Secondary Butterfly Removal

[TommyyJ]

i was readin up on the secondary butterfly removal in the faq section, has anyone done this on an s14? pros/cons? if so, are the instructions the same...?thanks

[Nismo_Freak]

You will lose a little non-WOT response and torque. It can cause idling problems but a minor adjustment of the idle screw should remedy this. Its job is to provide low end torque by increasing the air speed under partial throttle, it is worth maybe 2-4 whp at the top end. It is very similar to the newer ECU controlled variable intake systems on the Maxima, Altima, SE-Rs, etc.

[R240NA]

i was readin up on the secondary butterfly removal in the faq section, has anyone done this on an s14? pros/cons? if so, are the instructions the same...?thanks

No one has done that on an S14. The secondarys were only used on 91-early 93 KAs. Later 93s and up no longer used them.

[brickerj]

so does that mean tha 1990 dosent have one?

[pmkls2]

the 89-90's have them as well. I believe he was referring to the ka24de's only had them until early '93.

[neverlift]

I just got mine out 2 weeks ago and its a 90 sohc so yeah they had em lol

maybe its me but I like the pull up top from the removal of them. IMHO ka has plenty of torque without them, maybe thats why they hit the can. Although they probably greatly help in the mpg game for those that dont do much hard accelerating.

[The_Chosen_One]

from some of the dyno results I've seen when people disabled them and enabled them, you lose around 15-25ft/lbs of torque when you disable or remove them. They're their for a reason.

[Moto Man]

Really??

On my car, it seems they snap open as soon as the throttle is opened even slightly.

[The_Chosen_One]

do you have the actuator hooked up to a vacuum source or the solenoid that controls it?

The secondary butterflies are controlled by the ecu, and when the engine gets to a certain rpm usually its around 4000-5000 rpms the ecu signals the solenoid and opens the valves.

[Moto Man]

I'd forgotten about this thread.

Anyhow, my car is all stock. The swirly valves are controlled by a vacuum motor, which is controlled by a vacuum solenoid, which is controlled by the ECU. All the bits are working as designed, as far as I can tell.

[nismo s-13]

hi man I opened the butterflys in my 93' ka24de a couple of weeks ago, not removed them, the swirl control valve is still conected i just pinned the lever that controls them to be opened at all time, now sometimes when I run it for like 10 minutes and stop it idles badly the RPM start to go up and down, even black smoke comes from the exhaust, like if it was getting to much air and less gas and, I have a fuel pressure gauge and it's at 35.0 psi of fuel, I dont have a FPR so I can't control the fuel psi. What could it be?

[Moto Man]

Are you sure you didn't block them closed?

With the engine off, the valves are open. The vacuum motor closes them when signaled by the ecu.

[hellboy006]

Are you sure you didn't block them closed?

With the engine off, the valves are open. The vacuum motor closes them when signaled by the ecu.

With the engine off, the valves are closed. The vacuum motor opens them up according to how much vacuum is being pulled... when there is no vacuum they are closed because there is a spring that is pulling them closed. The vacuum counteracts and over comes the spring according to throttle.

hi man I opened the butterflys in my 93' ka24de a couple of weeks ago, not removed them, the swirl control valve is still conected i just pinned the lever that controls them to be opened at all time, now sometimes when I run it for like 10 minutes and stop it idles badly the RPM start to go up and down, even black smoke comes from the exhaust, like if it was getting to much air and less gas and, I have a fuel pressure gauge and it's at 35.0 psi of fuel, I dont have a FPR so I can't control the fuel psi. What could it be?

Black smoke is unburned fuel... it means your mixture is rich, not lean.

Here is my question... how can tell if my secondary valves are opening at all? my car runs like **** and im thinking the thing that opens them might not be working at all.

[Moto Man]

With the engine off, the valves are closed. The vacuum motor opens them up according to how much vacuum is being pulled... when there is no vacuum they are closed because there is a spring that is pulling them closed. The vacuum counteracts and over comes the spring according to throttle.

Our cars do NOT have carburetors!

The swirly valves are not like vacuum secondaries.
Modified by Moto Man at 9:44 PM 4/19/2008

[ken240sx]

from some of the dyno results I've seen when people disabled them and enabled them, you lose around 15-25ft/lbs of torque when you disable or remove them. They're their for a reason.

Total bs...

S14's don't have the butterflies because they were deemed useless by nissan. They did not effect gas consumption enough at idle and cruise to keep them in there. Since the butterflies were removed the car gained hp, so in order to keep the 240 around the same hp range, and under 160 which will effect insurance they had to use less aggressive cams. This is why you gain 4-8hp or so putting s13 cams in an s14, and same goes for putting an s14 manifold on an s13...or just removing the butterflies properly. Since there is a rod that does through all the runners, if not sealed 100% there will be a vacuum leak, which is what causes most problems associated with people removing them.

