be in such a way to avoid loss of downforce when the wheels are turned (=> less area near the end plates is availalble). Which inturn means you need a daft extra wing section that goes over the nosecone.

Much easier if you use the figures for km/h per 1000rpm. Using the same formula. 4000rpm in 4th = 114KM/H. So Ek (linear) = 501J/kg. Ek (rotational) = 987J/kg based on a flywheel of 300 dia, uniform thickness. So just less than twice as important. Tellingly, based on a wet weight with driver of an R32 Gt-R being 1600kg, the Ek of the mass of the car (without any rotational component) is 2,550,000J. So our gain of 987J/kg is pretty inconsequential. Also it is worth noting that you are storing energy in the flywheel, so when you change gear you get it back. It isn't lost unless you need to put your foot on the brakes. Lastly, in 1st it is pretty irrelevent given nearly everyone stuggles with traction. For alot of people this is true of second.

Well any company that names their product for an obscure dimensionless number has my vote. Stickers would just be a bonus. http://en.wikipedia.org/wiki/Biot_Number More importantly, how can I get my hands on this stuff? Appears to be cheaper/friendlier than the straight up Brembo kits...

Easy. Click reply (not fast reply). Type some stuff in. Find the browse button which turns up. Click it, then find your jpeg file. Click upload. Wait for a bit. Click add reply. Job done

Yeah. I got different numbers. MAybe you need to show how you workerd them out. My method was. Find gearing in km/h per 1000rpm. Select a speed an/or a speed range (doesn't matter) Work out how much Kinetic energy (or change in) a 1kg mass has in a llinear circumstance. Work out its equivalent for the flywheel. Divide one by the other. I got slightly less than 2 for the car in fourth.

Well the explanation wasn't the issue. The conclusion & the equivalence was at issue. Anyway I don't have the thickness & diameter for the RB26 flywheels, so I can't do any calcs..... Anyone know how big they are???

Oh. Well I was going to get a stroker kit for my Rb26. But seeing as it will add the equivalent of about 100kg of mass to the car I guess it will just make it slower. (Joke, don't get angry) If you really (really, really) want & you can find the flywheel dimensions (diameter, thickness) I can do the calculation to and thereby find an equivalent mass (in each gear) for some flywheel lightening. Oh and don't forget when you change up a gear whatever energy is stored in the drivetrain is then returned to the car...

http://www.skylinesaustralia.com/forums/in...=169697&hl=

If you have the money, yes.

Well for my 10 cents worth I would decontent the car. What the hell does that mean? Simply find some ok rims & put them on your GT-R. Then advertise it for say, $20k. Sell the Gt-R rims seperately for $2k. You should get much more interest at a lower price. There again sometimes it is just easier to take the pain & get on with life....

I don't disagree with your explanation, just your conclusion.

Yes. If you are replacing it anyway & can live with the lesser flywheel effect when you are driving/launching the car then put one in. The second paragraph has me baffled, however. The general rule of thumb is that for a less powerful car you will be using all of its power (however much that may be) more often. So the gains of a lightened flywheel will be more important (Although as I have tried to explain, ad nauseam, not significant) If you want to confuse the mechanic you could ask him what the "minimum standard" is.

Well try this plot then. What I am saying is that a near on 45% gain in rwhp doesn't produce anything like that difference in acceleration. A change in mass (yes rotating mass) that is much less than one percent of the total will have a proportionally smaller affect on the acceleration. My point is that I characterise that change as being negligible. But you are right, ofcourse you can feel the difference of much more powerful engine - although you do get used to it really quickly. You are correct in saying it is more significant in lower gears at lower speeds (less aero drag for one & more rpm per km/h), but this is fairly unimportant because you are invariably traction limited. Well up to you, but I was trying to quantify the change & give people an idea of what sort of order of magnitude to expect. Make 5kg if you like, but you don't chuck 5kg worth of gear on your car and suddenly turn it into a slug. All of which goes to show the minor influence the flywheel has on proceedings. Which is my point. Thanks for theo offer, but budget is a bit tight this month. Anyway I already have a lightened flywheel, so to a degree you are preaching to the converted.