CA 4 Port head

[pnblight]

Hi Guys, Did a bit of a search and didn't find to much. So i was wondering what you guys know about the 4 Port CA18DET motors as i stripped down my doner motor for the new project CA20 motor and found thats it's one of the 4 port europene motors. Are these very common is there much you can tell me about them. I will say the port and manifold physical look a much better design for make top end mumbo.

Pete

[wa-chiss]

I wish I knew.

[davidricardo86]

Hi Guys, Did a bit of a search and didn't find to much. So i was wondering what you guys know about the 4 Port CA18DET motors as i stripped down my doner motor for the new project CA20 motor and found thats it's one of the 4 port europene motors. Are these very common is there much you can tell me about them. I will say the port and manifold physical look a much better design for make top end mumbo.

Pete

Well from what i can tell you Pete, the 4-port Euro CA isnt any better or worse. I'd say its upto the person and what theyre trying to do with the engine. I will try and explain this as best as i can.

4 port ca18det

The 4 port engine is uncommon and not to many have them. They are more difficult to find when compared to the 8 port. Some might say the 4 port is "better" because the ports and runners are larger. Also the ECU is supposed to have some revised tuning to compensate for the higher flow/fuel differences. A larger port will flow a higher volume of air at higher rpms. A larger port will also have low air velocity in lower rpms. This low speed air flow might feel laggy or weak at lower rpms to some but benifits the most at higher engine speeds and vice versa. The 4 port engine also doesnt use the ecu actuated butterfly system the 8 port uses. I've also read that repairs and parts are more expensive for the European version of the CA. Parts can be found online, Nissan dealers, or automotive parts stores so im not sure why that is. As far as repairs go, it depends on the technician and the experience of the people doing the repairs. I havent heard or read of anything else being majorly different.

8 port ca18det

The Japanese/Austrailian or all 8 port CAs are basically the same. These type use a butterfly system to help the relatively small displacement low torque engine produce useable torque at lower rpms. Nissan, Toyota, and Honda are some of the other manufacturers that have used this type of system. It does this by using two runners per cylinder with one of the runner using a small throttle-like plate which opens or closes depending on engine speed. The plates remain closed upto about 3500-4000rpm. After that the ECU sees the engine speed and tells an electronic vacuum control valve to allow vacuum at the butterfly vacuum motor. Vacuum is applied to the motor and atmospheric pressure pushes the four throttle-like plates open. What this does is allow or increase air flow at higher rpms while providing a good amount of torque at lower rpms. Cars with the majority of the power in the higher portion of the powerband tend to feel weak at lower engine speeds and suffer from poor airflow at lower speeds. Usually a car setup this way isnt to great for the streets. An engine like this is usually rev'd a little higher to get it going. The butterfly system gives the 8 port ca a little more "oomph" at acceleration and imporves fuel economy, respectively. It also helps with spooling of the turbo. You might also find emission related equipment differences on these motors too depending on place of origin and what regulations they had.

This here is straight from Wikipedia:

The CA engine is a 1.6 L to 2.0 L Inline-4 piston engine from Nissan designed for a variety of small Nissan vehicles. It is an iron block, aluminum head design with a timing belt. Earlier versions featured SOHC and 8 valves. Later versions featured DOHC with 16 valves for increased high RPM efficiency and smoother power delivery. It is effectively a Nissan RB block with two less cylinders. Components from valves to lifters, as well as bearings, are similar if not identical to the RB and VG series engines. The motor was expensive to produce being cast iron, so it was replaced in 1991 by the SR series as the primary Nissan 4 cylinder engine.

The CA series engine was the workhorse of the 1980s and was a bulletproof little engine. The power ratings were heavily choked by emissions regulations and Nissan's desire for high gas mileage. The CA design ended in 1990 with the ultimate CA engine, the CA18DET.

The 1.8 L CA18DET was the last version of the CA engine to be released. It produces 175 hp (124 kW) and 169 ft·lbf (228 Nm). It received a brand new DOHC aluminum head with 16 valves. The turbocharger was also upgraded to a Garrett T25 (.48 A/R) unit for increased flow capacity, and as such, was fitted with an intercooler to help volumetric efficiency. Fuel was delivered via Multiport Fuel Injection. Bore is 83mm, and stroke is 83.6mm. This near square design, coupled with the head design, allows CA18DETs to spin well beyond 7,000 rpms, even in stock trim. The CA18DET is a robust built engine considering that many people have produced up to 600 hp with modification. Often referred to as the four cylindered RB engine.

There were 2 versions of the CA18DET available, yet only one was produced for Japan. The Australian and Asian 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 flawed complex and heavy rocker arm actuation of later motors like the SR and QR series), many enthusists consider the CA18DET to be the best engine platform since the FJ20ET that powered the legendary DR30 Skyline DOHC-RS.

[rico05]

Haha. Glad to see my Wiki is still mostly in tact. This guy and I got into a edit war on there for a while, lol.

[pnblight]

yeah found the wiki also

so it looks like i got lucky as i am building a high end performance motor out of it and mid and top end will be the main requirements for the comp car and i will say the simplified manifold and head are a welcome relief for porting, as the last 8 port i did took ages to do properly.

And as i said before the orginal owner of this motor are stated this was the fastest CA he had owned or race again in std form (i bought two motors off him) and he wasn't sure why. Just got me thinking went i strip it to find it was 4 port.

Can't wait to get this build under way now

pete

[float_6969]

The UK guys have also found that the same setup on an 8 port head sometimes makes less power. It's possible though that they are using ECU tunes designed for the 4 port head and they aren't using the butterflies at all, which could account for the difference.

I'm hoping to do a writeup comparing the two heads in the next month or so.

[themadscientist]

What about the 8-port with no butterflies?

[sideways danny]

don't know why it should be more expensive to repair, apart from the head casting all you'd need diferent to build a 4 port or 8 port head is the head to manifold gasket, every other part is identical

[Swedish Mike]

The 4 port got one problem, the intake ports are too big.Many serious companies here weld them or use bondo to make them smaller.This head is a pure GTI head with massive intake ports and mini exhaust ports.

I usually port the exhaust side and leave the intake untouched but that´s only in budget engines.If you follow a concept from a cam company it always involves smaller ports and higher air speed.

I would love to try the 8 port, never seen it.

[sideways danny]

The 4 port got one problem, the intake ports are too big.Many serious companies here weld them or use bondo to make them smaller.This head is a pure GTI head with massive intake ports and mini exhaust ports.

I usually port the exhaust side and leave the intake untouched but that´s only in budget engines.If you follow a concept from a cam company it always involves smaller ports and higher air speed.

I would love to try the 8 port, never seen it.

???? the inlet ports are excellent as standard, the exhaust ports are the problem as they are restrictive and flow badly.

[float_6969]

Is this due to size or configuration of the exhaust ports?

[Swedish Mike]

???? the inlet ports are excellent as standard, the exhaust ports are the problem as they are restrictive and flow badly.

Yeah, that´s what I said, the exhaust side sucks. But the best head guru´s we got here hate the inlet ports.They all say the same thing after flow testing them.

I personally don´t like bondo and crap but the expensive CA´s often got new and better inlet ports.

Edit: Forgot, this is nothing a normal CA guy shoud do, way too much work and cash according to me but you get a lot of advices when you flow test a head.Always nice to know how the perfect CA head would look like if you want to build it some day.

Modified by Swedish Mike at 11:59 AM 1/2/2007
Modified by Swedish Mike at 12:01 PM 1/2/2007