If interrupted airflow creates more torque than uninterrupted then why do people p&p their heads, port their manifolds, use mandrel bent tubing...HP = TorquexRPM/5252 ..... So what you're gaining with better airflow is torque at a higher rpm...this is what creates more hp at a higher rpm. I cannot think of one thing that you can do to the KA to decrease the torque numbers as much as stated other than plugging the intake or exhaust..which is the opposite of airflow.

The swirl control valve was named that way because the butterflies close off when vacuum is present and causes the air to "swirl" to mix with the fuel more "efficiently" but doesn't do enough to say so.

Someone correct me if I'm wrong...and if I am, then please be the one to tell me the differences between the s13 motors and the s14 motors that would be the reason for nissan having to de-tune the cams for the s14's. Head flow characteristics are the same, bore, compression, stroke, exhaust flow, etc. are all the same. The main differences are the intake manifolds and in the later s14's the internal coil distributor(which may at most count for 1 hp)...find me 5 hp somewhere else.

This topic has been covered and covered and covered and covered....search is there for a reason.

[The_Chosen_One]

Total bs...

S14's don't have the butterflies because they were deemed useless by nissan. They did not effect gas consumption enough at idle and cruise to keep them in there. Since the butterflies were removed the car gained hp, so in order to keep the 240 around the same hp range, and under 160 which will effect insurance they had to use less aggressive cams. This is why you gain 4-8hp or so putting s13 cams in an s14, and same goes for putting an s14 manifold on an s13...or just removing the butterflies properly. Since there is a rod that does through all the runners, if not sealed 100% there will be a vacuum leak, which is what causes most problems associated with people removing them.

If interrupted airflow creates more torque than uninterrupted then why do people p&p their heads, port their manifolds, use mandrel bent tubing...HP = TorquexRPM/5252 ..... So what you're gaining with better airflow is torque at a higher rpm...this is what creates more hp at a higher rpm. I cannot think of one thing that you can do to the KA to decrease the torque numbers as much as stated other than plugging the intake or exhaust..which is the opposite of airflow.

The swirl control valve was named that way because the butterflies close off when vacuum is present and causes the air to "swirl" to mix with the fuel more "efficiently" but doesn't do enough to say so.

Someone correct me if I'm wrong...and if I am, then please be the one to tell me the differences between the s13 motors and the s14 motors that would be the reason for nissan having to de-tune the cams for the s14's. Head flow characteristics are the same, bore, compression, stroke, exhaust flow, etc. are all the same. The main differences are the intake manifolds and in the later s14's the internal coil distributor(which may at most count for 1 hp)...find me 5 hp somewhere else.

This topic has been covered and covered and covered and covered....search is there for a reason.

So your telling me that the dyno results that one of the mods posted is fake and really a lie? Damn didnt know bro.

[ken240sx]

not everyone does the install correctly, you're telling me that all the other dyno's are fake that show 5-8hp gain??? I've personally done the mod 3 times, and no one that I know lost any noticeable torque that ahs used a manifold I modified. Have you ever actually done the mod or are you just going off what other people say? Do you even know why people get aftermarket manifolds and throttle bodies?? it's not to loose 15 ft-lbs of torque, it's to gain top end torque. You're not loosing any air at low rpms, so why would you loose more than 1 or 2 ft-lbs of torque, and even then you'll gain much more than that up top, so it's worth it. If someone dyno'd a car with the butterflies "disabled" how do you know they weren't stuck closed, that would mean a good torque drop cause it would be plugging the air.

Tell me the differences between the s13 and s14 engines...please do. Why did they remove the butterflies int he s14's....the manifolds are the same except some emissions related junk such as the scv(butterflies). Yet the engines have the same output, even with the s14 cams are de-tuned.

I have yet for you to tell me why someone would put an s14 mani on an s13 and gain power....it's not because they are different, it's becasue htey don't have the airflow impeding butterflies int here.

GOD people on here need to search I'm getting so irritated at people arguing things that they've never experienced or done. Go work on your car some more and use the search button.

[Rucca]

Yes that is all that makes sense really. Removing restriction and losing torque? Nah

[ken240sx]

Nissan "thought" that the butterflies would noticeably effect low end torque production and fuel consumption at idle and cruise, but they discontinued the use of all secondary butterflies in all the models of their vehicles as far as I'm aware. The torque loss on low end is very minimal but the torque gain in higher rpm is much more than the loss, and it's better to have torque at a higher rpm, as it will exponentially effect your horsepower production. I'd sacrifice 2 ft-lbs of torque from 1500-3500rpm to gain 4-10whp across the rest of the powerband... it's all about the area under the curve. To say that someone lost 15ft-lbs is ridiculous and I can't think of any one thing you can do to lose that much torque.

Face it non-believers, they are a restriction in your airflow...you may only gain a couple hp top end if your engine is otherwise stock, but when you open it up with other mods you will see even more hp gain...kind of like if you put an aftermarket manifold on a stock engine you might see like 2 hp top end, but when you do other mods to support it where your engine will need the extra flow characteristics, you'll gain much more power.

