Custom Headers

sts70004

Registered User
If I was going to build my own headers, would there be any downside to the tubes being unequal length or should I try my best to keep them equal length?
 
Equal length is usually held as the ideal, but it's usually impossible to achieve that on a street car. I would say that a good-flowing header with tube lengths as equal as reasonably possible is what you should shoot for.
 
Ok thats what I thought... I didn't think it would be possible to fit it all while doing equal length. The reason I want to do custom headers is so it all fits. Gonna measure the clearances from the stock manifolds and then try my hand at home "mandrel" bending... We'll see how that goes.
 
As equal as possible. Stick with a 6" collector length..And I wouldnt go larger then 1 3/4 primaries with a 3" collector.

Of course you can vary from that and see what works and doesnt...But for a high performance engine its a good place to start.

Just my opinion of course base don reading here and there.
 
How are you going to "mandrel bend"?

You can get a cheap Mustang long tube and cut apart and reshape. Probably easier than starting from scratch.
 
You may want to THINK equal length, but in the SC's case, that's a no deal.

Exhaust wave tuning has everything to do with intake wave tuning. The intake flow is not balanced very well at all. The rear cylinders run lean and the front run rich.

To compensate for it, I would make the rear runners longer (more radii) and the front ones shorter (straighter). BUUUTTT equal length is the least you can do.
 
How are you going to "mandrel bend"?

Well a mandrel bend is not the technique of bending, its the property of bent pipe to not deform through the bend, as in half way through the bend if you were to cut it, the cross section would still be a circle. Typically the way pipes are mandrel bent is they are filled with a supporting material before hand. I've done a few experiments, where I filled a tube with sand, and capped it, and bent it, and from the preliminary results, it works great. The hard part is that you can't heat it to aid the bending, but I think I'll be making a jig before I do the headers. I've thought about buying cheap mustang long tubes, but they're still more expensive than the raw materials by a pretty significant margin. While my time added to the material cost, it might be more than the long tubes, I have an abundance of time, and a shortage of money...
 
Exhaust wave tuning has everything to do with intake wave tuning. The intake flow is not balanced very well at all. The rear cylinders run lean and the front run rich.

What can be done to remedy that? Is that a byproduct of a poor intake manifold design? Would enlarging the plenum help?
 
The SC feeds in at the back of the intake.

I picked up a set of Mustang Long tubes for $100 shipped to Canada brand new in the box. Can you even get all the materials for that?
 
Why not buy a selection of madrel bent tubing and cut and fit as necessary? A lot easier than trying to bend tubing yourself.
 
AS far as I know, there has never been a before and after test done on a car with manifolds and then headers and full exhaust done. Everything to date is flow testing and theoretical.
 
From what i have read here the stock headers are not that bad it's the res, and the bends to the stock cats that restrict the flow. If their is not any documented proof on hp/tq gains what would be the point .
 
Why bother?...Ive never seen any documented gains from headers on these cars...

Well i want better angles for the down tubes when I do the entire exhaust myself, so Long Tubes or Mid length headers will hopefully flow better with less turbulence and at the same time make it easier to make an exhaust for.
 
Simplicity is key

Oh btw my plan for the headers was to keep it as simple as possible, Looking in on the car, I see plenty of room to make 3 - 1 1/2 or so pipes running right on top of each other and then mate into a collector right where the cats currently reside. As of right now, I see no complicated bends needed either. Of course this is all being said before hand... we'll see how it turns out hehe.
 
Oh btw my plan for the headers was to keep it as simple as possible, Looking in on the car, I see plenty of room to make 3 - 1 1/2 or so pipes running right on top of each other and then mate into a collector right where the cats currently reside. As of right now, I see no complicated bends needed either. Of course this is all being said before hand... we'll see how it turns out hehe.

I'm sure you've used the search option on the forums here, but if not search again and you'll see a handful of people that have made headers themselves. It might be helpful information.
 
To bad you don't have a dyno, so we can see your custom vs stock headers performance. Is their a way to document the performance with out a dyno? The reason I'm asking is right now i have been debating if headers are worth the time, and money or i will get the stock headers ported , maybe you can use your butt dyno and let me now what you think before, and after if you would?
 
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To bad you don't have a dyno, so we can see your custom vs stock headers performance. Is their a way to document the performance with out a dyno? The reason I'm asking is right now i have been debating if headers are worth the time, and money or i will get the stock headers ported , maybe you can use your but dyno and let me now what you think before, and after if you would?

Sure I'll look around and try to find a Dyno, and I won't do any other engine mods till I get these headers done. Keep in mind this is a winter project so it could be a while.
 
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