Finally... a 3" brake duct solution for the Evo
#31
Evolving Member
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Golgo, sorry if i came off a little harsh. I wil try to explain the principle a little better when i get some time. By the way, I am en engineer working for a major aerospace company. :-)
I love forums, they're such a great place to have an open discussion, share information and knowledge with anyone and everyone!
Anyway, after reading a bit more about Bernoulli's principle regarding his compressible flow equation, I believe that my straw analogy still holds.
Can we get a real engineer to chime in and clear up some of my conjecture? I'm not a fan of spreading misinformation!
spdngdragon, help me out here:
Thus, wouldn't you need a higher flow rate (vehicle speed in this case) to offset the pressure differential of ducting with smaller area (2")?
Using the interactive flash animation on this site really helped a layman like me understand the compressible flow equation:
http://mitchellscience.com/bernoulli...iple_animation
I love forums, they're such a great place to have an open discussion, share information and knowledge with anyone and everyone!
Anyway, after reading a bit more about Bernoulli's principle regarding his compressible flow equation, I believe that my straw analogy still holds.
Can we get a real engineer to chime in and clear up some of my conjecture? I'm not a fan of spreading misinformation!
spdngdragon, help me out here:
- Flow rate is constant (due to the mass of air and speed of the car remaining unchanged between ducting)
- Area was originally n but is now y (where n is 2" and y is 3")
- Pressure drops in the ducting due to the increase in area (flow volume)
- Velocity remains the same since the ducting diameter is constant in both cases once past the inlet
Thus, wouldn't you need a higher flow rate (vehicle speed in this case) to offset the pressure differential of ducting with smaller area (2")?
Using the interactive flash animation on this site really helped a layman like me understand the compressible flow equation:
http://mitchellscience.com/bernoulli...iple_animation
#32
EvoM Community Team
iTrader: (134)
I had a friend over today that's also an engineer (car guy too) so we talked about it. He helped me understand the flaw in my logic.
Thanks for all of the input, everyone! You learn something new everyday!
Now to see how well that 3" ducting actually does cool.
#33
Evolved Member
iTrader: (1)
Or you could just use an inline fan on each duct and be assured of flow at any speed. size it to the CFM needed.
that also works well when the car comes off the track and you want to cool off the brake system without having to roll the car back and forth to reduce possibility of hot spotting the rotors. Just turn the fans on high
Also you need a split inlet box if you want to take air from the oil cooler side of the bumper. that way you wont steal air from the oil cooler. Make sure the side of the duct going to the cooler seals properly to the oil cooler so you get no spillage. front of the duct box has to go all the way to the bumper. split can be sized then in terms of area to get the correct flow to the brake and maintain the flow to the cooler.
oil / |
| | / fan /
| | / /
| |/ /
| || |
| || |
bumper
Sorry my art is getting squashed a bit but you see the point kind of like siamesed ducts
that also works well when the car comes off the track and you want to cool off the brake system without having to roll the car back and forth to reduce possibility of hot spotting the rotors. Just turn the fans on high
Also you need a split inlet box if you want to take air from the oil cooler side of the bumper. that way you wont steal air from the oil cooler. Make sure the side of the duct going to the cooler seals properly to the oil cooler so you get no spillage. front of the duct box has to go all the way to the bumper. split can be sized then in terms of area to get the correct flow to the brake and maintain the flow to the cooler.
oil / |
| | / fan /
| | / /
| |/ /
| || |
| || |
bumper
Sorry my art is getting squashed a bit but you see the point kind of like siamesed ducts
Last edited by WRC-LVR; Sep 25, 2011 at 03:16 AM.
#34
Newbie
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Hey OP, I didn't know you raced at lap battle as well. I have the orange evo that slammed into a wall last week :| What's your name?
Anyway, I'm dying for some ducting options. Do you know if quantam would have any options for BBK's? I have brembo GT front calipers and nobody makes a bolt on duct plate. Also interested in rear ducting. Thanks for the post, looking forward to more development on these!
