Need Proof That More Aggressive Lobes Are Better!
All this car stuff, its usually about area under the curve right? Peak dynos dont matter, its average hp that matters. Peak flow #s dont matter, its mid lift flow that matters. Similar with cam lobes. Faster ramps increase the total time the valves are open, the area under the curve so to speak.
Vince, did ya know that the Thunder Racing 224 is smaller than the T1? Yup, thats right. As you know, Thunder uses a really fast ramp. Its smaller at .006", smaller advertised duration than the T1. But, its ramps are so much faster, that at .050" its bigger. Now duration at the valve seat (.006") is what really has a lot of effect on driveability and powerband. Thats how the "smaller" TR cam has better manners, lower powerband, and similar/more power all while being smaller in total duration at the seat, because it uses a fast ramp rate. Make sense? Fast ramps increase the total time the valves are open, so you can make more power with a smaller cam that drives better.
Want a real world example? Look at all the solid cams. One of the greatest advantages of a solid lifter is it can follow a more radical lobe. Duration at .050" looks huge on those, but Jason's 230 idled better than his T1 and TR224. It also made a lot more power, but the powerband didn't change much. Why's that, well its because the solid ramps are so much faster. An added benefit is that solids can rev higher, but thats a different discussion.
Idle better, same or better power, usable power that is lower in the powerband, whats not to like about fast ramps? Does it make a little more sense now?
J.
savvy?
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<strong>Trevor, I would think you would see an improvement at 29 degrees of timing. That is the MINIMUM you should be running.
savvy?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I understand that a few more degrees of timing may net some more HP, but I'll play with that once I have LS1 Edit. I don't want to send my PCM back and forth umpteen times trying to get my timing exactly where I want it. I know of a few cars, "Just Me" included, that had optimum timing at 28 degrees. Anything past that showed no gain or a slight loss in power.
I would like to see some dyno numbers with some of these XE-R lobes used with a properly designed rev kit. This would allow lower valvespring pressures to be used.
<strong>If aggressive cam lobes are so badass for performance (hype?) then how come the manufacturers didn't just skip the less aggressive lobe patterns and start with the "badass" ones?
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well 1st of all, they try to - the new LS6 cam, for example.
But they generally don't because there's no way the springs and valves would be able to take that beating for 100,000 miles.
I remember last summer tons of guys were having 941 Comp Cam springs break. It was all guys with the real aggressive lobe cams. And I think install problems were some of it (guys not calling comp and getting their specs on how to set up the springs). I just ran the little comp 212/218 cam with all comp valvetrain for a year with 0 problems. I called comp to get their exact reccomendations for install height on the springs and such and followed them to the t.
Thats because your compression is higher Terry.. You would have issues if you ran more timing.. Back to the topic..
</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">It's 11.3:1. Isn't that what we all run?






