4 port vs 8 port

hey dan,

huge apologies man... you were definitely right. i finally got around to finding those pics on the nico forums.

the link is here, http://forums.nicoclub.com/zerothread?id=185406&page=1,

and its an excellent pictorial reference for anyone rebuilding a CA18DET.

but beware - there are many hig res pics of the CA!

i chose just those that relate to this discussion!

A 4 PORT HEAD.

AN 8 PORT HEAD

AN ILLUSTRATION OF THE DIRT THAT CAN BUILD UP WITH THE 8 PORT HEADS. MY GUESS IS THERE IS NO FUEL THERE TO WASH EVERYTHING DOWN.

A LITTLE EXPLANATION OF THE SIZE OF THE PORTS.

HOW THE PORTS BUTTERFLIES ARE ACTUATED.

THE UP/OPEN POSITION.

THE CLOSED POSITION

Do you not think that the butterflies themselves would be a restriction at high air flow??

they could be i guess...

but its like saying i dont want to have sex at high air flow, because the condom themsselves would be a restriction.

or maybe like saying ...

nah, never mind... i think you're splitting pubes there sunnybooi! 😈 😈

lol thanx veecee, no prob mate.
I havent got the best way with communication.

Anyway those pics u put up show what i was trying 2 say about how dirty things in there are. Mine was terrible.

have you got narcosleepy????

huh what

narcosleepy!

its a reference to the word "narcolepsy". but i used it in the wrong context.

nevermind!

but 2am is no time to post here, you should be sleeping or having sex!

:200sx_confused1:

you too, boywonder!

VC you say that the area of the 2 ports in the 8 port head are bigger than the 1 port in the 4 port head, it doesnt look like it in the pictures!?

Any one got any measurements for the 4 port head??

thats what i read somewhere. probably on that same nico thread.

its hearsay, dont get pissed with me if its wrong!

Thanks for the pics VC....the nico club is blocked here....VC can you try and find out what happens if you set this "screw"?

That screw I would amagine would do the same thing as on side draughs, it is there to match the one set of throttles to the other, you would need a murcury gauge to set them up.

i dunno man.

all the butterflies are connected to a single shaft.

so i would imagine that "nut" would set the closing position???

veecee wrote:

i dunno man.

all the butterflies are connected to a single shaft.

so i would imagine that "nut" would set the closing position???

Yip....that is my first impression, or it could be the setting of when it opens....with other words, it needs more boost for it to open....

ya!

So i conducted a little test.....it seems and I say seems because this was not any tests done with scientific proof.....with the butterflies connected, it seems the car is a bit more smooth and uses a litlle less petrol, with it disconnected it seems that the boost comes in a bit later....looking at the guage, funny enough I can not feel any power losses and can't say there is more or less power with or without it connected.

Even though it seems as if the boost is coming later on throtle the power does not ship up the rev range....my low and mid feels still the same on the same revs...... :?:

So they butterflies just made the car smoother and lighter on petrol, no real torque difference??

Not that I could feel with my butt dyna....then again I did a mod a long time ago that gave me around 15kw on the dyna more but it felt slower to me....so there could be but I did not feel a differance.

Chanses are that there might be a small diffs because of the boost seemingly coming in urlyer on throttle position...

A BUTDYNO is the only dyno I trust, if you cannot feel the difference it is pointless in doing the mod unless you race for times.