Your thoughts on the enormous new hole in my bumper.
02-23-2009, 11:20 AM
#88
Newb
Join Date: Sep 2008
Location: Miami, FL
Posts: 22
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Wouldn't making more holes in the nose just add to the already poor CoEf of drag? I realize that for autoX that might not be a big deal, but on a track car, it might. (Increases with the square of speed
Looking at the nose of the C6R posted earlier made me think. That car puts out far more than stock horsepower. The air intake at the front is relatively small (stock size), but the hood has an agressive extractor. It is also a very high spped car where reducing drag is important. Balancing airflow in and then out of the radiator should be the goal. Increasing air in will not necessarily improve cooling unless the air can flow effectively out. Are there any wind tunnel or other airflow studies on the Miata front end? I would suspect that air flow out of the engine compartment is not particularily efficient given the undertray and the engine taking up a fair percentage of the space behind the radiator.
Looking at the nose of the C6R posted earlier made me think. That car puts out far more than stock horsepower. The air intake at the front is relatively small (stock size), but the hood has an agressive extractor. It is also a very high spped car where reducing drag is important. Balancing airflow in and then out of the radiator should be the goal. Increasing air in will not necessarily improve cooling unless the air can flow effectively out. Are there any wind tunnel or other airflow studies on the Miata front end? I would suspect that air flow out of the engine compartment is not particularily efficient given the undertray and the engine taking up a fair percentage of the space behind the radiator.
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02-23-2009, 11:25 AM
#89
For example, if you put a huge single electric fan on the radiator, similar to what m2cupcar runs, you're car would never ever ever ever ever overheat. Period.
Or if you shroud things as to duct the first few inches worth of the IC's heat away and from the other exchangers and shroud things properly, the front opening will be plenty big enough. Dr. Turbo I believe posted some good shrouding a while back.
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02-23-2009, 12:06 PM
#91
Tour de Franzia
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Location: Republic of Dallas
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I think a lot of people don't know how to improve the cooling system's ability to dump heat either.
For example, if you put a huge single electric fan on the radiator, similar to what m2cupcar runs, you're car would never ever ever ever ever overheat. Period.
Or if you shroud things as to duct the first few inches worth of the IC's heat away and from the other exchangers and shroud things properly, the front opening will be plenty big enough. Dr. Turbo I believe posted some good shrouding a while back.
For example, if you put a huge single electric fan on the radiator, similar to what m2cupcar runs, you're car would never ever ever ever ever overheat. Period.
Or if you shroud things as to duct the first few inches worth of the IC's heat away and from the other exchangers and shroud things properly, the front opening will be plenty big enough. Dr. Turbo I believe posted some good shrouding a while back.
I'm going to try making a little cup into my shrouding for the first 1/4 of the fmic...maybe this **** will work.
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02-23-2009, 12:34 PM
#94
I don't think a fan can move enough air to cool an engine at speed. The hood bulges from pressure at high-speeds...which tells me that we should focus on getting the air out, rather than adding fans.
I'm going to try making a little cup into my shrouding for the first 1/4 of the fmic...maybe this **** will work.
I'm going to try making a little cup into my shrouding for the first 1/4 of the fmic...maybe this **** will work.
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02-23-2009, 12:57 PM
#95
Are the fans wired to always be on? Electric water pump? The fluid isn't moving in this situation even though the fans are blasting 1million cfm through the radiator. The fluid in the radiator can be ice cold but the fluid in the motor will be satans asscrack hot.
On an old track car I had, I used this same method. Giant shrouded pusher and puller fans on a koyo to cool the water, with no oil cooler. In this situation where the motor stalled on track you could hear the fluid boiling untill the motor was started again. Granted this has nothing to do with giant holes in your nose, but more about the problems with relying only on a giant fan.
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02-23-2009, 01:21 PM
#96
Are the fans wired to always be on? Electric water pump? The fluid isn't moving in this situation even though the fans are blasting 1million cfm through the radiator. The fluid in the radiator can be ice cold but the fluid in the motor will be satans asscrack hot.
On an old track car I had, I used this same method. Giant shrouded pusher and puller fans on a koyo to cool the water, with no oil cooler. In this situation where the motor stalled on track you could hear the fluid boiling untill the motor was started again. Granted this has nothing to do with giant holes in your nose, but more about the problems with relying only on a giant fan.
On an old track car I had, I used this same method. Giant shrouded pusher and puller fans on a koyo to cool the water, with no oil cooler. In this situation where the motor stalled on track you could hear the fluid boiling untill the motor was started again. Granted this has nothing to do with giant holes in your nose, but more about the problems with relying only on a giant fan.
ASSUMING he's driving the car on a track and racing and the engine is running while doing so, producing power, and needing to reject heat, I would suggest a large electric fan would supply adequate airflow through the radiator as to maintain a high rate of heat rejection to keep coolant temperatures in a safe operating range. As a benefit, when he slows down or turns or gets in traffic, airflow through the radiator will remain much more constant allowing the cooling system to catch up vs. falling behind.
But really I'd address other things like shrouding and extraction before looking for more frontal area. IMO, more frontal are isn't the problem.
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02-23-2009, 01:34 PM
#97
Exactly. Has nothing to do with this discussion.
ASSUMING he's driving the car on a track and racing and the engine is running while doing so, producing power, and needing to reject heat, I would suggest a large electric fan would supply adequate airflow through the radiator as to maintain a high rate of heat rejection to keep coolant temperatures in a safe operating range. As a benefit, when he slows down or turns or gets in traffic, airflow through the radiator will remain much more constant allowing the cooling system to catch up vs. falling behind.
But really I'd address other things like shrouding and extraction before looking for more frontal area. IMO, more frontal are isn't the problem.
ASSUMING he's driving the car on a track and racing and the engine is running while doing so, producing power, and needing to reject heat, I would suggest a large electric fan would supply adequate airflow through the radiator as to maintain a high rate of heat rejection to keep coolant temperatures in a safe operating range. As a benefit, when he slows down or turns or gets in traffic, airflow through the radiator will remain much more constant allowing the cooling system to catch up vs. falling behind.
But really I'd address other things like shrouding and extraction before looking for more frontal area. IMO, more frontal are isn't the problem.
It's relevant in that the gaping holes could be used to provide airflow to an oilcooler. If you have a big fan, a standard mouth mounted intercooler, and a big radiator your space for mounting an oilcooler is reduced.
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02-23-2009, 03:07 PM
#100
street car. If your car was a race car you could chop up the front and tube it out, add a V-mount, some serious fender and hood extraction, and then you would only need a small fan for idling and cool down.
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