I have been thinking our intake manifold could be improved for performance, at least in the higher RPMs. I have wanted to make my own manifold for a while, but until recently I just haven't been able to put time into the project. I have found time to work on a model and have been tweaking it for the last week or so. I have had to make changes to keep making it simple, I still have a lot to work out but I am far enough along to share the idea. I have a large 3d printer that I have to finish, then ill be able to make a physical copy to test. The plan as of now is to print the runners out of carbon fiber reinforced nylon, which shouldn't have a problem surviving under the hood. I want to be able to tune the intake to an RPM so I have left plenty of room in the plenum to be able to swap out velocity stacks for the intake runners. As for the plenum itself, its going to be around 4-5L which is a bit more than what we currently have and I am certain that this will help up top. I am not sure how I will make the plenum itself. I will likely 3d print the first one to test but I don't think that is a good long term choice and am thinking about making a mold to resin cast one in one piece for strength.

 

Two questions:
1. Will that fit under the hood?
2. Why not use the OEM aluminum bottom half of manifold and only fab the top half? Then you would already have a working interface to the head and injectors.

One suggestion: You might consider using the TB and intake tube/filter arangement from an IS F. That would give you a bigger TB, and (IMO) more consistent path for the air into the plenum and to the individual runners.

 

You'd need to bump the hood up a considerable amount to get the nominal 2.5d distance you'll want from the bells. Building the plenum would be quite simple, one-off it with polystyrene-cored composite, with the PS being melted out with acetone after resin cure, or make a plug out of MDF and gelcoat/release agent it or line it with that stupid-expensive PTFE tape so you can pop the cured part off. Easiest ways I can think of to fab the runners are to get an aluminum (or other soft metal...brass would sound gnarly) tube with the same interior cross-sectional area as the 2GR-FSE's intake port, make a die shaped like the port, and clamp the tube inside your die, then weld/braze/epoxy the runners to an injector plate of your choice. If you've got a 3d printer, then lost-PLA casting will likely be the easiest, if not most time-consuming, way to get consistent runners, whether you're laying up composites, or sand casting, or epoxy casting, or whatever.

One of the projects I'm just now making headway on is a forced-air waste oil burner. Primarily because it's way too cold in my garage, I have too much WMO, and enough scrap to pull it off, but also because I've been wanting to do my own aluminum casting ever since some truly brilliant 2>4 members made their own crankcases, manifolds, and other one-off parts. It really is not rocket surgery, man has cast metal for longer than we've been recording it. One of our members made an ar15 lower out of beer can tabs.

 

The plenum isn't finalized yet, I need to make a couple more measurements to know for sure that it will fit. This intake is about 4-5cm taller than the oem manifold with the engine cover snapped on top. I would like to reuse the lower intake, but each runner starts to head off into its own direction and I don't think id be able to make something nice with it. As for using ISF parts, we do not have the hood clearance for that to be a real option.

I have always wanted to get stuff to do metal casting, but that isn't an option for me right now. I have been into 3d printing for a while now and I'm fairly confident that this could work out. The thinnest wall thickness is 4mm and that is likely more than enough with the material I intend on using. I know I could one-off a plenum pretty easily with the process you described, but I want to be able to repeat whatever I do in the off chance that it all works out well and someone else wants one. I have been thinking about it and am leaning towards printing the plenum in ASA and wrapping it in carbon fiber for strength and of course looks.

 

Getting a proper IM made that actually increases performance is well-beyond my knowledge; so I wish you well on your journey. Just keep us all updated! For YEARS I've thought of how to adapt a 350Z aftermarket IM to our vehicles; but it's just not feasible, PLUS will it actually make power?

Best of luck!

 

If you eventually came up with a sample piece. I am willing to pay for it and test it on my car.

ported lower manifold gave me about 10ish WHP. I am sure that it will make power if design properly.

looking forward to see your work.

 

Let me introduce you to one of my favorite youtube personalities...

Oil burners operate on gravity and forced air. The amount of available forced air you have determines the amount of oil you can allow to burn. The ignition system is pre-heating the combustion chamber until it's hot enough to vaporize the oil on contact, then the oil does the rest.

I'm tinkering more with a smith's-style forge that can take a crucible, instead of a scrapper-style like in the video, but the physics are all the same. Air+oil=heat, heat+metal=forge.

