DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Painting intercooler black - good or not?

Thread Tools
 
Search this Thread
 
Old 03-04-2009, 08:55 AM
  #41  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

Originally Posted by patsmx5
Assuming:

h_air = 50 W/m*k
h_aluminum = 221 W/m*k
h_polyethylene = 0.50 W/m*k (closest thing to paint I can find...)

I found some formula and got a heat transfer coefficient of:

without paint: 40.774155458486 W/m*k
with paint: 40.774153752544 W/m*k

For a reduction in heat transfer of 0.0000042%. Not a whole lot. Not 100% sure I did it right though. I'm going over it.
You should probably calculate what % of surface is actually getting coated. We typically use intercoolers with 3" wide fins and only coat the very edges of them.

Using the IC posted above, there are 14 rows of fins at 3" wide. Lets say that laid out straight they are 48" long, and .02" thick.

.02 x 48 x 14 (# of runners) = 13 sq in. of edge surface surface gets coated.

Maybe a little gets onto the flat edge of fins about a 1/4 of an inch : .25 x 48 x 14 (# of runners) x 2 (# of sides)= 336 sq in. of the fl

so we coat a total of 349 sq in. of cooling surface when painting the IC...out of 4045, or 8.5%.

If coating the whole thing is 0.0000042% less efficient, than I assume painting just the front is what? Only .000000357% less efficient than a non-painted IC?
Braineack is offline  
Old 03-04-2009, 10:10 AM
  #42  
Elite Member
iTrader: (16)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 9,298
Total Cats: 477
Default

Originally Posted by y8s
emissivity of aluminum = lo fi

emissivity of flat blackness = hi fi

add that to your calcs and smoke it
No idea what you just said. Those calculations were only for convection. Dunno how much heat would radiate off and how much .001" of paint on 1/100 of the surface area would effect that.
patsmx5 is offline  
Old 03-04-2009, 10:18 AM
  #43  
Elite Member
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 2,023
Total Cats: 19
Default

Originally Posted by patsmx5
No idea what you just said. Those calculations were only for convection. Dunno how much heat would radiate off and how much .001" of paint on 1/100 of the surface area would effect that.
You obviously didn't have James Sucec to teach you heat transfer....
skidude is offline  
Old 03-04-2009, 10:19 AM
  #44  
Elite Member
iTrader: (16)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 9,298
Total Cats: 477
Default

Originally Posted by skidude108
You obviously didn't have James Sucec to teach you heat transfer....
Haven't had heat transfer.
patsmx5 is offline  
Old 03-04-2009, 10:20 AM
  #45  
Elite Member
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 2,023
Total Cats: 19
Default

Originally Posted by patsmx5
Haven't had heat transfer.
That explains it too.
skidude is offline  
Old 03-04-2009, 10:23 AM
  #46  
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,338
Total Cats: 573
Default

Originally Posted by patsmx5
Haven't had heat transfer.
bitch I had that class twice! once for practice.

haha

anyway, it's doubtful it does radiate much but if you're going to calculate to the 34th decimal place, it matters.
y8s is offline  
Old 03-04-2009, 10:33 AM
  #47  
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
Default

I like it when engineers argue.
hustler is offline  
Old 03-04-2009, 10:39 AM
  #48  
Elite Member
iTrader: (16)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 9,298
Total Cats: 477
Default

Originally Posted by y8s
bitch I had that class twice! once for practice.

haha

anyway, it's doubtful it does radiate much but if you're going to calculate to the 34th decimal place, it matters.
Yeah, I took Cal 4 for practice once so far, this might be my second practice session. Hope not though. So radiant heat is negligible. I'll do some more reading on heat transfer and try to make sense of that e-word you mentioned.
patsmx5 is offline  
Old 03-04-2009, 11:32 AM
  #49  
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
Default

I had to take cal 1 and cal 2 three times each to pass, then change career paths. $15k later, I'm still paying for it.
hustler is offline  
Old 03-04-2009, 11:37 AM
  #50  
Elite Member
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 2,023
Total Cats: 19
Default

