Improved Iron Head Intake

[camaroyoungster]

I really don't want any fighting on here please. I am just trying to share my ideas but if some don't agree. Like stated before, this is a learning experience for me for fabricating and basic engine modifying. When this intake is done I will try it out and then improve on it.

[robertisaar]

this is how you get people who have legitimate knowledge/experience to quit contributing.

OP: do what you want, but you have veterans telling you not to expect eyemelting results. take that however you will, just be aware that the deck is kind of stacked against you. I have my own "probably not worth it" intake design that I'm waiting to justify building, even if for nothing more than it being unique and at least as capable as a stock part.

[camaroyoungster]

Yes I will still continue my journey and will update you guys in the process. I eventually want to apply this to making manifolds for aluminum heads just because there will be a much larger gain. But I do not have an aluminum head engine laying around where I can mock stuff up but undo have iron head stuff.


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[ericjon262]

it'd be nice if a moderator would delete the drama from this thread...

I do agree that spending massive amounts of time and money on an iron head intake will result in a sub par return, compared to available aluminum head top ends. if this is just a spare time project out of scrap, do it, have fun, and learn the techniques to build something that doesn't just bolt together.

I can't see a custom upper doing much more for an aluminum head engine that a modded LX9 upper can't do, which, if true, would mean a whole new assembly would have to come into play. It's been talked about more than once on here, the biggest hurdle is the valve covers, because they seal to both the heads and intake. if not precisely machined, you won't get a good seal. the other issue, there's just not a whole lot of space to work with in the lifter valley like a 90* engine has.

[1QUICKHATCH]

Looks like a fun project! I would try to get the injectors as close to intake valve as you can. if you look at most modern engines the injectors are very close to the intake valves or even in the cylinder it self. My self I would try a different TB than the tpi one, maybe an lx5 tb then you have it for an aluminum head intake project down the road. Might be an idea to make an updated 3.4 intake with some better flowing runners/plenum.

[camaroyoungster]

Ok so i just had a crazy idea that might work and might not work depending on what you guys think. What if I were to put the injectors right on the side of the plenum box that has the tb and completely get rid of the runners and set the box right on top. I would obviously have to weld up the stock injector bungs in the manifold and get some injectors that shoot straight and don't really spray so I can aim them at the intake valve. I will try to get some pictures of what I mean up.

[camaroyoungster]

So here are some pictures. I hope you guys get the idea that I am getting at. If I do this then there will be no runners at all and the box will be sitting right in the lower manifold.


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[camaroyoungster]

And the reason I decided to go with a tpi tb was because it had more air flow but it had the same tps and iac connectors that come on the v6 MPFI tb. If I went to a lx9 tb I fee like it would be a pain to rewire for tps and iac and other stuff that it has on and I am pretty sure the throttle cables come from the other way.

And my other dilemma doing it this way is that I would have to find some kind of fuel rails that will fit. I was maybe thinking a 4.3 rail but I don't know yet. So many possibilities.

Another thing with the v6 tb is that I could keep the manifold itself nice and narrow while the tpi tb would make it wider which would possibly run into issues. Give me your feedback on what you think is best. I might have to make all of these to see how they work.


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[geoffinbc]

Your first idea was better.

[ericjon262]

So here are some pictures. I hope you guys get the idea that I am getting at. If I do this then there will be no runners at all and the box will be sitting right in the lower manifold.

that won't work, injectors would end up inside the valve cover...

[camaroyoungster]

Well they would be angled up more.


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[34blazer]

The angle of which the injectors are clocked, and how much further away from the cylinder they are, will only cause issues in fueling by making the intake more of a wet flow design. Tuning will be more difficult, especially with accel enrichment. If you want to make a custom intake, fabricate the entire lower manifold, separate the runners, and keep the injectors as close to the intake valve as possible, while aiming the spray pattern directly at the back of the valve. This method should create a more even airflow distribution by separating the runners(near the top), and build a pizza box style upper, or get crafty and use an LX9 upper. Building a plenum right on top of the base will create poor airflow distribution into the intake ports. Study newer intakes with individual runners, all drawing from a common plenum, and the volume of the plenum. Another consideration is the runner entry, a sharp square edge will create a lot of turbulence, effectively diminishing the size of the entry. An entry that resembles the cross section of a toilet seat(lol), maybe slightly rounder, will help increase flow and keep turbulence to a minimum. You don't want to create a fancy looking piece that will display more unfavorable flow characteristics than the stock intake, like the garbage that was posted earlier in the thread. HTH

[camaroyoungster]

Ok thanks for the input. I guess I am scratching that idea. Do you know the angle that the port is at from horizontal. That would be help to get the angles right. What do you think about using a tpi tb instead of a v6 one? Too much airflow?


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[34blazer]

Forgot the actual numbers that a 3.4 ironhead engine could flow, but iirc its less than 400 cfm. Forgot to mention, part of the valve cover sealing surface needs to be integrated into the lower intake.

[camaroyoungster]

Yeah I was thinking in the future chopping up a lower all the way up to the valve covers and starting from there.


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