No direct port no care....

 

Better than no spray at all.

 

Good job Irish....

Phase-3 adds a Home Depo downspout to the hood for true forced air, right?

 

Irish, does having the resonator box (white thing below the scoop) make any difference? I took mine off because it was about to fall off anyways, I didn't know though if it would affect performance in any way considering thats what we're going for with the porting, ect.

 

mine has been off for a while...I have a piece of white PVC attached there which gets air from just below the front of the engine...though I don't think it made any difference at all.

 

I tried find a web site called Kunz Korner that has a lot of data on intakes. While mainly for Ford Rangers/Bronco II's this Kunz guy is a guru on the
subject. I was hoping to find the link but it looks like his site is down... Anyhow, the data is something like this: 1% HP gain for every 7 degree F you drop the intake air temp. I have true CAI (OK home built "ghetto" style) with a K&N cone and noticed overall power gains throughout the rpm range but that is on my '90 Bronco II 2.9 tricked in every way imaginable... Haven't tried anything GAB-like on my Max... But if under hood temps are only between 5-10 degrees different between true CAI ~vs~ GAB it makes sense not to go all out and do true CAI for only a 1% gain at BEST and that depends on outdoor ambient temp (time of year) ETC... on my BII I don't notice nuch in winter when it is in the 20-50 degree range... summer at 100+ degrees there is a big difference but that is mainly rock crawling in Moab in 4 Low-Low at about 1/2-3 MPH

 

actually, I'm going to add a roof-height snorkel next, so I can ford rivers without killing the engine...

 

And therefor the point of spending 300$ on a CAI for a gain of 5-10hp when you can do minor mods like the GAB designs for free and still recieve similar results is....

 

That would look great!

 

Is the resonator box the circular thing thats right after the fake "ram air" right in the beginning of the intake assembly? its sealed off on the botton but why not cut it out and put a filter with some tubing on it? Or is that exactly what you did?

 

i assume the resonator box is the white box, under the scoop which is visable more from the underside. Are you talking about that pointless looking bubble piece on the back of the scoop? If so, I've been told it's a silencer... ? Maybe Irish can help out here ha

 

after having a free cai, then a variation of several types of GAB i reverted to stock a few days ago. i am loving it. the engine, the sound, everything basically made the car feel 5 years younger.

i couldn't stand the noise anymore.. i thought it wasn't there at highway speeds but man, it sure is now that i am back to stock. i can't feel any difference so.. butt dyno (yeah i know) says whatever.

but i've seen the drilled air holder before.

 

I thought it was ghetto air box/blaster... as in subwoofers lol

 

Forgive me for asking a question that may have been dicussed to death already. But, why would increasing the amount of air available to the engine cause decreases in power? Wouldnt allowing the engine to breathe as much air as it likes increase power all over the spectrum? Thats what my intuition says, but im sure im missing a subtlety.
Fascinating project, Irish. I look forward to seeing the dynos.

 

it decreases torque because the air isnt being "sucked" into the car as much so to speak. The stock airbox seems choking because it is ment to cause the air to GO INTO the engine instead of the engine taking it in as is the case with a wide open intake. However more air does create higher end power... it's a tradeoff. Right now I have the ported hanger and the resonator box off, I like the feel and sound of this setup in 2-5 gear, however I am sure that the stock box pulled through 1st better which is dissapointing because everyone likes a quicker acceleration.

 

Intake and exhaust will both affect the power band. The engine NEEDS a certain amount of exhaust back pressure to run at peak power. Same wth intake... On the exhaust side it has to do with the mixing of exhaust gasses in from the heads and the pulses from each cylinder. IE; if your exhaust is too wide open it causes flow to run back and forth instead of a more steady flow only towards the tail pipe. One cylinder may partially cancel out the pulse of another.
On the intake side it works kind of the same... imagine in super slow motion the intake gasses as pulses lining up to be drawn into a cylinder. That flow needs to be at a certain pressure positive or negative (vacuum) to keep the intake mix flowing steadily.
Another way to look at it would be like this... Imagine walking though a building, where each room was connected to another BUT there were six doors to choose from each room to room. Now, someone was in each room waiting for you and would open the proper door when you came IN. You would walk through this "building" without stopping. Now, lets say that the guy opening the door in each room was working at the same speed BUT you ran through each room, you would be in the room before the next door was open. You would be forced to pause.... waiting for the proper door to open... BOOM you run into the next room... same thing.... pause.... BOOM run into the next room over and over... your speed through the building would be the same as it was had you walked except for the last room and door would give you a slightly faster speed than walking. Clearly demonstrating that running compared to walking didn’t make that much difference in overall speed. In fact, imagine how you would feel in the scenario running, stopping, running ,stopping, etc… compared to walking though. You would be less “winded” walking... Now, throw this into the mix... There are 500 other people single file right behind you almost stepping on each others heels… imagine the confusion of trying to get 500 people to stop and start over and over though all the rooms. The flow would be much more steady and efficient if all were walking. Our engines are passages, rooms and doors throughout so speed of flow is not what you would think.
I also just described how a traffic accident off the side of the freeway out of traffic can screw up the entire freeway… people slow down to look…the next guy does too… soon the whole damn thing is messed up. If everyone would just stop rubbernecking and maintain one constant speed (even slow) then everyone would get through much more quickly.
Sorry this got so long…

 

I believe you mean that maximum exhaust velocity is needed for peak power and not backpressure. NO backpressure is wanted at all. Yes, if the exhaust is too wide open, it isn't ideal either, but only because there is insufficient velocity and not because there isn't any backpressure.

