rwhtide

been searching around but cant really find anything at all, except oem replacements, for the black plastic-looking intake manifold on top of the block. now please correct me if I'm wrong, but it looks pretty dinky. maybe Toyota had very good reasons for using a non-metal manifold, but it looks pretty lame to me and I have been looking for upgraded manifolds. to top it off, I cleaned my throttle body last night and it was pretty dirty. inside the black plastic manifold was also incredibly filthy (carbon build-up related). I really just wanted to remove it entirely and giving it some love, but then got to looking at it and decided that if I could find a decent "upgrade" for it, id just switch em out and not worry about cleaning the old one... will definitely seafoam the car soon, but I don't feel that it will fully clean the intake system (especially with how gunked up the walls of the manifold appear to be.

Anyone know of aftermarket (preferably metal) intake manifolds for the 2is 250? I'm pretty handy with a wrench and I'm sure I have all necessary tools to remove, clean and install (though it does look like quite a daunting tasks with all those little bolts)

rwhtide

might crack her open again tonight and get pics of the filth, though filth is filth. posting pictures isn't gunna help diagnose anything I suppose. think I just like taking pictures

Jeff Lange

iTrader: (1)

I've not seen any replacements, plastic was always used.

Jeff

rwhtide

manifold could be larger in some way, designed more efficiently, could allow air to flow better, maybe be more durable, keep temps lower, I dunno, just somehow better. seems like there are "upgrades" for just about everything else... or maybe even a manifold spacer? ive seen throttle body spacers for the 250, but no manifold spacer. and there may not be anything along these lines. I'm just coming from a 2002 Volvo s60, which had performance manifold spacers and throttle body spacers made by a few aftermarket manufacturers.

2013FSport

iTrader: (2)

Even if you find something out there, unless a lot of R&D goes into it, new and metal, may not be any better.

Engineers use a flow bench and the intake, heads, and cylinder walls to port match flow throughout the engines usable RPM range. So unless they show some proof of improved throttle response (think smaller ports, higher velocity /not bigger ports), tq/hp and all that, you may actually hurt it.

Sizing is all about trade offs. Too big of runners whether intake or exhaust and you drop port velocity and loose response. You may gain peak HP at WOT but loose performance off idle through the midrange or usuable power band....

Now if they made the right size headers for this, I would start there! But it seems most of them have primary tubes that are even large for the 350 unless one is simply seeking peak HP....

2013FSport

iTrader: (2)

Here is an example of what they did on the 250 vs 350 lower intake to increase throttle response from idle.
Notice the 250 has ECU controlled port runner restrictors to increase port velocity off idle. Saying these are closed during normal light throttle driving and open to achieve mid-range to WOT.

One thing I find odd is the oval upper intake mating to a nearly round port. No clue why they did that.
Attachments with 250 in the label are 250. The others are 350 components.

rwhtide

that is weird, but very informative! you really know your *****; thanks for the guidance. new to the IS community. still learnin the ropes. I figured Toyota had a reason for using certain parts, made a certain way, to produce the most efficient system possible. but I typically try to find one major part of the different car systems and purchase an upgraded version to swap out. insodoing, I end up learning about the entire system while replacing the one part. cut out resonator and replaced mufflers, learned a lot about our exhaust systems and the way things flow. installed H&R's and replaced brakes and pads, learned a lot about how our suspensions are setup. ETC. figure i'll go ahead and try to figure out how to remove the plastic intake to thoroughly clean it out. hopefully learn somethin else in the process! thanks again for the info