In general, what determines rev limit?
08-16-2002, 02:18 PM
#1
In general, what determines rev limit? What exactly is the limit on engines that prevents one from revving high? What can be changed and how far, in theory, can an engine go? Alot of LS1s rev to 7K on build motors. Can they rev to 8K lets say? I know durability will go down. But as long as it stays intact for some time, its all good.
08-16-2002, 02:48 PM
#2
Re: In general, what determines rev limit? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Dom:
<strong>What exactly is the limit on engines that prevents one from revving high? What can be changed and how far, in theory, can an engine go? Alot of LS1s rev to 7K on build motors. Can they rev to 8K lets say? I know durability will go down. But as long as it stays intact for some time, its all good.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well, there's several factors. 1st is that your engine has to flow well enought to make power at those high rpms. This is why on dyno graphs of stock LS1s you see power fall off around 6k rpms or so. Engine gets choked off, no reason to rev higher if you can't make power (tho you want to shift after your power peak, so you will be further up your power band in the next gear when racing). 2nd is your valvetrain has to be up to snuff, so you do not get valve float, and subsequently piston-valve contact at those rpms. And finally, the rotating assembly, bottom end, of the engine must be strong enough to withstand the added force of high rpms. Certain characteristics of an engine determine how high it can rev without damage. Stroke is very important. The longer the stroke, the faster the piston has to travel during its stroke at a given rpm. The faster the piston moves, the more momentum it has, and therefore the more force that will be exerted on things such as the rods and bolts to force the piston to change direction at the top or bottom of its stroke.
<small>[ August 16, 2002, 02:49 PM: Message edited by: NHRATA01 ]</small>
<strong>What exactly is the limit on engines that prevents one from revving high? What can be changed and how far, in theory, can an engine go? Alot of LS1s rev to 7K on build motors. Can they rev to 8K lets say? I know durability will go down. But as long as it stays intact for some time, its all good.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well, there's several factors. 1st is that your engine has to flow well enought to make power at those high rpms. This is why on dyno graphs of stock LS1s you see power fall off around 6k rpms or so. Engine gets choked off, no reason to rev higher if you can't make power (tho you want to shift after your power peak, so you will be further up your power band in the next gear when racing). 2nd is your valvetrain has to be up to snuff, so you do not get valve float, and subsequently piston-valve contact at those rpms. And finally, the rotating assembly, bottom end, of the engine must be strong enough to withstand the added force of high rpms. Certain characteristics of an engine determine how high it can rev without damage. Stroke is very important. The longer the stroke, the faster the piston has to travel during its stroke at a given rpm. The faster the piston moves, the more momentum it has, and therefore the more force that will be exerted on things such as the rods and bolts to force the piston to change direction at the top or bottom of its stroke.
<small>[ August 16, 2002, 02:49 PM: Message edited by: NHRATA01 ]</small>
