Eagles Canyon track day Nov 17

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11-21-2012, 11:32 AM
SirHustlerEsq

Quote:

Originally Posted by shanem

yep, i plan to follow your recommendations. you had recommended that magic funnel before. i added the lip in front of the hood vent that is supposed to be for removing heat that you had recommended before btw. I forget who recommended adding some vents on the sides of the hood, it could have been you. Something like this:

http://www.flyinmiata.com/index.php?...umber=29-40000

Also the car has no thermostat, the guy at MRT that did the engine swap said they "always" remove those for cooling. it also has no heater core.

Your hood vent needs to be in front of the OEM hump.
The FM vents are too far back and do nothing.
Running no thermostat is retarded.
11-21-2012, 11:55 AM
shanem

Quote:

Originally Posted by mr brg

Your hood vent needs to be in front of the OEM hump.
The FM vents are too far back and do nothing.
Running no thermostat is retarded.

yep, you have said that before. Remember, i didn't build the car or spec it out, I bought it as it is.

I thought the point of those FM vents was the ability to put them wherever you wanted? As for the thermostat and taking it out, you would think MRT would know what they are doing. but they are also the ones that said the bumper opening, hood lifters in the rear, and hood vent were commonly done for cooling miatas on the track, all of which you and others have said makes things worse.

Anyway, i work with what i have and rely on people that know more than me on this stuff since I'm not familiar with the platform or what it takes to cool them. apparently the wrong things were done to it during the build and im left to figure it out.

maybe i will seal that bumper opening with some of the material i used for ducting and the hood extraction area and see if that helps things at the toy run. i could just tape some plastic in there, do some sessions with and without them plugged and see how things go.
11-21-2012, 12:20 PM
mach1

Quote:

Originally Posted by mr brg

Is you ducting pointed at the hub or the rotor? Where do the hoses pull air?

Both, 2.5in hose, i fabbed up the plate, the "output" is 1/2 on the rotor ring and 1/2 inside the ring.
I made some tapered cones and they are under the front bumper, 4" tapered to 2"
I just ordered a front lip with the holes so it doesn't look so shitty.
11-21-2012, 12:59 PM
SirHustlerEsq

Quote:

Originally Posted by shanem

I thought the point of those FM vents was the ability to put them wherever you wanted?

The idea is to put them somewhere with lift, or negative pressure to pull air out. If the are even or behind the hood hump, they are not working or sucking-in air.

Quote:

Originally Posted by shanem

As for the thermostat and taking it out, you would think MRT would know what they are doing.

You would, I don't. Removing a thermostat does not increase cooling efficiency or capacity, it unnecessarily increases flow.

Quote:

Originally Posted by shanem

but they are also the ones that said the bumper opening, hood lifters in the rear, and hood vent were commonly done for cooling miatas on the track, all of which you and others have said makes things worse.

Lots of people think they understand aero, most don't. There is incredibly high pressure at the cowl/back of the hood. If you open the hood there, it will always increase air-flow into the engine bay, increasing pressure in that chamber, and decrease transition or movement of air through the radiator. That's not open to debate, that's a fact. The extra opening in the bumper is stupid. There is no problem with volume entering the mouth, the problem is pressure differential.
See that little dividider/foil in the mouth of the bumper, under the top-side of the mouth?
http://i240.photobucket.com/albums/f...bispec/916.jpg
It's 1.25-1.5" below the top of the mouth and that effectively cools a 400hp Miata in 105* desert heat at WSIR on the big track. Do you think you need 20x-40x more airflow than that car at a measly 230whp? Matt also ran a 190*f thermostat in that car.
That bumper hole in your car does nothing more than dump unnecessary air between the interooler and radiator, significanly reducing intercooler performance. You're call will make a ton more power without that extra hole.
http://www.aviation-history.com/theory/venturi.gif
Your radiator is the choke point. Building a chamber from the mouth to the radiator will increase pressure slightly higher than the incoming air, further helping the radiator cool. This is why you want the orifice to be smaller than the negative area of the radiator (area of the radiator - fins and tubes).
Before you ask, fans will reduce the efficiency of the radiator.

