88IntegraLS

Thanks for the info on making the meter, but I am not interested in measuring a pressure increase in the airbox relative to ambient. I am interested in measuring a reduction in intake manifold vacuum. The boost sensor for the ECU is plumbed to the lower manifold for a reason; the lower manifold pressure corresponds to the amount of O2 entering the engine for a given engine speed and intake temperature. This is what determines how well the engine is breathing, not some arbitrary pressure upstream.

It is probably true that your meter would prove that .3psi boost airbox pressure is possible, but perhaps I wasn't clear in my goal for this project. That goal is to prove or disprove that ram air intakes, defined as intakes which intend to harness the energy in air resistance for the task of increasing engine breathing ability and power, do in fact increase engine power.

If a reduction in intake manifold vacuum is not enough evidence for some of you, let your minds remain unchanged. I'm not doing this to convince everyone out there that ram air can or can't work. I'm doing this for the sake of discovery, for myself and anyone else who may have been curious. If my data is not in the form that everyone wants, oh well. You're getting this report for free!


Here's some more progress on the box:

Wankel7

The autospeed artical shows and proves that ram air works. You could just save a lot of time by reading he artical. The artical is about the exact same stuff you are doing.
http://www.autospeed.com/cms/article.html?&A=0629

So what if you have goobs of ram air occuring at the filter. If your intake is restrictive enough the effects might be canceled by the time it hits the TB. So how do you know? You need to measure at some point before the TB. With your current system for validating your work. You are introducing so many varribles. Lets say that you put your sending unit at the intake. You now have the restriction of your TB, trottle plates, rubber thing that bolts to the TB, rubber hose, afrm.

Ram air works.

Lo Prestio is a company that does speed mods for airplanes. They built a cowling (Fiberglass that covers the engine) that has a hole in the front that forces the air into the intake. This in cruise will give you an increase of 1" of manifold pressure. Ram air baby

http://www.speedmods.com/M20cowl.htm


Okie man, I am not trying to be a little bitch and stir anything up. I am just trying to say the artical might help you do what you are trying to do. Again, good luck with it all. And your work is apricated. I am probably just envious that you get to fidle with your car. Mine are so far removed from me

James

NZConvertible

The velocity through the filter is determined by the size of the filter, not by the size of the box. To increase the velocity through the filter you'd have to increase airflow (good) or reduce the filter area (bad). You don't want to increase the velocity through the filter anyway, as that'll also increase the pressure drop across it.
You should be, because that is the best way to accurately measure the gains from what you're doing.
That doesn't mean you'll be able to measure it. Your gauge has a one-atmosphere scale, without sufficient divisions or markings, and you're trying to see gains that'll be well under 1% of the total scale! I can't see how you were going to report any changes you saw using that gauge.
Manifold pressure is not necessarily an indicator of airflow. A pressure reading taken before the TB is not "arbitrary" at all, it is exactly where the gains will be seen the clearest.
The only way you'll be able to accurately measure the performance gains will be from high-speed (60+mph) acceleration runs, which you've said you're going to do. The results from your manifold vacuum gauge (if you can read them) will not be a worthwhile indicator of a performance gain.
It's not enough evidence, but that doesn't mean I don't think it works, only that you're using the wrong method of measurement. If you want to measure changes in pressures you should be measuring pre-TB pressure drop before and after installation, as described in the Autospeed articles. This will give you a very clear and accurate measurement of the effectiveness of the intake modifications. Acceleration testing will show any performance gains, but that won't conclusively prove the effectiveness of a ram-air intake, as part of the gains will be from lower intake temps.
If you data is in a form that means nothing, then you haven't proven (or disproven) anything. I'm quite sure there will be benefits from your design, but your pressure measurement method isn't doing to show then in any useful form. With the right measuring device you'll have all the proof you need. Like I said earlier, you're not going to discover anything new, but you will be able to see how effective your design is and if necessary make changes to it based on those results.

88IntegraLS

Not that it matters NZ, but as of this writing, you are number 5 in my ignore list. It takes a certain thread-ruining quality to get on this list.

Congrats!

NZConvertible

Wow, that is a spectacularly immature attitude.

Everything I've posted on this thread has been to assist you in completing your project successfully. If you think that my information "ruined" your thread, and ignore it just because you don't like what you hear, then you aren't half the engineer you claim to be. You haven't offered a single argument to any point of mine that you disagree with, and seem like you're going to completely ignore advice backed up by several other posters.

BTW, just because you're ignoring me, doesn't mean I won't post if I feel I have something useful to contribute. Hopefully someone else will learn something even if you don't.

