venompwr2

iTrader: (27)

I'm just going to stop worrying so much about this, why doesnt some company somehow make a ram air intake and just call it a day.

SXN

what about a hybrid...not too long but not sucking up as much hot air? or run a HAI with piping to get cool air to it? i dunno...ram air, or something new would be cool

Ninos_Maxima

iTrader: (5)

Isint this conversation the whole purpous of a MEVI? A Mevi has butterfly valves and other intresting trincets inside that controll this

PoePoe2797

If you followed the thread, you would have noticed that I mentioned this as a cheaper alternative to a MEVI....also, with a MEVI you replace the whole manifold

meccanoble

iTrader: (22)

i'm not sure if u r saying the same thing but how bout we have both installed, one pipe that splits, to hybrid setup and to CAI and just have it open all the time. It will bring in cooler air from below and hot air from the engine bay. That type of setup may work real good.

sryth

Not open all the time...but have a valve that will switch between the two. The valve could be hooked up to an RPM switch.

The question of the day: Are the gains worth any of this? Are they there at all? The problem is that these gains are so small that it's difficult at best to test for them.

IMHO, I doubt there is much difference between either setup. I can't find dynos that show it.

bobjohnson

iTrader: (2)

OK OK OK OK..... everyone keeps talkin about this again and pointing out the same specs over and over and why we are doing this and that.

My 2pennies are this:
Once SOMEONE can make this switch contraption to switch between them with 'Reliability' and You have a Drawing, a Photoshop Of how this works , THEN all of you will be happy. THat switch and its reliability everyday use Is the MAIN concern , Without that where are you? Has anyone even gotten anydrawings or Switch ideas to try this.
or are we still at first base.?

endus

iTrader: (1)

God this debate is so played. Nonetheless I will add to it.

My theory is this...my K&N/Frankencar does seem to lose a little bit of low end. This is most likely due to the fact that it is sucking hot air from under the hood. I do not buy the whole pressurization thing, because I don't think you are getting that much air coming in there at low speed. The stock intake does have the scoop, but the scoop isn't really out where it's getting air rammed into it...maybe a little, but not enough to make a difference after all the piping and resonators. Throttle response with the hybrid is *clearly* better that the stock intake. Rev matching is much simpler as throttle blips are quicker...probably due to a just generally freer flowing intake.

The HAI gives you gains at significant speed. This, I beleive, is because by the time you're doing 50+ mph there is enough cool air getting blasted under the hood so that you have a less restrictive intake sucking more or less the same temperature air that it would get with the stock intake. There is no missing the improved acceleration from 65-110mph with the hybrid.

The problem is that you can't really prove this on a dyno since you're not getting the same airflow that you would get on the road. The results will definitely be different than "real world" because I think the HAI relies on air getting under the hood at speed to make power.

endus

iTrader: (1)

OH and another thing. You guys are ridiculous talking about this switch idea. I mean I guess it would be a fun project, but you're talking about an elaborate setup for very, very small gains. The difference with the intakes isn't huge enough to make it worth this whole crazy project (to me). Besides that, we go through all this trouble buying frankencars and all that to create good, smooth airflow into the intake. This switch would have to allow you to go back and forth with minimal disruption to airflow while switching, and in position...otherwise you just lost horsepower. No way is this idea ever going to seriously work. The only thing I could see making sense would be to do some kind of OSCAI/Frankencar where both intake were open at the same time.

endus

iTrader: (1)

Sorry sorry sorry...one more...

It seems to me like another good way to solve all this would be a CAI with oversized piping made out of a material that doesn't get hot and is extremely smooth on the inside. Make it out of carbon fiber or something so that it doesn't get hot and heat the air inside up. Make it super smooth to allow air to flow over the inside surface of the intake as easily as possible. Make it oversized and keep bends to an absolute minimum to make it as easy as possible for the engine to suck the air in.

Ideally you could even try to have it get some air rammed into it OSCAI style...although that would take a lot more bending...but it might be worth it.

Ninos_Maxima

iTrader: (5)

Okay, if your not going to replace the whole manifold that whats the whole point? You can just run it with out a filter and it will do that job

Street Reeper

The loss of low end with the midpipe designed intake has to do with resonance tuning

http://www.users.bigpond.com/pgscott...resonator.html

http://www.users.bigpond.com/pgscott...rsAcoustic.htm

Midpipe designed intakes only give you gains above 4900 rpm (Paste each of these into a new WORD document, then print each one out, put them over each other and hold it up to a light.)





It has nothing to do with what speed you are going, whether your in first gear or 5th gear it only matters what RPM you are running whether you are getting gains.

Regarding your last response, have you ever seen a car dynoed? They prop the hood up and blow a huge fan on the engine. This is going to give you a lot more direct air flow to your filter than your hood closed and air having to come from underneath your car, up to the top of your engine bay where your air filter is. If anything the dyno gives HAI intakes an advantage.

