I use my scoops for ice cream.

 

He's probably seen one too many engines blow up in his day...

 

Nah he just dosent want to be like dave chapple in the pepsi commercial(the one with the robot vaccum)

Your Rotrex It at my pants there was nothing I could do.....

I mean that would be pretty awkward.

 

I wish the model those grad students used was actually modeled after a MINI. However, I'm sure the same principles and numbers apply to any hatch-back.

 

I agree, on both counts. I took away 2 things from those models: it's a little brick, but we all knew that, and I wish there were a way to get the rear flow to behave. If it would actually come back around and *push* the car forward, that would be really cool...

 

ha! make up some covers like intake covers for navy jets just for when it's parked at an event .

 

I'm not going to say it's impossible, but from what I remember of the fluids course I took several years ago it'd be very difficult to get the pressure higher behind the car than in front of it. I will admit that I would love to find a way to make the car more aerodynamic; the only thing I could think of so far involves putting a conical extension on the rear of the car, but I don't care about aero enough to ruin the looks of my car like that .

A comment on the models they used: That's not even close to the outline of a MINI...I imagine that if they used a correctly drawn model it would give very different results. We'd still see the fun stuff going on behind it due to the shape of the MINI, probably more so since they made their model with more rake on the back window than the cars actually have.

A comment on the topic at hand: If the airbox also draws air from above the radiator like the MC does (judging by some posts in this thread I assume it does) I would question if the air pressure is higher in front of the car or at the base of the windshield. Judging by their model (accuracy is arguable...) it is lower at the windshield than the radiator:

Adding the scoops would increase the pressure there, but I doubt it would raise it enough to overcome the high pressure drive from the front of the car. In a nutshell: I feel that based on this analysis that the air would actually flow out the behind-the-hood vents.

Of course, one thing I've learned in engineering is that if you change the model a little you can get whatever results you want - changing their model to be a more accurate representation of the actual vehicle could change the flow enough that my conclusions are no longer valid.

 

The cowl spaces aren't really coupled to the underhood air pocket. There is a very small hole in the driver side baffle to couple it to the base of the airbox, but not the underhood space. The gradient that is relavent is the area in front of the radiator shroud to the air box, and the base of the windshield to the base of the airbox. What goes through the radiator, or under the car, or through the scoop isn't really important for the stock airbox.

Matt

 

The way I was looking at it was fluid flows from high to low pressure. I assumed the air could flow freely along the intake tubing which connects the above-the-radiator cowl to the airbox to the vents. Based on the picture it looks like the pressure is higher in the radiator area than in the vent area, therefore I assumed the air would flow along that path. Of course, now that I think about it more, this logic would only work if the engine was off - with the engine on the intake is very likely a lower pressure than both intake spots and probably sucks enough air that excess air to flow out the vents doesn't exist.

 

Exactly 101101, as Dr Obnxs has shown previously, the MCS sucks over 400cfm (I cant' remember all the control specs, maybe at redline?) Anyway, it sucks a lot of air, so the airbox is essentially at a very low pressure compared to most of the sources of air from whence it gets it. (Whoa, that's a convoluted sentence.)
As far as I know, my FAD is the only Mini with a direct scoop-sourced air flow to the airbox. Otherwise, the cowl is a very good source of air, and the OEM front duct the major source for stock airbox setups.

 

I put the Orciari scoops on mine because they look great! Then I got the BigAir Modified cowling partion ( one big hole in the back instead of lotsa small ones), because I figured IF any more air came in thru them ( and I really dont see how it cant) I could help it get to the intake.

 

I have the Orcini's but they are just for looks. I doubt they do anything do to the small size. CARBONIZED made a carbon fiber scoop that sits up taller than anything I have seen and in anyone is functional his would be.

 

i was just studying for my vehicle dynamics exam tomorrow and came across the following lecture slide (see attached)

figure is from:
Gillespie, Thomas, Fundamentals of vehicle dynamics, SAE Press, 1995

where does the idea/logic for the mini having low pressure at the base of the wind shield come from?

i know it is a general car being spoken about so there might be a reason for the mini to be different...

 

Mis-thought reasoning behind velocity & pressure?

Pressure should be highest at regions of little air movement...supporting your slide. Lowest at regions of quickest moving air.

I myself could never figure where that idea came from as well. I have seen wind-tunnel models where the air flows and velocity are, but never much mention of the associated pressure impacts.



Even seeing the above image (posted by 101101 above) shows that velocity should be highest near the front ridge, top, and backside. The orange/beige color, if my eyes aren't off, seems to be well on the positive pressure (low velocity) side of things...an area also covering the scoop location. Seems to go along with your data as well, UKCoopeR.

- Matt

 

maybe it was another one of those false things that got out of hand



i posted a picture like that last year but it wasn't quite as pretty so i don't know if anyone trusted it

https://www.northamericanmotoring.co...3&postcount=16

 

I don't know. The two pics look nearly identical to me:

 

MS Paint FTW
pretty much the same as CFD, right?

i wore a lab coat, glasses, and had a clipboard while drawing it in paint

 

the general idea is that the total pressure is pretty much constant as close as a few inches to the car (couple places that this isn't true) so there is a trade off between static and dynamic pressure. So areas where air goes faster, the static pressure is lower. This explains the low pressure over the top of the hood where the air is really moving, and the higher pressure where the verticle surfaces "block" the air. The points about flow separation has to do with the angles of the surface relative to the flow direction, and can cause turbulent flow the drastically increases drag.

Back to your normally scheduled thread.

Matt

ps, it is a good book, but a bit of a dry read. Lots of good no-nonsense info, and the math isn't too bad. I think it's about $70 though... It's nice to read stuff like it, as you get good info, without having to wade through the noise usually present in internet threads...

 

so because the mini windshield is so steep this slows the air velocity down alot and we should have access to a higher pressure than a more swept back/standard car right?

how tall are these scoops? i don't have one myself... also my intake in is lame r50 land lol

yeah i liked the book too (the author taught the course the last few years (i go to UM-Ann Arbor)), i had to learn that one pretty throughly before even trying to read "Race Car Vehicle Dynamics by Milliken & Milliken" another fav of mine