 

good idea, they did that kind of thing to the C4 vettes back when I played around with those

 

Some backpressure is needed but how much depends on the engine and the intake... For instance, if you run a stock intake and wide open exhaust the exhaust pulses start to mess with the velocity because there is no pressure at all and that causes the exhaust pulses to move in both directions affecting the net flow. If you have an increased intake then the exhaust can be more open too. When you try to run one without the other then the flow is goofed up.
But, even with both intake and exhaust flow increased it still all depends on the bottle neck/s which then become the throttle body, heads, valves, and manifolds/headers. Each component in the entire "system" has to be considered as part of the whole.

 

Your explanation still doesn't give me any evidence as to why backpressure is needed, but I'm not gonna debate this with you any further for the sake of keeping this thread on track.

Here is what I'm basing my opinion on, which IMO is the correct way to think about it:

http://www.magnaflow.com/05news/magazine/05sportc.asp

 

awesome idea, let us know how it turns out, i would do it, if you can gain top end and also retain the low end.

 

We are basically saying the same thing just different ways of thinking about it.
I agree not to get this thread further off track...

 

my setup now is, ported hanger, removed silencer and resonator from scoop, plugged silencer hole, cut resonator box neck down flush with scoop and plugged it. More like stock acceleration now, and a LITTLE better midrange, not as much sound. I say this is good though, to have better all around power rather than sacrificing low for high or vise versa. I'm still debating whether or not to keep the resonator hole plugged... i just think it has better high end with this open... we'll see

 

Ok, I put 4 plugs in (1/2 open) and it "feels" like the low end is back, but the high end is still there....still going to toy with it more, but looks like this may be the ideal setup.

I repainted it more low-key, while I was at it

 

wouldnt you want the middle open at least, for the air to flow directly into the MAF ?

 

Wonder how hot weather would affect the set up, i.e. if more or less holes would work better...

It would be very nice if you could dyno various "settings" and in regards to engine/ambient temp rather than relying on good old botox, though when I played with GAB difference was easily noticeable off the line... It would put some concrete evidence to it escpecially when fiddling with number of holes to open/close at what conditions, etc...

 

I agree that dyno would be nice, but unless I get some free/cheap dyno time, I probably won't.....I would rather spend my automotive budget on actual parts, rather than charts.

 

I don't think it really matters - but like I said, I'll continue toying with it. I have 8 plugs, so I can do whatever combinations I want to..

 

oh boy irish44j, see what you started! we got one guy over here giving us plans on the best fire escape with doors, windows and ****. another who has the whole backpressure thing down with quantifiable results, and a few who are totally discombobulated. Just joking people. KEEP THE DISCUSSION ALIVE!!!

 

Very cool if you have been able to get the car to pull more at higher rpms and still retain the low torque. Personally, i like having lots and lots of acceleration ...guess ill stick with the stock box.


Thanks WasatchY2KMax, JaKillz2 and Puppetmaster.
Its a bit more clear to me now. The thing I missed is that air doesnt move in a perfectly continuous stream through a 4stroke engine but in packets.
Hey Irish, who is the attractive young lady in your avatar?

 

Christina Scabbia of Lacuna Coil.

 

same as the one that's been in my sig for the last year

I'm not going to bother posting pics again of her....if you like hot women and good, heavy music, check out www.emptyspiral.com....'nuff said.

 

i like that a lot

 

PUPETMASTERI actually thought it is necessary...........If irish does dyno, then I would like to know the dimentions to get a similar performance gain.

Also something to take in affect, irish has many performance mods, and each persons dyno results will vary by mods.

 

Wow, reading this and then recalling the information posted in the forced induction tread regarding how a manufacturer would spend millions of dollars and thousands of hours developing and testing an engine to reach the best POWER and keep REALIABILITY... really gives you something to think about. It would be so much easier to just test various intakes on an engine out of a car on a hoist.. but that can prove difficult. What I'd like to see is how this mod would work with the 350z intake manifold on the maxima's engine.

 

Wow, reading this and then recalling the information posted in the forced induction tread regarding how a manufacturer would spend millions of dollars and thousands of hours developing and testing an engine to reach the best POWER and keep REALIABILITY... really gives you something to think about. It would be so much easier to just test various intakes on an engine out of a car on a hoist.. but that can prove difficult. What I'd like to see is how this mod would work with the 350z intake manifold on the maxima's engine.

Keep up those mods.

-edit sorry about the double post..

 

if i were you i would edit the whole post^^^^ but on a different note irish what did you plug those things with?

 

also keep in mind, though, that the stock airbox is designed to minimize engine noise for their "luxury/sport family sedan", while the various GABs and intakes make the engine louder to various degrees.

 

I just bought some appropriate-sized plastic plugs from home depot....you can find them in one of the little drawers in the screws/nails aisle for about 50 cents each...there were also metal ones.

I had to shave down the "lips" on them a little bit to fit between the ridges, but they have little tabs so they click into the holes securely.

 

Also this gets me thinking. Wouldn't you want to increase the engine internals. Items such as bore size, increase the compression.. to make use of the higher volume of air being taken in? I obviously know doing such modifications are pretty costly, but its just me thinking and learning.