4" intake on 3rd gen 3sgte, disscussion topic! GIVE YOUR 2 CENTS! Options

[lagos]

Jim, the theory that a vortex will create more power is the same theory behind those Tornado gizmos they sell.
The truth is, that your turbo is already creating a vortex when it spins and sucks in air from the intake. However, the output of that velocity is limited by the size of the turbos 2in outlet. So in essence, how ever free flowing the intake is, it will always be choked by that 2in outlet on the turbo. Its the same as having a huge jug of water. The jug might be very wide in diameter, but the water will only flow out as fast as its restricted opening will allow.

I think the reason why their car made more power on the dyno, is because for whatever reason (maybe the intake did play a role in this) the car was able to hit more boost on the dyno then most ct20bs can. I guess the best way to know for sure is to wait for your dyno results.

I'm looking forward to physics class next semester. Its fascinating how all of this stuff really functions.








This post has been edited by lagos: Dec 1, 2008 - 11:39 PM

[dlx742]

I'm looking forward to physics class next semester. Its fascinating how all of this stuff really functions.

and you will learn exactly why the 4" makes a difference... and you will really be scratching your head when almost everything can be explained by energy

[presure2]

since you are changing your filter going from 3" to 4" the only real way to test is to do a few pulls on the dyno, all without any filter at all.

get back to us with proof.

from my first post:

im hoping we can get back to back dynos at some point real soon with a 3" intake vs this one

we WILL be testing this setup, that was the whole idea of this thread. to discuss peoples opinions on the setup, improvments that could be made, ect.
right now, it looks like we will be testing this in a couple weeks on the weekend of the 13th.
jim is coming up for a b-day party for a friend, and i will be fabbing him up a new b-pipe on that weekend after the dyno. (his current one hits the crossmemeber, it had since he got the car IIRC)
providing we have time, i will perform the following tests:
stock airbox
3" intake
4" intake
no filter
each test will be performed at least twice, with cool down time between each setup.

that should provide us with enough data to actually get some solid results, and see where we stand with each setup.

[DEATH]

since you are changing your filter going from 3" to 4" the only real way to test each test will be performed at least twice, with cool down time between each setup.

I had wondered about that after we talked about how to keep the filter from effecting the results but I figured that would just make it cost prohibitive. You must be good friends with your dyno owner

This post has been edited by DEATH: Dec 2, 2008 - 11:25 AM

[presure2]

since you are changing your filter going from 3" to 4" the only real way to test each test will be performed at least twice, with cool down time between each setup.

I had wondered about that after we talked about how to keep the filter from effecting the results but I figured that would just make it cost prohibitive. You must be good friends with your dyno owner

not really, i mean im not gonna let it cool an hr between runs...5-10 min is more than enough.
his rates are just very reasonable compared to anyone else ive seen @ 60$ per hr with unlimited runs.

[1bwilson]

I wish dyno's around here were 60 a hour. Mines on the dyno now at 175 a hour

[DEATH]

Damn - but that's with tuning tho right?

[1bwilson]

Yes yes. Im hoping to get a call today about it being done. They have had it 3 weeks tomorrow. The dyno has been busted, it broke the car before mine 2 weeks ago.

[Terracar]

Curiousity has me intrigued - how does a dyno break a car? I mean I am sure there are ways, but none tht would necessarily guaarantee breakage.

-Terracar

[lagos]

Curiousity has me intrigued - how does a dyno break a car? I mean I am sure there are ways, but none tht would necessarily guaarantee breakage.

-Terracar

They dont. Its impossible.
If a car brakes on the dyno, there was something already wrong with the car that would have broken on the street.

[playr158]

^dynos can break cars. I've been at one when it seized and snapped axles. its a VERY VERY rare occurrence but it can happen

[dlx742]

so i was thinking about why the 4'' intake would add power and i came up with this
if you didnt factor in turbulance then its just simple continuity of hydrodynamics where the continuity of flow Q=velocity x area remains constant.
so, if area 1 is 4π (pi) and area 2 is aprox. 1.89π (area of a circle is πr^2) then the equation is 4π(v1)=1.89π(v2) or v2= 2.12(v1) meaning that by the time the air gets to the inlet of the turbo it is traveling twice the speed as when it entered the intake, and since a 4'' intake can collect a higher volume of air than a 3'', the turbo is getting more air at a higher velocity = more power

[_Jim_]

Jim, the theory that a vortex will create more power is the same theory behind those Tornado gizmos they sell.

This is different. The compressor housing is CREATING a vortex due to spinning at speeds above 100,000 rpms, where as those tornado gizmos just alter the air coming into the intake to "spiral" the incoming air at very slow rates. It just alters the air flow direction more than anything.

The truth is, that your turbo is already creating a vortex when it spins and sucks in air from the intake.

Agreed. But an opening under vortex conditions can flow much greater than the same opening not under vortex conditions.

However, the output of that velocity is limited by the size of the turbos 2in outlet. So in essence, how ever free flowing the intake is, it will always be choked by that 2in outlet on the turbo. Its the same as having a huge jug of water. The jug might be very wide in diameter, but the water will only flow out as fast as its restricted opening will allow.