Dave B

If you doubt the validity of the intake resonator between the throttle body and MAF, then don't bother getting the MEVI. It relies on the same intake principles.


Dave

Dave B

The Place Racing CAI pipe I'm running is 3" ID and is mandrelly bent. It doesn't get hot either after driving in stop in go traffic in 80+ weather. While the rest of the motor is baking, this pipe stays cool to the touch.


Dave

endus

iTrader: (1)

re: the other responses - Okay, fair enough.


So what you're saying is that I need to get me a Place Racing CAI to try out to see how it does against the stock airbox and frankencar. Okay, fine I'll buy one.....nooooooo too late to talk me out of it now...haha. Seriously though, that makes sense I suppose.

I was thinking of trying something else next summer since the Frankencar is, admittedly, really miserable in hot hot weather. The thing is definitely making more power than stock at high speed. Yes I know engine RPM is what matters, and yes i get the dyno thing now and I agree, but that doesn't change the difference between 1-50mph and 60-110 mph in the real world...you ARE getting more air under there (not compared to dyno, compared to low speed), and the thing IS sucking hot air until you get moving...all I notice is really the lack of low end until > 60mph.

I suppose what I was thinking about before is basically ghetto ram air for the Max. People seem to like the OSCAI...I wonder if there is a better place to put the thing and a better way to do it to basically stuff more air into the CAI...if you could get some pressure going it would probably eliminate the fact that it's harder to suck the air through the longer piping.

sryth

I think endus was referring to (when he talked about high speed) was the air making it's way into the engine compartment...I'd imagine (no proof to back this up) that the engine compartment is cooler at 100mph than it is at 2mph.

As for the MEVI...I was under the assumption that the design was to allow different size runners for different air flow at different speeds. Smaller runners provide high-velocity low-throughput air flow (low rpm), while bigger ones give low-velocity high throughput (high rpm). Is this not the case?

As for the resonance, all current intakes are static intakes (IIRC). The volume of the intake doesn't change, nor does the shape. If this is the case, resonance will give you nothing more than a spike in a dynamometer plot. It will only help when the resonant wavefront's periodicity is an integral of the timing of the valves.

Oblongshapes

iTrader: (1)

interesting, do it and tell us all

SXN

i still dont know why you couldnt have both tubes open at the same time...

Street Reeper

Because your car would only draw from the least restrictive one, having another one would serve no purpose.

SXN

what about a hybrid with a scoop or a tube running cold air up to it? less effective than a CAI, but more free flowing. couldnt you kinda use the scoop shaped stock intake for this "ram air" mock up?

sryth

That might not be a half bad idea...in fact, that's the best 'solution' I've seen to the 'problem'.

Remove/relocate the fog light...put a scoop in there (like the eclipse guys do) and have a pipe run up to feed the mid-pipe...Only problem there is, unless you have a fan pumping the colder air in, you are still sucking hot engine-bay air in at low vehicle speeds.

I don't really think it'd be worth the work.

Street Reeper

Already done that and yes, this is the intake that I reccomend. A JWT/Stillen intake that is fed cool air. That way you would have a straight shot to the throttle body, the resonator still in place, and an intake that is fed cool air. I positioned my scoop under the car, this is where a ton of air flows. You can pick up some air duct tubing that will bend and stretch how ever you want at Loews for about 4.00

SXN

so you get the pop charger high end, with the cold air intake low end?

bobjohnson

iTrader: (2)

Yeah , Thats EXACTLY WHAT I have done to my car.

CA Comes Into the Hybrid/ Frankencar Midpipe.

It's A CAI w/ Only a Midpipe and Filter.

Its not that hard to understand thats what ur all worried about is the tourqe on Hybrind/ VS ./CAI

READ THE QUOTE ABOVE 'OR ill get pics of my CAI/HYBRID Tommrow.
Just FORCE AIR, not 2 intakes

Dave B

The MEVI only uses one set of runners. It uses resonance tuning to make the high rpm power. The MEVI isn't a dual plane intake manifold like used on the 3rd gen VE or 5/6th gen Maxima. The MEVI volume doesn't change, but the resonance changes having an almost SC-line effect.


Dave

SXN

wouldnt it be much larger in size with two runners?

meccanoble

iTrader: (22)

if that was the case, they all equal out, we just have to determine what the maxima needs most. Maxima is real strong in the low end but every extra mod u can basically buy for the maxima helps the mid to high end. So IMO the best combo would be a CAI with a full exhaust including y-pipe. CAI pushes u through 3k rpm and the y-pipe finishes u off till redline. That sounds better than lagging in beginning and having twice the power (not really) pushing u at mid to high end. Unless u always on the highway...

sryth

Wow...after verifying what you've said, I realize now that resonance is truly a wonderful thing. My faith has been restored, and my work on my continuously variable intake will be continued! Thanks Dave!

endus

iTrader: (1)

re: feeding cold air to the HAI...

