Does CS Hood actually help air flow??

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Does CS Hood actually help with airflow and/or heat release?

Definitely, a whole lot!
9
45%
Yes! BUT, only with airflow...
1
5%
Yes! BUT, only with heat release...
5
25%
Yes! BUT only in other aspects...
0
No votes
Ehhh, it does help to some degree.
1
5%
Nope, to some degree, but hardly practical.
4
20%
 
Total votes : 20

Postby Simba » Sat Aug 05, 2006 6:16 pm

You're not getting any more through the rad/ic area with a CS hood. The airflow immediately gets turbulent after the cores, then hits the brick wall that is the engine block.

The only way to prevent that is with ducting.
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Postby maxaud » Sat Aug 05, 2006 8:17 pm

was that a reply to my post? I would think you would get much more airflow w/ a cs/rc hood (not talking about tmic, that would just be stupid), it gives an out for air to go when a st185/184 hood would do nothing of the like.
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Postby Simba » Sun Aug 06, 2006 2:43 pm

Yes. I've no doubt the CS vent allows a good deal of hot air to be sucked out of the engine bay, but there's no uniform flow to it. Without ducting, all of the air that flows in there is very turbulent, low pressure air that more or less goes where it pleases. There's nothing behind the rad allowing the cowl induction effect of the vent to actually help pull air through it.

From a cooling standpoint, I highly doubt the CS hood moves any more air through the rad, given the flow dynamics over the engine.

It's easy enough to prove either way. Just get yourself a bigass fan, an IC camera, and a smoke machine.

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Postby JDMGT-4 » Sun Aug 06, 2006 7:47 pm

I have kinda an off topic question....

The side vents on a ST185 hood, do you think it would be better to flip them around so that the 2 side vents and the main scoop all face forward or not?
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Postby maxaud » Sun Aug 06, 2006 8:03 pm

alot of people turn the left side one around to draw colder air in to an intake
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Postby Gurr » Sun Aug 06, 2006 8:38 pm

I'm with simba on this one. I don't believe the CS vent flows more than a stock scoop at speeds. the only advantage to having one would be for hot air release when your standing still or moving slow.... I see no advantage besides that. And the drag created by th scoop is not nearly as much as it is made to seem as before.
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Postby Simba » Mon Aug 07, 2006 1:06 pm

JDMGT-4 wrote:The side vents on a ST185 hood, do you think it would be better to flip them around so that the 2 side vents and the main scoop all face forward or not?


Flipping them forward will get more air into the bay, but there's really nothing directly under them that's worth cooling. They were designed to vent hot air out, while the scoop forces it in.

You could flip the drivers side vent to get some cooler air near the intake, but again without an air box or ducting of some sort, it'd be a marginal difference.

Air flow isn't a laminar sort of thing like a liquid. Unless it's going very fast or is constricted by a vent or duct of some sort, it tends not to remain in an organized stream. If you want to get air from one place to another, you need to duct it.

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Postby muneo » Mon Aug 07, 2006 6:53 pm

Were kinda comparing apples to oranges here regarding air flow

ATA - the stock 185 hood will win hands down. Even if heat escapes through the scoop, at least its escaping somewhere besides the side vents. I remember talking to a lot of alltracers around here that bought the cs hood but have the ATA Top mount intercooler. They have worse heatsoak problems than regular 185 hoods.

For front mount/WTA, the bumper has more to do with cooling than the hood since the actual cooler is place in the bumper area.

Coefficient Drag wise, Simba is correct. Tha actual numbers: stock .34 vs CS/RC .3
.04 is substantial at higher speeds

CS hood probably vents more hot air stationary since one of the main heat sources (Turbo manifold/Turbo) lies directly under an opening. I'm also pretty sure that the CS hood works similarly to the EVO hood in regards to its purpose. I bet at speeds, the engine bay doesnt have to get rid of as much hot air from the turbo since most of it would be escaping from the center vent.
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Postby AlltracAvenger » Mon Aug 07, 2006 10:41 pm

Hm. I'm speaking from relative inexperience, but the design of the hood on both the 185RC and 205 seem to suggest not actually moving air through the engine bay per se, but reducing underhood heat as to make the ambient underhood temperature much less than what it would be with a full hood. Both cars have W/A intercoolers, and with that there isn't as much of a need of direct airflow to the IC itself(a lot of that work is done by the front radiator; I have had a dramatic improvement in IC temp on my '165 by adding a secondary, and that's with a non-vented stock hood). However, heat soak is a major problem without much way for heat to escape... '165s in particular suffer greatly from this.

From what I see, the 'lip' to the vent creates a low pressure area right above the vent, which would for the lack of a better word 'suck' the heated engine bay air out of the vent when the car is at speed, as well as allow the heat a route to escape while stopped... keeping it away from the TMIC altogether. Now, since A/A ICs need airflow to operate, the RC vent will serve as an airflow restriction to a stock '185 IC. The point is, I think that if you have a RC or '205 IC on your car, then a vent is a very very good thing to have. If you have a stock '185 IC, don't do it, or go for a front mount. As far as mounting a front mount, would a RC hood be of any benefit? I think so; not for the IC per se, but to reduce underhood temps in general, which could reduce heat soak of your intake piping, too.

Sorry if things aren't totally clear here... I'm running on two hours of sleep. If anyone needs any further clarification, lemme know. :)
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Postby maxaud » Mon Aug 07, 2006 11:01 pm

I think that was nicely put.
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Postby alltracman78 » Wed Aug 16, 2006 1:28 am

AlltracAvenger wrote:Hm. I'm speaking from relative inexperience, but the design of the hood on both the 185RC and 205 seem to suggest not actually moving air through the engine bay per se, but reducing underhood heat as to make the ambient underhood temperature much less than what it would be with a full hood. Both cars have W/A intercoolers, and with that there isn't as much of a need of direct airflow to the IC itself(a lot of that work is done by the front radiator; I have had a dramatic improvement in IC temp on my '165 by adding a secondary, and that's with a non-vented stock hood). However, heat soak is a major problem without much way for heat to escape... '165s in particular suffer greatly from this.

From what I see, the 'lip' to the vent creates a low pressure area right above the vent, which would for the lack of a better word 'suck' the heated engine bay air out of the vent when the car is at speed, as well as allow the heat a route to escape while stopped... keeping it away from the TMIC altogether. Now, since A/A ICs need airflow to operate, the RC vent will serve as an airflow restriction to a stock '185 IC. The point is, I think that if you have a RC or '205 IC on your car, then a vent is a very very good thing to have. If you have a stock '185 IC, don't do it, or go for a front mount. As far as mounting a front mount, would a RC hood be of any benefit? I think so; not for the IC per se, but to reduce underhood temps in general, which could reduce heat soak of your intake piping, too.

Sorry if things aren't totally clear here... I'm running on two hours of sleep. If anyone needs any further clarification, lemme know. :)


DING!
He gets the prize. :)

The hood is designed to vent hot air from the engine. It sits right above the hottest spot in the bay, the turbo.
As for how well it vents at high speeds, the higher the speed, the better it vents. To a point of course.
Someone mentioned Bournellis Priciple.

Bascially, when you have air rushing over a hole, it creates a vaccum. The more air/faster the air travels, the more vaccum.
A carburator works on this principal.
The hood has a VERY large hole in it.
Note the "dam" at the front of the vent. To create more of a defined hole.

As for who designed it, certainly not Carlos Sainz.
He was a driver, not an engineer.
It was probably a team of TTE/Toyota engineers.
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