noddaz said:
Pete. (l33t FS) said:
noddaz said:
I must be out of touch, but nearly $500 for a set of headers isn't cheap. But I am probably out of touch.
Most headers I installed for rare, esoteric vehicles like '69 Camaros and late 60s GM A-bodies were $750, ten or so years ago. This was for coated headers.
And the Camaro, at least, needed the collector mooshed for clearance.
Ok, I finally had to look. The expensive (to me) headers are because:
1) They are Hooker Headers
2) The headers are coated
3) I am out of touch with header pricing
I did see headers listed for as cheap as $182.95. And since I have not bought headers for over 20 years I guess I will go with #3 above.
You would be shocked to see what the highest quality and most power making header cost for a BRZ.
https://www.counterspacegarage.com/ace-a350-rhd-gt86
In reply to z31maniac :
I assume that header is for non OE management. Combining left and right banks like that could throw the computer all into a tizzy when it tries to adjust fuel trim based off of the wrong sensor's reading. (assuming Subaru is doing left/right bank control, and not just combining all four cylinders into one "bank". I have zero practical Frisbee experience here)
i also assume that the header will crack, stainless is an awful material for headers.
Looks awesome!
By slip-fit is that where one literally slips over the other and you use a ln exhaust clamp to crush the outside pipe down? Can't imagine anyone would ever describe them as easy to disassemble!
In reply to jfryjfry (FS) :
Designed properly, you do not use a clamp. The fit is close enough that the inner pipe expands into the outer with exhaust heat. There is surprisingly little leakage.
One of the cars I did had three piece headers because Ford. The front two tubes on each side were attached to the collector, the rear two tubes were individual pieces that you had to slip into the collector as you offered everything up. Extremely fiddly but it worked well.
In the post-collector part of the exhaust, what you do is install a couple tabs that bolt together to hold the pipes in the proper orientation.
jfryjfry (FS) said:
By slip-fit is that where one literally slips over the other and you use a ln exhaust clamp to crush the outside pipe down? Can't imagine anyone would ever describe them as easy to disassemble!
You dont use a typical muffler clamp in this situation, its a proper fit and use either a formed bandclamp or a accuseal clamp.
You can also do springs or bolts.
Also I like to use double slips when I can when set up right no clamp is needed and they don't leak or at most very minor until some carbon builds up. I typically use them when routing wastegate exhaust back into the downpipe
Very helpful. Learned a little bit today
dean1484 said:
How much would a set of custom welded headers cost? How hard would it have been to roll your own with a header kit and a tig. I was with you until you bent them to access the spark plugs. Yes I know the it has a minimal if any effect on performance but it just looks bad to me. Call it header OCD on my part. And besides I would have liked to read your impressions of trying to build your own from one of those header kits I see used in builds. That would have been an interesting read.
There has to be a manufacturer out there that makes a header that you don't have to bend to fit. To me that is poor design on the manufacturers part. Even if it cost another couple hundred bucks to get a properly engineered set to me it would have been my choice as every time you open the hood people will see the deformed pipes. (That OCD thing I have again).
I hope everyone understands that most prebuilt "headers" are just tubular exhaust systems.
Real headers have equal length ( and volume ) primary pipes length based on the camshaft ( s) used. Contrary to the sales literature the goal is not to make. Peak power. That's just bragging rights. The goal is to gain the most under the curve. Or the RPM used on the race track. If you race between 4500-6500 that's you goal. You may use a smaller diameter primary pipe of longer diameter to achieve that. If you honestly race between 7,000-9,000 rpm then that's your design goal. There are plenty of free sources to figure out length and diameter.
One final point. The real goal of a racing header is to assist the intake to fill each cylinder with as much fuel and air as possible. Measure each intake port carefully. A single 4 barrel intake manifold will often have a pretty serious difference.
In reply to docwyte :
Suggests to me that perhaps the tubes were too big to begin with for the combination, or that they are purposely made a bit large because they too-often need customer custom dimpling in order to fit! If only the shape is being changed, e.g. from round to oval while not affecting the cross sectional area, I can see there would be little impact (pun).
Pete. (l33t FS) said:
In reply to z31maniac :
I assume that header is for non OE management. Combining left and right banks like that could throw the computer all into a tizzy when it tries to adjust fuel trim based off of the wrong sensor's reading. (assuming Subaru is doing left/right bank control, and not just combining all four cylinders into one "bank". I have zero practical Frisbee experience here)
i also assume that the header will crack, stainless is an awful material for headers.
Looks awesome!
Yes, you don't put on a header like that without a tune 
Of course I wouldn't put any header on without a tune.
