intake manifold musings

[SuperHO]

for some reason, i've been putting what's likely an inappropriate amount of thought into this for the last couple of days, so i figured i'd comment on it. i've read and heard in more than one place that the intake manifold is one of the biggest weak points when it comes to making power out of our burly V8...that being said, why hasn't there been more research done to find a way to either improve on the existing design or replace it completely with something that while may not be as visually appealing, might have a bit more function to it? maybe something with shorter runners or a set of tuned velocity stacks leading into a single plenum a la BMW? just throwing some ideas out there...

 

[roland]

not worth the money I guess :/

Maybe with some MTX's running around that'll spur some more interest in getting more power.

 

[E1 v2]

Shorter runners would take away from low end torque, a place where we already need all the help we can get.

You won't need long runners if you force feed it

I've seen that dual surge tank picture several times and this question next comes up - Why no long runners in the middle?

 

[SuperHO]

well, some of the ideas i had involve either the same length runners that're already in place, only larger diameter with a larger plenum or get real extravagant and go with a dual runner setup (which wouldn't fit under the hood with the idea in my head) and using the linkage off the lincoln continental and set up the secondaries mechanically rather than electrical or vacuum operated. the only drawback to that design is that i don't know how that'd effect low end power, as it would with the V6. i think the biggest problem with doing anything custom like that would be the clearance under the hood...cuz though the sight of the geek SHO gives me a warm tingly feeling, i'd just as soon not have a big ass sheet metal intake sticking out of the hood of my daily, ya know?

 

[SeanMc]

Cut a hole in the hood and install velocity stacks with 8 throttle bodies

 

[SHOZ123]

The shorter external runners have longer internal horns.

 

[SHOZ123]

Easiest improvement is to eliminate the secondaries plates and the shafts. This frees up ~3 sq" of volume in the direct path of the incoming air.

 

[motomurph]

Roland, Gotta love the CERT sticker on that cam cover. That picture was taken at some point in the development process in the bowels of Dearborn.
Good stuff!

 

[TwistedD85]

When it comes to velocity stacks it's pretty simple. The lower you want your power in the RPM range the longer you want the distance to be between the lip/opening of the velocity stack and the valve, hence why N/A dragsters way back in the day had huuuuuge Hillborne stacks. If you want the engine to operate at higher RPMs you need the distance to be shorter, that's why F1 cars practically have no distance between the mouth and the valves. There's alot more that goes into making an intake if you want to make a functional, drivable car. The more I learned about that the more I realized the V6 SHO's intake is a real work of art and engineering, even if it could do with a little more volume in the runners for what some want to do with them.

 

[SuperHO]

so ideally, two seperate plenums feeding two different sets of velocity stacks would yield the best results? say, one plenum active whenever the throttle's open to feed the longer velocity stacks, then have a vacuum/electronic butterfly plate that opens at a predetermined engine speed that'll allow air to be fed to the shorter stacks...similar to the dual runner setup, but rather than each stack feeding from the same air supply, the different length stacks are getting their air from a seperate source. any benefit to something like that over the basic dual runner setup that makes the V6 look so sexy?

 

[TwistedD85]

I'd say the V6 intake has it down if you want drivability, but if you're going for power just make eight runners and call it day, especially if you're use a supercharger or turbo. But if you're gonna go F/I I wouldn't bother with big runners, just make a box style sheet metal intake.

 

[E1 v2]

But if you're gonna go F/I I wouldn't bother with big runners, just make a box style sheet metal intake.

Egg-Zachary!

The air WILL find its way when under pressure.
But this is best ONLY under boost. With a small turbo or centrifugal blower, you still want some runner length for low rpm grunt until you build a little boost.
With a PD blower - roots, whipple, etc. - it don't matter. Touch the throttle, you got boost.

 

[TwistedD85]

Woohoo boredom, here's you a simple S/C intake. Since the injectors are housed in the same piece as the secondaries I had to put them somewhere else, back in the middle would've been a pain to get in and out so they go on the outside. You'd have to siamese the two intake ports into one on each cylinder but it'd look awesome sitting on there all polished up. Oh and the throttle body ****** is left off so you can see the inside, otherwise it'd be welded on as you'd expect. And it could be bigger as well, but this is a five or ten minute sketch, a quickie.

 

[ThatShoGuy]

Woohoo boredom, here's you a simple S/C intake. Since the injectors are housed in the same piece as the secondaries I had to put them somewhere else, back in the middle would've been a pain to get in and out so they go on the outside. You'd have to siamese the two intake ports into one on each cylinder but it'd look awesome sitting on there all polished up. Oh and the throttle body ****** is left off so you can see the inside, otherwise it'd be welded on as you'd expect. And it could be bigger as well, but this is a five or ten minute sketch, a quickie.

nice now someone needs to make something like this

 

[E1 v2]

nice now someone needs to make something like this

OK

 

[hawkeye18]

Whoa.

 

[ThatShoGuy]

nice
!!!!!

 

[TwistedD85]

Puuurdy welds

 

[SuperHO]

that can't possibly fit under the stock hood...however, if you'd like a guinea pig for testing purposes, i've got a slow as **** but mean sounding 98 sitting in my garage that's just waiting for something special...

 

[TwistedD85]

lol I just realized how damned tiny my intake would be if it was actually made.



With as deep as the valley is between the heads when you remove the secondaries you should be able to make a pretty decent supercharger manifold and still squeeze it under the hood. Damn, I really misjudged the size, that's what I get for using an overhead picture for reference.