tried searching on here but didnt have any topics on delta fin intercoolers.
Thinking about buying a Apexi Intercooler but not sure if i would benefit more from a Bar and plate style intercooler or a Delta Fin.

Goal is 450-500 whp

 

i prefer the bar and plate.....

 

Delta fin intercoolers are made with trapazoidal cores, every other core flipped over. Essentially looks like every other fin space funnels more air into the space, and the next space gets normal airflow. The funneled channel has tighter packed fins, the other spaces get loosely packed fins. Cross-section, front to back (4 cores, 3 air channels):
_____
\____/
|___|
/____\
|____|
\____/
|___|
/____\

In theory you maximize efficiency by maximizing air velocity, as it causes less turbulance. The problem with this is air turbulance is the key factor in heat exchange, as you want to disrupt the very thin boundry layer around the cores. If you look at intercooler fins, they look to be preforated as they go into the depth of the intercooler to the other side. They are basicly split many times to promote turbulance.

Bar & plate works great because you have high velocity air hitting the flat faces, and the resulting pressure pushing the air between the fins. The air keeps a relatively high velocity due to being squeezed in there, but has a shitton of turbulance.

Which one works best, I can't say for sure. But I'm a fan of turbulance when it comes to air exchange, given the unlimited external flow you see with a car.

 

GREAT Explanation.. But numbers are what matter to me. so which SHOULD make better numbers

 

???????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">Delta fin intercoolers are made with trapazoidal cores, every other core flipped over. Essentially looks like every other fin space funnels more air into the space, and the next space gets normal airflow. The funneled channel has tighter packed fins, the other spaces get loosely packed fins. Cross-section, front to back (4 cores, 3 air channels):
_____
\____/
|___|
/____\
|____|
\____/
|___|
/____\

In theory you maximize efficiency by maximizing air velocity, as it causes less turbulance. The problem with this is air turbulance is the key factor in heat exchange, as you want to disrupt the very thin boundry layer around the cores. If you look at intercooler fins, they look to be preforated as they go into the depth of the intercooler to the other side. They are basicly split many times to promote turbulance.

Bar & plate works great because you have high velocity air hitting the flat faces, and the resulting pressure pushing the air between the fins. The air keeps a relatively high velocity due to being squeezed in there, but has a shitton of turbulance.

Which one works best, I can't say for sure. But I'm a fan of turbulance when it comes to air exchange, given the unlimited external flow you see with a car.</TD></TR></TABLE>

I'm sorry but that is a little off, turbulence is bad in an intercooler because it does not allow the heat exchange effectively and let new unheated air pass through the intercooler. The perforations in the fins are not to create turbulence but to increase the surface are where heat can be exchanged from the metal to the air. As for the bar and plate having a flat face which as you say increases pressure between then bars is wrong the apex'i design does a much better of that because it is forcing more air into a tighter spot via the angled faces as opposed to just pushing through the air with a flat face...

 

hmmmm i smell a debate coming up. MORE INPUT. Johnny five is alive

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Soccerking3000 &raquo;</TD></TR><TR><TD CLASS="quote">The perforations in the fins are not to create turbulence but to increase the surface area</TD></TR></TABLE>

I'm talking about front to back, looking at it face-on. You must be thinking of how the fins 'squigle', looking at the fmic side to side. http://img408.imageshack.us/im...8.jpg This pic shows these preforations/serations I speak of.

As for turbulence: air is a natural INSULATOR. If you had air molecules passing straight through with zero turbulence, you'd have only the air nearest the metal take any heat away. The air in between the metal fins would still be ambient temps.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wikipedia &raquo;</TD></TR><TR><TD CLASS="quote">When designing piping systems, turbulent flow requires a higher input of energy from a pump (or fan) than laminar flow. However, for applications such as heat exchangers and reaction vessels, turbulent flow is essential for good heat transfer and mixing.</TD></TR></TABLE>

Just take the amount of air that hits the fmic at even 30mph. A core thats 8"x24" moving at 30mph moves through 31,680 inches of air per minute. 1 CFM is 1728 cubic inches/min. (8" x 24" x 31680") / 1728 = <U>3,520 cubic feet per minute</U>. MORE than enough volume to cool the core down, but it won't do squat if it can't touch the metal. Tell me now that exchanging a small amount of speed for a large amount of turbulence is going to vastly affect the amount of air pushed through the fmic.


The apexi design is still pushing the same amount of air through the entire intercooler; it pushes more through sections with denser fins, and less through areas with less dense fins. 2x air in an area that has 2x the fins + 1/2 the air in an area that has 1/2 the fins = same amount of air contact. You have such a large amount of air pushed through the fmic that the air will not slow much at all, regarless of air being channeled in by ramps or 'blocked' by the flat faces.

Not trying to be an *** (its easter after all!), just being very thorough.

BTW why don't you see more race teams, drag/autox/drift, using the delta fin than bar/plate?

 

its all about preference. most of the delta fin coolers arent rated to flow as much as bar and plate, my apex-i doesnt flow the same as a percision 750 per say, but is probably right there if not better then the precision 600, which is similar in size. ive had both a bar and plate intercooler and a delta fin, both worked fine, both made the same # on the dyno, but on the other hand have never driven the car at 120 to test out how much power its making with real airflow on the intercooler...

 

so the precisions are bar and plate?

 

yessir