Radiator Hood Vent
#1
Senior Member
Thread Starter
Join Date: Oct 2011
Location: The Race Track & St Pete FL
Posts: 640
Total Cats: 59
![Thumbs up](https://www.miataturbo.net/images/icons/icon14.gif)
I have been looking at different designs for this on other cars on the web, but haven't seen much in the line of Miata's. If anyone else have seen good designs, please post them up. I want a open discussion and ideas on the subject.
So after doing some measurements this is what I came up with for the front half of the duct. I will be going turbo eventually, so this design will be changing down the road.
If you have specific build questions on the car and not on the subject, please don't post them on here. Go to my build https://www.miataturbo.net/build-thr...2/#post1088581
I cut the steel bumper, toe hooks and top radiator support to lean the radiator from a 7 deg angle to a 13 deg angle.
![](https://www.miataturbo.net/attachments/race-prep-75/98879-radiator-hood-vent-20131230_133415_zpsf61e9d18.jpg?dateline=1388896196)
After some test fitting
![](https://www.miataturbo.net/attachments/race-prep-75/98880-radiator-hood-vent-20140104_162918_zpsb19fd47f.jpg?dateline=1388896196)
![](https://www.miataturbo.net/attachments/race-prep-75/98881-radiator-hood-vent-20140104_163023_zpsca7cd3f7.jpg?dateline=1388896196)
![](https://www.miataturbo.net/attachments/race-prep-75/98882-radiator-hood-vent-20140104_163049_zpsb845da14.jpg?dateline=1388896196)
I'm not done mounting but you get what it looks like
![](https://www.miataturbo.net/attachments/race-prep-75/98883-radiator-hood-vent-20140104_164829_zps9a3cf7d3.jpg?dateline=1388896196)
![](https://www.miataturbo.net/attachments/race-prep-75/98884-radiator-hood-vent-20140104_165130_zps292f8d2a.jpg?dateline=1388896196)
More pics to come on part 2 I hope this help some other people with their race cars, I hope to see some more.
So after doing some measurements this is what I came up with for the front half of the duct. I will be going turbo eventually, so this design will be changing down the road.
If you have specific build questions on the car and not on the subject, please don't post them on here. Go to my build https://www.miataturbo.net/build-thr...2/#post1088581
I cut the steel bumper, toe hooks and top radiator support to lean the radiator from a 7 deg angle to a 13 deg angle.
![](https://www.miataturbo.net/attachments/race-prep-75/98879-radiator-hood-vent-20131230_133415_zpsf61e9d18.jpg?dateline=1388896196)
After some test fitting
![](https://www.miataturbo.net/attachments/race-prep-75/98880-radiator-hood-vent-20140104_162918_zpsb19fd47f.jpg?dateline=1388896196)
![](https://www.miataturbo.net/attachments/race-prep-75/98881-radiator-hood-vent-20140104_163023_zpsca7cd3f7.jpg?dateline=1388896196)
![](https://www.miataturbo.net/attachments/race-prep-75/98882-radiator-hood-vent-20140104_163049_zpsb845da14.jpg?dateline=1388896196)
I'm not done mounting but you get what it looks like
![](https://www.miataturbo.net/attachments/race-prep-75/98883-radiator-hood-vent-20140104_164829_zps9a3cf7d3.jpg?dateline=1388896196)
![](https://www.miataturbo.net/attachments/race-prep-75/98884-radiator-hood-vent-20140104_165130_zps292f8d2a.jpg?dateline=1388896196)
More pics to come on part 2 I hope this help some other people with their race cars, I hope to see some more.
Last edited by 1993ka24det; 01-04-2014 at 11:54 PM.
#5
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
This is the only picture I can find of my old hood. I just cut a rectangle the width of the radiator that stretched from the radiator to the valve cover, and then bolted a piece of 1/8" aluminum angle to the front edge to create a simple louver. It dropped IATs significantly and worked great on track, but I was still street driving the car at the time and it was terrible when it rained because the rain just dumped onto the alternator belt and it would slip like crazy at cruising RPMs. I should have just cut the front edge and the side edges and bent the cutout down into a nice radius, then riveted on some side panels. Whatever you do, just make sure the belts and any electrical connectors are covered.
