Intake Butterflys On The KA

[TheDrumAndTheBass]

While having my block torn down to change my head gasket on my KA24E I noticed a set of butterfly valves in the intake manifold. The only purpose I could find for these is to keep positive air pressure for when the accelerator is quickly opened. And in typical fashion (for me anyway) I decided to remove these for any from of HP gain I may experience. But aslo in typical fashion, I didn't think of any detrimental effects this may have. If anyone has done this before could you please let me know what the effects were?Ryan

[Mayhem_J30]

are the butterflies connected directly to the TPS? that would be a big problem right there.

[RobDET]

I'm almost positive mine are stuck open. I fiddled with the vacuum actuator for them and i couldn't get anything to move. The only thing i have noticed is that the idle is a little rough. Other than that everything is alirght.

[M635CSL]

I don't know about KA24DEs but, some cars (mid eighties toyota corollas for instance) have multiple path intake manifolds to maintain excellent emissions at lower RPMs while allowing more power at higher RPMs

[Nismo_Freak]

IIRC, the addition butterflies are there to provide intake air velocity at lower RPMs for torque production down low. I'd think that by 3000rpm or so they would be full open.

[[Zero-S]]

absolutely correct. closed down low, open at upper rpms. I was planning on taking mine out but 6hp doesn't warrant a rough idle.

[Movingviolation240]

Sorry to bring back an old thread but I did it on my old KA and it sucked. For a solid day's worth of work to get all that crap appart and back together, weld up the holes left behind, and buy new gaskets ect. it wasn't worth it. I never did get my idle to come back to 'normal'. However I did the same mod on my CA and it worked great. I think that's a funcion of the CA having 8 intake runners and the KA having 4. On the CA they just completly shut off 4 runners. The smaller pipe diameters on the CA helped keep velocity up enough that the car would idle and drive around decient offboost. On the KA the port is just too large and the velocity falls off so much that it dose not want to idle at anything under 950rpm. Not to mention that on the KA I really didn't notice any gain (def not 6hp by my seat of the pants dyno).

Unless your building a high compression, high lift and durration track motor, stay away from it. Maybe for a turbo motor it would work (it did for Jay)

Paul

[TheDrumAndTheBass]

Well, the whole reason I tackled this project on my KA is because I allready had the intake manifold off for a head gasket change. I should have my car up and running in a day or two, so I'll let ya know how things go then.Ryan