How much do vented hoods reduce temps?
09-21-04, 11:38 PM
#51
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IIRC, amemiya have a caution note about clearance and the AD bonnet - might have been about using the bonnet with a strut brace and the rain guard (memory is very foggy, and it was in japanese - I'd have to go look up the website).
An interesting point for those using v-mounts - (according to interviews I've read) both knight sports and HKS highly recommend the use of a vented bonnet with their v-mount systems (and hks don't even sell their own FD vented hood - so it probably isn't a case of trying to make an extra buck)
An interesting point for those using v-mounts - (according to interviews I've read) both knight sports and HKS highly recommend the use of a vented bonnet with their v-mount systems (and hks don't even sell their own FD vented hood - so it probably isn't a case of trying to make an extra buck)
09-22-04, 01:33 AM
#53
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Originally Posted by generalchaos
arent you guys afraid of water getting into those vents one way or another?
12-08-04, 10:27 AM
#57
Mr. Goodwrench
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I ordered the N1 hood from RE for:
Cooling
Looks
Weight reduction
Although CF is strong I think it would not be beneficial in case of a crash since aluminum and sheetmetal crumples and absorbs force while CF shatters. I pop my hood and turn on my A/C every chance I get. After I stop I open the hood and run the A/C for 3 minutes, then kill the engine and run the A/C for 5 minutes, then stop everything and leave my hood open for 15 minutes (keeping an eye on the car). I do this EVERY time even if I am late. This is why I need a vented hood. As far as washing the engine it's nice for looks and a clean engine also runs cooler but I am scared to wet the filters and electronics. I just wipe and scrub the engine here and there occasionally. I amagine misting the engine would reduce temps rapidly since evaporation takes a massive amount of heat exchange. I pop my hood when in line for the car wash and I can see the needle drop a bit from the overspray.
Cooling
Looks
Weight reduction
Although CF is strong I think it would not be beneficial in case of a crash since aluminum and sheetmetal crumples and absorbs force while CF shatters. I pop my hood and turn on my A/C every chance I get. After I stop I open the hood and run the A/C for 3 minutes, then kill the engine and run the A/C for 5 minutes, then stop everything and leave my hood open for 15 minutes (keeping an eye on the car). I do this EVERY time even if I am late. This is why I need a vented hood. As far as washing the engine it's nice for looks and a clean engine also runs cooler but I am scared to wet the filters and electronics. I just wipe and scrub the engine here and there occasionally. I amagine misting the engine would reduce temps rapidly since evaporation takes a massive amount of heat exchange. I pop my hood when in line for the car wash and I can see the needle drop a bit from the overspray.
12-09-04, 12:05 AM
#59
Originally Posted by BATMAN
Please state:
the make/model of the hood
the make/model of the hood
After my rebuild I drove around for afternoon without the hood on.
I figure that's the max vent you can archive
Originally Posted by BATMAN
Please state:
how much of a temp drop (if any)
how much of a temp drop (if any)
I figure the radiator & thermostat were doing their job.
I did notice the temps rise above 95 C with the hood off. It was sitting in the driveway at idle, but the fans kicked on & the temps went back down to 82-83 C
12-09-04, 03:50 AM
#60
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Originally Posted by Sled Driver
No hood at all...........
After my rebuild I drove around for afternoon without the hood on.
I figure that's the max vent you can archive
NONE.....Car ran at 81 C with hood on & off.
I figure the radiator & thermostat were doing their job.
I did notice the temps rise above 95 C with the hood off. It was sitting in the driveway at idle, but the fans kicked on & the temps went back down to 82-83 C
After my rebuild I drove around for afternoon without the hood on.
I figure that's the max vent you can archive
NONE.....Car ran at 81 C with hood on & off.
I figure the radiator & thermostat were doing their job.
I did notice the temps rise above 95 C with the hood off. It was sitting in the driveway at idle, but the fans kicked on & the temps went back down to 82-83 C
Maybe this is why-
Originally Posted by turbojeff
That might actually increase temps by discouraging air from passing through the radiator. Not sure but... No hood does not equal vented hood.
12-10-04, 03:18 AM
#62
Actually I didn't dive around at all with my hood off.
I was trying to make a point.
A vented hood will not make your engine run any cooler or make any more hp.
Your radiator & thermostat dictate your engine temps. Your fans create the necessary airflow when at a standstill
A vented hood will not make your intake temps cooler. Your intercooler size & location, along with airflow through it, will.
A vented hood will not make your engine wire harness last any longer & prevent it from becoming brittle over time.
Since the harness is routed less than 1/2" above the combustion chamber. The peak temp is the same, only the duration of time it's hot will change (slightly)
Much like the fixation on the "true" weight of your car & how taking 50 lbs off is going to make a huge difference.
Don't kid yourself............... your not that good.
I autocross solo & with a passengers. My times improve with the # of runs, not due to lack of weight. I've posted my fastest times with a passenger.
Drag racing is the same. You think you can be so consistent that you can record the difference with 2 % less weight?
Granted, take 500 lbs off (20%) & now you got something.
Buy the hood for looks....
If it makes you feel better that you can see the heat haze from your engine compartment at stop lights, so be it.
I was trying to make a point.
A vented hood will not make your engine run any cooler or make any more hp.
