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Header Collector?

3K views 8 replies 5 participants last post by  MrScharfenberger 
#1 ·
In the past I've used relatively cheap headers such as the Heddman Hedder units with the ball and socket type collector. Or just a flat end connector that you put a gasket in, run the 3 bolts through the header flange & exhaust pipe flange and tighten them up. Now I have a set of Mad Dog headers that match my motor plate. These headers have a collector where one end of the collector slides up over the 4 individual header pipes. Then the other end is just a 3 1/2 inch opening with no flange what so ever. How am I supposed to attach an exhaust pipe to these? Do I just weld to the collector end? Or is there some type of clamp that goes over the collector and the exhaust pipe? Sorry for the novice question but I want to make sure that I do it the right way.
 
#5 ·
Thanks for the replies guys. I think I'm going to go with the 3 bolt collector flange. After I saw the post I looked them up on Jegs and they had many flavors to choose from. I'm going to be running some electric exhaust cutouts along with mufflers so it is going to be a good amount of weight on the back side of the exhaust system so I'm thinking the 3 bolt flanges will work best. Again thanks for the replies.
 
#6 ·
It's all a matter or personal preference (obviously), but if it were me, I'd ditch the electric cut-out idea. Those things are heavy and are just that much more "stuff" to possibly go wrong.

A properly set-up exhaust will not give up any power versus an open header/exhaust setup, additionally.

Even Jon Kaase discovered this on one of this Engine Masters setups.

What size are your collectors, what's the rationale behind the electric cut-outs and how far out the back were you wanting to run your tailpipes? Reason I ask all of this is because it's all pertinent.

Knowing what bit I do about your car's build (from your thread), first and foremost you're not going to be able to run full tailpipes out the back of the car (at least not in the stock location) with the suspension that's been discussed (i.e. anti-roll bar installed). I realize you don't have an AR bar installed at the moment, but ultimately it's going to help your car's suspension/chassis work a lot better. That said, installing one is going to limit your tailpipe options.

While I'm not a fan of this set-up for a street driven car (which I don't think you have any intention of doing...or, at that, in limited amounts), I'd simply run the exhaust from the headers through a cross-over pipe, through some mufflers and then run some dumps directly before the rear end housing. Reason I don't like this setup for street cars is it tends to lead to a lot of resonance in the car...which is annoying after a few minutes if it's a car you drive regularly on the street.


Also, I ask about collector size because as the exhaust travels down the exhaust path, it loses heat (dissipated out the tubes) and because it loses heat it loses velocity, as well. Granted an exhaust setup like I suggested above is not a very length exhaust (relative to a car with tailpipes all the way out the back of the car), but presuming the collectors are 3.5" in diameter, I'd probably reduce that diameter down to 3" immediately after the collector (or after the crossover section) and run it through 3" mufflers (given the dynamics of your build).

I know it sounds odd, but down the length of the exhaust, you want to reduce the diameter of the pipe to some degree depending on the engine build & displacement, length of the exhaust and the operating range of the engine. By reducing the diameter, you keep more heat in the exhaust, you keep velocity higher and both contribute to better scavenging.



If it were me, I'd ditch the electric cutouts altogether and run it through the mufflers 100% of the time, but that's me. Some guys like the open header sound.
 
#7 ·
I appreciate the feedback Zac.. It is most helpful. Here is my rational for using the electric exhause cutouts. I want to take this thing on HotRod's drag week one year. I know I won't be able to do it with the motor that I have now. It has a solid roller cam, high spring pressures, high stall converter, etc... But I plan on building a second motor for the car. Or perhaps just using the 466 that I have in my 1974 F100 right now for drag week. I know what you are saying about the exhaust and in thruth if this were a total max effort build I would agree with you. But the truth is I don't think I'm going to be competative bracket racing and the thing is going to be pretty fast regardless of a slight bottle neck in the exhaust and the extra weight the cuts outs will be. I go to my local track and I see these bracket racers run to the hundredth the number that they are dialed into exactly. I can't see me ever being able to do that. Not because I don't want to. But because I just won't have the time to run it every weekend like they do to be able to become that familiar with it. This thing is just going to be more for fun than anything else. It just brings me joy to own it. Maybe I'm wrong about the bracket racing thing. Don't get me wrong. I'm going to try but the car dosen't have to be just as fast as it can be for me to be able to have some fun with. I did have the car registerd and I do have a license plate for it so there is a chance that from time to time it will see some street duty when I have another motor for it.

With all of that being said I do have 3 1/2 inch header collectors. I was planning on reducing them to 3 inches after the colletor. I can't claim brilliance on this because I wanted to keep the speed of the exhaust up but the reason was because the Dougs electric cutouts that I have are of the 3 inch diameter. The facts that you mention above just play into the senario very well on the reasons to reduce the diameter. I was also planning on dumping the exhaust right in front of the rear axle as well. I know the resonance can get very irritating quickly but I have a plan for that. I am also a pilot. I have 2 sets of David Clark aircraft headsets. I was thinking about rigging up an aircraft style intercom using the headsets. This would be pretty easy and in expensive to do. These would not be used on short trips. But rather on the long "Drag Week" style trips.
 
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