MarcJD

I was thinking how much people try and improve their intake by either using a CAI or a large cone filter. Well, I was thinking that one could easily use a y-pipe and have two intakes with filters...such as the CAI or more easily I presume the cone filters. How stupid of an idea is this? Any thoughts?

Gotrice4

You would lose considerable low end torque/horsepower b/c even with a single cone filter the max seems to lose some low end torque and/or horsepower. In my mind unless some other things are modified, maybe bored out throttle body or something else that would require increasing airflow.

_DRU_

need low end power? get a 5spd and rev it up...

MarcJD

That is one of the potential "problems" I thought one might encounter. I have heard of this many times with both the exhaust and intakes, but have any dynos been done that actually show it? With a heavy background in physics and mathematics I do not doubt it, but am always interested in seeing some hard numbers.

I guess what could be done...although I don't know if it would be worth it...is to somehow rig it so the second intake pipe is not "opened" until the RPMs get higher. This would be somewhat similar to the exhaust systems now on the Maximas that allow for a higher exhaust flow when the RPMs are up in a higher range.

With this in mind, one could instead simply make one large intake filter system, but have it be variable...thus preserving your low-end and perhaps significantly increasing your high-end. Obviously there will be a point where increasing the intake flow will do nothing for performance, but I do not know where this point is.

dwapenyi

iTrader: (3)

The ideal dual intake would be something that starts out as a CAI and then somehow "morphs" into a POP charger. This is because the CAI improve mid-end power and loses pep up top, above 5000 rpm. The POP charger's strong suit is mostly up top, at 5000 to 7000 rpm.

Thinking that, you can make a CAI, and in that CAI have some servo-activated switch that, at 5000 rpm, switches the airflo to a shorter pipe, like the POP charger. That would give you the best of both worlds.

DW

Jeff92se

iTrader: (82)

Probably will not do anything. The Z guys even ask if a dual pop for the TT, will work for the na Zs. They all say no. Look at it this way, the na engine will only draw so much air. Any more filtering potential will not mean more power if the engine can only draw it so much anyway. If you want to test if this, I suppose you could run w/o any filter for a VERY SHORT TIME so see if you car runs any better w/o a filter. I doubt you will see much if any difference.

Jeff92se

iTrader: (82)

Probably will not do anything. The Z guys even ask if a dual pop for the TT, will work for the na Zs. They all say no. Look at it this way, the na engine will only draw so much air. Any more filtering potential will not mean more power if the engine can only draw it so much anyway. If you want to test if this, I suppose you could run w/o any filter for a VERY SHORT TIME so see if you car runs any better w/o a filter. I doubt you will see much if any difference.

got rice?

iTrader: (2)

It's pointless since a naturally aspirated V6 engine, 3.0 liter, is not pumping enough to warrant a dual intake setup. Twin turbo 300ZXs don't need a dual intake until they push 550-600+ hp. A conical intake is more than enough for any supercharged Maxima on the road. Top it off with NOS and you're still not overloading the intake.

Neptune97

If you do run without a filter, and notice any difference (no matter how small it is), and you like the difference, then a dual-intake would be beneficial. Pressure drop is pressure drop...doubling the filtering surface reduces the volume of air going through a given area of filter. This ultimately leads to less of a pressure drop through the entire filter, which would lead to better flow through the engine (ie what happens when you completely remove the filter).

I agree that most likely you wouldn't me able to detect much difference. In addition, who is to say that the extra elbow/connection that you put in doesn't add more pressure drop than the increase in filter surface area takes away.

I guess in this case I would actually trust the 300ZX fanatics more than I would physics.

But if youre willing to do the work for a couple hundredths of a second off your 1/4 mile time, you should go for it

Jeff92se

iTrader: (82)

Yeah but just using a larger filter would be more than enough filter area. IF there are gains(big if), what's it worth 1-2 hp? Fab a new y connector + a new filter costs what? $50-$100? Not a good hp to cost ratio. There are alot of better things to do before looking at this.