I had to take calc 3 twice but only because I didn't like the D the first time. Thermodynamics 2 was roughly the same story. I'm almost done though!
skidude is offline  
Old 03-04-2009, 11:53 AM
  #51  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

i took algebra 2, thus is why I could only go so far as calculating surface area.
Braineack is offline  
Old 03-04-2009, 12:38 PM
  #52  
Junior Member
iTrader: (1)
 
papasmurf's Avatar
 
Join Date: Oct 2007
Location: Utah County
Posts: 127
Total Cats: 0
Default

Originally Posted by patsmx5
Haven't had heat transfer.
Ugh, I hated heat transfer. However I did a custom "cai (cowl intake)" for my project on the miata when it was n/aPainting intercooler black - good or not?-dscn1037.jpg. My prof is still using it as an example of a good project lol.
papasmurf is offline  
Old 03-04-2009, 12:55 PM
  #53  
Elite Member
iTrader: (5)
 
johndoe's Avatar
 
Join Date: Mar 2007
Location: NYC
Posts: 1,970
Total Cats: 1
Default

I took "logic" in college for my math credit...philosophy ftw.
johndoe is offline  
Old 03-05-2009, 12:56 PM
  #54  
Elite Member
iTrader: (51)
 
gospeed81's Avatar
 
Join Date: Nov 2008
Location: Spring, TX
Posts: 7,257
Total Cats: 26
Default

Originally Posted by skidude108
I had to take calc 3 twice but only because I didn't like the D the first time. Thermodynamics 2 was roughly the same story. I'm almost done though!
At my schools D don't count, have to score C or better in all engineering classes. This is why I took Numerical Methods for practice. It's a little better this semester.

On topic, I'm painting mine, even if it lowered efficiency a whole whopping 1%. The older Begi intercoolers mount off-center, and are small to boot. It has no bling factor, and I don't want cops/ricers to know it's there. It's going to be black.
gospeed81 is offline  
Old 03-05-2009, 03:35 PM
  #55  
Elite Member
iTrader: (9)
 
buffon01's Avatar
 
Join Date: Sep 2008
Location: Michigan
Posts: 5,609
Total Cats: 13
Default

Wow lot of mathematecians around....I have a Calc 3 test on tuesday that means the weekend wont be as fun for i have to study i dont want to take any classes over...and as for the painting goes I will definetly paint my Ic, when i get it, i think that will help to keep the lusting ppl away from my baby
buffon01 is offline  
Old 03-05-2009, 03:41 PM
  #56  
Junior Member
 
Sleeper_MX5's Avatar
 
Join Date: Jan 2008
Posts: 269
Total Cats: 0
Default

I like to show off..so i'll keep mine aluminum...great idea though..
Sleeper_MX5 is offline  
Old 03-05-2009, 03:53 PM
  #57  
Elite Member
iTrader: (16)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 9,298
Total Cats: 477
Default

Originally Posted by skidude108
I had to take calc 3 twice but only because I didn't like the D the first time. Thermodynamics 2 was roughly the same story. I'm almost done though!
I got through cal 1, 2, and 3 ok. Cal 4 I got the hardest meanest teacher at MSU and she failed me. Got her again and I'm passing, but.... Our study group studied for ~25 hours over the course of a week prior to her last test. We'd all take turns working homework problems on the board and explaining them to the group. We all learned a lot and made sure everybody understood the problem before doing the next one. Did one section every day and the last two days we did a big review and went over old test too. I still think I failed the test she gave us. Her test are just stupid hard. 3 levels harder than anything we see in lecture or HW. I don't even know where she gets this ****. We cover 30 methods and she test us on 5 of them. Grrrrr. And she doesn't give partial credit for ****. It's either 100% correct or it's wrong and maybe she'll give you 1-2 points out of 20 for that problem. Even if you just missed a sign or got X^3 but in the next step you copied it as X^2 and then continued to work the problem showing you understood the method, though you'll get the wrong answer as you made a mistake copying the problem at an earlier step. Where say in any other test they would count off for that but still give partial credit if I showed I understood the method.

I like all my other classes though and am doing fine. I'm in thermo II right now and got an A on my last test. Woot!
patsmx5 is offline  
Old 03-05-2009, 04:06 PM
  #58  
Junior Member
iTrader: (1)
 
AlexandertheOk's Avatar
 
Join Date: Apr 2008
Location: Los Alamos/Las Crues New Mexico
Posts: 98
Total Cats: 0
Default

Haha, i got an "A" on some of my thermo 2 tests too. Apparently a 11/20 on a 1:15 multiple choice exam is an A.

Curves FTW!
AlexandertheOk is offline  
Old 03-05-2009, 04:14 PM
  #59  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

I got an A in advertising campaigns.
Braineack is offline  
Old 03-05-2009, 04:20 PM
  #60  
Elite Member
iTrader: (16)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 9,298
Total Cats: 477
Default

Originally Posted by AlexandertheOk
Haha, i got an "A" on some of my thermo 2 tests too. Apparently a 11/20 on a 1:15 multiple choice exam is an A.

Curves FTW!
What's a multiple choice exam? What's a curve? I've never seen or heard of these things at MSU!!!
patsmx5 is offline  


Quick Reply: Painting intercooler black - good or not?



All times are GMT -4. The time now is 08:54 PM.