GregBBRD

That's exactly how I've been making the ones I need, for years. I don't think there is another way to put the angle on them, in a lathe, is there?

Still wondering why there's 20 posts about this trivia, when the question was about air flow past a bigger butterfly in a stock intake.

Strosek Ultra

Good, then you are doing it right. Now move on to other questions.
Åke

ptuomov

You're contradicting yourself in so many ways that I can't keep count.

slate blue

Maybe ATPower or somebody handy with a lathe and mill could convert they S4 style throttle body to shaftless design. This change will pick up 6% in airflow and achieve more airspeed with good throttle modulation. Or maybe bore out the throttle body a touch and make that mod? The gain could be as large as 15% in airflow quantity.

My mod is with the 2 valve manifold so I won't distract you guys too much but I replace the MAF with the LSX 90 mm throttle and make other custom pieces to support airflow to a 5.35 litre engine.

mark kibort

i had this vivid dream last night of getting a hold of a AM intake and i cut of the legs ready to mount to the cutt off legs of the 928S4 intake.. then, the magnizium started on fire when i was welding it.. i forgot the S4 intake is magesium!

so, i guess the only way to make this hodge podge intake with the AMV8 intake would be to use Carls lower intake? and weld to that, or what about the 85 intakes are they aluminum?

uh oh... the holbert intake legs (and intake) are aluminum..... we cant kill that part of 928 history though, so no can do that!

James Bailey

Ah, another " STOCK " S-4 part ....

mark kibort

stock in shape, not in material.... remember, ron's car and mine made the exact same hp with the same exact mods. (his was a GT vs mine being the S4 with 85 cams).... so, i know what you are saying, but the point is kind of moot, right?

James Bailey

Nope, Mark all you KNOW is it looks similar but is made of a different metal....I mean given that you did not even know the size of the throttle body on an S-4 you clearly do not know what you are looking at or talking about...not that there is anything wrong with that. The runs at Nardo were much faster than any "stock" S-4 has ever been capable of and you of all people subscribe to the laws of physics They averaged 179 MPH....

GregBBRD

Always figured you couldn't count to one, without consulting the Internet.

Because there's only one wrong detail in all of my statements:

I didn't think about the fact that making them that way on my lathe made them very slightly eliptical....I just made them and used them.

Guess I should have just read the Internet and not actually have done it, like you do.

Oh wait....then I wouldn't know that a bigger butterfly made no more horsepower on a stock manifold...which was the answer to the original question.

James Bailey

Some post just to "prove" how smart, well educated, well read, experienced , they think they are.... Reality is that all that theory just allows you to design and make something which may or may not WORK and until it is actually tested no one KNOWS for sure.

Now that it has been tested we all know a larger throttle body on a stock intake does not work.....end of story !! No matter what the actual butterfly shape is

might as well be discussing the Salsbury 4850 D plenum design.....

jcorenman

So speaking of the Salsbury:

I'm not going to talk about my vivid dreams, other than to say that they are a LOT more interesting than that..

But I really don't get the obsession with the AM intake. That's a 4.3L motor, right? Which, after tuning, made what? 330 hp? (here and here). That's the problem when you are only making 250 ft-lbs of torque. RPM can only multiply whatever torque is available.

Is that your goal, Mark, 330 hp? Heck, any mildly tuned GT can beat that with a stock intake... Rob's 6.5L is good for ~400 rwhp with a stock intake. We did almost that with 5.9L and an intake that looks completely stock, picture here. What makes you think that an intake optimized for ~300 hp is going to help you out?

Strosek Ultra

If you have a look at the complete intake system of the S4 engine where the air from the front of the car is passing through very long air ducts to the air filter housing, through the air filter, mass airflow sensor, throttle body and up the intake manifold where it turns several times before it passes through the curved runners into the intake port and behind the open intake valves. This is a very long way, the air is making numerous turns all adding up in a lot of friction and pressure drop.
Compare it to an ITB intake where the air has a straight shot down to the intake valves. That is a massive difference. Not only the intake manifold has to be considered when designing a good flowing intake system.
Åke

Strosek Ultra

If you do not want to go the ITB path one of the better intake manifolds I have seen is the one made by Todd Tremel for his turbo car. However the runners are too short to be properly tuned for a NA engine, probably to be able to keep everything under the hood.
Åke

http://www.erik27.com/todd/turbo/01-...ake/index.html

Strosek Ultra

A couple of more pictures of the Todd Tremel intake.
Åke

Ducman82

I'm coming up with about 14" for runner length for a NA engine. doe that sound about right?