MaDMaX024

the CAI improves mid range power because of its piping or because it pulls in colder air? does it run out of pep because the piping isnt flowing enough air?

dwapenyi

iTrader: (3)

Yeah, that's what I've observed. Apparently, the long piping restricts the air somewhat in the 5000 to 7000 rpm range of the VQ. You notice it most in 4th and 5th gear. Remember, these are butt dyno measurements. I don't have any dynos of my VQ. It could simply be that the CAI improves everything, even the top end, but the mid-range is more improved than the top end, hence the relative feeling of loss up top because I'm comparing to mid-range. You won't feel it in 1st 2nd gear.
3rd gear you'll notice it a bit.

DW

dwapenyi

iTrader: (3)

I should add this: my car still has the stock Nissan Y-pipe, so maybe the restriction I'm feeling is the Y-pipe. Once I upgrade to the Cattman SS Y-pipe, hopefully that should open things up up top. That's where they say that the Y-Pipe really puts on the power. An intake and a Y-pipe are probably the best power adding combo (keeping things NA, of course) you can get for the VQ.

DW

MaDMaX024

hmm...my plan is to have a pop charger in an aluminum box with 2 ducts coming from the front of the car and/or the fender well to feed it cooler air. i'm hoping this will work. also, i'm wrapping all the exhaust stuff thats under the hood with headerwrap, i'm doing to same to the intake box and the ducts. i'm hoping this will do something..lol

MarcJD

If nothing else, it will give you and your Max some nice "bonding" time together.

MaDMaX024

lol. it'll do something..the popcharger improves performance...at least i'll get that..i'm hoping for some benefit of the CAI with the ducts though. we'll see when/if my MAF adapter ever comes in.

NeverEnough

I seem to remember that the velocity of the intake charge increases the efficiency of the motor, in effect giving more power (torque), after all, an engine is basically a glorified air pump, right. So, perhaps we are looking at the benefit of the dual intake setup from the wrong perspective. The benefit may not be that we can flow more air, but that we can flow air faster, and therefore increase torque. This would be the benefit of having a dual inlet system, but make them of different lengths and diameters; one long and narrow, for the low rpm usage, and one short and wide, for high rpm breathing. If you really wanted to get trick, mount a low-draw squirrel cage-type fan just inside the cold air inlet, so that it pulls in cold air, even at rest, and then pushes it into the engine, effectively creating a supercharger effect, though on a much more reduced scale.....and the cool part is that is not a draw on the crank, so it costs nothin in terms of power loss. Well, that's just the mad scientist coming out to play....I'll put him back in his cage now, and leave you to debate this.

-Lee

ps. If I'm not mistaken, Jeff told me that the VE engine has a dual stage inlet that effectively mocks this short/long setup....and he siad that it looks like it might fit on our engines, so put that in your pipe and puff on it for a while....you might just catch a nice little buzz.

MarcJD

I see what you are saying, but the engine is only going to draw so much. This vacuum that the engine will create will draw the air in. Thus, the larger the diameter for the intake then the slower the air will be forced to come in due to a higher volume of air coming in. Either way, the same amount of air will be coming in...but since you are talking about velocity I thought I would point this out. The higher the velocity of the air traveling through the cross-section of the intake then the higher the pressure of this air at that point.

Just think of an actual vacuum. You know when you use that hose attachment but you need a little more suction power? Well, you put on that attachment to the end of the hose with a much smaller area which therefore gives it more sucking power since the same vacuum power is being used for a much smaller cross-section. Make sense?

MaDMaX024

i already have a VE, so i do have dual plenum intake system...i think i'm just going to experiment till i either get tired of experimenting or find something that gives me good gains on the butt dyno.

