TMIC ducting / engine bay pressure

[JSmith]

Pressure behind the engine, under the exhaust manifold, perhaps?

Foam (home depot brand) to seal off around the radiator as well as seal the front of the FMIC to the bumper?

[Voltwings]

I has data. I'm just going to dump what i have now for the sake of discussion, and i'll update the OP once i have the rest of it. I have also decided i'm not going to do tests with and without the undertray, its kind of a PITA with the front mount on, so i'm just not going to mess with it. It's just going to stay on.

So here is the data i have gotten in the past 2 days:

FMIC installed / undertray installed / Pressure read in the hood scoop in the "void" between the hood and cylinder head:

40 mph - .2
50 mph - .2
60 mph - .3
70 mph - .6
80 mph - .8

I figure i could have read right on the valve cover, but i didnt want to risk small pockets of air giving a false reading since this tool is measuring a very small amount of air "pressure."

FMIC installed / undertray installed / pressure read in front of core:

40 mph - .5
50 mph - .7
60 mph - .7
70 mph - 1.1
80 mph - 1.4

Now the really interesting part, measuring between the FMIC and condenser.

FMIC installed / undertray installed / measured between FMIC and condenser:

40 mph - .2
50 mph - .3
60 mph - .3
70 mph - .6
80 mph - .6

It seems having the core but right up to the crash bar does a pretty good job of having it "ducted" on all sides and actually causes a pressure differential. I really expected the numbers on either side of the core to be closer, and i imagine if i looked at like a UR setup with their crash bar i'd probably be right.
Also, compare the numbers above to what is normally in front of the radiator when TMIC (Taken from OP):

Pre radiator:
55 mph - .35" of water
60 mph - 1.15" of water
70+ mph ~1.5" of water


Last test before i install Jsmith's TMIC duct was to measure the new pressure on the back side of the radiator. Again, this was measured right behind the "flaps," while still giving them room to fully open.

40 mph - -2
50 mph - .3
60 mph - .3
70 mph - .5
80 mph - .6

Compare that to the TMIC numbers in the OP:
Post radiator:
50 mph - .1" of water
55 mph - .2" of water
60 mph - .3" of water

80 mph - ~.5" of water

They're shockingly similar... wonder where the hell all that air is going from the hood scoop then. I'll be installed the TMIC duct tomorrow and getting the last bit of testing done.

[Voltwings]

Interesting day after installing the scoop duct, pictured here for those that are curious. Pretty simple, just directs the airflow once it comes through the scoop.



So i got to thinking... we know that the cowl is a high pressure zone, and if you remove the weather stripping you're really pumping air in, not out. Well, i compared the hood scoop data and cowl data in the OP and saw they were really close. I figured i'd just save myself the trouble and do a quick tuft test to see if we were now getting any flow out of the cowl with this installed. We were not.



Now, the strings were not being sucked in quite as it appears, they were really just kind of chilling. They clearly were not being blown out however, so we'll say that's the end of that. Speed was checked all the way up to 80 mph with really no change in movement. The strings did appear to favor moving inward, but there really was not any super obvious motion either way.

Now, on the way to school i figured i'd test pressure on the back side of the radiator now with this duct installed, and the data is surprising.

40 - .2
50 - .3
60 - .5
70 - .6
80 - .7 to .8

You'll see this data is slightly worse (more pressure post radiator) than with the duct uninstalled. This leads me to believe one of two things:
1. User error. I try to get the hose in the same spot every time to get a reading, but maybe i was off.
2. There was a cold front that came in last night so its about 20* colder and windy as hell today. The added wind may have made more Pre-radiator pressure, thus resulting in more post-radiator pressure.

To test theory 2 i was going to get another pre radiator test on the way home from class, but it was bumper to bumper the whole way. I will do my best to double check this data in the morning. It's so close it almost makes no difference, but still.

[JSmith]

Which exact model gauge are you using for these measurements?

Are you taking pictures of the setup before each measurement run?

[Voltwings]

Originally Posted by JSmith Which exact model gauge are you using for these measurements? Are you taking pictures of the setup before each measurement run?

