Thumper Posted April 2, 2006 Share Posted April 2, 2006 I searched and only found one answer but he had aftermarket pistons. I am wondering what will stock turbo crank/rods/pistons will handle rpm whise untill something breaks or falls apart. The head will be able to handle 7500rpms. And I should be making power up to atleast 6500rpms. But if i'm still making power I was wondering what is the max I can take the rpms so that I can optimise my shift points. The engine is a turbo engine running high boost. I will need to spin it to 6500 atleast but would like 6700-6800 just to make sure I'm not making power there. Thanks Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted April 2, 2006 Share Posted April 2, 2006 I'm actually amazed at what the little inliner can take, I'd assume that with some rod bolts 7K is certainly not out of the question. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted April 2, 2006 Share Posted April 2, 2006 Depends on a lot of things: How much boost pressure you are running (boost on top of the valve reduces the effective valve spring rate and therefore valve bounce threshold) How balanced the bottom end is (who knows?) Cam timing/duration (no point revving the snot out of it if its not making any more power) Almost definitely others. Dave Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 2, 2006 Share Posted April 2, 2006 Stock L24 redline was 7K. I think L28 was 6500, but I think that is a bit conservative. The first thing to go is the harmonic balancer, I had a stock F54 block with a 280ZX balancer and I put 40K miles on it racing and autoxing and driving it daily. I revved it to 7000 all the time, a couple times a little over. Then the balancer came apart and F'ed up the snout of the crank. No problems with rods or any of that. New engine is balanced and has a Euro damper. This one gets a 7200 redline. There is supposedly a bad crank harmonic issue at 7500, that's why I'm staying below that number. Get rid of the balancer and get a better one and you won't have any trouble at all at 6800 rpm IME. Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted April 2, 2006 Share Posted April 2, 2006 its the stock balancer... which is junkyard. stock internals so therefor stock balanced. engine is in good shape though. boost will be ALOTA stock rod bolts im sure, would be nice to have ARP ones though. im thinking 6800rpms will be redline.. just gotta be careful mike Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted April 2, 2006 Share Posted April 2, 2006 Biggest proublems I heard of is the balancer and the lack of power at higher RPMs. Any I've driven have been limited by the cam, intake, etc... Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted April 2, 2006 Share Posted April 2, 2006 Can't hurt to start out lower and work your way upwards. I don't think you'll notice the difference between 6500 and 6800. I find myself short shifting on the road and it makes almost no difference to the acceleration. Maybe start lower and work your way up if you're unhappy? Dave Quote Link to comment Share on other sites More sharing options...
Thumper Posted April 2, 2006 Author Share Posted April 2, 2006 If you would like to know the specs of the build please see this thread. http://forums.hybridz.org/showthread.php?t=109709 Thanks Quote Link to comment Share on other sites More sharing options...
dapiper Posted April 3, 2006 Share Posted April 3, 2006 I've noticed that my data acq shows maybe 500 rpm increase above my shift point when I drop the throttle at around 6K RPM. Should allow for this margin, since engine will coast on up some, especially with lighter flywheel and lower gear and higher power which makes engine grab revs faster, thereby increasing inertial effect. My flywheel stock 2+2. OBTW, I set my rev limiter to 7K RPM Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 3, 2006 Share Posted April 3, 2006 Lighter flywheel will have less inertia, so less acceleration after you let off the gas. That's why an engine with a light flywheel revs up AND down faster than a heavy flywheel. I would assume it would also change direction faster as well. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 3, 2006 Share Posted April 3, 2006 Be careful and dont get caught up in the N/A high RPM mentality. Just because it is capable of revving to 67-6800 does not mean it should be revved that high. If it has the stock cams, there is no need to rev it much past 6200 and I am willing to bet, with the boost level you are running, that if you shifted the 1-2 & 2-3 at 6200 and let the engine spend more time under load in 3rd and 4th, it will go quicker and faster! Quote Link to comment Share on other sites More sharing options...
Thumper Posted April 3, 2006 Author Share Posted April 3, 2006 Be careful and dont get caught up in the N/A high RPM mentality. Just because it is capable of revving to 67-6800 does not mean it should be revved that high. If it has the stock cams[/b'], there is no need to rev it much past 6200 and I am willing to bet, with the boost level you are running, that if you shifted the 1-2 & 2-3 at 6200 and let the engine spend more time under load in 3rd and 4th, it will go quicker and faster! I don't want to say the specs of build while i'm not in the protected thread. But my question was what is the max rpm for the stock block? Thanks Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted April 3, 2006 Share Posted April 3, 2006 its not stock cam if that helps any.. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted April 3, 2006 Share Posted April 3, 2006 If its got the valve springs/cam to support it, and a decent dampener, 7200. Make sure you have good oil pressure, I just chewed my bottom end bearings because of a dodgey pump. Dave Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 3, 2006 Share Posted April 3, 2006 ohh Ted has experience with bad pumps.. LoL how many is that now Ted ? 4 oil pump failures? Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted April 3, 2006 Share Posted April 3, 2006 ya ted knows his oil pumps now.. why is it that everybody knows of ted by of how many things of the samething he has broken! haha mike Quote Link to comment Share on other sites More sharing options...
Thumper Posted April 3, 2006 Author Share Posted April 3, 2006 Ok lets see. I've blown 1 bottom end, 5 oil pumps, 4 t3 turbo's and 1 holset turbo (bad oil pumps), 4 trannys, 1 headgasket, and 1 halfshaft. Anything I've missed? Quote Link to comment Share on other sites More sharing options...
drzed Posted April 3, 2006 Share Posted April 3, 2006 Stock bottom end is good for 7000 RPM. Both my cars have seen regular use with junkyard engines up to and slightly past 7K. My NA 240Z did have balancer and flywheel bolt failures when used just above 7K at a couple of autoX events whick required one section of the track to be run at 7200 to avoid shifting and at the 1/4 mile where I was trying not to shift into the next gear at the end of the track. This is my 3rd season with my 260Z at the 1/4 mile track without any problems on the factory F54 bottom end. The balancer is still OK and no flywheel problems - it's an auto HA HA! Now on to the important part - do you really need to spin it up that fast? IMO no. My 260Z is actually quicker in the 1/4 by shifting at 6700 rather than 7000. This enables the engine to stay in between the torque and HP curves for more of the run. Unless you have a larger cam than mine I doubt you will need more than 7K. Good luck with the project. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted April 3, 2006 Share Posted April 3, 2006 Sorry to thread hijack, what oil pumps are you guys using now? I see curtousy nissan sell a `competition pump', and that you can get std volume melling replacements. Do melling make a high volume one? Back on topic, I am not too sure how the whole spinning up past a rpm when you rev it then clutch it. Given the generic sigma F = ma (same concept applies to rotational movement), I don't see how you can get any chance in rotational velocity without an acceleration (torque). Any ideas where the torque/acceleration would be coming from? Dave Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted April 3, 2006 Share Posted April 3, 2006 They sell a high pressure spring I believe. The limit now is the cast pistons and the harmonic balancer. The balancer needs to be inspected, and JeffP has some mods for the bolt and washer. There isn't a substitute for a BHJ damper compared to even the euro one. They all seem to fail under repetitive high rpms use. Mario Quote Link to comment Share on other sites More sharing options...
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