NeverEnough

MarcJD,
Yes, I do understand that point, which is why I mentioned it. I know that the engine creates vacuum, and may be I'm mistaken, but it seems as though the amount of air that is being drawn in varies with RPM; higher RPM=more air to complete work (horsepower). Given this and assuming that this is true, the velocity of air moving into the engine would also vary with RPM; higher RPM=greater velocity, that is until it reaches a point at which it can no longer pull air in at the rate at which it needs in order to continue to work, at which point it begins to starve for air. This is illustrated by the CAI seeming to give up some power high in the powerband vs the pop style intake. I believe this is due to the rate at which the air can travel from point A (the intake), to point B (the cylinder). The question is was trying to ask, and I apologize for not making this more clear, was whether or not we could keep the velocity higher throughout the power band by varying the length and diameter of the intake tracts. Fast down low, like a CAI, and fast up high like an open element pop style seems to me to be the most efficient way to let the Max breathe. Sorry I didn't make that more clear to start, butI was trying to go to lunch, and I didn't go into enough detail. And don't take this as me saying duh, either, I just want to explore all avenues with everyone, as I have found this is best way to create and apply new ideas. So with my little disclaimer out of the way, I ask again, whaddaya think, man....can we do this?

-Lee

Neptune97

I don't think that will work...although you could shrink the cross-sectional area of the intake piping to increase the speed of the air inside the pipe, ultimately the pipe still has to expand out to the 3" connection with the MAF sensor. At this point, the air is going to slow back down to whatever speed the air goes through this 3" pipe at normal conditions.

Now its true that some of the momentum from this faster moving air may actually help to push air through the engine a *little* faster than normal. But the increase in speed of the air through the pipe will increase the pressure drop through the pipe (the pressure drop the engine has to overcome), and most likely will negate any benefit the faster moving air would provide.

Also, the engine wouldn't be able to differtiate between the two different air path options. It would choose whichever path has the least pressure drop, and this would *always* be the short stubby cone filter connection. The only way to ensure you would get air flowing through the long skinny pipe would be to completely block off the cone filter connection. Its possible, but you would need some kind of wastegate (like in a turbo) and some kind of control system.

Not saying you couldn't do it, but I don't think you'll benefit from it.

Anyone else think differently?

infinitiblast

iTrader: (2)

Hmm this dual intake thing kinda sounds cool to me. Well anyways recently in a car meet I saw a s2000 with what I guess is kinda a dual intake. It had an intake that came out of the engine but the filter was cool looking it had two ends so a pipe could be mounted on both sides. So they had the intake to a certian point in the engine bay then another pipe that hooked up to the second end of the filter and went to the bumper.
Maybe thats not a dual intake but I thought it was cool cause it could pull air from around the filter and thru the pipe that comes out the second side.
Well just my .02

ArcticMax

dont you guys know that there are dual path intakes on 5th gens?

too bad for you 4th gen people.

Neptune97

Yeah, this is kind of what we are talking about. I guess the benefit of the S2000 configuration was during initial launch, the engine can pull air in from the engine bay (the least pressure drop), and then once it was moving, there was a ram air effect that pushed air through the pipe, reducing the amount of air pulled in from the engine bay. This way the engine could choose the least path of resistance without actually having to make any control decisions.

NeverEnough

Nice point, and I bet that would be fairly easy to do, as well....the best of both worlds. The other thing is this...we could make a dual stage plenum, but I think the weight gain/expense would negate any benefit, but it was fun to think about, and now we have a new idea from it.... good stuff.

-Lee

dwapenyi

iTrader: (3)

That's it!!

Get the CAI and cut a hole (or holes) around the mid-piping. Then mount a filter to go around those holes. Brilliant. Simple. The best.

Any takers?? Don't look at me I'll get my Y pipe first and see if I can live with that.


DW

Neptune97

I couldn't think of a better way to waste time at work my question is, how do the filters come into play? Do you have one filter or two? Do you use cone filters or inline filters?

Neptune97

Well, that won't really work because the CAI has no ram air effect...the engine would always choose to pull air in from the cone filter in the engine bay. What you would need would be a CAI that mounts to the front grille/bumper so you get forced air through it.

dwapenyi

iTrader: (3)

Party pooper j/k

Hmmm, back to the drawing board. You know, I think the idea I suggested earlier would work. With the switch, the flo is determined by the switch, either the CAI below 5000 rpm, and switching to the shorter pipe above 5K rpm.

