Marc Shaw

Good job and thanks for posting the update.

If I am reading this correctly though, the stock airbox is still the winner for temps.

Anyway to modify it for a more ram air effect?

Marc

wsybert

You are correct Marc. Again, even though I think the data is a little skewed for the stock box, because of not letting the car warm up completely, it still shows slower increase in temp after idle at the end. Plus in the middle of the test it stays steady.

etom

I am a novice when it comes to the technical data associated with cold air intake and air flow, but would the data change when the car is actually moving and the air flow in influenced by moving air as opposed to a test with the car not moving?

Hell, what do I know?

MPB993

I decided to take the bend out of my intake having used a simulation program used for pipe design which suggested a 1st approximation of 0.5lb difference at 550 cfm by adding a square bend to the system. I also note little difference to intake temperature at speed with the tail up by having the filter at the back of the engine compartment. But as suggested above I did notice a difference at town speeds using scantool. I needed to reduce intake pressure drop as the TPC kit that Colin built 4-5 years ago is sensitive to pressure drop. Here's a picture of how it has ended up having added & then removed bends, chargecooler, intercooler and seen the effect on the simulated pressure drop and flow from doing all this.

BR, Mark.

Red rooster

Bill,
That data is pretty good. Looks like you have confirmed that the development guys at Porsche may have known what they were doing with the air box !

In flow rate/snorkel terms it is sometimes forgotten that the Flap air intake is seriously smaller than the standard airbox tube so flow rates are not such a problem .

Be very good to see your further tests , all in the interests of science !!!

All the best

Geoff

Chris M.

Did the drilled airbox still have the snorkel on?

wsybert

I did the temp tests with the car moving, the pressure drop tests were done in the garage.
I don't believe the pressure drop test would show any difference with the car moving. (We'll see when I can get my setup mobile, and test to full RPM)

Yes, the drilled airbox still had the snorkel.

Marc Shaw

I have a Fabspeed (cup-style) open airbox you can borrow if you'd like to test that combo too.

Marc

SimonExtreme

So, for the simple amongst us (me!), I think this says that the standard airbox performs best wrt temperatures and it provides enough airflow so as not to be a limiting factor in tuning. Am I right? If so, why did Porsche use Cup intakes???? (I happen to believe they make no difference)

MPB993

wsybert,

I think you need to be at full load / power to see the pressure drop as at lower loads/air flow, I doubt that the pressure drop would be noticeable. It may become noticeable at full power where peak flow occurs as opposed to testing under light load in the garage. Unless of course this was done on a dyno where the load could be varied at higher rpms. It would be interesting to see the pressure drop if this test were run on a dyno.

BR, Mark.

Red rooster

Simon ,
I did suggest a little noise as a motive but got attacked as the Cup box must have a very complex , technical reason hidden behind it !

The Cup was a stand alone series acting as a support to F1 . I still believe that the Cup box was a zero cost part of show business !!

Let the attack begin !!!

Geoff

SimonExtreme

I fully support that view as well! It is all about noise. Compared with an F1 grid, the Cup cars must have seemed very quiet. Anything for more noise! I would say that this type of airbox is unsuited to road use. Furthermore, in the UK people have enough trouble getting their car onto tracks because of noise limits so I would suggest that this and drilled boxes are really counter productive.

wsybert

I can run it and test it against my known setup, for reference. I don't think there would be any difference over a drilled box. Willing to give it a shot. Let me know.

Correct.... what was i thinking . There will be much more air entering the engine under load.
I just need to make my setup portable. Probably this weekend.
I should be able to load the engine fully by braking and keeping the engine at a constant speed... say at 6800 RPM. At least for a few seconds. I can aquire the data pretty quickly... probably 250 ms per scan. So I should get some good data.

Red rooster

Before a clutch is fried , where is this flow rate stuff coming from ?

Do a quick check on the flap intake area + flow rate and then compare with the snorkel area. Pressure drop in the filter is more to do with the flap strangling the motor and so creating pressure drop .
Thats one tiny part of the reason for the MAF system . Even the MAF has to be sized in tube size to enable the motor flow rate.

Intake flow and filter/inlet systems is a massive subject and unfortunately it is very easy to convince yourself about the wrong thing !

Maybe thats part of the fun !

Geoff

wsybert

I am measuring at a point just before the AFM. The adaptor plate that holds the filter has a 1/4" NPT hole, that I was able to put a line on to take a pressure reading.

I am not concerned with what is after that point b/c most of us don't have a MAF system.

The point of this excersize is to determine how much drop there is from a cone mounted directly to the AFM vs adding an elbow and length of tube to get it under the spoiler. I may even add in a stock box for fun, if I have the time.

Bill