This is the closest one to mine i can find. Mine is a series 2000 as well, which is supposed to be accurate to 2%. The only difference is mine goes 0-3 in either direction.

https://www.amazon.com/Dwyer-Magnehe...gnehelic+gauge

So obviously this has 2 ports and you can measure differential between two locations. What i typically do is leave one port open to atmosphere for reference and just place the other where i am testing.

I do not take pictures, but i have reusable cable ties and i just mount the hose in the same spot(s) with those cable ties every time to try to keep it consistent.

[WetzMS3]

@Voltwings; how do you think a scoop block off would affect the engine bay pressure and cooling efficiency of both a FMIC and the radiator? Assume a complete solid block off, no gaps or anything.

The way I have interpreted your posts and data here and in other threads gave me the assumption that it should improve air flow through FMIC/radiator, I could be all wrong on this, but I have no idea how that would change engine bay temps. I have a plan in the works for a solid scoop block off based on these assumptions and a tiny hope for improve aero on the drag strip (really a pipe dream/hope for nothing detremental at least).

[Voltwings]

Originally Posted by WetzMS3 @Voltwings; how do you think a scoop block off would affect the engine bay pressure and cooling efficiency of both a FMIC and the radiator? Assume a complete solid block off, no gaps or anything. The way I have interpreted your posts and data here and in other threads gave me the assumption that it should improve air flow through FMIC/radiator, I could be all wrong on this, but I have no idea how that would change engine bay temps. I have a plan in the works for a solid scoop block off based on these assumptions and a tiny hope for improve aero on the drag strip (really a pipe dream/hope for nothing detremental at least).

This is just me shooting from the hip immediately after reading your statement. Once i've had a chance to digest, and others have had a chance to discuss, the consensus might change.

So i had a chance to check the readings above that i found odd, and they were odd, everything checked out this morning. So really, what we see is

Pressure pre rad:

40 mph - .5
50 mph - .7
60 mph - .7
70 mph - 1.1
80 mph - 1.4

Then the following pressures:
TMIC post rad:

Post radiator:
50 mph - .1" of water
55 mph - .2" of water
60 mph - .3" of water

80 mph - ~.5" of water

FMIC open scoop post rad:
40 mph - -2
50 mph - .3
60 mph - .3
70 mph - .5
80 mph - .6

FMIC ducted scoop post rad:
40 - .2
50 - .3
60 - .5
70 - .6
80 - .6


Really it doesnt seem to matter what we do as far as directing hood scoop air, so maybe eliminating it completely would be interesting. That being said, you have to remember the perspective here, 27" of water is 1 psi, so when we're talking .5" of water that's not even 2% of 1 psi. Its such a small amount it almost doesnt matter you know? That's just my thoughts on the matter.

What i would really love to do is find some way to make the scoop a vent. The idea i have in mind would be ugly as sin, but it would be cool.

[JSmith]

The attached may help visualize the data so far. Pretty sure it can be polished more.

Voltwings testing data_12Dec16.xlsx

[Voltwings]

That's awesome, i appreciate it. I started a new job monday so i've had a lot less free time lately. I'll take the time to clean up the OP like you suggested, and i'll add that sheet.

[JSmith]

Originally Posted by Voltwings That's awesome, i appreciate it. I started a new job monday so i've had a lot less free time lately. I'll take the time to clean up the OP like you suggested, and i'll add that sheet.

I was suggesting cleaning up the Excel file!

Do you (or the audience) think that including an atmospheric pressure reading to the each data set would help? For example: https://www.wunderground.com/us/ca/orange

[PapaBruno]

Both bumping and subbing. This was quite an interesting read and I'm definitely curious to know more. I have been trying to think up ways to block off the areas to the left and right of my FMIC to force the air into the FMIC, but am not quite sure where to start or if it'd cancel out air getting to my radiator.
I was also thinking about the possibility of doing a fog light delete and trying to find someone to fab up an air inlet that could run up close to my intake, but again, not quite sure where to start. I guess maybe finding someone who is good with CAD, going to a 3D printing, and then maybe a molding?

[JSmith]

Originally Posted by PapaBruno Both bumping and subbing. This was quite an interesting read and I'm definitely curious to know more. I have been trying to think up ways to block off the areas to the left and right of my FMIC to force the air into the FMIC, but am not quite sure where to start or if it'd cancel out air getting to my radiator. I was also thinking about the possibility of doing a fog light delete and trying to find someone to fab up an air inlet that could run up close to my intake, but again, not quite sure where to start. I guess maybe finding someone who is good with CAD, going to a 3D printing, and then maybe a molding?