A friend of mine has a Jetta that he put an intake on. The intake is a carbon fiber cyninder and he tells me there is a cone filter inside. A tube runs out of the cylinder to the front of the car somewhere.

If there was some way to rig this up for our cars you could basically have a scoop under the car or in the foglight or wherever blasting cold air into the HAI. There is no way in hell that a cylinder is going to fit in there on my car with the frankencar installed, so you would have to ditch the midpipe to do this. According to the resonance tuning stuff I guess that wouldn't be a bad thing since we could reinstall the stock resonator.

The one thing that's sketchy with his is the size of the hose coming out of the cylinder. I doubt it's big enough. I suppose the ideal would be to have solid 3" piping like the CAI, just running towards a scoop.

I dunno if there's enough room under our hoods to do something like that though. Maybe it would be possible with smaller, flexible tubing, but I have a feeling that making that the only source of air would be a bad thing...the problems of the CAI sucking air through a lot of piping multiplied.

dwapenyi

iTrader: (3)

You're right that the MEVI isn't a true dual runner setup, but the volume actually does change. It's the volumetric change in that 'pouch' that makes the MEVI 'act' like a shorter runner/long runner depending on whether the butterflies are open or closed.

DW

sryth

I know they make short/long runner variable manifolds, but I was under the assumption that some designs use small/large runner diameters as well...smaller diameter will restrict flow, but increase velocity, while the large diameter runner will increase air flow at the sacrifice of velocity. If this is the case, then the MEVI is not optimal.

outkastist

back to the design....what if you, just after the split, on the HAI side - install something similar to the trottle body that only opens and closes at a given RPM. It should not be that hard to run a sensor for the rpm to a capacitor or something that would trigger the "TB"

sryth

That would work...you could get a 2 state solenoid to hold the valve open. That would do the trick.

Run a sensor to a capacitor? Not sure what you mean here. I'd just get an electronic RPM switch. They make them already, so they're tested and "perfected".

The ultimate question is: is it worth it?

Dave B

All the true variable intake manifolds I'm experienced with (Ford/Yamaha SHO V6, Contour SVT, 5th gen Maxima, Sentra SE-R) have same diameter piping, but the lengths are different. Short runners increase breathing in the higher rpms and long runners increase lowend power. While the MEVI isn't quite as effective as the true variable intakes, it does work and works very well. The only real performance increase in the 00-01 VQ came from the variable intake. When you overlay a MEVI/I/Y dyno with a 5th gen 3.0 VQ with I/Y dyno, you'll see the 5th gen barely makes any more except from 6000-6500rpms and the difference is only around 5 fwhp. To me, the MEVI does flow pretty well for not being dual plane. My peak power went from 182fwhp@5400 to 189fwhp@6100rpms (prior the JWT ECU). Yes, not much gained peak power, but the real the gains are come from the fact that my MEVI continued to breath straight to 6500rpms with only a drop of about 5fwhp from 6100-6500rpms. I've seen dyno plots of the MEVI with JWT ECU and power simply holds on the whole way. The stock intake manifold looses HUGE power after 5400rpms. Check my homepage to see a comparison of how much more power I'm making after 5400rpms vs stock.

In a nutshell, the MEVI is able to compensate for the turbulence of air that occurs at 5400rpms. At a preset moment (~5300-5400rpms), the butterflys open up to the upper resonance chamber which creates a pressure wave that cancels out the reverberations of the turbulent air in the intake manifold. What ends up happening is the pulse is smoothed out and the intake is able to continue to breath strong to 6100rpms and pretty much sustain that power for another 900rpms or so. At least that's my understanding of resonance tuning.


Dave

venompwr2

iTrader: (27)

WAY too much work for a couple of hp

sryth

On the other hand, if someone were willing to do all of the work, and start selling these things as kits, it might be a good idea.

You could argue that all of the aftermarket intakes fit into this category; too much work for a few HP. These intakes were still developed, though. While it may be too much work for every .org member to do individually on their own car, if one .org member did the work, and made a kit, it'd be a great thing (if it actually increased power).

dwapenyi

iTrader: (3)

The aftermarket developed their kits and gained from 4 to 6 hp over stock. The ideas being bandied about in this thread would at most make a 1-2 hp difference. You can gain that from just replacing your air filter. Diminishing returns.

DW

sryth

So, what you're saying is: if the choice was between the two types of kits (one that gave 4-6HP and another that yielded 5-8HP), people wouldn't lean toward the kit that produces more HP?

dwapenyi

iTrader: (3)

OK. Someone go ahead and do it. Let's see what happens. I'll sit back and watch.

DW

venompwr2

iTrader: (27)

the CAI "chokes off" at top end because of not enough air circulating in the wheel well? Right? Well why not use a cai, and then have a tube from the foglight opening going right up to the filter, thus possibly even making a ram air type deal that will always have plenty of cool air, and rain cant very well shoot vertically up a tube (unless driving through very deep puddles/flooded roads, which isnt smart anyways)