340 dyno chart thoughts

Lustle said
So you're agreeing with me then? Or maybe you didn't understand what I'm trying to say. I have no idea why you keep using advertised duration, when I use valve events. Advertised duration is just that an ADVERTISEMENT.

As I said. Valve events determine idle quality. Not duration. Not LSA. Yes, generally with more duration idle is worse. And with tighter LSA idle is worst. BUT that's because of valve events, they determine idle. Period. Part of my point with that, is that as cam technology got better, you could have larger duration with better idle because of improved valve events.

Well the overlap on the solid was 66.

And I use intake valve closing angle at zero (ok well .006") to find overlap. Because that's how you should do it. Yes, I calculated that on the hughes cam.

So once again, my point is that valve events are what you need to look at. Not advertised duration. Because that's an ADVERTISEMENT.

STOP focusing on advertised duration. And start focusing on WHEN the valves actually open and close.

This was exactly my point. To bring up the cams I mentioned before?

Hughes STL5054AS-8 250/254 -108ºLSA - Intake valve closing angle 64.
Comp XE274H - 230/236 - 110 LSA - Intake valve closing angle 63.

Which just proves that you can have a crazy big duration, but still have mild valve events. Pay attention to valve events. They tell you what the cam is doing and when it's doing it.

There are too many people that are getting mixed up in my answers. In going to try and stop doing that. Wish I knew how to quote just part of a post and then answer it. Copy and paste is too tedious for me.

Anyway, I agree not to get all caught up in advertised numbers, but they do matter. Once the valve is off the seat about .020-.025 you start getting some flow. If you up the pressure it happens earlier. We know that at overlap, the pull on the intake port can be as high as 120 inches on a decent prepped street head. So with long slow ramps you get into issues with reversion. That's why GM in the aforementioned 30-30 Duntove junker and some other junk GM cams that I can't recall the nomenclature on, had LSA's as wide as 116. It was to help with the bi seat to seat numbers. They were **** cams.