Have been mucking around trying to work out venting positions for heat release and possibly finding better cold air intake spots. Major idea - KEEPING AIR SUPPLIED TO CYLINDERS COOL and HAVING A LOT OF AIR AVAILABLE WITHOUT RESTRICTION (good flow characteristics). The Broad Band Manifold on the I6 gets bloody hot which results in hot air being sucked into the engine - which kinda sucks.


I thought I had it sussed, until reading AutoSpeed article and deciding to spend an afternoon driving up and down a straight road checking the pressures of various bonnet positions.



The image should be pretty self explanatory - the blue writing is the pressures on top of bonnet, the magenta is the pressures below the bonnet.

The car does have the standard Ford plastic from bottom of front bar to front of K frame near sump for those thinking the under bonnet ones seem high. I ran the gauge through the left indicator hole and plugged the hole up real good around it, so it should be just like a normal unit.

You can see a few odd patterns here.



Remarkably, the most pressure is at the side of the numberplate, and about 2 inches up the windscreen in dead centre! Now - I had to drive up and down three times checking the results of the two positions above that windscreen result. And, yeahp, they all came in within 0.25 of the original result.

Therefore, I am lead to believe, according to science, that
THE AIR PRESSURE AT THE MIRROR ON THE INSIDE OF THE WINDSHIELD IS ACTUALLY *GREATER* THAN THE PRESSURE ON THE OUTSIDE OF THE WINDSHIELD AT THE SAME POSITION! By quite a margin actually!

This seemed almost impossible and totally improbably, which explains driving up and down three times!

Anyway, you cannot argue with the result. I always had the end of the instrument at 90 degrees to airflow, but even changed it to 0 degrees and 180 degrees at this position. And - similar results.


Okay, I found that amazing. You may not.


As it turns out, I am trying to find a place or two that will vent heat from the engine bay. The best place for bonnet vents has a low pressure on bonnet and high underneath, meaning the high pressure air will move towards and out the bonnet to the low pressure area.

To cool the Broad Band Manifold for the air induction you could cut a hole over the front half of the BBM, but not the back. At 70km/h the windshield would actually be pushing air into the engine bay. You may actually decide that will be okay for the application, up to you.


The Police were called on me twice driving up and down the same bit of road 30 or 50 times! Took a couple of hours, possibly due to the extreme length of time taken explain the procedure to someone in blue who is obviously only pretending to be the least inclined to understand and is actually just stalling for time whilst they work out if they can book you for driving a car with hoses sellotaped all over the place. Thankfully none of them actually had a speed checker with them, otherwise they'd have figured that my test configuration called for readings at 50, 70 and 90. As it was a 50km/h zone, I gave up on the 90 pretty shortly after first spotting the red and blue lights.




Oh - The middle of the PLUS or MINUS sign preceeding each measurement is as close as I could possibly get to recreating the actual recording spot. Photos were taken every time the position was altered, and by using these photos the points are as accurate as I can make them.

Have now added the front air dam results. The +4 is taken from middle of front bar, but this seems to dissapear as you move back further towards the air con radiator, possibly as the dam hole is only a few inches high, and the radiator sitting behind it is a couple of foot...


RIGHTIHO then...... Make of it all what you will...

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Last edited by fiend on Sun Feb 15, 2009 10:17 am, edited 4 times in total.

i'd be interested in seeing what the pressure is like from inside the radiator dam.

[self-deleted]

Last edited by blackjack_original on Sat Jun 07, 2014 1:32 am, edited 1 time in total.

good work as always...u are rapidly becoming the most interesting poster on the forum

typical cops....theyd have no idea what or why u would want to do this....absolute mindless robots most of them..

what did u use to do the measurement? could u post up a pic?

very good,have a look at the xr bonnets,thats where the vents are,now if you improve them it may be a winner.

damn good work dude

i do know the article u are talking about

good to see some one actually doing this themselves

for the heat part
i have removed the rubber seal on top of the firewall to help move air out over the windsheild, have noticed in the wet it helps move water as well




now with the -3.0 just above where the airbox sits is where the XR vent goes
now the -3.0 if im reading this correct is a low pressure zone that makes fords placement of the vents in the best possible place?