The nice pipe insulation from Home Depot cuts well and would fit into those areas.

[PapaBruno]

Originally Posted by JSmith The nice pipe insulation from Home Depot cuts well and would fit into those areas.

For the negative space to the left and right of the FMIC? Like this roll? Also, what, just cut and ziptie?

Sent from my SAMSUNG-SM-G900A using Tapatalk

[JSmith]

More like this stuff.

Everbilt 3/4 in. x 6 ft. Rubber Self-Stick Pipe Insulation-PI346RSS - The Home Depot

Edit: Just cut and tuck it in if you can.

[Voltwings]

Originally Posted by PapaBruno Both bumping and subbing. This was quite an interesting read and I'm definitely curious to know more. I have been trying to think up ways to block off the areas to the left and right of my FMIC to force the air into the FMIC, but am not quite sure where to start or if it'd cancel out air getting to my radiator. I was also thinking about the possibility of doing a fog light delete and trying to find someone to fab up an air inlet that could run up close to my intake, but again, not quite sure where to start. I guess maybe finding someone who is good with CAD, going to a 3D printing, and then maybe a molding?

I think blocking the "dead space" on either side is a good idea.
I do not think making an intake pick-up from the fog light location is a good idea however. The foglights are pretty far outboard already, and the air is already moving quite a bit to the side, and a little less "straight on" at that point. Without some sort of lip on the outside (away from center line of car) to catch the air, I do not think that area will actually pick up much air.

[PapaBruno]

Originally Posted by JSmith More like this stuff. Everbilt 3/4 in. x 6 ft. Rubber Self-Stick Pipe Insulation-PI346RSS - The Home Depot Edit: Just cut and tuck it in if you can.

The round tubing for the sides? Not sure I follow. Attaching a quick mock-up of the areas I am looking to block off.

Originally Posted by Voltwings I think blocking the "dead space" on either side is a good idea. I do not think making an intake pick-up from the fog light location is a good idea however. The foglights are pretty far outboard already, and the air is already moving quite a bit to the side, and a little less "straight on" at that point. Without some sort of lip on the outside (away from center line of car) to catch the air, I do not think that area will actually pick up much air.

Reason I had asked/looked into making something for the driver's side fog was because I found this pic of a car for sale in TX (posted a few years ago). More than likely it's a duct for brake cooling. Tried emailing the guy about it, but haven't heard back yet.

EDIT: Just wound up calling and talking to the guy - super nice and the car is still available!
http://www.racingjunk.com/GT/1827175...=0&from=search
He gave me a couple leads that I'll be checking out.

[JSmith]

The round tubing, when cut to length and slit into 1/2 or 1/4 sections is easily put into the gaps to the left/right sides of the radiator.

For my Cobb FMIC with the stock grill, the tubing (full sections) I posted is enough to block the left/right areas. That picture with the blue looks like you may need something more structural/sturdy to cover that much area.

[Voltwings]

Originally Posted by PapaBruno The round tubing for the sides? Not sure I follow. Attaching a quick mock-up of the areas I am looking to block off. Reason I had asked/looked into making something for the driver's side fog was because I found this pic of a car for sale in TX (posted a few years ago). More than likely it's a duct for brake cooling. Tried emailing the guy about it, but haven't heard back yet. EDIT: Just wound up calling and talking to the guy - super nice and the car is still available! SpeedSource Mazdaspeed 3 Conti Tire / WC / Time Attack— for Sale in AUSTIN, TX | RacingJunk Classifieds He gave me a couple leads that I'll be checking out.

I ran my brake ducts from the dead space on either side of the radiator that you are looking to block off. The air is highest pressure right at the front of the car, the further down the side of the bumper you go, the less useful that air is.

I'd need to see a better picture, but those ducts in that car appear to be more "show" than "go." Air typically isnt inclined to make steep 90* turns at speed without some serious coercing. If you're already blocking the space on either side of the radiator off anyways, just get a 2.5" bezel and slap it in the middle. Then you can run it to either the brakes or the intake.