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Discussion Starter #22
greddytunedhatch said:
I guess I'll sound stupid, but isn't that header a little long with a lot of bends? I know a couple of guys that own/race a car, and their exhaust had smaller bends and went straight out the side of the front bumper. It seems to me that that header has to many bends to be as affective as you'd want a race car to be. I'm just curious to know how you came up with that design. Let me know...

Looks mean tho!
here is a little reading from www.bisimoto.com

bisi states, "My experimentation with fluid dynamic concepts of "flow in pipes" proves that you can achieve the same flowrate and fluid friction in a given straight pipe in one of specified bends if sized properly. In simple terms, a smaller stright pipe flows the same (and experiences the same friction losses) as a calculated "bent" one of larger diameter. There is plenty of scientific documentation on this subject as well. Hence, this concept is one I use on my own race car to generate ideal HP and torque numbers, with a very simplistic setup: simple carbs, a SOHC, and ignition!"

his production header uses approx. 26" primaries with 1 5/8" piping and seems to do very well. this as well as other research lead me to shoot for the upper 2x" area for this unit, and i when i get my motor in i find out how it performs. i will also be running Mikuni PHH44's with a TWM intake manifold on this motor.
 

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Discussion Starter #24
i have had the piping for about 5 months, finally figured i had enough info to know what i wanted to shoot for, so i started cutting. i also finally had a little stretch of time where i could get to work on it, since it was about 0 degress here lastweek, without the windchill factor.
 

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I have seen custom fabbed headers on competitive cars with primaries as long as 31".
 

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Discussion Starter #32 (Edited)
b20vtec said:
nice header, have you thought about using stepped primaries?
yah i thought about it but decided not to do it on this header. also this will fit 92-95 chassis i know, because that is what i built it for, but i dont know about EF or EK chassis. im thinking EK probably wouldnt be a problem, but EF's seem to be a tighter squeeze.
 

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D15B7 said:
hey isn't that my previous avatar?? btw great header..can't wait to see results.
fits most applications?
I have no idea?? I got a couple more pics of her, I'll change it if you wish...

Thanks for the info Lohatch. I'll be very interested in seeing the numbers! Do you have a stock header you can use as a control (with the same engine)? That would be a great comparison.
 

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i'd pay a good 220 or so, to have one, welded just as it is, not even nice and shiney, lol. and we all know how much power the bling gets you :p
 

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Discussion Starter #40
eventually i might get into header production, but i dont know if it would use this same design or something different. this one is just kinda one-off for my car. i bet i have over 30 hours just in mocking it up to the point you see it in the pictures. so if i sold one for $220, after the $130 for the mild steel materials, i would be working for about $3 per hour. handmade headers arent cheap. here is something jason posted over on HT about ANR headers(there was a conversation about some cracking issues they had back in the day)

Here's the deal - this cracking situation is 95% due to installation and usage. Meaning the way the end user installs it and says they are going to use it vs. the way they really intend to. An-R has no cracking problem - but they are always trying to step up to what ever demands this and other sites like it put's on them at any giving time - example.

I dont hear mush crying about the DC header cracking situation......DC is and has been one of the biggest Header makers ( import ) is the past 10 or so years. I can tell you we get atleast 2 headers a week at my shop that have cracks between the flange and runners........DC has an anwser sorry, or send it in and we can see what caused it. But that's ok because it's DC - And let's not even get on other part makers or hell shop's

Everyone wants a "race header" a "race car part" and "whatever makes the mostp power" but for the cheapest price.

If you have ever made a turbo manifold or header -- it's not the material cost that makes a 1 off header 600+ dollars, it's the time/design/testing/advertizing that you are paying for. Hell at 600 it is dame near too cheap...

If you want a race part make sure you know what that is, if you want a street price get something that is made overseas @ 1000pc at a time....see what they do for you when it cracks. The people that make parts are the best until someone copies it for 10.oo less.

As for fixing the cracking issue - it is fixed with mounting your custom header to you custom car and swap ( honda factory has 2 as well as a flexpipe ) also installing the header the way it was designed and explained buy the company you buy it from ( if the company cant answer your questions call another one ) and coating a header will allow it to last instead of rust ( but then the cost to make it will go up / so will retail cost so understand )

Jason Whitfield


some good reading right there. over a year ago i was looking into doing an all motor sohc build and i was doing a lot of reading and the bisi header looked like it would be a nice peice to have, but i was like damn $560. to me at the time that was a HUGE investment for a couple HP, and i never did buy one. i ended up running a turbo setup instead. but now i completely understand and appreciate the price of handmade parts. if you want top of the line stuff, expect to pay top of the line prices. thanks for all the replies guys, it is good to see :)
 
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