99Automagic

All of you 99 cali spec owners know we have this round thing that gets in the way when we do our KS replacement. The technical term for this annoyance is, Swirl Control Valve Actuator. I never paid much attention to this part til a few days ago. I was tinkering around under the engine, decided to play with the throttle a bit just annoying my neighbor.

I've read somewhere this actuator does something past 3k rpm. But when I was reving the engine, I did not see the actuator react to the rpm changes at all. It's setup with a lever/hinge joint but it was not moving at all, it just sat there stationary. I tried moving it by hand and it moved freely through out it's range of motion.

Since i was under the hood anyways, I decided to throw the stock air box on for a change of pace. I've been running the stock mid pipe with an Apexi filter.

So the stock box is in nice and tight, I begin reving the engine again, and low and behold, the actuator starts moving. Just to be sure, since I was bored, I threw the cone back on. As I suspected, the actuator does not respond when the engine is not running the stock box.

Now for the *** dyno test. I took it out on the highway and drove like a teanager chasing tail for about half an hour or so. I dunno, but my *** dyno tells me, I don't feel the power drop off as much past 5.2k rpm. It pulls really nice all the way until my auto shifts. The drop off was really noticable with the cone filter.

What I'm thinking is, that actuator was Nissan's first attempt at increasing airflow at higher rpms. I saw a video with someone's mevi and it has the same lever on the side of the intake manifold that kicks in at certain rpms. It's not as efficient of course, than the mevi, but this sort of makes sense to me. Nissan came out with a true VI in 2k. Maybe they tested the theory out on the last yr of the 4th gens? Or am I just thinking too much into it, and it really is just for emmisions like people say?

1FSTMAX

iTrader: (29)

that's no vi.. the swirl control system helps lower emissions when the car is cold.

njmaxseltd

iTrader: (19)

The Swirl Valves only operate when the engine temperature is cool. Once it's up to operating temp, they stay open all the time.

If you'd like to see then operate, check them first thing in the morning, cold engine. Start the car and slowly raise the RPM's while watching the actuator. At around 2500 RPM's they open up. Again, once the engine is up to operating temp, they are open all the time.

99Automagic

Ok so I did think too much into it. I did try it out with the engine at operating temp though. It kicks in with the stock air box, but not with the cone. But either way it's just for emmisions. Okely dokely.