PX29

FARK x4...!!

I recieved my exhaust through Nengun a couple of days ago. They said 4-5 weeks, and I got it in a month...so I'm happy. I've also used greenline. Cheers,

Hope you dont think you get full carbon backing for the extra $60..!!?? I'd recommend GTR seats over any cheepo's.

^^^^...I'm with you on that one mate...hehehe. I recommend putting up a shed in backyard if you got enough space and buy your own tools. High initial costs but worth it in the long run........ONLY if you make use of it though...!!

At the end of the day, one would ultimately want laminar flow though the inlet and outlet piping. This kind of flow would get the air from turbo to plenum with the least amount of energy. This laminar gaseous flow obviously isnt possible under the given conditions and hence all you can do is reduce the pressure drop ie larger piping, smoother transitions, bigger cooler etc, but with this you will get a laggier throttle response. The scope of thermodynamics extends far beyond uni engineering units..!! (though this is the basics)

Thanks, but I'm after a 30/32 chassis. I'm also after a cheap 7x5 trailer......anyone...?? Cheers,

Thanks for all comments guys, if anyone is selling a kart please let me know. Cheers,

How did you find push starting the kart on your own..?...or did you always have a person with you..? Cheers,

Didnt know about this B grade licence for 125's, is this for senior class also or only for the junior classes.? Cheers,

Thanks, I've been to a few club day meets down at Henderson and looking at getting a 30/32mm chassis with a Rotax/Leopard. Which catergory did you race..? I wanted to go the 100S but it seems too troublesome needing a push start all the time, I want to be able to go out on my own and do a few laps when I want without needing someone to push start me all the time. Thats why I'm going the 125's. Cheers,

Hey guys, Anyone here do karting.?. I'm looking at getting a kart and start practicing....Need some tips... Cheers,

Apart from the smartest thing to do (buying a house), I recon it would take a lot of mods to get a Gtst to performe power and handling wise to match a standard GTR - and even then you dont have 4wd, then you got the interior differences.........and the main thing.....the BADGE which signifies a long proud history when it all began in Bathurst....hehehe

Put a pic of a GTR up and a money jar under it......A BIG ONE..!heheh

You can do all the mods on a gtst, but whats the point when you got no traction. Get a GTR.......DO IT..... Then again, maybe I'm biased.

Yes the calcs proove something, but taking into all other factors its up to the individual if they think its worth doing the mod. I Agree with your statements there djr81. Cheers.

I dont know what you've done there..???. Yes the extra energy is stored with heavier flywheel hence reducing energy available for acceleration. Do you still disagree that the 100kg figure is wrong or insignificant..??... Yes more power hinders traction in first.......yet we still want more power.......so then we get wider tyres.. I agree there are many other factors to take into account, driveability, traction, etc.... its up to the individual at the end of the day. We could go into this alot further but I think thats enough.....

Ok......here's the calcs.. This is just the way I did it, I'm sure there are other ways also. Just put in the values for flywheel mass (Mf), flywheel radius, diff ratio, gear ratio and tyre radius and the result (Mc) is the equivalent mass "on" the car for that gear ratio. So if your flywheel has a reduced outer mass of 5kg compared to standard, then as posted before you get an overall reduction of 5x20kg = 100kgs (1st gear) - 32gtr (assuming flywheel radius 15cm, tyre radius = 30cm). Does anyone know the flywheel diameter for r32gtr..? Cheers, FlywheelCalcs.pdf

I dont know how to add attachments to the post, doesnt seem to work. I basically assumed that if we have two identical cars and one had additional mass on the flywheel and the other has an addditional mass on the car which allowed both to accelerate at the same rate, then at any point in time, both cars will have the same kinetic energy. Equating kinetic energy equations for the 2 cars gives a result which relates the additional flywheel mass to the mass added on car. This shows how the flywheel mass effects the load the car experiences. Look what you started MR R34...... Cheers.

