Lets talk science, Stillen Gen3 Intake
 

Disclaimer: Not an engineer, I deal with molecules or smaller.

So can someone explain the physics that is occurring behind the Stillen intake? From my understanding longer tubes cause a reduced pressure within the tube due to increased drag. Reduced pressure typically means less power due to getting less air into the manifold. The only thing that I can account for in the power gain is colder air, reduced turbulence from the smooth surface of the piping, larger air filter. I think I am missing a key factor. Discuss.

I guess if they sucked it might actually be a good thing : )

Your physics sounds right to me. I think maybe add less resistance through the air filter to the list.

Yep. You want as little restriction on the intake side as possible.

Cold air takes less space than warm air, therefore in the combustion chamber you can fit more gas. More or less, this should be the idea behind CAIs.

Do you mean cold air is denser than warm air, so you can add more fuel to match the larger amount of O2 in the cylinder?

Overall, I haven't heard that they're much better than a K&N w/ a post MAF silicon tube.

But, they cost more money so they have to be better...right?....right?

:icon18: More my friend...much more. I think this is the funniest semi-accurate way I've ever seen a CAI explained. It's kind of like "Kids say the darndest things."

I laughed. He's definitely not wrong.

LoL..Kinda wrong, sorta right. LOL!

Bingo!

CAI for the 370 are all way over rated and over priced. Its not needed. Just drop some reusable K&N's in there.

This is how I feel & what I do
 

Notice how a car when viewed from the side is shaped like a wing. Much more air & pressure is under the car than over the car. Just like a plane's wing. Flat under car vs roof & over the car. One of the places that the car's pressure (under car) goes/escapes is up through that space in front of & toward the the two stock intake openings. I & the second person on the top 25 list(redline06) run with our air cleaners off. That's not on the street, just at the track. I think I & him get lots of cool pressurized air into my stock intakes. Being in the # one spot & him being second, that idea/set up might be working very well.

I use dry K&N filters. On the street & most of the time at the track.

The vast majority of the gains come from a higher flow filter.

There you go! :tup:
http://www.davemulder.com/wp-content...g-science.jpeg

science? thought it was just to make the engine bay look like it had a turbo and intercooler piping.

It would be cool if someone invented a gizmo that pumped gobs and gobs of air into the intake rather than just letting those lazy *** oxygen molecules wander in. I might have the plan that makes me MILLIONS!

Even better, we could use wasted energy to run it. Maybe some type of exhaust-powered turbine.

They did it's called "Forced Induction" :icon17:

LMAOOO!!! Patent it QUICK! Before someone like GTM or FI or even Greddy get their hands on that kind of technolo....oh...$hit.

Well that's not a very politically correct name; sounds so brutish. How about something like "highly encouraged induction?"

Ok, that's not going to work. Maybe if we drove it off of a belt instead of the exhaust?

Whaaaa?!?! Unheard of!!!! This is some Bill Nye stuff..obviously unattainable in the near future. Maybe 2040. Yeah, when the human mind has evolved enough.

Maybe "Bribe pipes" would work.

Sounds like just having larger filters would provide the largest gain. Don't understand why stillen went the long tube route other than the providing colder air. The only way this is logical is that the reduced pressure is minimal and the gains from the denser air compensates for the loss.

Are you assuming air is being forced into the intake? I'm not sure what pressure you're concerned with reducing. Air is being sucked in from the motor, not forced in from outside.

Air is being pulled into the motor due to the increase in volume of the combustion chamber. Increasing the path of the gas, increases the drag slowing the gas fill rate of the chamber. In theory, this should actually cause less O2 to be present in the chamber.

Not if the piping is less restrictive than stock. Between the tubes being smooth unlike stock and the less restrictive filter, its a net positive.

Did some searching and came across this article. Explains the reason for the long tubes beyond the denser gas intake.

Performance Air Intake Systems - Fact of Fiction - Import Tuner Magazine

I'm going with smoother pipe and a better filter. I'm not going with colder air! The stock intake already is basically a CAI with a nice opening in the front end and it doesn't have the bends the Stillen does. I'm also not going colder air because the aluminium pipe gets HOT! While the plastic and rubber pipes stay cooler.

My CAI I made is almost all silicone pipe. Id put it up against the Stillen and say I make more. Specially on the 3rd pull of a dyno where the Stillen will become heat soaked.

Anyone have a dyno sheet showing 1-3 pulls and is the 3rd lower than 2 or maybe 1?

Hahaha love it!! Shovel where you at?

...successfully proved Helmholtz resonance can be used to increase exhaust gas scavenging and help your ride put out a few extra ponies compared to other aftermarket offerings...

Oh I like sciencey threads. This old physics relation shows what many of us already know from experience or intuition:

http://www.the370z.com/members/mandi...-h003-eq-1.gif

Resistance (R) is directly proportional to the length (L) of the tube and viscosity of the fluid (a constant in this case obviously). R is inversely proportional to the radius to the 4th power.

So as length increases, resistance increases (we know this already). What isn't as obvious is that as radius of the tube increases, resistance decreases dramatically.

Of course we need more complicated math (computer models) to see how turbulence is created by bends in the tube and how that affects resistance. The flow through the filters could even be explained by the above relation in a sense, but it would require calculus and lots of data we can't get.

Basically, the large area of the K&N filters used on the Gen3 overcomes the negative effect of having longer tubes (I think their radius is a little larger than stock as well? correct me if I'm wrong). The lower IAT due to the filter location is not what gives the noticeable power increase. The difference in temperature between the stock draw location and the Gen3 location is too small to affect air density enough. Perhaps the computer is responding to the lower temperature readings and making adjustments that translate to more power?

Agree & the stock intakes get the fresh/cool outside air that is forced by pressure from under the car. Hard to beat the stock intakes w K/N dry filters.

my afe filters flow way better than dry k and n filters

Someone measured for me when I was making my intakes and said the pipe is same as OEM. 2.5" OD or 2.34" ID where it counts.

ok
 

I'm just not familiar with them.

AFE does have better air filters. Worth the extra money.

Proof? The only way it can be better is if it flows more and catches more particles. If it only does one of the two it's not better. It's not a good trade off to flow more and make more power when letting in sand to kill your motor. And if it catches more but makes less power its also not worth it because the K&N catches plenty based off of oil analysis's.

no filters is the best
 

O air restriction, also any particles that get into the cylinder just add to the compression then gets destroyed in the cylinder explosion & what's left goes out through the exhaust.

I think that's Stephen Hawkins quantum mechanics. :icon14:

What is the end game? How do you know that an intake has left no room for improvement?

Perhaps an extremely high resolution pressure transducer sampling manifold pressure and pressure just outside the throttle plates? I must assume that if you are achieving atmospheric pressure in your samples, there couldn't really be room for improvement other than colder/denser air.

With so many other factors that cause power readings to vary from pull to pull, it seems like anyone judging an intake by 1-2hp is doing themselves a disservice. It seems that you would want to isolate the results of the intake alone to know for sure.

The motor cant destroy atoms. Not hot enough or enough pressure. If it did we'd be driving nuclear bombs haha. But seriously, it will break down sand to silica which will not all get out the exhaust and will get trapped in the oil and show up on an oil analysis. All my k&n reports are better then average for filtration elements.