If you can somehow prove to me with a real-world application how less restriction in airflow is somehow bad for your engine, then do it. Otherwise don't post about things that you have no first hand experience with. I wouldn't tell someone how different differentials effect driveability if I've never driven anything but an open....same concept...apply it to life ok.

[Rucca]

Where is the butterfly removal how to? I couldn't find it. Just wondering how to remove the shaft and how everyone sealed it up and with what. Did you seal each runner or just the outer one?

[ken240sx]

personally I sealed each runner, you can never be too safe. I didn't want to encounter ANY vacuum leaks or flow interruptions. All tou need to do is remove your manifold and I'd recommend taking it apart into the 2 halves. take some metal cutters and needle nose pliers to the bish. Simply cut the butterflies out and then pull the pieces of the now destroyed rod out. remove the scv off the side of the last runner and plug that up too. Epoxy, JB Weld, a real weld, all do the job. Sand your **** smooth and clear out any debris. plug up any vacuum lines that went to the scv and reinstall everything with new gaskets. While you have it out I recommend replacing all vacuum lines and coolant hoses, etc. cause they have been rotting for at least 15 years and are brittle. Also, I'd take some throttle body cleaner to the inside of the plenum and runner, and degreaser to the outside if you have the mani off. I'm thinking about doing a writeup of this if someone is willing to give me a manifold to do it to, considering my 240 and extra mani's are in NY while i'm in AZ currently. I'll pay for shipping if someone wants to give me a mani....or if someone wants me to do this for them and I'll create a new write-up for it then ship me yours and pay for shipping back to you also. I won't change someone if they want to donate their mani temporarily for a write-up.

[Rucca]

The long runner actually just pulled out, there is a screw between runners 2 and 3 that holds it... You probably know that. Anyway, I'm have a spare manifold so I'm going to try porting it a bit just for something to do really. Maybe I'll post pics if I get motivated

[si1via]

I hear this mod talked about all the time, and everyone says it gives you more power high end. So, who thinks it's not a good thing?? I just don't want to eat up my gas mileage though. I'll be more tempted to drive hard. Gas costs $4.00 gallon where I live. Man I'm spending over $50 every fillup. I commute to work everyday with my s13. I already drive hard in 1-->2nd gear. I get average 23 miles per gallon for city/highway driving. With this mod I'm sure I'll get like 21 miles/gallon.

Modified by si1via at 9:04 AM 4/26/2008
Modified by si1via at 9:05 AM 4/26/2008

[albdrift]

Does it coke the engine

[ken240sx]

coke?

[UNVMY240]

Nissan still uses butterfly plates in their motors to this day.. Just ask a 2.5L motor owner and asked them if they have put a motor in their car because a plate came loose and got sucked into the valve area causing a cylinder misfire. (normally cyl 1)

[Rucca]

Of course, it helps with fuel economy and emissions. They would use them. It is more beneficial for a manufacturer to have lower emissions and higher mpg than a little top end hp.

[gingerbredman]

wouldn't just removing the flaps be effectively the same? of course the rod will still impede a little airflow, but hey wth?

..on a side note, i'm off to find some dynos of this done. Some good points are made. with more open airflow you will gain top-end power, lose a little low-end. it's practically the same principle as exhausts i.e. 2" versus a 3" or whatever.. the 3" will allow for more beneficial upgrades down the road, which is the name of the game right?

and also.. couldn't you tune it out if you're losing that much power? more air, then ya need more fuel

.. i just don't want my 40 running like a log truck or anything if i remove them

[Cone Junky]

Wow, this thread is all over the place.

The swirl control valve is used at idle only. Any throttle input opens them wide open. They don't change low end or cruise...idle only.

Back when these cars were made emmisions tests were done at idle and at 1500 RPM with no load. So these were to drop down idle emmisions. Now that smogs are done on a dyno under load, theses have absolutely no effect on the testing parameters.

Here is the "official" function of the SCVs-CIRCUIT OPERATION The swirl control valve (SCV), located in the intake manifold passage, partially closes off the intake passage of each cylinder at idle, restricting air flow. This causes the velocity of the intake mixture to increase, promoting more efficient vaporization of the mixture. This increase in velocity makes the fuel mixture burn faster, increasing fuel economy and engine stability. During all other operating conditions the SCV opens allowing the intake flow to encounter less resistance, improving power and acceleration. The ECU supplies the ground circuit to the SCV solenoid, cutting the vacuum source to the SCV. This allows the SCV passage to open, thereby allowing non-restrictive air flow.

[cmoody2006]

wouldn't just removing the flaps be effectively the same? of course the rod will still impede a little airflow, but hey wth?

I have been wondering this same thing..... Couldn't you just remove the 4 flaps and call it done? I have my intake torn apart right now at my comp desk with me and I'm going to see how it reacts with the flaps removed but leaving the rod in place... So there's no jb welding to do and there's minimal restriction