Rex4Life

Sorry 88IntegraLS, but NZ is right on the head with all of those statements.

I've got 15 yrs experience in aero engineering and testing so I feel qualified to say that.

He's just trying to point out the faults in your experimental process, that's all. In earlier posts I also tried to give you some info on how to take meaningful measurements.

In a nutshell, if you can't take measurements with the required accuracy and repeatability, then they are meaningless. Since the difference you're looking for is ~0.3 psi, you need better than 0.03 psi accuracy--that doesn't come cheap. Maybe the magnahelic will be good enough.

Good luck and hope it all works out.

Scott

Relisys190

iTrader: (4)

Guys, just leave him be... let the man complete the project, get some specs THAN speculate/criticize.

-Markus

Mephis

i got my mariah cold airbox in with my hks filter, the filter made a very noticable difference in sound and power ranges, the airbox made a slight difference once the engine was fully warmed up. the airbox also seals to the hood, so if i wanted to do this setup i would be able to, i think its really alot of work for just a few ponys, but thats what were all about here .

Black13B

iTrader: (1)

Brilliant.

Black13B

iTrader: (1)

And he speaks truth, 88IntegraLS.

I think perhaps you misinterpret his tone when making his recommendations to you. You seem abnormally harsh to NZConvertible when there is no need to be, he is merely making suggestions based on his experience.

I follow your threads all the time. I'd hate to see this one turn out badly due to hard feelings.

jinx22630

Can't we all just get abong?

88IntegraLS

Everything's cool.

I don't care if only one person benefits from my efforts, even if it is just in the form of inspiration. That will make it worthwhile for me. Everything comes back to you, good or bad.

NZConvertible

In this case you can get that accurate for nearly no cost. The water manometer in the Autospeed article costs peanuts to make, and 0.03psi = 2.1cmH2O (~0.8inH2O), which will be easy to read off the scale.

You can see why I keep suggesting this instrument. It perfect for measuring intake system modifications.

Here are three more Autospeed links that use the same method.

http://www.autospeed.com/A_0779/cms/article.html
http://www.autospeed.com/A_0892/cms/article.html
http://www.autospeed.com/A_1605/cms/article.html (you need to be a member to read this one)

Perhaps I need to use more smilies?

White_FC

Hmm I havn't done any glassing for a while....

I might make this into my next glassing project I think after my exams are over and I have my new engine/turbo here.
Although I will probably make mine differently, I think i'll have my filter in a sealed box in the brake duct area with piping going from there to the turbo.

Mainly because I like a very clean looking engine bay.

88IntegraLS

I got the vacuum gauge installed to a nipple adjacent to the one leading to the ECU boost sensor (basically tapping into the primary runners at the very bottom of the manifold), and had a chance to play with the car last night. I shifted the gauge's scale slightly so that the needle would rest in between the white and red ranges with the engine off, to indicate 1 atu.

Surprisingly, it only took about half throttle to get the needle to return back to its home position of 1 atu, straddling the red and white ranges, when the engine was running and under 2500 rpm. I didn't expect such efficiency out of my intake manifold and cone filter. This makes sense, because there are times when the engine is at lower RPM when burying the throttle further than about half will not result in any power increase.

Revving up the range at WOT, I observed the needle slowly rise into the red range to end its climb a few needle widths above the white at 7000 rpm. This data is telling. The efficiency of the intake system without the air box is much higher than I expected. Very little vacuum remains in the intake manifold at WOT near redline when I would expect a lot, and none exists when under 2500 rpm.

Thus, there will not be much vacuum to defeat with the air box, and any pressure related gains can be minimal at best. To reiterate the point of this project, it is to stuff incoming airflow, which is always generally at 1 atu of pressure, into the manifold such that there is no sucking of the engine at all - no pumping loss at WOT and more oxygen getting in. A cool side benefit is that it makes a seriously kick *** cold air intake.

This is why I took no interest in measuring a pressure increase in the air box upstream the lower manifold . . defeating residual vacuum at WOT is my goal, not boost.

Off topic, but the RX7 is an awesome car. I've been getting my front camber sort of dialed in and I can't believe how much a fraction of a degree can upset (or enhance) the car's handling. I never dreamed I could have so much fun driving on a twisty road like when I'm slinging it through some sharp turns and it's sticking like a cat. It kicks my Integra's A$$!

jinx22630

good work, just save me some effort. I just had two cortisone shots in my shoulder and shoulder joint, so I ain't doing anything for a couple of days. So do you just have and adapter, and open filament filter as the intake so far?

