ka24de intake manifold port matching??

[bonomoskat]

i have a ka24de and im about to port match the intake manifold but ive heard that it is bad take the "Bump" as seen in the picture away and make it smooth and port matched?? they said that the bump is there to speed up the velocity of the air to mix the air and fuel better. so what do yall think or have done??

[Robi1]

If it was me I would take it out to the sides not going too deeply into the port. What is important in port matching is that the maifold port & the head ports line up exactly. to do this what i do is to bore out the stud holes to 10mm (if the studs are 8mm) then cut small shims to fit the studs to locate the gasket & the ports then take out the ports to the edges of the gasket. th lump is there to create velocity. depending on what kind of rpm's you're going to be doing constantly will depend on whether or not it's a good thing, usually it's good for low medium rpm but you lose out at the top end.) When you replace the manifold to the head use the shims to locate both gasket and manifold and you will have a perfect fit. (note, when you make shims cut them smaller than width of manifold backing plate. cheers have fun.

[311 RB26DETT]

honestly... do not touch it. unless you are a skilled porter. and understand fuel sheering, mixture, and velocity and have recources such as a flow bench. take it to a professional. and gasket matching is a pretty easy way to decrease power and increase fuel consumption. and while porting the intake runner always do the entire runner not just the first inch or so into the runner.

[95lstegman]

not sure if i wholeheartedly agree with you, there.

#1. yes, i agree, unless you are very skilled and have a lot of experience with that particular engine and the particular sort of modifications and goals you're looking for, don't touch the ports.

#2. that said, port matching is not a big deal, as long as they are not really far off in the first place. if they are, you should probably start by drilling out the holes, as described, and trying to get it aligned better, as that is more likely the problem. if they are far off, i would try getting them a little closer, but i would never take off more than 1-2mm of material, and you would have to blend it into the runner well, which goes back to #1. so if it's not very close to perfect, don't bother, or don't do much. maybe just round off the edge that is interfering with flow a little.

#3. port matching to the gasket is probably useless, since the gasket may or may not sit so perfectly straight on the head, anyways. you should be trying to match the manifold to the head, then the gasket as well. i just can't see matching IM to gasket helping much. might even hurt if gasket doesn't fit head well (and of course, the gasket has a little bit of a loose fit to the head as well).