Quote:

Originally Posted by shanem

maybe i will seal that bumper opening with some of the material i used for ducting and the hood extraction area and see if that helps things at the toy run. i could just tape some plastic in there, do some sessions with and without them plugged and see how things go.

You need to seal the front of the radiator and be certsin your un-trimmed belly pan is in tact. Step one is sealing the front of the radiator, step two is assuring you have clean-airflow back to the front subframe, step 3 is closing the front bumper vent. I know I've been up your ass about this, but it's time for you to fix the car, the right way. Remember when I told you to do this yourself because no shop you or I can afford would do this right? I do. :)
Please remember that when my car made 50hp more than yours I could flog it in 105*f heat at HHR which is a slow course, tucked behind a Panoz for ~45 minutes, and never go north of 199*f on the water and 230*f on the oil.

Quote:

Originally Posted by mach1

Both, 2.5in hose, i fabbed up the plate, the "output" is 1/2 on the rotor ring and 1/2 inside the ring.
I made some tapered cones and they are under the front bumper, 4" tapered to 2"
I just ordered a front lip with the holes so it doesn't look so shitty.

The taper is reducing efficiency. If you ever build them again, get the air away from the rotor surface and into the hub.

Aero 101 is complete.

If you guys want some sweet aero articles from Racecar Engineering, let me know in email.
11-21-2012, 01:55 PM
mach1

I figured with all the air going into the hub area most of it would just blow right through the giant holes in the alum rotor hat (thanks wilwood)
If they were solid hat's I would have been all over directing it towards the middle so the air flows through the vanes in the rotor.
11-21-2012, 03:17 PM
shanem

Quote:

Originally Posted by mr brg

The idea is to put them somewhere with lift, or negative pressure to pull air out. If the are even or behind the hood hump, they are not working or sucking-in air.

You would, I don't. Removing a thermostat does not increase cooling efficiency or capacity, it unnecessarily increases flow.

Lots of people think they understand aero, most don't. There is incredibly high pressure at the cowl/back of the hood. If you open the hood there, it will always increase air-flow into the engine bay, increasing pressure in that chamber, and decrease transition or movement of air through the radiator. That's not open to debate, that's a fact. The extra opening in the bumper is stupid. There is no problem with volume entering the mouth, the problem is pressure differential.
See that little dividider/foil in the mouth of the bumper, under the top-side of the mouth?
http://i240.photobucket.com/albums/f...bispec/916.jpg
It's 1.25-1.5" below the top of the mouth and that effectively cools a 400hp Miata in 105* desert heat at WSIR on the big track. Do you think you need 20x-40x more airflow than that car at a measly 230whp? Matt also ran a 190*f thermostat in that car.
That bumper hole in your car does nothing more than dump unnecessary air between the interooler and radiator, significanly reducing intercooler performance. You're call will make a ton more power without that extra hole.
http://www.aviation-history.com/theory/venturi.gif
Your radiator is the choke point. Building a chamber from the mouth to the radiator will increase pressure slightly higher than the incoming air, further helping the radiator cool. This is why you want the orifice to be smaller than the negative area of the radiator (area of the radiator - fins and tubes).
Before you ask, fans will reduce the efficiency of the radiator.

You need to seal the front of the radiator and be certsin your un-trimmed belly pan is in tact. Step one is sealing the front of the radiator, step two is assuring you have clean-airflow back to the front subframe, step 3 is closing the front bumper vent. I know I've been up your ass about this, but it's time for you to fix the car, the right way. Remember when I told you to do this yourself because no shop you or I can afford would do this right? I do. :)
Please remember that when my car made 50hp more than yours I could flog it in 105*f heat at HHR which is a slow course, tucked behind a Panoz for ~45 minutes, and never go north of 199*f on the water and 230*f on the oil.

The taper is reducing efficiency. If you ever build them again, get the air away from the rotor surface and into the hub.

Aero 101 is complete.

If you guys want some sweet aero articles from Racecar Engineering, let me know in email.

