Making my own Headers!!!

[DMX]

I AM BUILDING MY OWN HEADERS LIKE THE PICTURE BELOW....

JUST NEED ONE QUESTION ANSWERED..... WHAT WIDTH OF

PIPING SHOULD I USE FOR THE 2 PIPES THAT CONNECT TO THE

MUFFLER FROM EACH HEADER.... I AM THINKING 3 INCH PIPES... I

WANT A THROATY SOUND, NOT A HIGH PITCH SOUND.... MAYBE I

SHOULD USE 4 INCH PIPES.... ANY ANSWERS.... THIS IS NOT MY

AREA.....


THANKS...

[ChrisBennet]

You need to do more homework before you start. Bigger pipes = lower velocity = no low end torque.
-Chris

[DMX]

I got the original older style pieces that fit right to my engine.... I am

just custimizing the pipe on each side that goes to the muffler... I think

either a 2 1/2 inch or 3 inch would be best for performance.... but not

too sure...

[emcon5]

What car, what engine?

Tom

[DMX]

2.7L '75 911.. ... I have a stainless muffler with an empty cat right

now and my car runs really strong... I am hoping to gain some

horsepower by adding a header system with dual inlets to the

muffler.. .. ...

[ChrisBennet]

If you want to add power, copy/study SSI's. SSI's themselves are an improved version of the factory '74 headers. They are a very good design - superior to the system you have pictured even.
-Chris

[DMX]

Do you think I will notice a big difference from changing to dual

inlets instead of the single inlet that wraps around the side of my

motor?

[ChrisBennet]

Originally posted by DMX
Do you think I will notice a big difference from changing to dual

inlets instead of the single inlet that wraps around the side of my

motor?

I know it makes a noticeable difference on 3.0 motors. Fabspeed contends that a Euro "premuffler" makes as much HP as SSI's on a 3.2 I think. Now the SSI's are a little small for a 3.2 so it's not really comparing apples to apples. I too wonder how a gutted cat compares to SSI's in your application.
-Chris

[TerryBPP]

When I sent my headers out to get jet-hotted I used a stock setup and I could definetly tell the difference the duals made. I use a headers, not cats, 2 dansks mufflers, and to 2 1/4" outs.

[DMX]

Hey Chris I am wondering the same.... I hope it's worth it... I may just

put the old style headers on and fabricate another inlet to my stainless

muffler... I hope it runs stronger... .. ... I think I will gain torque..

Terry.....
Did you notice a big difference in torque.... I heard that I would have

more torque in every gear.... Is this true.... and it will cost me basically

nothing to convert over my exhaust so I think it will be worth it...

[DMX]

Oh and by the way... Has anyone heard of by design.... That is my

stainless muffler.... is it good or just some aftermarket junk.... Sounds

good when the car is on so thats what counts to me.... HAHAHA

[Kemo]

Be sure and post some pics...this looks like a worthy project. Im sure that porsche put alot of time in developing the tuned headers up to 74...then SSI picked it up from there, not to mention Bruce Anderson's view of the early style HEs. So as Chris Bennet pointed out, you would be on the right track by copying someone that has already made a great product
...if anyone has dimensions on the stock early style HE's or 2.7SSI's, that would most likely be the right diameter.

[Kemo]

you could build in an 'X' pipe of some sort...that would be cool.

[DMX]

Anyone have a picture of the old headers.... I need to see what

they look like..... I cannot seem to find a picture of them....

[Kemo]

http://www.stuttgart.co.uk/ssi.html

this shows a pic...UK site tho.

[jluetjen]

if anyone has dimensions on the stock early style HE's

I have a set (sans heater boxes) in the garage which I just measured. Curiously the primaries are 1 3/8 (id) and the secondaries are 1 3/4 inches. I say curiously because everything that I ever read said that the early systems had 1 1/2 inch primaries. Hmmm. Go figure!

[TerryBPP]

There was definetly a increase in power.

[David]

I would do some serious calculations on all your diameters and lengths before starting, even if you copy someone else's design. If you make it out of stainless you will probably spend several hundred dollars, time spent in design would be well worth it. Here's a good site for material and tips: http://www.burnsstainless.com