Careless Posted March 28, 2009 Share Posted March 28, 2009 I measured the flywheel weight to 15 lbs with a mail scale. I've read that this is the optimum weight for performance without sacrificing driveability. 12 and 10 lbs flywheels are intended for more track oriented cars rather than street driven cars, not to mention the clatter. I have a fidanza 12lbs and I'll have to test it for chatter, but I've heard of honda guys running 9lbs flywheels with no issues like that. I didn't get my unit balanced because it was crunch time, but in hindsight I should have. Oh well. my comment was more towards SFI spec verses non SFI spec. If the weight was only a couple of pounds, I would go with the SFI unit as It's safer, and with less weight, in the case of a flywheel that usually means less material... so that's a double-negative... double-negative in cars does not equal positive. LOL. Raff Quote Link to comment Share on other sites More sharing options...
240Z_Master Posted March 29, 2009 Share Posted March 29, 2009 BTW, Fidanza flywheels are SFI spec'd flywheels. And the thing weighs 9.5 lbs (at least the RB20 Fidanza flywheel that I'm using is 9.5 lbs!) Quote Link to comment Share on other sites More sharing options...
zilvia_gt Posted March 29, 2009 Share Posted March 29, 2009 I have a fidanza 12lbs and I'll have to test it for chatter, but I've heard of honda guys running 9lbs flywheels with no issues like that. I didn't get my unit balanced because it was crunch time, but in hindsight I should have. Oh well. my comment was more towards SFI spec verses non SFI spec. If the weight was only a couple of pounds, I would go with the SFI unit as It's safer, and with less weight, in the case of a flywheel that usually means less material... so that's a double-negative... double-negative in cars does not equal positive. LOL. Raff Thanks for clearing that up. Your comment about the honda guys. Their engines are small little 1.5-1.8 liter four bangers and our rb's are 2.5-3.0 6 cylinder engines (with the exception of the rb20). I would imagine that the rotating mass required to keep the engine revs between shifts up would be quite different. The driving characteristics between honda and nissan engines are also different. Nissan motors tend to have more torque so they can deal with the heavier rotating mass. Just my thoughts though, I've never driven any car with a 9 lbs flywheel. Quote Link to comment Share on other sites More sharing options...
240Z_Master Posted March 29, 2009 Share Posted March 29, 2009 IMHO, driving my RB25DET with a 9.5lb flywheel is pretty easy. I don't have a problem stalling out, or worrying about little things too much. In fact I'm always driving probably in a higher gear just to keep the noise levels down. Quote Link to comment Share on other sites More sharing options...
Canadianz Posted March 29, 2009 Share Posted March 29, 2009 I had the stock unit lightened and balanced, seems to work great. I also got the stock pressure plate strengthened 50% over and the clutch disk re done in in a better friction material too. I guess in hind sight I could have gone the aftermarket route but Ive never had it slip and the engine feels nice and free when revving. Just another thought if there is a place near you that can do that type of work. It suited my build really well and the clutch pedal is still very nice too. Chris Quote Link to comment Share on other sites More sharing options...
streeteg Posted March 29, 2009 Share Posted March 29, 2009 IMport Intellegence is selling a stocker for 30 bucks http://importintelligence.com/FMPro?-DB=cart.fp3&-Format=garagesale.htm&-Token=12584643&-RecID=12584643&CustID=trimcord&-Error=index.html&-Edit Quote Link to comment Share on other sites More sharing options...
Careless Posted March 30, 2009 Share Posted March 30, 2009 Thanks for clearing that up. Your comment about the honda guys. Their engines are small little 1.5-1.8 liter four bangers and our rb's are 2.5-3.0 6 cylinder engines (with the exception of the rb20). I would imagine that the rotating mass required to keep the engine revs between shifts up would be quite different. The driving characteristics between honda and nissan engines are also different. Nissan motors tend to have more torque so they can deal with the heavier rotating mass. Just my thoughts though, I've never driven any car with a 9 lbs flywheel. Oh there's no doubt about that. Honda's barely develop any torque, even when putting the beefier heads on a bigger block to make up for displacement. It is something to think about though. If they make RB25 flywheels that are 10 lbs, and Honda flywheels that are 10lbs, and the difference in torque is almost two-fold, maybe any lighter for most passenger cars running a 1.5 or larger engine should not be using flywheels lighter than 10 or so lbs because the integrity of the flywheel is severely compromised. Yet another reason why I would run with a slightly heavier unit if it was indeed SFI-spec, and the other choice was not, but lighter. To lighten an RB25 flywheel, I believe some guys use KA24 flywheels. but then they need to use KA24 clutch packs (someone correct me on this if it's wrong), which to hold an RB25's increased torque ouput if you decided to up the boost or add some go-fast parts, would negate this being an 'upgrade', as the higher torque KA clutch kits are a heck of a lot of money. Quote Link to comment Share on other sites More sharing options...
240Z_Master Posted March 30, 2009 Share Posted March 30, 2009 I guess do it right and go SFI on everything. Maybe that's why I chose my setup the way it is. Quote Link to comment Share on other sites More sharing options...
voltron_boi Posted March 30, 2009 Author Share Posted March 30, 2009 Thanks to eric(stealth-z), I decide to go with his twin plate ocr setup. The ocr setup looks great, and I will post picture of it later today. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.