FW: Tubular header for MC?

[Eric Sanborn]

Tyson Varosyan wrote:

>Yea, to say the least.
>
>$12k Basic Mandrel Bender.
>$4-5k Mandrel tooling.
>$1k Semi-decent Mig welder.
>$2k Plasma cutter.
>$1k Air compressor with grinding tools, hoses and stuff...
>$2-3 Tig welder if you plan on working with Titanium and certain stainless
>verieties...
>
>I used to make custom exhaust systems for the 3000GT/Stealth cars. It's a
>pain and there is little money in it.
>  
>

You are right there is little money in it.  A friend of mine used to 
make race headers for Neons.  He made a couple hundred over a couple 
years.  He did it with a MIG welder and a lot of outsourcing.  Laser cut 
flanges can be had for amost nothing if you can give them a CAD file to 
start with  With a four banger merge collectors are easy to come by.  If 
you mock up the first mandrel bent tube and send it to a bender they 
will bend them for you for quite a reasonable cost assuming you want to 
buy minimums.

For the DIY guy buying mandrel U-bends, choping up, and welding is the 
way to go.  I made my entire 3" exhaust system from turbo flange to tail 
pipe for a touch over $300.  It was completely made of welded sections 
of mandrel bends.  Now it was mild steel, so stainless would have more.

http://www.sofadog.net/4ktq/Step2.html

Jim stated what I was going to in regards to header design.  The only 
thing that will fit is a log style.  Most people ditch the stock EM for 
one of two reasons.  Flow or cracks.  A log style manifold is likely to 
be worse for cracking and for pulling studs as the runners get hotter 
carrying multiple cylinder pulses.  Plus like Jim said you will not be 
able to make the most of the improvements while retaining CIS. 

I have tried all sorts of schemes to come up with a way to make a header 
that does not require major changes under the hood and I have not found 
one.  There is a lot less space under there than it seems.  You have the 
IM above you, the starter, engine mount, and passenger side accessory 
below, and are stuck between the CIS system and the block. 

My thought is if you are considering paying someone else to do it wait 
until you can do it right.

-- 
Eric Sanborn
'85 4ktq

http://sofadog.net/4ktq/