Hey everyone I'm new here which I guess is obvious by my post count. I don't plan to be a ricer here. Just get and share information like everyone else.
My question is about Intake Manfiold butterflies in the KA's. I've heard of people removing them and getting noticable HP gains but I don't know if this can be backed up by numbers or if its worth the trouble only to receive about 1/2 of a horsepower at 6500 rpms. Anyone? This is on a KA that may be running boost eventually.
-thanks
Intake Butterfly Removal
First off, the secondary butterflies are only found on 91-early 93 DOHCs. They are located right at the end of the upper plenum by the head, and actuated by a vacuum pump mounted behind the head by the firewall. Removing them requires removing the intake manifold. Each plate is screwed into a long rod, the rod is held in place by a set screw in the center and a bolt at the end. You'll ned to remove each plate first, then draw the rod out the back end. Replace the center set screw and tap or seal the bolt hole at the back and you're done. Pull the vacuum actuator off and cap the line going into it, or trace it back to it's originating point and cap it there. While you've got it off, you might as well ditch the TB cooling lines, as well as the cooling loop on the lower plenum. Whole job takes a few hours if you're a novice, and you'll need to order the upper plenum gasket to replace the existing one, it usually tears when the manifold is removed. Enough info for you?
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veil_side_
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veil_side_
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Dattebayo
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well mine was a custom job done by a local shop, and it cost like 200 (it was a hook up). I have it bored to 64mm and there had to be a custom butterfly made. I dont know how big the z32 tb is though. If it is bigger than that, i dont see how you could incorporate that without getting a custom manifold done...anything is possible with $$$
veil_side_ wrote:Hey 2BN_S13, how much did you bore out your Throttle body. I've been looking to get that done too. And is it possible to stick on a Z32 TB in there. I mean I don't know how much of a difference it would make or is it even possible.
KA throttle body is plenty big. Boring it out will give slightly better response, but not much power. The Z32 uses a smaller one IIRC.
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jrc90240sx
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- Joined: Mon Jul 29, 2002 9:21 am
Well I wont to just add a couple of things if i may. First the secondary butterflys are also on the 89-90 SOHC KA engine. they are located derectly below the injectors. I showed it to the guy at the machine shop, and all he could think of was that it was a stupied thing to do. but anyway, i am taking them out, along with porting my intake, and inlarging the TB. with my ported head, new cam, and 11-1 compression, every bit will help.
The reson they put them in is to help the air flow into the engine, it almost helps it ack as a short intake runer a low RPM and then a long runer at high RPM. not really a bad idea to help the over all power band, but with what i am doing its not needed.
The reson they put them in is to help the air flow into the engine, it almost helps it ack as a short intake runer a low RPM and then a long runer at high RPM. not really a bad idea to help the over all power band, but with what i am doing its not needed.
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