How much performance gain from headers ??

[jondee86]

I am seriously considering the HKS Super II header for my (RHD) AE86.
The factors that I like are :


(a) It is 50 dia outlet, which indicates to me a street/strip header.
(b) It is 4-2-1 design which is considered better for mid-range torque.
© It has a flexi-pipe built-in.
(d) HKS have been around for a while, and should know a bit about
designing and building a decent header.

The curious thing is, that after extensive research on the interweb,
I can't find a single dyno test or other piece of hard data. Nothing that
proves these expensive shiney things, actually have any performance
benefit over the stock cast iron manifold

And it doesn't seem to matter what brand... none of the manufacturers
web sites that I have visited has a dyno curve, or even a claim for how
much extra power you can expect from fitting their product !!! WTF ??

Do these things sell on bling factor alone ?? Should they be classed
with such other performance equipment as chrome shifter knobs, TRD
oil filler caps and those vortex fins you put in the intake tube ??

So, please help me out with some hard evidence. Has anyone actually
installed a header and made some measurable power ?? I'm not
expecting miracles, but a documented 5% increase would be great

Cheers... jondee86

[MartinS]

Try the fujitsubo website, the have a dyno sheet on their products.

[Project D]

http://www.fujitsubo.co.jp/product01.php...0000002592
http://www.fujitsubo.co.jp/product01.php...0000002597

[jondee86]

Yup... I have looked at those product specifications. This is a 4-1 design,
and the 4-1 design is known for making extra power at high rpm, while
losing power below 4000 rpm.

Such a design is less suitable for a street driven car.

Still, it shows >5% increase at the top end which would be a good result
for such a header. On the Toda site it says that their 4-2-1 design
achieved almost the same peak power as their 4-1 design, with 15%
more torque lower in the rpm range. I would like the Toda 4-2-1

However, the Toda piece is expensive !!!! For this reason I am trying to
establish if the HKS header would have a similar result for less money ??

Cheers... jondee86

[MartinS]

Dyno on the toda? anyone?

[Jango_Fett]

power gain is much lower then expected ( I have custom 4-2-1 )
yea you have ++ torque but money to power ratio is low.

[jondee86]

Quote:yea you have ++ torque...

This is what I want to hear Especially if this torque is produced in
the low to medium rpm range... say, 2500 to 5000 rpm. Jango, can
you be a bit more specific about when you noticed more torque ?? For
example, did your 4th and 5th gear acceleration improve ??

Quote:... but money to power ratio is low.

True. I have had a response from HKS saying that they recorded a
typical increase of 8 PS above stock (and I don't know if that is at the
wheels or at the flywheel). But, every little bit helps

What I am hoping to achieve is a long, smooth torque curve. Peak
power is of no particular interest, as that's only good for bragging rights
in the bar :wink: I want my car to punch out of corners in 3rd gear,
and accelerate strongly from 3000 rpm to 7000 rpm

Only time will tell if such a thing is possible.

Cheers... jondee86

[thanhngo]

thats full exhaust (obx header, cat, catback) setup vs a oem with back to back dyno testing.

This is probably one of the most factual/practical examples of 4age engine modifications i've come acrossed.
http://www.whyturbothat.com/project86%20.html

1 thing is for certain, trying to get more power out of a na 4age isn't cheap.

[Dimitri]

i dont think youre gonna find them improvement you hope for from exhaust modifications.

maybe a shorter final gear, or a 7age?

[Jango_Fett]

Dimitri Wrote:i dont think youre gonna find them improvement you hope for from exhaust modifications.

maybe a shorter final gear

Dimitri is wright .
biggest difference is that when I go up a little hill in a 3rd gear, 2500 rpm , whit stock exhaust I have to down shift and whit new one just a little bit more throttle car goes up hill whit no problem..
if you plan to put a 15" wheels go for the header ,it would be easer for the car to handle extra load...
but I payd my exhaust 500 euros , and there is one dude on this page selling
blacktop for a 950 euro, do you catch my drift ?