corolla_nut Posted October 28, 2009 Report Share Posted October 28, 2009 so howd you do at the gymkhana? Khanacross was really interesting this time around. Not only was the car a totally different animal, it was also raining! The axle tramp has disappeared almost completely and the car now gains traction and goes! The handling or ride does not appear to be adversely affected by the change in height and rigidity either. Lightened flywheels are the bomb! In places where i would normally only ever make it to in first on the track i was into 2nd and powering on, it spools up so quickly now - half the time i got it 8grand rpm so quickly i didn't realise how much the poor thing was revving before i was changing gears. If i can ever stop hitting witches hats and garages (an extra 5 and 10 seconds a pop respectively) I would have come around 4th or 5th, but due to hitting several in the last 1/2 of the day i came 11th out of 21. Cheers Quote Link to comment Share on other sites More sharing options...
SLO-030 Posted October 28, 2009 Report Share Posted October 28, 2009 How much came off the flywheel? pics? Quote Link to comment Share on other sites More sharing options...
corolla_nut Posted October 28, 2009 Report Share Posted October 28, 2009 very very minimal axle tramp (hardly any at all really) in the khanacross... combine this with 2.5kg less weight on the flywheel and a lot of rain and it made for a very fun day. Kylie was happily going places in 2nd gear at full noise (and good accelleration) where she could only use 1st before! Robert. Quote Link to comment Share on other sites More sharing options...
Boost+k Posted October 28, 2009 Report Share Posted October 28, 2009 I'm glad it worked out for ya... you can probally get rid of any left over tramp by playing with shocks Quote Link to comment Share on other sites More sharing options...
corolla_nut Posted October 28, 2009 Report Share Posted October 28, 2009 Robinson Tool Makers in Bathurst machined 2.5kg off the flywheel and balanced it with the clutch. They took the lip off one side and skimmed it and then scalloped the other - we weren't expecting nearly as much machining as that but are really happy with the job and how it performs :wink: Better than the engineering place in town who told us they could machine it but wouldn't and gave a Rob a big lecture how lightening flywheels is dangerous and he didn't want us coming back suing him or whatever. For f@$ks sake it's a racecar, we both know how to drive it and Rob's a mechanic - you'd think we'd have a little bit of an idea and an attitude of "Oh shit! I fuct up - maybe that's my fault and not the machine shops?" Anyway after giving Rob the big spiel about that he told him that he could get it machined elsewhere and bring it back to said engineering place for balancing...Yeah right!!! Quote Link to comment Share on other sites More sharing options...
styler Posted October 29, 2009 Report Share Posted October 29, 2009 nice to see the lightened flywheel worked out well, they are a really good mod but id recommend a scatter shield of some sorts over the bellhousing for a heavily lightened cast wheel at high rpm as they honestly do fail and you don't want to teach you legs that lesson! Quote Link to comment Share on other sites More sharing options...
KE55PIG Posted October 29, 2009 Report Share Posted October 29, 2009 2.5kg of isnt that much lightning though really is it ? Quote Link to comment Share on other sites More sharing options...
towe001 Posted October 29, 2009 Report Share Posted October 29, 2009 Not going to go into it all cause its been done over before. But try spinning two objects and one of them weighs about 2.5 kg less and it doesn't seam make but it sure spins up quicker. Quote Link to comment Share on other sites More sharing options...
SLO-030 Posted October 29, 2009 Report Share Posted October 29, 2009 I wonder how it'd be on a daily driven car? with the loss of interia? Quote Link to comment Share on other sites More sharing options...
Felix Posted October 29, 2009 Report Share Posted October 29, 2009 As previously stated a scattershield should be used, especially with a cast iron flywheel. Quote Link to comment Share on other sites More sharing options...
SLO-030 Posted October 29, 2009 Report Share Posted October 29, 2009 Remember thats a rotor which woulda pulled in excess of 10,000rpm? But one of the things id do if i got a lightened flywheel would be a scatter sheild. I like my feet where they are :wink: Quote Link to comment Share on other sites More sharing options...
Felix Posted October 29, 2009 Report Share Posted October 29, 2009 (edited) Remember thats a rotor which woulda pulled in excess of 10,000rpm? I realise that. The point is, look what can happen if a flywheel lets go. We are talking about a 4k flywheel which the factory would have forseen maybe 7000 rpm having 2.5kg's taken out of it. Not hard for a 4k with a warm cam to pull over 8 grand. Even if you don't mean it, it isn't outside of the realms of possibility to f@$k up a gear change from 4th to 3rd and hit 1st by mistake. :wink: Cast iron flywheels have their strength in the outer surface. Milling them down can make them porous and more prone to cracking. Edited October 29, 2009 by Felix Quote Link to comment Share on other sites More sharing options...
camerondownunder88 Posted October 29, 2009 Report Share Posted October 29, 2009 Wont go indepth here is a suspension thread. BUT I run a lightened flywheel in a daily car (stock NOS 3K only got 4000KM on it now..LOL) and one of the best things I have ever done cheap made high way cursing better SLIGHT fuel economy improve through city. Cheers Cameron Quote Link to comment Share on other sites More sharing options...
SLO-030 Posted October 29, 2009 Report Share Posted October 29, 2009 I realise that. The point is, look what can happen if a flywheel lets go. Hence the second part of my post :wink: Quote Link to comment Share on other sites More sharing options...
Saru Posted November 14, 2009 Report Share Posted November 14, 2009 Just want to add my 2 cents that lightening a cast flywheel is a pretty bad idea. At the very least run a scattershield. I have seen numerous aftermaths of doing this, none pretty. Most shops I have talked to wont do it anymore. The threat is real and the possibility of permanent human injury is very real. Quote Link to comment Share on other sites More sharing options...
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