Dave-
Since you know headers, perhaps you could explain the difference between "Tuned Headers" and "Timed Headers" and how the cam profile fits into it all.
Thanks,
Jak
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Dave-
Since you know headers, perhaps you could explain the difference between "Tuned Headers" and "Timed Headers" and how the cam profile fits into it all.
Thanks,
Jak
I'm gonna take a crack at this one :D .
Tuned headers are a certain diameter and a certain length....for a certain RPM for a certain sized engine. Clear wink .
Timed headers are the 180 deg type.
The (oldschool) chev firing order is 18436572.
The header for one side would be 1467
The header for the other would be 8352
This would lead to a exhaust pulse reaching the collector at a certain time to help either scavenge the cylinder better and to (or not to) affect the next cylinder in line to fire an exhaust pulse.
http://howeracing.com/images/exhaust.../180degree.jpg
I'm not really sure about the cam profile part but I would listen to the theories that would come of this discussion :D
Mike -
Go to www.burnsstainless and look at their X-DESIGN header spec sheet and you'll see what I'm getting at.
From what I know MikeF hit it pretty much right on. With a tuned header you change primary tube diameter and length, then collector diameter and length, not to mention the concept of stepped primary tubes. I was told by a designer @ Schoenfeld Headers that if our engine rpm didn't vary more than 1500 on a normal lap don't spend the extra $$$ for the stepped design. Our engine normally runs 6000-7500 on a given lap so we didn't. 180 degree headers take advantage of the firing order to maximize the scavenging effect and cylinder filling as much as possible. I could not open your link to the header company. Try and send another. Haven't been on the board lately.
Hey Bear, thanks for the link!! Some great info and parts availibility. We are going to put together a new exhaust system for the race car this winter and they will be most helpful!!!
Dave ... Your most welcome. Good luck on the new headers and in next year's season.