CA18DET JDM Head

[meminto]

This is a pic of the semi final stage work on my jdm ca18det head.... just one small aspect of my build...Enjoy

[themadscientist]

What did you do, grind out the port dividers?

[meminto]

I didn't but my engineer did... based on calculations of cross sectional area and flow requirements...

[themadscientist]

More techinical than me. I grind things out based on how much they piss me off.

[articzap]

So you removed the secondaries, killing your torque curve and have not fixed the position of the fuel injector? This just looks like its going to fail based on flow dynamics.

[themadscientist]

go fix your regulator smartie

[articzap]

Its 2am and I have no garage.

[themadscientist]

need a flashlight? 2 AM, go to bed man. Ain't nobody here but me and I ain't worth it.

He could weld and drill the sub manifold to center the injectors and the difference on the bottom end is likely negligable. The RB used to have that silly secondary butterfly BS and it was axed on the second generation. I'm not sure in the euro four port is a second gen CA18 head but I have no doubt if there had been one it would have lost the butterflies.

[meminto]

As I said it's a small aspect of my build...

Can you please provide some technical data based on why you think it will fail?

Not having a go, but I am interested to understand

[themadscientist]

supposedly the closed secondary butterfly keeps port velocity up in the open port and then opens as vacuum falls off allowing the socond port to flow at the top. I think it's a negligable gain at a part of the powerband nobody really spends any time in and is much more detrimental in the rest of the operating range with that big chunk of metal in the secondary port. Not to mention the injector firing down one port and not the other. Keep it up, I think you are on the right track. Get that injector centered though.

[meminto]

Sorry I was being a little facetious on that one mate

I understand how the butterflies work, what they are used for etc...

I did have a long chat to my engineer about retaining them, and at first he wanted to keep them however the flowbench calculated otherwise...

I also wondered about injector placement, but I trust my engineer's judgement... if it needs to move he will do it...

[themadscientist]

What exactly are your engineer's credentials? Is he is an engine builder primarily or crossing over from another field?

Have him take a look at this and see what he thinks. Since he has done almost exactly what I suggested to your manifold and head I would expect him to agree.zerothread/351176

[meminto]

He is an engine builder...

No other field, he is primarily contracted to build engines for the motorsport industry...

He has built motors before for me... But I have also been to other engineers that were supposedly reputable, but they have never come close to his level of workmanship...

[themadscientist]

keep us posted. I have a few guys I know much more knowledgable than me whose brains I can pick. I still do all my own stuff but it's nice to know I can throw out my ideas and have a smarter guy say or . Keeps me out of trouble.

[meminto]

I have already run the flow cfm and duration/lift results past a mate whose advice I trust more than anyone else when it comes to this particular motor... once I get the actual data sheet to him he will be able to understand it much better than I will...

I will send my engineer the link to that topic...

[ard]

i really do not understand you guys - why you build engines with those sh*tty lowport CA heads? as i wrote in other thread - get a proper highport (4port) head!i know that only early japan models had highports and almost all european had highports. in fact it is jdm emission bullsh*t and better torque blah blah blah built in late jdm cars. its a god damned restrictor on high rpms if you do not grind everything at those butterfly valves if you grind/port out highport you will get even better flow rates.

i do not know about prices in usa of 4port, but in europe it is 75-150usd for one with valves ant lifters (without cams).

some info from wiki

There were 2 versions of the CA18DET available, yet only one was produced for Japan. The late model Japanese CA18DETs received 8 port (low port) heads, with butterfly actuated auxiliary ports in the lower intake manifold which corresponded with 8 ports in the head.

Below ~3800 rpms, only one set (4 ports open, 1 per cylinder) of long, narrow ports would be open, accelerating the intake charge to the cylinder. This allowed for quick spool and good low end tractibility. At the 3800 rpm change over, not only would the ECCS shift into batch fire (as opposed to sequential) fuel injection, but it also opened the second set of short, wide ports (8 ports open, 2 per cylinder) which assisted in high RPM flow.

This motor is known for stronger torque characteristics, as well as faster spool at lower RPMs. However, due to displacement-based taxation and cost of emissions testing in Europe, the CA18DET was sold as the only available engine in the S13 chassis 200SX (Euro model) until replaced by the S14 in 1994. The Euro motors received the 4 port (high port) head and intake manifold, as well as revised ECCS ("Electronic Concentrated Control System") parameters.

Power was not increased, but high RPM flow was indeed improved, making the 4 port CA18DET the most desirable of the late generation Nissan turbo 4s. Due to superior head design (cam on bucket, as opposed to the complex and heavy rocker arm actuation of later motors like the SR), many enthusiasts consider the CA18DET to be the best engine platform since the FJ20ET that powered the legendary DR30 Skyline DOHC-RS.

[themadscientist]

The CA is not worthy of mention in the same sentence as an FJ20.

Power can be had from the 8 port head, well over 400hp when they were in abundance in Japan on the street. In all honesty most people here will never max the ports out even with the butterflies in place. I am a top end guy so I will remove them but don't yank them just because you think you are supposed to keep up with the jines or something. Leave that monkey see monkey do crap to the SR guys.

[niscort]

i really do not understand you guys - why you build engines with those sh*tty lowport CA heads? as i wrote in other thread - get a proper highport (4port) head!i know that only early japan models had highports and almost all european had highports. in fact it is jdm emission bullsh*t and better torque blah blah blah built in late jdm cars. its a god damned restrictor on high rpms if you do not grind everything at those butterfly valves if you grind/port out highport you will get even better flow rates.

i do not know about prices in usa of 4port, but in europe it is 75-150usd for one with valves ant lifters (without cams).

some info from wiki

care to actually explain the actual differences of this "high port" and "low port"?...

or is wiki your gospel?

and can you tell me at what cfm the butterflys become a restriction? or are you on the bandwagon...