Ronac

Hey 88IntegraLS
Did you measure the pressure when the car was stationary? Maybe if the car was moving, there wouldn't even be negative boost considering that you said the stock system with filter isn't all that restrictive.

88IntegraLS

The intake setup is a ported stock S4 manifold w/ ported / modded TB on a street ported 13B, and it has a cone filter on the airflow meter, which I also "ported". The filter is bare in the engine bay now with nothing shielding it from the warm air in there.

The vacuum observations were with the car moving at ~30-50 mph, winding up second gear. I'm considering this data a crude baseline. I didn't cover up the air duct when I did this but will do so when testing the setup with and without the ram box.

I'm really amazed that there isn't more vacuum present at WOT. One thing is for sure, having a bare cone filter without any heat shielding makes the engine noticeably less powerful when it is warmed up, compared having a crude (cardboard) shield around it!

RarestRX

Yo,

Dude, no offense, but NZ is one of the few people here who "Knows his ****." I have yet to see him post anything but factual information and well thought out points.

I don't know why you'd want to ignore him...that would be like ignoring RETed.

I think it's a mistake, but whatever...

Kevin
1989 GTUs "Not to mention he likes dual exhaust!!"

Genshie

I didnt have the patience to read the squabbling on these past four pages, but I just wanted to add my experience with my GTUs.

I added a K&N filter and bought 2 90 degree rubber bends with one short PVC (3" diameter) piece.

I relocated the washer bottle to the front (next to the coolant bottle and put the air intake where the bottle was originally located. I cut out the brake ducting piece in order to make the air filter fit. That gave me a fully enclosed, cold air box area that was getting fed huge amounts of air through the brake duct intake. I put the bend on the filter, cut a hold in the body, put the PVC through the hole, and the other bend that attaches to the air flow sensor.

In a word, the difference in performance is AMAZING. My acceleration and lap times at Thunderhill were significantly improved over the stock setup. I could only get up to 102-103 on the front straight of Thunderhill, whereas now I am pushing 110 as I come into the first turn.

My gas mileage has increased by about 15%, and it also makes this kick *** groaning noise as I approach 5K rpms and higher.

I dont know the "dyno" specifics, but the seat of the pants performance numbers are definitely up. This is not really useful for autocross (dont get going fast enough), but for the track, A MUST!

In addition, I have also been able to retain my stock airbox for the winter when it rains. It takes literally 5 minutes to unattach the modded intake and put the stock one back in. The only downside on this mod is that if I hit a big puddle....I am going to hydrolock the engine.

I can take pics if you wish. By far the best mod next to exhaust. I was going to do a s-afc to lean out the mixture a little, dont need it anymore with the new intake.

Kurt G.

Terrh

iTrader: (7)

you can't hydrolock a rotary.. but I'm sure that lots of cold water hitting very hot metal parts still wouldn't be good for it...

I don't see how you could get a significant amount of water past the AFM, up the intake, through the TB, around the intake manifold, etc, etc, etc.. the path is just too long!

Genshie

What do you mean you cant hydrolock it? Although a rotary engine compresses air differently than a piston engine, it still compresses air. Water does not compress. Therefore if water gets in the combustion chamber of an engine, regardless of whether or not it is a rotary or piston, it is going to do significant if not catastrophic damage.

Trust me, it is very possible to get water through an air filter up the intake and into the chamber. I have done it on a truck that had a really high intake point. I was out blasting through huge water puddles after a rainstorm...damn near hydrolocked it. A car does not have to be submerged to do damage to an engine. All it needs is a few really good splashes through the water right where the intake is and you will have trouble. It is especially vulnerable when the intake is only one foot off the ground!!!

Kurt G

88IntegraLS

Thanks for posting your experience with building your own ram intake. Sounds great.

pengarufoo

To make your data useful you should remove your ported manifolds and plumbing for the cold/ram air intake replacing it all with stock unmodified equipment and redo the tests. Compare results.

or at least just disconnect the ram air and compare those results. this "i'm surprised to see it so low @ WOT" stuff is pretty useless, you may have been surprised with a bone stock car.

88IntegraLS

Those vacuum observations were without the air box. The air filter was bare in the engine bay. How could any ram effect take place in that situation? I meant those observations to mean the baseline vacuum situation in my intake manifold WITHOUT the box installed.

Yes, the air duct was blowing air at the filter during those readings, but the final data will be taken with a cover over the duct to simulate a normal "bare" cone filter installation.