Not true, because the 2" outlet of the turbo on the compressor side is under pressure. Take that jug (coke bottle) and time how long it takes to drain out when you turn it outside down. Now, take that same jug and time how long it takes to drain out when you turn it upside down and apply pressure (squeez) the bottle. The opening diameter of the bottle didnt change, nor did the amount of water inside the bottle. The only difference was the pressure added to the bottle which allowed it to drain faster.

I think the reason why their car made more power on the dyno, is because for whatever reason (maybe the intake did play a role in this) the car was able to hit more boost on the dyno then most ct20bs can. I guess the best way to know for sure is to wait for your dyno results.

I'm looking forward to physics class next semester. Its fascinating how all of this stuff really functions.

I agree that the higher boost DEFINITELY played a role in those numbers. But I also believe that the intake played a role in this. Yes, the best way to tell for sure would be wait for the dyno results in 2 weeks, but its nice to get opinions and ideas about why or why not a 4" intake may make power.

[_Jim_]

so i was thinking about why the 4'' intake would add power and i came up with this
if you didnt factor in turbulance then its just simple continuity of hydrodynamics where the continuity of flow Q=velocity x area remains constant.
so, if area 1 is 4π (pi) and area 2 is aprox. 1.89π (area of a circle is πr^2) then the equation is 4π(v1)=1.89π(v2) or v2= 2.12(v1) meaning that by the time the air gets to the inlet of the turbo it is traveling twice the speed as when it entered the intake, and since a 4'' intake can collect a higher volume of air than a 3'', the turbo is getting more air at a higher velocity = more power

Well done.

[lagos]

Not true, because the 2" outlet of the turbo on the compressor side is under pressure. Take that jug (coke bottle) and time how long it takes to drain out when you turn it outside down. Now, take that same jug and time how long it takes to drain out when you turn it upside down and apply pressure (squeez) the bottle. The opening diameter of the bottle didnt change, nor did the amount of water inside the bottle. The only difference was the pressure added to the bottle which allowed it to drain faster.

Thats very true. You move more air under pressure then not. Thats how a turbo car can ingest more air then an NA car through the same sized pipe.
But the bigger intake will not add any more pressure to the system. All it is creating less restriction. So any gains would have to assume that a 3in intake is too restrictive.
Ultimately the car will make more power when more air is able to reach the cylinders. But you have to remember that a 3in intake is still bigger then your throttle body, and intercooler end tanks. All those things limit how much air can enter the engine. I think that you would have to upgrade ALL of those components to see a gain. Thats why you always see people with higher HP cars upgrade the throttle body, intercooler pipes and intake all at the same time.

4π(v1)=1.89π(v2) or v2= 2.12(v1)

I got... v2=2.11(v1)

This post has been edited by lagos: Dec 3, 2008 - 10:49 PM

[Etak28]

WOW that looks nice. i plan on doing something like that after i relocate my battery. my intake right now is just a 3" that goes pretty much off the turbo and i would say like an 75 degree bend down so it's flush with the bottom of the radiator fluid. looks like it was made for our cars and i just rigged it up out of a honda civics cold air intake i bought off of ebay. I just looked for one that had the nipple for the pcv and a bend nearby and bought it.

that looks real nice tho

[dlx742]

Not true, because the 2" outlet of the turbo on the compressor side is under pressure. Take that jug (coke bottle) and time how long it takes to drain out when you turn it outside down. Now, take that same jug and time how long it takes to drain out when you turn it upside down and apply pressure (squeez) the bottle. The opening diameter of the bottle didnt change, nor did the amount of water inside the bottle. The only difference was the pressure added to the bottle which allowed it to drain faster.

Thats very true. You move more air under pressure then not. Thats how a turbo car can ingest more air then an NA car through the same sized pipe.
But the bigger intake will not add any more pressure to the system. All it is creating less restriction. So any gains would have to assume that a 3in intake is too restrictive.
Ultimately the car will make more power when more air is able to reach the cylinders. But you have to remember that a 3in intake is still bigger then your throttle body, and intercooler end tanks. All those things limit how much air can enter the engine. I think that you would have to upgrade ALL of those components to see a gain. Thats why you always see people with higher HP cars upgrade the throttle body, intercooler pipes and intake all at the same time.

4π(v1)=1.89π(v2) or v2= 2.12(v1)

I got... v2=2.11(v1)

2.116 rounded up since we are at 2 sig figs is 2.12

[Etak28]

good ol' sig figs

[x_itchy_b_x]

meh, i cant see this influencing flow as much as it will help spool. its not going to change the trim of a turbo you know what i mean. sweet results and nice work Manny.

[Dr_Tweak]

I'm interested to see the results, I always wanted to play around with different sizes of piping and compare them all back to back. Are you going to do the tests with the hood closed (as it would be when driving)?

Hey manny, if I send you one of my intakes would you test that along with the others?





This post has been edited by Dr_Tweak: Dec 4, 2008 - 8:37 AM