Exhaust manifolds

[saxophonias]

Well not with the EJ1 . I would still love to visit Greece one day.

i have invited you many years ago and my offer is still on!
How could i make a protective shield guys?

[Firebass]

hehe dodo , now is the best time to come , just make arrangement in august

[Firebass]

yeah babe

http://yfrog.com/ju1000968oj
http://yfrog.com/mm1000971j
http://yfrog.com/5f1000972qj

i love the new sould that is mixed with bigger pipe+race catalyst+TOYO headers

[saxophonias]

it looks nice and shinny!

[Firebass]

well it is silver when is cold , and when is heated it becomes gold

[saxophonias]

this won't be happening for long. When it becomes dirty then the story is over

[Firebass]

nooooooooo , leave my headers clean and shiny :/

[Dodo Bizar]

Ehm... actually I got relatively fat runners (well most D-series headers have) but exit is only 48mm at the end. Measured it way way in the past. So that opens into 55 mm of the rest of the exhaust.

But there is a big but... perhaps this 48mm was only on the last part to make sure it fits into stock catalyc converter. It can be that 3cm earlier on the downpipe is 55mm. I know I have a similar bump at the end of the midpipe for sure. Tomorrow I'll attempt to measure outside diameter of the downpipe, that'll give me an idea. Probably 60 mm outside so inside 55mm.

[hondaNickx]

That bump on the midpipe is commen, i got that too on my ex SRS exhaust and that's more so you could use a stock rear muffler .That's actually a nasty choke point cause it goes from 63.5mm to 45mm.Atleast on my srs exhaust.I removed that choke point cause it killed the exhaust around 6800rpm and up.I could hear the sound getting softer because of that. I don't think such a bump would accur on your headers exit/downpipe.Mostly they actually open up from a choke point.

Well the smallest diameter is the choke point ,and most d-series headers come down to 50mm cause that's what the stock header's exit is too (i believe 48mm to be exact).
Some companies use bigger exits like Dc sports and those will perform better on d16 engines.
But for higher hp D14's they are great too.I had like 5 different headers ,Edelbrock,Srs,Xs power ,oem Esi,Ebay 4-2-1 and oem d14 offcourse and those all exit to 50mm except the ebay one that one was 55mm.My Bisimoto also chokes down to 55mm and then tapers open to 63.5mm.On lower hp D14 setups you might gain more with a 50mm exit ?Gain more torque and hp...?

[Dodo Bizar]

Hmmm I got some other numbers Nick:

I have 3 OEM headers lying around, they all have double inner tubing which chokes it for more:

-OEM D15B7 header: inside of the inner tube: 39 or 40 mm, sits deep so hard to measure. The inside of the outside tubing is 46 mm, the outside is 50 mm.

-OEM D16Z6 header: identical sizing as the D15B7, but the inner tube comes to the end and so I can measure it accurately, it is just 39 mm!

-OEM B16B header: inside of the inner tube: somewhat 55 or 56 mm . Inside of the outer tube: 60 mm! Outside of that tube, I did not measure since the half rotten gasket was still on it, my guess is it will be 64 mm.

I know my JCP header on the D14 was fitted with OEM gaskets, so outside diameter 50mm. Most likely no secondary inner tubing. Perhaps 1 extra mm can be smuggled in the OEM gasket, wall thickness that will ly between 1 and 1.5 mm gives an inner diameter of 48 mm, pretty certain about that. And I am guessing most aftermarket headers will accept OEM gaskets? Or do these gaskets (the conical ones) come in all diameters (50 - 51 - 52 - 53 - etc.?)