Removing secondary butterflys KA24E

[deviousKA]

has anyone here on the boards running a sohc ka24e removed their secondary intake butterflies? they are located right before the injectors on the intake manifold. im thinking of pulling all of them out and welding up the holes. it would be interesting to see what other people did. i could also use soft plugs pressed in. the welding seems like a better option what do you think?

KA24E build continues.......

[Bill Roberts]

They are useful as is. They are actually vortex generators, the cause of all that low end torque. It would idle rich without them. You would need to have the ecu modded if you took them out.

One large problem with KA-E's is the fact that some folks are driving around without them opening up. Just make sure they work is all.

To answer your question, I inquired about this myself and it was decided amongst several people that nissan put them there to swirl the F/A mix and produce boost in torque at low RPM's.

Well, if you want to try and report your findings...hey, go for it! The only way to know for sure is to try...right?

[Bill Roberts]

I found this and hijacked it:

The intake manifold houses a swirl control valve in each passage way of each cylinder. During idling and low engine speed, the valve closes to increase the velocity of airflow to each cylinder. This also promotes fuel vaporization and produces a swirl in the combustion chamber.

[Muzzy]

son of a bitch!!!

thas my problem..i always wondered y my motor floods so easily
and i wondered where all my low end went...damn it!!!

[deviousKA]

that is exactly the answer i was looking for. thank you bill. the engine will be going in tomorrow hopefully. i need to get my pistons fly cut real early in the morning so i can get it all together and installed. i was going to snap some photos of my creative build but i will explain it all later

[Bill Roberts]

I did more research.

For all out High RPM and drag racing,(above 7500) removing them would give slightly more airflow at the expense of needing an ecu mod and idle speed at 1400 or more. Leaving them in will increase torque 20 percent to 2K rpm.

Only with a radical cam and high speed idle for drag racing would I recoommend their removal based on all the research I did. In that case, a custom manifold and carborators would be the way to go.

I am going to leave mine in.

[sykikchimp]

fwiw - There are a couple guys running without them on FA. ADAM HUTCHINSON i believe is, but he's also running an FI setup on his KA-E.. Most of them agree if you track your car, and want the most top end you can get, remove them.

[MakotoS13]

hey i found an oldie but goodie. surely in two years we have some real data on whether or not turbo applications need the butterflies.

so what say you?

[Maeda]

Restriction = NO.

[240sxconversion]

they are the same thing as secondary butterflies on a gsxr or similar bike. LIke above, they are used to keep vilocity. As far as wether they are needed for a turbo car, the answer to me is still yes, when u wack that throttle open u are still going to lose some vilocity and they would help, i think??

[ledzeppelin240]

Alright the Swirl Control Valves create a high vacuume at low idle which does increase the torque. Unless you are going to turbocharge the engine just leave them. For what I am doing I have removed the butterfly valves on one intake manifold runners and left them on another. Once I get the engine build I will dyno it. Once with and once without the SCV and actually se what gains and losses there are.

Think about the forced induction though it sounds better withouth the SCV's.

[deviousKA]

Haha, ancient post.

Ive got one hell of a butterfly system on there now.



hilarious strut bar.

[someguy_240]

Originally Posted by ledzeppelin240

,,,For what I am doing I have removed the butterfly valves on one intake manifold runners and left them on another. Once I get the engine build I will dyno it. Once with and once without the SCV and actually se what gains and losses there are...

So have you dyno'd the manifold with and without the SCV? waiting for update

[ranisron]

correct me if I am wrong... the secondary butterfly on the KAE is like on the 4AGE bluetop TVIS systems, right? when I had my 86, I was told that disabling the TVIS system should increase power... well, I can't remember anymore...

[s13_gearhead]

Wait a second, Gabe...

I've got the secondary butterflies in my intake manifold removed, running a Ka - E, and I'm running a stock ecu with no problems whatsoever. Just make sure that when you remove the secondary plates you leave the rod in, as not to screw around with the swirl control =) That's what I did, and no problemo. Good throttle response, didn't lose a scrap of torque. If anything I gained a bit in the high end.

Good luck bro.

[sdtouge]

i removeed these on my ca in a few weeks when i get it running again and motor broken n ill post up how the do