secondary butterfly valves... again.

[dickie]

i know this has been done to death, but i cant seem to find an answer for this one. what im looking for is a picture or diagram of the damn things and where they are supposed to go... i have an intake mani that came from a car that i have no idea of the year, and it seems to be missing them or maybe never had them in the first place.

can anyone who has removed theirs kindly post a pic of their manifold pre- and post-removal, and maybe also a pic of the removed valves?

thanks in advance.

[ss82480]

I've always wanted to see the same thing. I saw an intake manifold off of a car and couldn't seem to find these mythical butterfly valves either.

[nis720]

Here U go.







Here's what U have to plug up when you're done.



I welded mine shut... along with the ones on the runners (where the rod passes thru... not pictured)

[pete240]

Can you leave the rod in there instead if you don't want to plug the holes. I know that sounds a little counter productive as your trying to free up intake obstruction but I'm just curious.

[S13FX]

JB weld FTW ...

[pete240]

well I left the rod in there. I should be fine as far as it not leaking right.

[fresno240sx]

i was wondering, some ka24de did not came with a secondary butterfly valves..... that sucks because isnt that suppose to make your car faster?is there any way to adapter the secondary butterfly valves to the wire harness?

[Moto Man]

i was wondering, some ka24de did not came with a secondary butterfly valves..... that sucks because isnt that suppose to make your car faster?

Nah, they're to improve emissions. You don't want them.

[yellowcar]

They are not for emissions, they are to inprove the spread of power throughout the rev range. Like movable intake trumpets. smaller/ longer intake runners will have better air velocity but bigger shorter runners will move more air (like the difference between blowing through a straw and a garden hose) The idea of the butterfly valves is to mimic a smaller runner (and increase velocity) at low RPM and then a larger one at high RPM (move more air one going) The only problem is that the valves will impede some airflow at high RPMs.by removing the valves you will lose some velocity at lower RPM (and therefor power) but gain power at upper RPMs because you cam move more air since the valves are gone.

[Moto Man]

They are not for emissions, they are to inprove the spread of power throughout the rev range.

Is that true?

Or is it just what the marketing department came up with?

I can't help but be skeptical about these things.

[Lost_In_Translation]

Well Nissan wouldn't have spend money on them if they weren't for something...And I don't see how they could help in emissions.

[wa-chiss]

He is corect. They just keep the velocity of air up. No emission purpose what so ever. You might even be able to feel when they open. Kind of a subtle urge in power somewhere around ~3000rpm IIRC (kinda like VTEC but not so OMG VTEC). W/ out them you get a smooth power band.

[Moto Man]

Really?

Mine open as soon as the throttle opens slightly.

[Moto Man]

You guys got me worried there was something wrong with my car, so I dug out my factory service manual:

This system has a swirl control valve (S.C.V.) in the intake passage of each cylinder.

While idling the S.C.V. closes. Thus the velocity of the air in the intake passage increases, promoting the vaporization of the fuel and producing a swirl in the combustion chamber.Because of this operation, this system tends to increase the burning speed of the gas mixture, improving fuel consumption, and increase the stability in running conditions.

Also, except when idling, this system opens the S.C.V. In this condition, this system tends to increase power by improving intake efficiency via reduction of intake flow resistance, intake flow.

The solenoid valve controls S.C.V.'s shut/open condition. This solenoid valve is operated by the ECM.

[wa-chiss]

I'm glad I removed mine. They wouldn't open up for a while after reving.

[eazye2000]

I have some of them removed on my DE... I then smoothed out the little ridges that were in there to aid in the butterflies purpose...whatever the hell that was.... And gasket matched them to the head.. Here's a few pics.





And here is the screw you can't forget to remove or that bar wont slide out. It's the one that I put back in, and RTV'd it..

[dickie]

hey eazye, that was EXACTLY what i needed! I dont understand why but neither of my s13 ka-de intake manifolds had the butterflies in them.

dont know if that means they came that way (from an s14) or what, but thats whats up

[driftknight]

would it change the way my car eats gas because from what i know more air means more gas and do you actually feel a difference in power i would like to know because i would like to remove me butterflies too

[driftknight]

i am pumping this thread back up because i would like to know more about this mod.

[bone_stock_240]

The easiest way to do it is just get an upper manifold from a 95 and up car. Don't have to worry about all that crafty and skilled stuff like welding.

I am pretty sure that it would have no effect on fuel consumption at all.

Lots of info here:

They are not for emissions, they are to inprove the spread of power throughout the rev range. Like movable intake trumpets. smaller/ longer intake runners will have better air velocity but bigger shorter runners will move more air (like the difference between blowing through a straw and a garden hose) The idea of the butterfly valves is to mimic a smaller runner (and increase velocity) at low RPM and then a larger one at high RPM (move more air one going) The only problem is that the valves will impede some airflow at high RPMs.by removing the valves you will lose some velocity at lower RPM (and therefor power) but gain power at upper RPMs because you cam move more air since the valves are gone.

[yellowcar]

The ports on the earlier manifold are a very different shape then the later manifold does that make a difference?Are the intake ports on the earlier head the same as on the later head?