i have an engine to assemble using all the good parts from two engines. one engine is the kind we're used to. it has 4 intake runners.
the other is a JDM spec 8 port runner system.
which is better to use, specially considering that the car its going into was a eurospec ca18det, and therefore doesnt have all the stock hardware that it needs to properly control the butterfly - i would really only be able to control it with a vacuum/boost reference.
also i found this on the nico forums, the dude thinks there was lots of deposits because the runner's butterfly wasnt opening properly.
so i'm not entirely convinced that 8 port runners are the way to go in this case - is this concern of mine silly, or do you guys agree???
ReeceZ wrote:I'm sorry... I couldn't help it. Please no one wish any hateful shit on me, I own an SX already
I've seen it summed up quite simply on the Nico Club forums:
8 port gives better low down torque and throttle response at low rpm but chokes higher up the rev range
4 port has less low down torque but flows a hellava lot more higher up the revrange
From what I've heard for all out power stick with the 4 port, its one of the most sought after parts in USA as they get all the 8 ports motors from japan.
VC apart from what is best, as you know you will get thousands of responds to suggest one or the other, there are never a onesided answer, to me it comes down to something simple, try and buy a gasget set for a Ca18det, they all come with a 8 port gasget, I haven't seen a gasget set witch has the 4 port gasget, unless you buy from nissan....and most properly would be 8 port aswell....
I'd say use the 8 port but try and remove the butterflies and work without them, to get that working properly anyway is a mission.
Draco wrote:VC apart from what is best, as you know you will get thousands of responds to suggest one or the other, there are never a onesided answer, to me it comes down to something simple, try and buy a gasget set for a Ca18det, they all come with a 8 port gasget, I haven't seen a gasget set witch has the 4 port gasget, unless you buy from nissan....and most properly would be 8 port aswell....
I'd say use the 8 port but try and remove the butterflies and work without them, to get that working properly anyway is a mission.
Or you buy a Payen gasket set... which fellas' I'm sorry to say is now extinct, Alert contacted Federal & Mogal for me and said they don't have any more stock.
Just remove the butterflies completely. Surely the diffrence cant be that much and your not trying to build a 600hp CA18 either?
Id understand if there was general consensus on this matter and some proof in the form of flowcharts and whatever. But since there isnt the diffrence must be negligible
Ok...I bypassed the pressure regulater or vacuum tank to the butterflies, so the butterflies are still there but they do not work, they stay open all the time.
I haven't taken the time to take the intake and manifold off to see if I can totally remove the butterflies, although they are open all the time I feel they are still restricting air a little, so my advice....if you can take them out totally without any problems, do so.
You remember the problem I had with the car when I change gear then the nose dives and then pulls like hell....it was because of the butterflies closing on gear shift (vacuum) and not opening fast enough when giving foot again. The whole principle of what they are trying to do is great but if the the timing and setting on the spring(small screw in middel to set angel) of the butterflies are not right it will influence the whole thing and this then turns into a restriction rather than a low torque "upgrade".
Also, my logic, if you could take the butterflies out and flow and match port everything I think it would be a big flow diff between the 4 and 8 port.
Sorry to chime in again, but why the HELL are you guys suggesting he keep the 8 port intake, but remove the reason they made it 8 port, i.e the butterflies, so all he's gonna end up with is a KAK flowing intake, with no high velocity air atlow revs when the butterflies are closed!
Fit the 4 port and get it over with, if you only get 8 port gaskets I can borrow you a scissor you monkeys.....
Flow people, FLOW, Crikey! how many times must we say it!!!!
Sokar wrote:Hmmm, I see now that the HEAD itself is also 8 port.
So..... I'd angle grind the mofo!
FLOW!!!!!!!!!!
Stop whining you dingbat.....I drive like this and I have a good amount of power(eg flow), remember I was on the stock turbo housing with less flow than phinx and I stayed with him on the first run till the BUTTERFLIES screwed me, they cept opening to late....he had a bigger turbo, which I found out the other day and some other stuff where I had not, so don't tell me the 8 port can't flow beemer chick
PS.....other than what people post on forums, give me the scientific proof that the 4 port flows better....please
Here's a Snippet:
----------------------------
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. 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.
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.
--------------------------
PS. Shmuck! I just loooove the way I keep schooling you about your own car....
