Hey guys, I was reading an article talking about the MINI B48 having sound insulation on 4 sides plus the top cover. Then the other day I popped the hood (um, bonnet) to check something and nearly burned myself... this was 4 hours after parking in my garage. Got me thinking, the engine is surrounded & "sealed" in. How much air flow gets through the intercooler/radiator, and where does it go? Would a scoop/vent be partially useful, or really useful?
Any thoughts?

 

I've read a few topics on the idea of the effects of adding a scoop to a car. From what I have gathered, not scientifically, is that you can dramatically decrease the amount of air being pulled through the intercooler & radiator by adding a scoop. Air will take the path of least resistance and will "favor" the limited resistance of the scoop and hence will reduce the amount of airflow through the more restrictive fins of a radiator and intercooler. Also, you are creating an increase of pressure inside the engine bay which would also decrease the air being shoved through the radiator and intercooler.

There is another argument that by trying to decrease the temperature of theengine compartment, you are also decreasing the efficiency of the engine itself, as it does require a relatively hot operating temperature to properly keep liquids such as oil operating at correct temperatures. (I don't know there veracity of either of these claims, but they do make sense on the surface.) IMO, if the engine would operate better with a hole in the hood, I think it's safe to assume the manufacturer would have figured it out while spending the millions of dollars it takes to test and develop a car for peak performance.

I would love to know the science behind the answer to this or if anyone has real world results of adding a scoop to the Mini.

 

I've always been curious to why they put the hood scoop vent on the new "S", but it's actually just for cosmetic looks only, because no air can pass thru it. Why is it not open to let air pass in?

 

Drag.....open up a hole...that scoops up air....and function...the scoop on the gen1 was for the intercooler, on many classic cars it is a " RAM air" intake...so it's just for looks on gen2+3...
Then everything that gets hit by the air must be OK with getting wet, salty, sandy, dirty, buggy,...
The trend is to keep engine bays tightly sealed, and let in a controlled amount of air...just enough...and control the flow EXACTLY....
All about efficiency...
A gen1 with a scoop can do 19-29 mpg on the highway depending on the speed...sure it's a SC, not a turbo...but every little improvement made adds up..
A few % there....a few % there....even fractions adds up...
Notice anteanas are getting smaller or going away...drag...gutters to prevent water from dripping into your car and onto your seat in the rain or open your trunk...drag...handles recessed? Drag...windshield wipers drop down under the edge of the bonnet out of the wind...drag...
Need I go on...

 

I'd actually love you to. As it is fun thinking about all the ways engineering has made cars more effective.

On the note of the hot engine bay, BMW did this specifically to keep the temperature at operating temperature for as long as possible while parked. The majority of damage, emissions, and other negative things happen while the engine is cold. Warm oil moves quicker to lubricate turbos and bearings, warm cats work better at removing harmful emissions. These are the major reasons they did this.

Edit: forgot to add. An opened hood scoop on gen 3 cars is about as useful to the car as vinyl hood stripes. If it allowed air into the engine bay it would work really well to cool a piece of plastic, the hood scoop was important on gen 1 because of the top mount intercooler, now that we have much more efficient front mount coolers, no need to direct cool air there.

 

You could also use the hood scoop on the gen 2 cars for the intake. I had the AEM Intake on my '07 fed by a M7 hood scoop.

 

If you operate outside the normal "appliance" comfort zone that cars are designed for - tracking, autocross, hot temperatures, upgraded charger, tune, pulley etc (doesn't your midwest have a problem with bugs and/or grain blocking radiators?), a rear facing vent to let more air out can only help.

This online car mag has some great articles about airflow, cooling, aerodynamics and other random stuff. And it is all backed up by testing that he personally does. He includes stories of how his ideas didn't work and how he overcomes this too. This specific article talks about optimising a top mount intercooler and references his series of three articles making a custom undertray and bonnet vents. Well worth spending time reading his stuff.

I am currently trying to find some nice vents to add to my R53, and a gauge to find the right spot for them. Where I live in Australia regularly gets above 100 of your Fs, and in traffic I can see up to 160F inlet temp, so anything to help the IC shed heat is going to be a boon for me.

James

 

Hey guys, thanks for input.
Partly my bad, I should have been more clear that I was referring to an OUTlet vent toward the top-back or side-back (scuttle?) so air flow has an exit.

But I totally get what you're saying about keeping engine temp warm & steady. Just thinking radiator & intercooler work better if the air has somewhere to go.

Here in Arizona we are expecting to hit our first 100 F of the season this week. Though I know Connect says my engine runs 212 to 217 once warm.

 

Check his article. The back of the bonnet is usually a high pressure area as the air bends around the inside of a corner. The front just behind the transition from front to top is usually the lowest pressure area as the air bends around the outside of a corner.

James

 

I'm not sure how applicable this is to the discussion, but I've been wanting to share these photos.

I spent some time In Death Valley in the summer of 2015. Air temperature was 120 degrees F. Temp as measured by my MINI was 117F as seen in the photo. Notice the car's temp gauge is right in the middle. This is with

the AC running. Once warmed up, the temp gauge has never varied from smack dab in the middle. So I'm very pleased with the MINI's cooling system.

 

Pretty amazing. That is bloody hot!

I have always read that the temp gauge has a fairly high "fudge factor" built in and it only moves away from the middle when it is too late. In my Wife's Toyota I have had the coolant up to 225 of your Fs according to the Scangauge with no movement on the factory dial.

James

 

I thought I might add, it's not the engine temp I was thinking about, although I understand it's also affected.

I was really thinking about volume of air through the radiator and intercooler. How well does it flow through the radiator & intercooler and then into a near sealed box (engine bay). If nowhere to go then wouldn't the volume of air flow be low? And would it be an advantage to somehow increase that air flow?

 

Nope, it goes out around the turbo and exhaust, and I am guessing actually creates a venturi effect to make the velocity increase, increasing turbulence, and thus heat transfer.

 

+1
I'd bet $$$ that MINI /BMW did some modeling in computers, windtunnels, and real-life to optimize it....
My current daily driver a VW TDI, is still warm in the winter 6+ hrs later the engine compartment is so tightly sealed...has openings in front of the radiator that the car opens and closes as needed (as does the hybrid)...long story...hope to get a mini again soon...maybe the VW buyback...
Wife's CRV similarly stays warm for several extra hours in the winter...great for a trip to get lunch after its been parked for a few hours....the extra under car panel's seem to help lots...no more waiting 3-5 miles to get heat on my 2005 r53...progress is nice in some areas.

I'm guessing since the gen3 motors are rumored to be so aggressively de-rated...down from as much as 300 HP, that the motors have lots of spare cooling capicity...and it won't limit the car in any way till pushed much harder than it is in the MINI .

 

Know the factory guages (non chrono pack) that are STD do the same on the gen1....
We call them dummy guages....they stay in the middle to make the owner happy, and reduce owner questions....but move too late to be of any use when things go wrong....

 

Nice real world test, MINI and BMW test there mule cars ( Pre production car ) in death valley all the time.

 

Just wanted to throw it out there that the new motors are heavily insulated to keep heat in the engine bay. It prevents engine wear and keeps emissions systems running at their best. They spent a lot of time designing that area.