By saying "it helps move water" I take it you mean the water moves UP your windscreen faster than it used to? That kind of ruins my theory.... Which goes something like this.......

You are reading it correctly, and yes - Was quite impressed with Fords standard vent placements! Obviously having a huge gaping vent (with shaped to increase air speed at vent) the whole way across the bonnet between the two standard XR6 vent positions would be primo. In fact, it may just pay to go and buy a new Mitsi Evo or Subaru WRX bonnet, as they do just that...

As for removing the rubber seal at the top - my theory would suggest that at virtually any speed at all the air pressure would actually be pushing air down into the engine bay and out the bottom of engine bay - which does provide positive cooling but does stand a chance (however slight) of increasing air pressure behind your radiators meaning less effecient water cooling. If the engine bay was a sealed unit underneath than this is obviously stupid - Since engine bays are not sealed (particularly open at the back end) I'd guess the air just goes straight down firewall and under the car making a slight ventury effect that would actually displace hot engine bay air and could, in theory, actually increase the radiator performance.

Hahahaahahahahahaahahahaahaahahaa.... I can feel another 30 laps of Owhiro Bay straight coming on...... This time with the rubber removed.....



Yeahp, actually opening them up (in the case of stick on poser ones) might improve them. I did actually buy some fibreglass molded ones at one point, but will eventually make my own. Don't like the look of the drivers side one being directly above alternator........... But what do I know....




First, I used a 10mm clear tube with the end cut at about 45 degrees and a couple few smallish holes within 5mm of the end. I cut the end like this so as to attempt to nullify any extra suction caused by placing it in a air flow. I have a sneaky suspicion that the readings at top of windscreen are errors becuase of the way the air would be charging up this nice slope. I did try aiming the opening towards the front of the car, the back, the side... And all read fairly consistantly, so the results had to be put on the graphic - - I still don't believe there is more pressure at the mirror on the inside of the car than the outside at the same point. It just defies my resources that have been set aside for logical thought......

All things being equal, which they aren't....

The tube of 10mm opening hose is about 15m long. I coiled most of it in passenger foot well and lifted two sections in the middle up and around the mirror. This section then sags down to the gearshift area where it was taped and held in the exact same position for the duration of trial. The hose inside the car terminated at the mirror and the hose going out the window was taped as well. NO MOVEMENT OF THE HOSE FROM WINDOW OF CAR TO TERMINATION OF HOSE COULD HAVE OCCURED.

The hose was also taped to the front left guard. The only bit of hose to move was the three metres or so forward of that.

All measurements were taken with the hose 90 degrees to airflow (my own estimate on exact airflow, but found little variation with changing its angle). As the end was cut on a 45 I tried different angles of placing the cut and found that what I thought was most accurate was having the long side of the cut on the bonnet, and the short side of the cut away from the bonnet.

All measurements were taken on the same piece of road in the same conditions - speed - wind - temperature....

I could show a picture or two when I next find my cellphone to move some pictures to computer. Am sure I left it here somewhere.......





Too right. A nice little lip shaped a little like a "kicker" or small ski jump across the front of any opening would work wonders. Looking at the high pressure two inches up the middle of the window, I'd suggest some bright spark start making intercoolers in dashboards with a window chop.

It's not fascinating that I would be bothered doing this test. It's merely mildly amusing.




YEHP. As soon as I created this picture I was saying the same bloody thing to myself. Thankfully I have not touched the test rig overnight and will put it back to the same positions for calibration and then try it on one side and centre. Is also worth noting the pressure on the opposing side of radiator at bottom, side and top (at the moment we can guess about "+2" on my system. Interesting the front bumper at side of numberplate scores so highly - maybe Ford got something else right with these cars?

By the way - I hate the new open bottomed look of the new cars. They look like you could kick them in the middle and the car would stand a chance of cracking down the middle leaving two useless halves.....

I admit, I am an idiot for not doing this whilst wasting all that gas, rubber and time.

Was purely looking at bonnet pressures for vents, not intakes. Should have just done a few more spots around front of car and inside engine bay.

Maybe you could put it down to becoming bored.....

Ahahahaha, omg, that's awesome

All come from http://www.fordmods.com/forums/post913441.html#913441 ... You know how hot extractors can get?!!!!! Hehehehehe

Anyways, I have not heat shielded the steering column, as the part that does get hot is happens not to be the working bits - just the shaft in the middle.