Based on the following details, see the "Equivalent" mass decrease on car per 1kg reduction on the rim of a flywheel of diameter 30cm. For R32 GTR Diff Ratio: 4.111 Gear Ratios 1st: 3.215 = 22.8kg 2nd: 1.925 = 8.83kg 3rd: 1.302 = 4.58kg 4th: 1 = 3.11kg 5th: 0.752 = 2.19kg Reverse: 3.369 = 24.98kg These figures may sound impressive, but you have to remember that this is only valid for mass removed from the outer edge of the flywheel. I'm not sure on the geometrical size/weight of the standard & nismo flywheels. So just by finding the difference in weight between standard and aftermarket flywheels and multiplying by the above figures isnt accurate. Anyway, this shows that reduction in flywheel mass does in my opinion make a significant dercrease in "effective" total car mass in the lower gears. Far from the "1 milk bottle on the flywheel = 5 milk bottles in the car" analogy. I guess we will find out once MR R34 gets back to us. Can someone confirm these figures as a check.......? cheers.

Ok, I just didnt want to turn this into an Eng calcs thread. Thought the explanations was enough without going into the calcs........BUT bring it ON.... Cheers.

The equivalent mass reduction on the car is far more than 5kg, its more like 20kg/1kg flywheel reduction.....this value is highly dependent on the gear/diff ratio as I mentioned before. Any rotating parts in an engine absorbs the energy which it produces, lowering the mass of rotating engine components allows for more of the energy to be transfered to the wheels. So if you took 5kg of the outer diameter of a flywheel, then the "Equivelant" mass reduction is in the order of 100kg (approx in 1st Gear).......These are only approx figures guys. MR R34, Yes if I was in your position I would get it. Make sure you buy a good quality flywheel and DONT get the standard one lightened (Well unless you really really trust the machinist). Let us know how you go mate.... Cheers.

hahaha.....We still see things differently and it seems like my explanations are not good enough to make you agree. Fair enough, when I got time I'll hit you up with a more detailed explanation. P.S. Some "converted" ones dont know why they converted. Cheers,

Mate, I dont know how else to explain the effect a lightweight flywheel has on acceleration.....I'm not saying that your plots are wrong, but looking at it diagramatically the difference in acceleration may "seem" insignificant between the two cars, but you cant possibly try and tell me that you cant "feel" the difference in Gee's between the two cars....especially when one has 130rwhp more...? Also the fact that the data-logging was carried out around a track makes it abit more complicated to compare, since your not in first gear much(when light FWheel is most effective) and other factors. I dont agree on your 2Litre milk bottle analogy as explained in earlier posts. Terminal velocity comparisons are completely useless when trying to quantify lightweight flywheel influences. I understand that the difference in speeds at the end of the track is minimal (7km/hr) for the extra 130rwhp, but this is due to many other factors such as engine efficiency, increaced mechanical losses and the extra energy to get 1400kg from 204km/hr to 211km/hr is ALOT considering the high areodynamic drag experienced at these speeds...!! I think we are going of the topic here. If its for the street, then in my opinion you will feel the difference in acceleration, but if for the track and your trying to cut 0.5 sec/lap then yes the flywheel makes a very small impact on times.! If you want, I'll take you for a spin in my GTR and then you can pay for a lightweight flywheel to be put in and if you cant "feel" the difference, I'll give you your money back..!! Cheers.

djr81, are you implying that from your datalogging the 435rwhp gtr has similar acceleration to the 305rwhp gtr and hence suggesting that the lightweight flywheel is insignificant..??...I must be missing something here.. Curious about your findings..?

You may need to adjust your idle rpm alittle higher or atleast when taking off you need to increase your rpm or you may stall. Driving at low speeds around the city may be uncomfortable, as taking off and changing gears will not be as smooth. You will need to get used to providing the extra revs just before engaging the clutch to give the now lighter flywheel the extra momentum. Basically the loads transfered between the drive-train and engine would not be "smoothed out" as much since a heavier flywheel can maintain the momuntum longer. You need to compromise between the driveability and performance. On the other hand, too light a flywheel will be a disadvantage. Engines are designed a way for a reason, the engineers decide on a suitable geometrical size and weight of a flywheel to optimise performance, driveability and cost. If you want to pay more and sacrifice alittle driveability for the increaced performance then all I can say is go for it..! This is just my opinion.....and not everyone is always right (inc Me), so do your research and make a decision..........after all it is YOUR car. Cheers,