eyefi Posted April 5, 2003 Share Posted April 5, 2003 does anyone know a suitable (safe) rev limit, above stock, for the stock internals. Link to comment Share on other sites More sharing options...
Syed Shah Posted April 5, 2003 Share Posted April 5, 2003 Probably around 7500rpm. Some in the US have 8500rpm rev limits! On standard engines, but this is probably not a good idea. Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 5, 2003 Share Posted April 5, 2003 How do you raise the rev limit? - I assumed it was controlled by the ECU? When my car was dyno'ed, the power was still climbing when it hit the rev limiter... Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 5, 2003 Share Posted April 5, 2003 Originally posted by eyefi does anyone know a suitable (safe) rev limit, above stock, for the stock internals. You may get away with 500 rpm more for shortish periods, it's a long stroke engine and without trick internals will never reaaly be happy for long periods at or above the redline. Something like a Skyline engine is much better if you want a revver, or base an engine on the Soarer 2.5, it's a much better bore stroke ratio for high rpm performance building. 8500 is NOT a good idea at all, unless you promise to bring it me for the rebuild Link to comment Share on other sites More sharing options...
Thorin Posted April 5, 2003 Share Posted April 5, 2003 Hmmm now there's an idea, has anyone ever bunged the Soarer's 2.5 in a supra with high rev limit? would be interesting. Link to comment Share on other sites More sharing options...
eyefi Posted April 6, 2003 Author Share Posted April 6, 2003 the reason im asking is the power fc i have has a raised rev limit of 7500, and i wondered how conservative the stock limit was. im not after a 10k redline. does anyone know what the piston speed will b at 7500rpm? Link to comment Share on other sites More sharing options...
Syed Shah Posted April 6, 2003 Share Posted April 6, 2003 Piston speed at 7500rpm would be around 4230fpm. Stock (7100?) it would be just over 4000fpm. A really trick road car can safely attain av piston speeds of 5000fpm. Mario runs his pistons in excess of 5750fpm!!! Near F1 standards! Chris, out of interest, what would the cost be for a crank to de-stroke the 2JZ down to around 78mm? Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 6, 2003 Share Posted April 6, 2003 Guesstimate based on Farndons figures would be 2000, maybe 2250 for a one off. You'll obviously need more than just the crank though. Link to comment Share on other sites More sharing options...
Ian C Posted April 7, 2003 Share Posted April 7, 2003 The stock rev limiter seems a bit random, Matt Harwood's kicked in at about 6800,6900ish, yes? I hit 7090rpm yesterday and didn't hit the limiter... -Ian Link to comment Share on other sites More sharing options...
Digsy Posted April 7, 2003 Share Posted April 7, 2003 Don't forget the valvetrain, guys. You'll need to make sure the spring are up to the job if you don't want the valves to float at high rpm. Link to comment Share on other sites More sharing options...
eyefi Posted April 7, 2003 Author Share Posted April 7, 2003 Originally posted by Ian C The stock rev limiter seems a bit random, Matt Harwood's kicked in at about 6800,6900ish, yes? I hit 7090rpm yesterday and didn't hit the limiter... -Ian is the rev limit different on autos? Link to comment Share on other sites More sharing options...
eyefi Posted April 7, 2003 Author Share Posted April 7, 2003 Originally posted by Darren Blake Don't forget the valvetrain, guys. when do the valves start to float? Link to comment Share on other sites More sharing options...
Ian C Posted April 7, 2003 Share Posted April 7, 2003 When you flood the engine! Ahhh hahahahahahahahahahahahahacough. -Ian Link to comment Share on other sites More sharing options...
Digsy Posted April 7, 2003 Share Posted April 7, 2003 Originally posted by eyefi when do the valves start to float? On the J2Z specifically, I have no idea. If you know the valve acceleration curve from the cam profile and engine speed, and the mass of the moving parts of the valvetrain (tappet, valve, retainer, collets +50% of the spring mass) you can work it out. The spring force at a given valve lift sould always be higher than the inertia force produced by the mass of the valvetrain. Spring force > valvetrain mass x cam acceleration Link to comment Share on other sites More sharing options...
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