Glue a bunch of plies of Medium-Density Fiberboard together, sculpt it to the shape you want, then do something to it to make composite resin not stick to it, like gelcoating it and never forgetting the release agent when you lay up a fresh series, or whatever you feel like. Indefinitely reusable...it's what small- to mid-size composite companies do for almost all of their small part molds. Heck, some boat molds are still effectively just MDF. You could ostensibly do all your parts with MDF plugs, if you put a taper on the primaries.

If you must use the stepper-motor-controlled hot glue gun, I'd think the most print-friendly way to do it would be to make your initial prototypes on the print table, then cast them in something like 16-lb polyurethane foam to use as your plugs, since the printed objects 1: take forever to make and 2: have the lifespan of a cardboard straw. I've kinda given up on 3d printing and am instead of the opinion that print filaments can be used faster and to greater effect through DIY injection molding and vacuum forming, both techniques that don't require me to learn a new 3d modelling program, or acquire a valid 3DSMax license. I've tried learning Blender at least a dozen times now...there's just something about the program you initially learn to model on, when you pirate it in middle school and that's all you have for a decade-plus...

 

I've been dabbling on this idea almost everyday. Partially a lower intake manifold that could adapt to a top mount S/C and/or larger intake manifold. I am confident that Lexus did well with their plastic one although it looks ugly and useless. I was thinking about grabbing a couple lower intake manifolds and seeing what supercharger would mount up top of it in an orderly fashion and start making adaptor plates or even start drilling. Sounds like hack work but it could end up being progressive. I want to do something unique that works even if I need to mess around with a hood option.

 

Early on, in the brainstorming phase of my go-faster ideas, I had the Eaton M90 supercharger off of a L67 GM3800 engine just laying around my garage, and found that the base of that blower is ideally sized to go atop the OEM midplate, especially if you find an appropriately-sized copper heater core (like <1.5" thick) to sandwich in there to run water up to a independent ice-able radiator...y'know, a baseplate intercooler, but not $2k...but the M90's throttle body housing or the car's firewall/hood surround would've needed some significant surgery to make all that work, as well as sticking way out of the hood.

But the belts would line up. And with the right pulley, you could flow ~500hp@14k shaft rpm.

Inasfar as the stock plastic intake, you can see in my cutaway intake that Cylinder #5 in this photo is trying to pull it's charge perpendicularly to the highest-energy crossectional area of it's half of the plenum (assuming ACIS closed)




And here, you can see the pinch point that forms just upstream of where Cylinder #6 gulps from.



The engineers did a dang good job of giving us port velocity and a commendable job all-around with induction energy within the tract overall, but my big complaint is right there before the last two cylinders. With ACIS open, it doesn't really matter all that much--aside from being the smallest ID of anywhere in the 6-signal portion of the intake tract (why throttle bodies don't gain us anything)--because the highest-velocity air is being pulled on by all 6 cylinders; but with ACIS closed, the rearmost cylinders in the 3-signal plenums are stalling the energy that could otherwise be retained for the frontmost 2 cylinders in each 3-sig.

2GR-FSE doesn't have the air doodads, but you still have that pinch point.

 

Yeah the IS350 upper manifold is laid out very similarly, I am wondering if the upper manifolds are interchangeable between the IS350 and IS250. It would be interesting to see if the IS350 picks up any low end from the split plenum trick used on the IS250. As far as making a lower for a blower, I would be all over this if I could cast a lower. I have complete confidence in a 3d printed lower for NA, but have doubts about it with the extra heat and pressure from a positive displacement blower. I do doubt that the M90 is the right way to go, its just too small and you would have to work it pretty hard to make more power than a FBO IS350. I think a better option would be an M112 from an 03/04 cobra. One of those would be a good match for the car if you could get around the pulley setup and hood clearance.

 

Nope, the 2GR can't swap intakes with the 3/4GR. The 3GR intakes can be used on the 4GR to gain plenum volume, but you'd want to re-cam to open the valve earlier and increase lift, as well as opening up the exhaust duration to take advantage of that. Also, the 3GR's throttle body is in a different location than the 2 and 4 GRs.

Inasfar as the M90 not being enough blower...it's designed to force-feed engines up to 5 liters. 90 cubic inches of air get pooped out the bottom with every rotation, the 4GR's cylinders are each ~25ci, and the 2GR's are each ~35ci. An M112 is appropriate for most V8s, and would really only be a good idea on our engines if you dropped the CR to like 8.0:1 or so.

 

Posting for the heck of it.
2GR-FSE cut away pic...