I'm not debating the validity of your suggestions, only my ability to do them myself! lol
11-21-2012, 03:37 PM
mach1

Quote:

Originally Posted by shanem

I'm not debating the validity of your suggestions, only my ability to do them myself! lol

That upper hole may just be sucking all of the air from the lower hole
http://www.tyjames.com/rx7aero.jpg
11-21-2012, 03:59 PM
SirHustlerEsq

Quote:

Originally Posted by mach1

I figured with all the air going into the hub area most of it would just blow right through the giant holes in the alum rotor hat (thanks wilwood)
If they were solid hat's I would have been all over directing it towards the middle so the air flows through the vanes in the rotor.

I believe there is enough turbulence over the wheels and the hub that air is going through the rotors rather than out the hub-holes. I'd bet a fairly large sum of money on it.

Quote:

Originally Posted by mach1

That upper hole may just be sucking all of the air from the lower hole
http://www.tyjames.com/rx7aero.jpg

It certainly is. This shop should be ridiculed for doing this to his car. I didn't even consider that it might be sucking air out the top hole.

Look, these guys know what they are doing:
http://photos.motoiq.com/Event-Cover.../JEF3250-L.jpg
11-22-2012, 12:08 AM
johnwag

Quote:

Originally Posted by mr brg

The idea is to put them somewhere with lift, or negative pressure to pull air out. If the are even or behind the hood hump, they are not working or sucking-in air.

You would, I don't. Removing a thermostat does not increase cooling efficiency or capacity, it unnecessarily increases flow.

Lots of people think they understand aero, most don't. There is incredibly high pressure at the cowl/back of the hood. If you open the hood there, it will always increase air-flow into the engine bay, increasing pressure in that chamber, and decrease transition or movement of air through the radiator. That's not open to debate, that's a fact. The extra opening in the bumper is stupid. There is no problem with volume entering the mouth, the problem is pressure differential.
See that little dividider/foil in the mouth of the bumper, under the top-side of the mouth?
http://i240.photobucket.com/albums/f...bispec/916.jpg
It's 1.25-1.5" below the top of the mouth and that effectively cools a 400hp Miata in 105* desert heat at WSIR on the big track. Do you think you need 20x-40x more airflow than that car at a measly 230whp? Matt also ran a 190*f thermostat in that car.
That bumper hole in your car does nothing more than dump unnecessary air between the interooler and radiator, significanly reducing intercooler performance. You're call will make a ton more power without that extra hole.
http://www.aviation-history.com/theory/venturi.gif
Your radiator is the choke point. Building a chamber from the mouth to the radiator will increase pressure slightly higher than the incoming air, further helping the radiator cool. This is why you want the orifice to be smaller than the negative area of the radiator (area of the radiator - fins and tubes).
Before you ask, fans will reduce the efficiency of the radiator.

You need to seal the front of the radiator and be certsin your un-trimmed belly pan is in tact. Step one is sealing the front of the radiator, step two is assuring you have clean-airflow back to the front subframe, step 3 is closing the front bumper vent. I know I've been up your ass about this, but it's time for you to fix the car, the right way. Remember when I told you to do this yourself because no shop you or I can afford would do this right? I do. :)
Please remember that when my car made 50hp more than yours I could flog it in 105*f heat at HHR which is a slow course, tucked behind a Panoz for ~45 minutes, and never go north of 199*f on the water and 230*f on the oil.

The taper is reducing efficiency. If you ever build them again, get the air away from the rotor surface and into the hub.

Aero 101 is complete.

If you guys want some sweet aero articles from Racecar Engineering, let me know in email.

One thing to add to this... This photo of matt's car was well before we redesigned the aero on the front of the car. Matt filled in the 5 holes in the bumper and the brake duct holes. Trey and I modified the splitter and splitter mounts at WSIR. Later that season, Matt and i added more downforce to the front of the car. Matt fabbed a set of canards for the front area and I created a wheel spat/downforce generator.
11-22-2012, 09:06 AM
shanem

Quote:

Originally Posted by johnwag

One thing to add to this... This photo of matt's car was well before we redesigned the aero on the front of the car. Matt filled in the 5 holes in the bumper and the brake duct holes. Trey and I modified the splitter and splitter mounts at WSIR. Later that season, Matt and i added more downforce to the front of the car. Matt fabbed a set of canards for the front area and I created a wheel spat/downforce generator.

it sounds to me like you two are the fix my car dream team... free beer and cat food???!!
11-22-2012, 09:26 AM
SirHustlerEsq

Quote:

Originally Posted by shanem

it sounds to me like you two are the fix my car dream team... free beer and cat food???!!