Your radiator & thermostat dictate your engine temps. Your fans create the necessary airflow when at a standstill
A vented hood will not make your intake temps cooler. Your intercooler size & location, along with airflow through it, will.
A vented hood will not make your engine wire harness last any longer & prevent it from becoming brittle over time.
Since the harness is routed less than 1/2" above the combustion chamber. The peak temp is the same, only the duration of time it's hot will change (slightly)
Much like the fixation on the "true" weight of your car & how taking 50 lbs off is going to make a huge difference.
Don't kid yourself............... your not that good.
I autocross solo & with a passengers. My times improve with the # of runs, not due to lack of weight. I've posted my fastest times with a passenger.
Drag racing is the same. You think you can be so consistent that you can record the difference with 2 % less weight?
Granted, take 500 lbs off (20%) & now you got something.
Buy the hood for looks....
If it makes you feel better that you can see the heat haze from your engine compartment at stop lights, so be it.
12-10-04, 02:04 PM
#63
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No, a vented hood will not gain HP or cool your charged air but it will allow those components to work more efficiently. Certain hood designs will reduce heat soak too which will again, improve efficiency which has an indirect performance benefit. Why do you think the original Mazda FD design over heated so much, bad air flow through the radiator and a bigger one isn't the only way to fix it. Air flow air flow air flow! Vented hood just makes it better.
12-10-04, 03:34 PM
#65
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Originally Posted by Rhode_Dog
I still cast my vote for a Jun Hood, if you can find one for sale is a differn't story.
I have that hood. I paid about $1200 for it, and it took about 6 month to order.
12-10-04, 03:40 PM
#66
Originally Posted by luizajeff
No, a vented hood will not gain HP or cool your charged air but it will allow those components to work more efficiently. Certain hood designs will reduce heat soak too which will again, improve efficiency which has an indirect performance benefit. Why do you think the original Mazda FD design over heated so much, bad air flow through the radiator and a bigger one isn't the only way to fix it. Air flow air flow air flow! Vented hood just makes it better.
So those big gaps around the motor in the engine compartment (open to the bottom of the car) don't flow air?
The 99 bumper has a larger opening for the radiator to allow more air to pass through. After the air goes through the radiator core it's exhausted through the engine compartment (out the bottom).
The original design overheated due to people increasing the hp by 40-50 %. Plus the air separator tank & radiator endtanks are plastic & prone to failure over time.
The components in the engine compartment are designed to survive in temps that are uncomfortable to humans. You are stating emotion not documented facts.
Much like the Honda boys drilling big holes in their back bumpers to free up all that trapped air slowing them down.
12-10-04, 09:20 PM
#67
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I recieved and installed my CF N1 hood. It looks stunning, is extremely light, and my BOV can be heard super loud now (+5 bonus ricer points). I do not see a drop in the temperature gauge but I can see heat escaping the vents. I am working on the fitting to get it perfect, although just throwing it on allowed it to close fine and look decent. I have to get pins since it shakes from being so feather light. Overall I am satisfied and happy with it. It makes 350Zs tuck in their non existent tails around here and they better too. Hood was a great upgrade.
I also like the Mazdaspeed and the KS.
I also like the Mazdaspeed and the KS.
12-10-04, 10:58 PM
#70
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Originally Posted by Sled Driver
How's about every production car ever made.
See any with a vented hood added due to "extreem" underhood temps?
See any with a vented hood added due to "extreem" underhood temps?
12-11-04, 12:09 AM
#74
Evo has a vent for the intercooler, not the engine
Viper vent is for the intake, not the engine
What no air cooled Beetle pics or Porsche 911's? That actually did reduce underhood temps
Look, bottom line, review all the posts from people with vented hoods.
Notice a trend? "Looks good" is the main response. Hey, no problem with that, I agree, they do look good.
Now lets go back to the original post.
Type of hood & reduce temp if any.
Answer?
Doesn't matter
None.
Dyno your car at 81 C & then repeat @ 95 C engine temps.
The major factor is intake air temp, not engine temp.
The reason some tuners offer a 170 ' thermostat is to "fool" the computer to run richer (this was popular in the 80's). Now we have PFC's to do that.
All the components under the hood are designed to operate in a hot environment.
Viper vent is for the intake, not the engine
What no air cooled Beetle pics or Porsche 911's? That actually did reduce underhood temps
Look, bottom line, review all the posts from people with vented hoods.
Notice a trend? "Looks good" is the main response. Hey, no problem with that, I agree, they do look good.
Now lets go back to the original post.
Type of hood & reduce temp if any.
Answer?
Doesn't matter
None.
Dyno your car at 81 C & then repeat @ 95 C engine temps.
The major factor is intake air temp, not engine temp.
The reason some tuners offer a 170 ' thermostat is to "fool" the computer to run richer (this was popular in the 80's). Now we have PFC's to do that.
All the components under the hood are designed to operate in a hot environment.
12-11-04, 06:09 AM
#75
Originally Posted by Sled Driver
Evo has a vent for the intercooler, not the engine
Originally Posted by Sled Driver
Viper vent is for the intake, not the engine
If you want to put old VW's and Porsches in there you could also add:
Honda NSX
Toyota MR2 and MRS
Ferrari's
Fiero
Some Jaguar's
Lamborghini's
Lotus Elise
Lotus Esprit
Shelby Series 1
and that's just a few more off of the top of my head.