Suggestion for Butterfly Actuation

[mdb4879]

I had this idea probably about a year ago and just now remembered to make a post about it. I know there are several ways to hook up the vacuum setup for the secondary butterflies (for those still using them) and I think I came up with the simplest one yet. Instead of using the vacuum pots how about an actually solenoid. I got the idea when my boss was working on his boat and he was messing with the choke. It's a Yamaha 150 and the choke has a fairly small (maybe 1" or 1.5" diameter, I can't remember) solenoid that pulls some linkage to close the choke. So I figure instead of using a vacuum source just make a little bracket and mount the solenoid to pull the butterflies. you could use the signal the ecu sends to the solenoid to open the vacuum source from the factory. I haven't done any research, but if I had to take a guess I would think the vacuum solenoid gets a 5V signal with little current and the choke probably gets more current at 12V. If that's the case it could be solved with a relay, right?

I know some think it's old technology ready to fail and cause problems, and other think you may as well just do away with them just because. But for those who still want to use them for benefit of higher intake velocity at low rpm I think this is a simple way to set it up. So what do y'all think?

[float_6969]

Solenoid moves too quickly. You want the slow actuation from a vacuum source. You could replicate that action, but it would take a separate controller.

[mdb4879]

Why do you want them to open (relatively) slowly? I have a few ideas in my head why, but I don't feel like typing them all out. Plus they're kinda farfetched.

[float_6969]

smooth transisition of power and tq. When I first had the system running with my standalone, I didn't have any of the delay valves installed and there was a VTEC like change in power. And if I happen to be sitting at the changeover RPM, it was REALLY annoying as the valves would open and shut constantly and the power was all over the place. Once I put the delay valves in to slow the actuation down, it was fine.

[themadscientist]

Why are we screwing with the OEM setup? What's the gain? It sounds all too familiar.

[float_6969]

Because they have been proven to improve low end torque and decrease spool time. You do loose a little top end with the valves in place, but at sub-300whp levels, the differece was barely measurable on a chassis dyno.

[mdb4879]

^^^Bingo

Although I thought I read they were ok for around 400whp, but I'll take your word for 300whp before my fuzzy memory, lol. Not like it matters to me. I've got a long ways to go before I need to worry about 400whp.

Couldn't you move the point of engagement to make for a smooth transition. It may be more difficult to tune than on VTEC motors because our stock ecus don't have "high" and "low" maps to switch between so you can't tune them separate then choose an engagement point. And I don't think we could tune it to engage at x rpm and disengage at y rpm. At least not on a stock ecu. Idk about standalones.

So on another note, is the flow improvement from proper removal of the butterflies comparable to a 4 port head? I seem to remember saying the flow difference between the two heads wasn't much, so I didn't know if modifying the intake gave flow like what a 4 port would have.

Also, I got to thinking about it and having the injector only in one port per cylinder doesn't seem as efficient and having it in both ports. So even if the flow numbers are theoretically the same would a 4 port head make more power because the air/fuel mixture would be finer because it doesn't have to mix as dense? Whereas in an 8 port one port just flows air so twice as much fuel per volume has to mix in the other port. (I figure the more "humid" the air the harder it is to mix in more liquid)

[boost_boy]

I'm with the mad man on this one, you can actually tune in the torque you need to move your car off-boost with the use of a standalone. I love that flexibility and I love the way my S13 drives with that GT35R and with the .63 hot side housing. If you have the little pissy turbos, the engine goes into boost so fast that again, the function of those "slow moving" butterfly valves becomes nearly mute. And they are worthless on the top end, so it would come down to the user. Their function is much more noticeable on the CA16DE and CA18DE engines respectfully. I've enjoyed the function of them in my first CA16DE swap in 1997 and then the upgrade to the CA18DE later that year. I used them for a while in 1998 on my first CA18DET engine and eliminated the system in 1999, never to use those valves again. It's all about the user's desire, but beware as you have been warned by the CA18 veterans, so the choice you make will be your very own.

[float_6969]

You can move the engagement point with a stanalone (and I did), but there was never a perfect transition there. You would have to attach the valves to a servo so that around the switchover point the valves would be kept at a partially open point. Do-able, but harder.

The flow between the 8 and 4 port heads is negligible. Technically the 4 port head has more area, but only a small amount, and round ports are better at moving air than oval ports, so it basically cancels out.

I can see what you're saying about the injectors, but I think the higher port velocities created by separate ports create better atomization before the combustion chamber. Ideally, there would be one injector per port, with one injector running at lower RPM's and loads. When that injector reached high load (80%?) then the ecu would switch on both injectors at a rate equal to the flow rate of the single injector (half of duty cycle of the single injector, only using two injectors) and continue that until redline/the load drops back down. It would probably also be associated with the opening of the valves as the 2nd injector couldn't begine to fire until it opened. I had planned on implementing this concept, but when the oil filter failed and ruined the head, I decided to use the 4 port head I had already instead of trying to source another 8 port head and starting over with it.

I honestly think the 8 port is the better head, and if it was paired with a manifold that was optimized for the 8 ports, that it would be the best performer.

[TheMAN]

many late model cars now employ the use of butterflies to improve emissions and/or torque.... they have gone to using electric servos to actuate the butterflies... they are not cheap to get but worth looking into

[float_6969]

I think what's being argued is that the same effect can be acheived with tuning and that they're problematic. Although I can agree that the seals failing on the valves can be an issue, and if they do, I don't know that anything can be done to replace them (are they still available through Nissan?) In principal they do work.

[mdb4879]

Since you can achieve the same effect through tuning, wouldn't it just be even more enhanced if you had well functioning butterflies in addition to these tuning methods?

[boost_boy]

I think what's being argued is that the same effect can be acheived with tuning and that they're problematic. Although I can agree that the seals failing on the valves can be an issue, and if they do, I don't know that anything can be done to replace them (are they still available through Nissan?) In principal they do work.

You would have to buy the whole assembly and that set-up was very expensive (don't think they're in no one's old stock anymore). The seals are old and starting to harden from the heat, usage and age. They will fail and when they do, you will have issues that you cannot figure out. I'm giving no advice on this subject, but users beware: when you start posting about your car running rich and losing boost and stuff like that, the leaks usually takes place between the two halves of the secondary plenums, so good luck playing with that..lol

[TheMAN]

those seals are typically about the size of throttle shaft seals.... I'm sure some replacement can be found eventually

[boost_boy]

those seals are typically about the size of throttle shaft seals.... I'm sure some replacement can be found eventually

Again, good luck playing with that .

[sjbsuperman1425]

The buttefly system is just complicated and annoying. I took mine out back when I first got the car and have never cared about the low end. If there were parts laying around to make it work PROPERLY, I'm sure I (along with some others) probably would have kept them. IMO, removing them unclutters the manifold and makes it easier to work on/fix things that are actually functioning 100% unlike the butterflies..

[Sideways s12]

i'm having mine removed as well after reading around I didn't want to deal with it...