Once I get my TV display back in the car I may just stick heaps of wool thread hanging from the bonnet and the firewall and put the infrared camera in the engine bay looking up and backwards from the alternator region to see what the airflows are doing under there.

One day....!


AHAH... I wondered where I had seen this graphic before, and it completely agrees with my testing! YAY, I re-invented the wheel

Although it, too, shows a remarkably low pressure zone at top third of window which confirms that query I had about my own data from this area...
http://www.autospeed.com/cms/A_107826/article.html
Although it is similar, the EF bonnet, size of car, slope of window, etc all contribute to slightly different characteristics, which is why we now have data specific to the EF or EL as supplied by the geek from NZ - Fiendipoo.



PRESSURE IN THE RADIATOR DAMN
=======================
Is disappointingly low at 2.50 about half way between radiator itself and forward opening on right hand side. Would have expected more to be honest. Am going to recheck this figure in all sorts of ways and situations now. Bloody hell...!

PRESSURE IN THE INDUCTION
====================
I have a BA intake fitted and simply removed my pod filter from it and tested @ 3,000rpm stationary vehicle. Test rig supplied result of 1.25 going up to 3.25 @ 5,500 RPM stationary vehicle. This would suggest that if you could find a spot of 3.50 or higher for a duct straight to the original EF Airbox you would provide positive pressure to the engine at 70km/hour or above - even at 5,000 rpm!!!

THAT SUPRISED ME and now has me leaning towards putting the airbox back in as the air pressure around my pod filter in my "open box" design is about 2.00, but this is not directly "forced" to the throttle from that position. It will cut the effort required by the motor to suck air in, but having a positive air pressure at the throttle body sounds like an interesting proposition. And you are not going to get that from the standard snorkel without putting holes through your bonnet in front of it, no matter how big you make the snorkel opening.




Bugger - this is getting crossed with the other thread about airbox mods at http://www.fordmods.com/forums/post913441.html#913441

I wonder how you go about combining two threads and maintaining a relative order?!!!

Hmmm, very interesting.

Sooo, when I put my XBGT EB bonnet on my EB, what effects should I expect in regards to cooling?

In addition, is it worth me fabricating an intake to feed the airbox via the GT intake scoops. I presume that as the shape of my bonnet wil be different, I should expect different readings if I was to undertake the same test.

This is confusing me after a hard days yakka.

BenJ

Well now --- Let's see a photoshop of where everything is going to sit and let's start a guessing game...

The bonnet and front bar of the earlier E's is different, but the windscreen, car width, etc are about the same, so you may find remarkably similar results...


Don't quote me, I'm actually a non human entity who'd just love to see the Internet bought to its knees via millions of irrelevant posts.

im doing my part

why not cut a hole under the head light where the pressure is 7.25 and duct that into the bottom of the air box.

Cheers

Indeed, cutting a hole at the 7.25 mark and ducting to air box would be a positive outcome of this whole document.

However, as soon as you cut the hole and measure the pressure back a few inches in the ducting I'd guess the pressure would be halved, even less. Air moves in a mass like water and putting a small 3" (not that 3" is very small when it comes to putting a hole in the front of your car) will not actually utilise the whole pressure. Have a look at the result of FRONT AIR DAMN at +4. The measurements taken behind this point decrease dramatically.

I'd say the easiest way to get a positive air pressure at the throttle body may be to put an old style dish air filter sticking out your bonnet with a hood on it to grab air from the +4 zone which is wasted at the bottom third of the windshield.....

Sure, you'll look like an old school hoon from the days of "Grease", but you can see these old style hot rodders either knew what they were on about, or simply thought it looked cool and fluked it!...

I suppose the next test would be to get a 3" flexi duct and put it places like you suggest and then measure the pressure that at the other end after a metre or two of ducting. Hmmmph. If someone cares to donate a front bumper assembly that will be returned with holes from A to B, I have the spare time.......

Here is a quick sketch of my setup. I tried to achieve something similar, by ducting the XR vent from the air box i was hoping to draw more air throught the CAI using the pressure dfference. the vent sits behind the pod as per the sketch, hopefully forcing or at least helping more air up the intake...

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