How much money do you have?
11-23-2012, 03:32 AM
shanem

Quote:

Originally Posted by mr brg

How much money do you have?

$4.73
11-23-2012, 07:34 AM
SirHustlerEsq

Just drop the car off in Lewisville, with the $4.73 in the glove box.
11-23-2012, 07:51 AM
shanem

Quote:

Originally Posted by mr brg

Just drop the car off in Lewisville, with the $4.73 in the glove box.

I can go baller and dig another $.57 out of the washer if that's what it takes.
11-23-2012, 08:57 AM
ken o

I looked at the car and it does need the area in front of the radiator sealed off. What if you ducted the upper hole in the bumper into the radiator like in the picture of the S2000?
11-23-2012, 09:11 AM
SirHustlerEsq

Quote:

Originally Posted by ken o

I looked at the car and it does need the area in front of the radiator sealed off. What if you ducted the upper hole in the bumper into the radiator like in the picture of the S2000?

It will still reduce airflow through the intercooler, unless you make two chambers, which the car doesn't need. I guess he could put the oil cooler there and duct it out the side. I'm still not entirely certain air is going "into the hole". It may be flowing backwards, from the mouth, through the FMIC, out the hole. I don't really know enough about aero to know if that's even possible but considering the ultra-low pressure area there and turbulence, I'd eliminate it.
11-23-2012, 09:15 AM
shanem

Quote:

Originally Posted by ken o

I looked at the car and it does need the area in front of the radiator sealed off. What if you ducted the upper hole in the bumper into the radiator like in the picture of the S2000?

If all that extra air ins't needed it seems better to figure out a way to just seal that thing off. I keep thinking maybe i just need a new bumper cover and hood to eliminate this issue altogether. then i would have to have the parts painted though, which is a PITA and adds to the cost, especially since there is no way to know what color blue those stripes are. Then again, i could just spray the whole car in that plastidip stuff or wrap it in vinyl. I've seen sprayable kits for plastidip, I'm not a fan of the green/blue stripes on the car anyway.

I could probably find someone not interested in track performance that would want to buy the bumper and hood off the car. i don't even want to think how long it took the bodyshop guys to make those fabricated openings in the hood and bumper. The hard parking crew seems to like the hood and bumper.

I'm going to fiddle with it this weekend and see what i can come up with to seal them without resorting to lots of rivets that would ruin any value the parts might have in resell. i also need to figure out some way to reseal the firewall under the hood since MRT didn't give me back the weatherstrip they removed when they lifted the rear of the hood.

Trey ive been thinking about it, i doubt much air is going into that bumper hole since its a low pressure area. it would have high speed air flowing across it though, which would create a suction and suck air out of the radiator area using the venturi effect. It would have to suck at least some of the air that passes through that lower factory opening out i think.
11-23-2012, 09:19 AM
SirHustlerEsq

Just close it up, test, see if the car runs cool, then decide. If I were you, I'd duct that hole to an oil cooler, or copy my set-up. No need to spend anymore money on cosmetic shit like that.
11-23-2012, 09:27 AM
shanem

Quote:

Originally Posted by mr brg

Just close it up, test, see if the car runs cool, then decide. If I were you, I'd duct that hole to an oil cooler, or copy my set-up. No need to spend anymore money on cosmetic shit like that.

open to suggestions for closing it up this side of duct tape lol. if no or minimal air is entering there, i doubt it would work for an oil cooler anyway.
11-25-2012, 12:09 AM
Nails

Here's my only vid of my car on the track that day. I had a wheel bearing fail at lunch cutting the day short. Lotsa good footage of Shane till he drops back for a cool down lap. My goal was to get a 2:10 by the afternoon. Got a 2:09 in just the second session when I caught an open track for a lap.

http://www.youtube.com/watch?v=njbzM...ature=youtu.be

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