I see a few questions posted about headers.
For those of you who are allowed to run them, are your RPM's limeted to a certain amount or percentage over stock?
I've built several headers and helped on several more. I've had people tell me that there is no way a header will help. But that's not the truth. A well designed and built header is one of the most important (possiably the most important) components of a performance minded build. A poor header isn't much if any better than a stock manifold. And those nice sets of "zoomies" or individual pipes are the worst, great for a blown application but terrable for naturally aspirated.
On my own tractor I had used a friends header, I was waiting on parts for mine to arrive and time to build it so I simply put his shorty header on the engine for the time being. It worked alright and when the parts arrived and time allowed we built a tuned length, equill length runners with a good paralell merge collector in rotational fireing order. Did a lot of figureing on tube diameter, length and collector sizeing. I gained 25% hp and 1200 RPM on top speed with a "good exhaust header", not changeing anything else other than tuneing adjustments. There's likely more to gain, but one can only try to fine tune something to a point but then the real work has to get done and the fun projects have to sit. The first time out with the new header we tried it in the normal gear for the class and then came back and shifted up a gear and the engine still lit hard and went for a win.
For those of you who are allowed to run them, are your RPM's limeted to a certain amount or percentage over stock?
I've built several headers and helped on several more. I've had people tell me that there is no way a header will help. But that's not the truth. A well designed and built header is one of the most important (possiably the most important) components of a performance minded build. A poor header isn't much if any better than a stock manifold. And those nice sets of "zoomies" or individual pipes are the worst, great for a blown application but terrable for naturally aspirated.
On my own tractor I had used a friends header, I was waiting on parts for mine to arrive and time to build it so I simply put his shorty header on the engine for the time being. It worked alright and when the parts arrived and time allowed we built a tuned length, equill length runners with a good paralell merge collector in rotational fireing order. Did a lot of figureing on tube diameter, length and collector sizeing. I gained 25% hp and 1200 RPM on top speed with a "good exhaust header", not changeing anything else other than tuneing adjustments. There's likely more to gain, but one can only try to fine tune something to a point but then the real work has to get done and the fun projects have to sit. The first time out with the new header we tried it in the normal gear for the class and then came back and shifted up a gear and the engine still lit hard and went for a win.