DW

LoveSick

Why don't people just do huge air chamber, like the ones in the Type-S Prelude? This way, the engine can suck the air reserved in the air chamber that will increase both low end and high end response......

La Jolla Max

Sounds like a variable runner-length intake manifold to me

MaDMaX024

exactly...except this manifold isnt getting enough air into it. what i'm thinking is this. how is the manifold itsself setup? how is the second runner opened? could we have a normal setup with a CAI and a popcharger all hooked up to the MAF sensor then where the CAI and pop join, have the same sort of "flapper" that opens to the pop when the second runner in the manifold is opened? i dont think it would be terribly complicated. just have a rubber flap covering the inlet to the pop, then at a certain throttle position or RPM, have it open so the engine will suck air from the path of least resistance, thus being the popcharger. then, when the RPM/throttle back off, the flap closes to give you all the benefits on the CAI. or since with the popcharger, you wouldnt be getting air as cold as the CAI, you could setup 2 CAIs, i'm pretty sure that 2 CAIs can flow as much air, just as quickly as a single popcharger. its just something to think about, someone please answer my question about the manifold setup, i'm actually going to look into this sort of setup.

MaDMaX024

bump
i really want to pursue this..i need more info though..

Maximamike

The reason this won't work:

Say you're breathing through one of those straws from 7-11 or some **** and running track. You're really huffing and puffing but that straw gives you more than enough air than you can injest naturally(without it being forced in). Now say you take a dryer vent hose thing(you know, like 6"s in diameter or some **** and you're breathing through that. Even though more air can go into it, you still can't over breath the system. You need either bigger lungs(displacement) or force it in(boostage!).

DA-MAX

iTrader: (10)

I always agreed with those who said that "front mount intake" would be a waste!

Maximamike

Yeah, **** that ricer bull****..

MaDMaX024

i dont doubt you are correct, but there has got to be something to overcome this "situation" if you will..if running dual intakes will cause a huge loss in low end torque and running a single intake will show little to no gains in high end power, there has got to be something to give the best of both worlds. the CAI helps performance because it sucks in cooler air, this runs out of steam on the top end because its piping doesnt flow enough air.. right so far? i could be wrong on this, if i am, let me know.
so the pop charger makes more power on the top end because it flows more air than the CAI.
there has got to be some way to switch between the two. this is so stupid, the answer is right in front of me and i cant see it.
yes, i'm stubborn like a rock.

MarcJD

When I originally posted this I was thinking of what you guys have been talking about...having both the POP and the CAI. Using a Y Pipe with a valve on each side with a control lever on the outside. The "valve" would be something as simple as a little piece of metal that covers the hole to the pipe you do not want to use. It would have the axle of rotation in the middle of the pipe with one end sticking out. It would not take much force to open and/or close it. A wire would be hooked to each of these axles which would be hooked to a simple switch. The switch would be controlled by the RPMs. When one is closed the position of the switch would also cause the other one to open.

This would not be too complicated to implement or even to build a prototype for, but would it be practical? Now that is the question. I begun this thread just to see what you guys thought...I honestly don't know how practical it would be.

DA-MAX

iTrader: (10)

I swear I heard this before...I think Cheston was talking about the same thing a while back after he decided to take off his CAI and go back to a standard cone style...this a conincidence, maybe you too should hook up and get a design going! definently a very interesting idea!!!

MaDMaX024

ok, i'll have my dad fabricate the ypipe tomorrow, i just need to know how to get the switches and valves and all that stuff together. who wants to send me instructions on how to get this valve activated by RPM..i would assume, the optimal time for this valve to select the pop intake would be where the second intake runner opens or maybe a few hundred RPM earlier to get the air flowing...
i also need measurements for making a CAI(just pipe lengths, if anyone has a CAD program and could draw it up, that'd be great too),i'll have my dad fab those pipes tomorrow too
thanks