ITB info for posterity

[float_6969]

The area of the intake port on a 4 port head is 1610mm2. This works out to be the same area of a circle with a diameter of 45.3mm.

The area of the port on the upper manifold that connects to the lower manifold is 1496mm2. This works out to be the same area of a circle with a diameter of 43.6mm.

Any other known info, pics of ITBs on a CA, etc. is welcome!

[sldwys]

just cos i can

[themadscientist]

WTF is that plenum? I am not used to not knowing such things.

[sldwys]

4 port ca18det runners to Nismo ITB Adaptor, To GTR ITB's with all new t/b seals, To a custom Adaptor plate setup to join to a genuine F2 Race car item... HKS Power Surge tank from one of the old ca18det silvia race cars!!

[D_Stirls]

Can you post up the 4 port runner dimensions for me?

Cheers

[float_6969]

D_Stirls, do you mean the dimensions of the sub-manifold?

[D_Stirls]

Yep the dimensions of the ports where the secondary manifold joins the head.

[float_6969]

4 port head intake port dimensions
5.7cm across, 3.2cm tall, oval shaped ports.

Upper manifold, runner port dimensions
5.2cm across, 3.5cm tall, oval shaped ports.

I've still got my 8 port head in the garage, I'll get a measurement of the diameters of the ports this weekend.

[D_Stirls]

EDIT!!
Maths was wrong,

[themadscientist]

Can you turn it into an image?

[D_Stirls]

Yeah i can, but people can't check my maths (excel formula's) with an image, lol:
I'm sure the maths is correct anyway.

EDIT!!
But i'd be Wrong LOL

[themadscientist]

I'm ill-equipped to question your math unfortunately. I suck at it.

[D_Stirls]

Well my maths is wrong, LOL

VVVI'll post up a fixed up version.VVV

[float_6969]

Did you actually measure both ports on the 8 port head? They're not the same size. The port with the valve is larger IIRC.

[float_6969]

The way I measured port area was to get a piece of engineering paper (the paper with the lines on it that are evenly spaced) and trace the gasket onto it, and actually count the area in mm². This does leave a margin of error as near the edges, I have to round up/down on the squares that were cut off. Your measurement is close enough to mine, that it's probably right. But the primary manifold port is way off from mine. Is that the math that's wrong, or is my count way off?

[criticalyet]

Life is like a chocolate in box, you never know what is the next!


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[themadscientist]

Life is like a chocolate in box, you never know what is the next!


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[url=mad done ripped out my spam[/url]

Yeah, not buying your chocolate, but I got something for you.

[D_Stirls]

Did you actually measure both ports on the 8 port head? They're not the same size. The port with the valve is larger IIRC.

Yep measured them with a bore mic', they are both the same size.

[diehl]

Hi, i'm new here but have had a ca18det in an s13 for a long time now and a long term project of mine has been developing and making an ITB setup for it.

it has 46mm throttle plates with wasted shafts, transitional casting from round to oval port shape. custom surge tank for idle control and fpr etc. uses std idle control gear and tps. custom cast plenum with integral belmouth entry into throttle port, i had a blitz bov on the side of the plenum but have lost that and replaced with a recirc bov in IC piping. All runs smooth and clean with factory computer too!

i hope these images are viewable since this is my first go at getting some posted!!!

[themadscientist]

Looks great!

[float_6969]

Very nice!!! did you cast all of that yourself? I've seen seriously considering playing around with aluminum casting for this exact reason.

[tommey]

Wow! Really nice!
Please post more pics!

[ska69]

could you please post some more pics and info?
are those motorcycle throttle bodies?

[sldwys]

Hey Diehl - Am I saying right, By saying you are from New Zealand ? Your cert tag looks familiar.

[diehl]

Hi again, yeah i'm from NZ, my name is Chris. here is some more info and pics for those interested.....

The throttle body housings and plenum are all cast, heat treated then machined. I made all the patterns myself but had a foundry pour the hot metal. I took this approach over billet or fabrications with the intention of making these to sell as complete bolt on sets (this was about 8yrs ago!)...... but like any good minded project there is always other distractions or commitments that get in the way so i only ever got around to making the 1 set you see in the photos.

Castings are always a nice option for production, as they are cheap and very functional if designed right. personally i think they can look really good too if done well.

With the original intention of selling these i made every effort to reuse components from the std manifold that would ultimately reduce the final cost and complexity.... eg the AAC valve, Air Reg valve, TPS, several idle air hoses and std throttle cable all have been reused. One thing that had to go was the air con idle valve but i lost the AC in my car along time ago so wasn't a big probleml for me. Also the clutch master cylinder had to be swapped for one from an R31 because it was slightly shorter.

It proved very challenging at times to get this all to fit and work as there is not a lot of room under the manifold when you have to try get idle control gear and a surge tank fitted under there.

Custom linkages, surge tank, shafts and butterflys had to be made along with IC piping to suit the lower position of the entry into the plenum.

here are some more photos....








I also made brackets and adjusters to shift the alternator to the other side of the engine, this was to help with access under the manifold if required, also doing this meant i could under-drive the alternator by running it from the smaller middle crank pulley.....

[themadscientist]

Any chance you could spit out another one?

[ragenasian]

Any chance you could spit out another one?

And maybe two

[roplusbee]

I may be interested as well. All depends on whether or not my deal goes thru for a 240SX /CA for sale on the forum. One quick question though, is it impossible to keep the AC with this setup? I'm going to be in either TX or AZ with this and both places are hot as ballz. Thanks.

[float_6969]

I think he just moved it to make it easier to get under the manifold for things like the oil filter, starter, coolant lines, etc., so I'm sure you can keep the A/C.

[ska69]

speaking of the alternator relocation - iirc, the fwd ca18de has the alternator mounted on the left side of the block, as both blocks are identical, is it correct to say that fwd alternator bracket would allow relocation to the left?

I'm too interested in keeping the a/c, I could sacrifice the p/s though