[ragenasian]

Well here in Germany good lucking paying 75-150 USD for a head. I can get them all day long but people are starting to collect this stuff and not let go of it. Kind of like TMS here

I guess us EURO guys are lucky with getting the 4 ports. I don't have to grind anything or move anything.

Butterflies? What stinking butterflies? We dont' have those either

[themadscientist]

There was a different casting on the JDM CA18DETs in the S12, maybe the same for the US spec CA18DE in the 200SX. the kouki 8 port and the euro 4 port have the same port height so grinding out the divider on an 8 port and centering the injector would be pretty much the same.The 4 port was not sold in Japan. Some guy is selling a 4 port on the auctions for about $1500. I would not be surprised if Rage sold it to him.

Well here in Germany good lucking paying 75-150 USD for a head. I can get them all day long but people are starting to collect this stuff and not let go of it. Kind of like TMS here

[jedimindtrick]ixne, keep me posted[/jedimindtrick]

[ragenasian]

Hey Hey watch it. You are my one and only over there

Hey if it sells I will send you 5 more 4 ports

[themadscientist]

thanks for the reminder, you're right. I'm off this week. I should be able to get it out.

[ragenasian]

Just messing with you

I am still waiting on my CA to be delivered from Austria anyways. Should be here next week. Then I can start dropping it into the AE86.

So take your time man no rush.

[ard]

i dont know what exact cfm 8runner begins to su$k horse di$k, but you can search at sxoc.com (uk biggest silvia community) for exact numbers etc.

8port runner has two narrow ports - one for low rpms (little diameter - you get better flow, better "air supply" (dunno how to write that in english)), on high rpm both ports are open to maintain the same air pressure and speed in runners.4port (highport) has 4 big ports - not very good air flow at low rpms, but you have no top end restrictors.read some theory about air flow, inertia and try to use your brain thinking about exhaust backpressure (the same air flow principles)

somewhere i had found flowrates of 8port/porter 8port/4port/porter 4port. ported 8port had few % better air flow than stock 4port. ported 4 port was unmistakable the best.

i do not rely on wiki's, but i wanted to show info about where you can find highports and lowports.

in fact my friend has both 4 and 8port heads. i really do not know how it got there in euro, but it is practically useless.

ps. sorry for my poor english

[themadscientist]

I think I have taken quite enough time. You have been patient as can be.

[themadscientist]

i dont know what exact cfm 8runner begins to su$k horse di$k, but you can search at sxoc.com (uk biggest silvia community) for exact numbers etc.

8port runner has two narrow ports - one for low rpms (little diameter - you get better flow, better "air supply" (dunno how to write that in english)), on high rpm both ports are open to maintain the same air pressure and speed in runners.4port (highport) has 4 big ports - not very good air flow at low rpms, but you have no top end restrictors.read some theory about air flow, inertia and try to use your brain thinking about exhaust backpressure (the same air flow principles)

somewhere i had found flowrates of 8port/porter 8port/4port/porter 4port. ported 8port had few % better air flow than stock 4port. ported 4 port was unmistakable the best.

i do not rely on wiki's, but i wanted to show info about where you can find highports and lowports.

in fact my friend has both 4 and 8port heads. i really do not know how it got there in euro, but it is practically useless.

ps. sorry for my poor english

Cars have pulled 9s on 8 port heads so your your statement is false.

[ard]

i'm not in mood for big argue, but take a look at norris desgins demo s13 - over 600hp (on crank), and i know one ca at australia with 550whp - he says it is most powerful ca outside japan. i don't know their 402m times, but they uses ported highport heads. all tuners uses 4port as a best solution for high hp.in fact i haven't found (did not search really) a fast 8port CA. if what you said is true - 9s lowport, i would be glad to get more info and specs.

[themadscientist]

there is no argument.

1 the four port flows more

2 the eight port flows a lot too but a lil less.

Here they are side by side

You have to be careful with blanket statements like "because this is bigger that is useless" You would find it cuts both ways should you stray into the SR20 home turf.

[ard]

sr20 good pointi did not want to be THAT categorical, i agree remember that all i say is my opinion - 8port is good for stock-little modded street/daily car, because of better and smoother torque curve. and drilled 4port for top-end power.

edit: btw - i own ca18det and sr20de

i do not see any advantages of lowport head in performance tuning - its only advantage is good air flow on low rpms with half of ports open, but you cut it out and port everything! so logically - whats the point of using it, when you can get 4port and with same amount of money/time/effort, get better head and intake manifold (or less effort to buy/make aftermarket one). i did not make a lot of research, but i found your thread talking about bad position of injectors - one more disadvantage of lowport.anyways i think that you know what i am talking about - look at it from builders side - what setup would you use? what setup requires less money/effort?but taking in hand that you want JDM engine which makes your car run "better" and you can write in modlist - i have something jdm, but i have no idea what are the differences between jdm and europe domestic market ca18det ones.

what are cost differences of 4port and 8port heads with manifold in us&a?
Modified by ard at 4:20 AM 7/26/2008

[niscort]

still confused... the ports look no higher, nor do they look any lower. so wtf is low and high? maybe you could use your brain to answer that question?

so... sxoc is the proof? lol. in the uk, where they have a 4port head? might bit a bit of a one sided view..no? and I highly doubt there are any data about flow for the jdm head on sxoc not to mention i doubt there would be a single person with a jdm head and ecu and vacuum tank that runs setup correctly.

probably best to stick to facts if your in no mood for an argument..