Exhaust manifolds

[hondaNickx]

Dyno it dyno it dyno it (but I believe...)

Have you seen Bisimoto dyno chart of his D15 ...?
I have seen more then enough proof to know these work

If i got the chance i dyno it for sure , although the header isn't made for my current D14 setup but for my level 2 cam and so... But it will make way more power then my cheap ebay header anyway.

[saxophonias]

of course it would be no surprise to give power throughout the powerband as it's a bisimoto magic thing , still i would say that this would be an overkill in low and mid revs. I had read in the past that it can produce power until 10Krpms

[saxophonias]

This is the header i found on bisimoto's site

We receive numerous inquiries around our unique, true merge collector, header designs. On a popular enthusiast message board, Engr. Bisi Ezerioha responded to questions around the logic behind his designs, and the reasons why they resemble Formula 1 units:

"Greetings all, I was notified of this post, and quite suprised at some of the comments generated. The rationale for the bends on my designed header is as follows: I noticed a given area beneath our vehicles that can assist with the scavenging effects of the header. This was realized with manometer/ pressure differential tests done on my crx, and 2 other civics. I was pressed to design a unit that could terminate at this area for obvious reasons. I also had the additional challenge of an ideal length and size of header piping to allow optimum exhaust pulse tuning, which was dependant on RPM range, displacement, etc.

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!

As for the F1 analogy, yes, clearance/aero package may be the reason, but I had compartment constraints as well. In regard to underhood temperatures, I always suggest ceramic coatings...just like on my vehicle. (This coating also promotes significant longevity of the header unit; stainless steel units provide the best longevity and strength) I am not a businessman trying to sell headers. I am an engineer, scientist, and racer who desires to bring great technology to the masses...at a decent price."

another picture here


the v1

[mynameisowen]

Its all great saying that bisi rocks, we know this. What other options are there available? are the ebay headers really that bad? Obviously the more the you pay the better gains and quality but what If I dont want to pay $600 for an exhuast manifold???

[Raimundo]

Owen, ebay exhaust are no that bad. Since you live in UK, I would recomend you use JapSpeed exhaust manifolds, cause they have high quality (for the price you pay) and are resistent to corrosion (and that is a problem in UK).

JapSpeed go for around 100pounds, I bought mine for 99pounds, with 34pounds of shipping to Portugal! (ebay domestic market!)

[saxophonias]

One question just out of curiosity
When Bisi produces a header for d14, what might be the differences to a d15 or d16 unit? The size of collectors and primaries?
Moreover the term race applies only for performance and the lack of p/s or a/c or does it have to do with the emissions as well?

[hondaNickx]

One question just out of curiosity
When Bisi produces a header for d14, what might be the differences to a d15 or d16 unit? The size of collectors and primaries?
Moreover the term race applies only for performance and the lack of p/s or a/c or does it have to do with the emissions as well?

The difference is he changes the primary & secundairy pipe diameter and length ,the exit diameter and the merge collector according to your engine specs.The basic design remains the same (the bends ) everything can and will be adjusted to your car.
The term race means it's designed for use in a race or track car.That's why there's no P/S-A/C .A header alone won't effect your emissions ,if you start with a level 2 cam and everything then it might.It really depends on what mods you got and a really good tune.

For most of us a regular 4-2-1 ebay will do the work and some of them are not that bad.A Dc sports is a good header ,but that aint cheap either .If you would pay a little more then a DC Sports header you got yourself a Bisimoto header.

N/A tuning parts cost a lot of money if you want to gain lot's of Hp.You can go cheap and make a nice gain but not the max gain.Or you can go expensive and gain lot's of Hp.In my opinion N/a tuning is more difficult then forced induction.
If you want cheaper Hp you're better off with a Turbo.
I did it the cheap way and i want to try the more expensive way now.

[Dodo Bizar]

Sometimes I am thinking of crossing to the turbo side of life.

But then I think and I want to understand everything and make something really 'good' and 'special' out of what I got.

So not the brute force approach, but trying to get out of it what is in it. At these moments a realise I should stay NA...

[saxophonias]

This is also my dream. Lightweight, 150-160hp, with close gears, good suspension and sticky tyres. For me it's all about feeling and driveability.

[demolik]

if you want turbo... beter get nissan or subaru

back to the topic, I've instaled yesterday some 4-2-1 custom (more like ebay) header and... I'm little bit dissapointed, I thought that get more power. Im not sure now if this headers dedicated to d16 is to big for d14 and fumes loose speed??
One dude on my local forum made test 4-2-1 ebay header with stock d16z6 4-2-1 header, and this stock d16 gave better resuts. But... ebay header are so so diffrent that propably you never find two thesame copies, becouse it's not made in proffesional garage . If you're lucky you get some with better performance.

Anyway my cluth is almost dead and it's might be reaseon why I don't feel incrase