Anyway, I'm dying for some ducting options. Do you know if quantam would have any options for BBK's? I have brembo GT front calipers and nobody makes a bolt on duct plate. Also interested in rear ducting. Thanks for the post, looking forward to more development on these!
#36
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I don't think that is something that would be a real world problem. I've never heard of over cooling brakes and unless you are using something that is much colder than ambient, I don't see that happening.
If your brakes are over cooled, you're not braking hard enough!
If your brakes are over cooled, you're not braking hard enough!
#38
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Sorry for the lack of updates. But I made a few changes to the setup and tested them at a time attack event over the weekend. First off, I decided running the stock dust shields was counterproductive and trimmed them to form only a support for the duct plates. I relocated the driver side ducting to provide more clearance because I ended up ripping the tubing off when I DD'd it one day last week... ****! haha. I still need to figure out the passenger side but it's more difficult due to the oil cooler and lines and it works good enough at this point so I'll finish the season in this configuration.
And pcskibum, whether you're running a BBK shouldn't matter. This mounts up to the hub on the opposite side of the caliper. Using trimmed stock dust shields isn't ideal but I haven't heard anything from Quantum on the production of the competition kit. If it comes down to it, I may end up making my own duct plate so I'm not running this ghetto trimmed stock piece.
For anyone who is wondering, I have no financial interest whatsoever in Quantum Motorsports. I'm simply trying to better the Evo motorsports community by experimenting with new designs and offerings. The Evo is essentially the only car that has accepted a 2" duct as the norm and I know many will be interested in either fabbing a 3" kit of their own or buying from Quantum if they end up offering a kit for sale.
Here's some pics of the new setup.
Someone was asking for a pic of the ducting after the first track day... this is the passenger side (has much more clearance than drivers) As mentioned, the drivers side was ripped off.
Didn't rub on the axles:
Trimmed dust shield:
Relocated ducting on driver's side:
Better pics of the inlets:
And pcskibum, whether you're running a BBK shouldn't matter. This mounts up to the hub on the opposite side of the caliper. Using trimmed stock dust shields isn't ideal but I haven't heard anything from Quantum on the production of the competition kit. If it comes down to it, I may end up making my own duct plate so I'm not running this ghetto trimmed stock piece.
For anyone who is wondering, I have no financial interest whatsoever in Quantum Motorsports. I'm simply trying to better the Evo motorsports community by experimenting with new designs and offerings. The Evo is essentially the only car that has accepted a 2" duct as the norm and I know many will be interested in either fabbing a 3" kit of their own or buying from Quantum if they end up offering a kit for sale.
Here's some pics of the new setup.
Someone was asking for a pic of the ducting after the first track day... this is the passenger side (has much more clearance than drivers) As mentioned, the drivers side was ripped off.
Didn't rub on the axles:
Trimmed dust shield:
Relocated ducting on driver's side:
Better pics of the inlets:
#40
Newbie
iTrader: (1)
Some funny comments about air flow and pressure drop in this tread. Snorkling comment hit the target... Hahah. But you are sort of right...
Anyways, one thing everyone forgets is that supply pressure does not change. This is pressure that your front of the car builds up with speed. Area of the car is lot bigger than 2 or 3 inch we are talking about so, pressure definetely will be close to constant. However flow at the same pressure thru bigger hose will be larger. Using r2x pi , 2x2 x pi vs 3x3xpi.... 4 vs 9 , so you get 2.25 times more cooling.
Anyways, one thing everyone forgets is that supply pressure does not change. This is pressure that your front of the car builds up with speed. Area of the car is lot bigger than 2 or 3 inch we are talking about so, pressure definetely will be close to constant. However flow at the same pressure thru bigger hose will be larger. Using r2x pi , 2x2 x pi vs 3x3xpi.... 4 vs 9 , so you get 2.25 times more cooling.
#44
Evolving Member
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I have quite a few picture of the way I did the routing in the link below, although my front ducts are a bit different as stealing air from the oil cooler duct has been proven to be a very bad idea on track and can spike your oil temps.
http://upshiftracing.com/engineering/
http://upshiftracing.com/engineering/