Lets talk science, Stillen Gen3 Intake

Mandingo · 10-31-2013, 05:37 PM

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

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?

andre12031948 · 10-31-2013, 05:44 PM

Quote:

Originally Posted by synolimit

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?

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.

critical · 10-31-2013, 05:49 PM

Quote:

Originally Posted by andre12031948

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

synolimit · 10-31-2013, 05:51 PM

Quote:

Originally Posted by Mandingo

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

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?

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.

andre12031948 · 10-31-2013, 05:57 PM

Quote:

Originally Posted by critical

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

I'm just not familiar with them.

MadChemist · 11-01-2013, 05:42 PM

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

synolimit · 11-01-2013, 06:17 PM

Quote:

Originally Posted by MadChemist

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.

andre12031948 · 11-01-2013, 06:43 PM

Quote:

Originally Posted by synolimit

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.

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.

phunk · 11-01-2013, 06:44 PM

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.

synolimit · 11-01-2013, 07:23 PM

Quote:

Originally Posted by andre12031948

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.

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.

critical · 11-01-2013, 07:37 PM

Quote:

Originally Posted by synolimit

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.

PRO 5 r

k&n doesn't publish flow rate or filtering efficiency data i believe. wonder why?

Sh0velMan · 11-01-2013, 07:41 PM

Quote:

Originally Posted by synolimit

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.

This is all true and accurate.

You can absolutely judge the efficacy of a filtration element in an internal combustion engine with oil analysis.

Sh0velMan · 11-01-2013, 07:44 PM

FWIW, I went with some bigass "Green Filters". I have the gut feeling that they are flowing better than the dry filters that came with my intakes, based on what I see on the dyno, but no data to back it up. They look cool tho.

H2O_Doc · 11-01-2013, 07:49 PM

Haven't there been at least a few independent comparisons? I remember one on the NICO webpage and a couple more elsewhere. It strikes me as odd that things like this are still somewhat ambiguous. There is almost a Sasquatch mystique to figuring out what, if any, horsepower gains various mods provide. Not a criticism, just an observation.

As I've said elsewhere, my MAZOC sticker has been repeatedly documented as providing +50 hp, and my dual 12" subs add another 27 hp.

synolimit · 11-01-2013, 07:54 PM

Quote:

Originally Posted by critical

PRO 5 r

k&n doesn't publish flow rate or filtering efficiency data i believe. wonder why?

Motordyne doesn't either and wants real people dynoing his stuff. Real people don't lie, manufactures will. Real people show his stuff making more power than others. There's something to be said for a manufacturer that doesn't gloat.

10-31-2013, 05:37 PM	#31 (permalink)
Mandingo Track Member Join Date: Nov 2010 Location: Dallas Posts: 624 Drives: '10 370z 6spd Rep Power: 3370	Oh I like sciencey threads. This old physics relation shows what many of us already know from experience or intuition: 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? MadChemist and critical like this. __________________ some mods

11-01-2013, 05:42 PM	#36 (permalink)
MadChemist Enthusiast Member Join Date: Sep 2012 Location: Florida Posts: 412 Drives: 2010 370ZR Rep Power: 12	AFE does have better air filters. Worth the extra money. critical likes this.

11-01-2013, 06:44 PM	#39 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,655 Drives: 370 Rep Power: 944523	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. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph

11-01-2013, 07:44 PM	#43 (permalink)
Sh0velMan A True Z Fanatic Join Date: Jan 2012 Location: Dallas/Ft.Worth Posts: 3,349 Drives: Noisily. Rep Power: 20	FWIW, I went with some bigass "Green Filters". I have the gut feeling that they are flowing better than the dry filters that came with my intakes, based on what I see on the dyno, but no data to back it up. They look cool tho. __________________ Buy My Car! \| Build Thread

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Stillen Gen3 intake alternative	Z370Z011	Intake/Exhaust	22	11-08-2012 01:13 PM
WTB: a stillen gen3 or injen intake	triadz	Wanted	0	11-29-2011 02:57 PM
Stillen Gen3 Intake and Hi-flow cat!!!	cycy89	Intake/Exhaust	6	09-16-2011 05:38 PM
Stillen Gen3 Intake Issues?	$hytz_!ntyn$e	Intake/Exhaust	10	01-21-2010 06:48 PM
Stillen Gen3 Intake, Berk Hi-flow cat, and Stillen cat-back exhaust	axio	Intake/Exhaust	82	07-31-2009 12:41 PM

11-01-2013, 07:49 PM	#44 (permalink)
H2O_Doc A True Z Fanatic Join Date: Apr 2013 Location: Northern VA Posts: 1,083 Drives: '14 370Z, '12 4Runr Rep Power: 14	Haven't there been at least a few independent comparisons? I remember one on the NICO webpage and a couple more elsewhere. It strikes me as odd that things like this are still somewhat ambiguous. There is almost a Sasquatch mystique to figuring out what, if any, horsepower gains various mods provide. Not a criticism, just an observation. As I've said elsewhere, my MAZOC sticker has been repeatedly documented as providing +50 hp, and my dual 12" subs add another 27 hp.