![](https://www.miataturbo.net/attachments/race-prep-75/98891-radiator-hood-vent-945899_10100197395609917_1240742982_n.jpg?dateline=1388905997)
#8
Senior Member
Thread Starter
Join Date: Oct 2011
Location: The Race Track & St Pete FL
Posts: 640
Total Cats: 59
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Here are some designs that I had on my computer from my research with links
Viper
http://www.timeattackforums.com/foru...louvers-3.html
![](https://www.miataturbo.net/attachments/race-prep-75/98909-radiator-hood-vent-2013-02-01_06-48-51_262_zpsac2dec81.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98910-radiator-hood-vent-2013-04-08_22-20-00_961_zps80bc4dd3.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98911-radiator-hood-vent-2013-03-19_06-43-05_946_zps970bf585.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98912-radiator-hood-vent-2013-04-01_22-28-29_303_zpse0048d7c.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98913-radiator-hood-vent-2013-04-09_18-36-28_255_zps8b558c49.jpg?dateline=1388933640)
AMS Evo X Time Attack
http://www.timeattackforums.com/foru...x-build-3.html
![](https://www.miataturbo.net/attachments/race-prep-75/98914-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409006_zpsf4010c99.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98915-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409008_zps34954c9c.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98916-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409013_zps5ac0a51c.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98917-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409012_zps5bca97d3.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98918-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409010_zps0dcd313d.jpg?dateline=1388933640)
GTX Eclipse
![](http://i526.photobucket.com/albums/cc345/1993ka24detgt/img31431_zps31ce8302.jpg)
![Name: img31441_zps2099ad9b.jpg
Views: 6109
Size: 193.3 KB](https://www.miataturbo.net/attachments/race-prep-75/185008d1501209859-radiator-hood-vent-img31441_zps2099ad9b.jpg)
![Name: img314511_zps69da78e8.jpg
Views: 6093
Size: 147.9 KB](https://www.miataturbo.net/attachments/race-prep-75/185009d1501209859-radiator-hood-vent-img314511_zps69da78e8.jpg)
![Name: img31451_zpsf0ebf0bc.jpg
Views: 10439
Size: 147.9 KB](https://www.miataturbo.net/attachments/race-prep-75/185010d1501209859-radiator-hood-vent-img31451_zpsf0ebf0bc.jpg)
![Name: img31501_zps9d8c685e.jpg
Views: 6947
Size: 186.7 KB](https://www.miataturbo.net/attachments/race-prep-75/185011d1501209859-radiator-hood-vent-img31501_zps9d8c685e.jpg)
Viper
http://www.timeattackforums.com/foru...louvers-3.html
![](https://www.miataturbo.net/attachments/race-prep-75/98909-radiator-hood-vent-2013-02-01_06-48-51_262_zpsac2dec81.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98910-radiator-hood-vent-2013-04-08_22-20-00_961_zps80bc4dd3.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98911-radiator-hood-vent-2013-03-19_06-43-05_946_zps970bf585.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98912-radiator-hood-vent-2013-04-01_22-28-29_303_zpse0048d7c.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98913-radiator-hood-vent-2013-04-09_18-36-28_255_zps8b558c49.jpg?dateline=1388933640)
AMS Evo X Time Attack
http://www.timeattackforums.com/foru...x-build-3.html
![](https://www.miataturbo.net/attachments/race-prep-75/98914-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409006_zpsf4010c99.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98915-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409008_zps34954c9c.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98916-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409013_zps5ac0a51c.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98917-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409012_zps5bca97d3.jpg?dateline=1388933640)
![](https://www.miataturbo.net/attachments/race-prep-75/98918-radiator-hood-vent-amsperformance-timeattackevoxbuild-042409010_zps0dcd313d.jpg?dateline=1388933640)
GTX Eclipse
![](http://i526.photobucket.com/albums/cc345/1993ka24detgt/img31431_zps31ce8302.jpg)
![Name: img31441_zps2099ad9b.jpg
Views: 6109
Size: 193.3 KB](https://www.miataturbo.net/attachments/race-prep-75/185008d1501209859-radiator-hood-vent-img31441_zps2099ad9b.jpg)
![Name: img314511_zps69da78e8.jpg
Views: 6093
Size: 147.9 KB](https://www.miataturbo.net/attachments/race-prep-75/185009d1501209859-radiator-hood-vent-img314511_zps69da78e8.jpg)
![Name: img31451_zpsf0ebf0bc.jpg
Views: 10439
Size: 147.9 KB](https://www.miataturbo.net/attachments/race-prep-75/185010d1501209859-radiator-hood-vent-img31451_zpsf0ebf0bc.jpg)
![Name: img31501_zps9d8c685e.jpg
Views: 6947
Size: 186.7 KB](https://www.miataturbo.net/attachments/race-prep-75/185011d1501209859-radiator-hood-vent-img31501_zps9d8c685e.jpg)
![Name: img31582bd_zps97fbb9c1.jpg
Views: 6634
Size: 223.3 KB](https://www.miataturbo.net/attachments/race-prep-75/185012d1501209859-radiator-hood-vent-img31582bd_zps97fbb9c1.jpg)
Last edited by 1993ka24det; 01-07-2014 at 12:13 PM.
#12
Senior Member
Thread Starter
Join Date: Oct 2011
Location: The Race Track & St Pete FL
Posts: 640
Total Cats: 59
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
No, due to its in front of the front suspension. The stuff in front of the front suspension and in rear of the rear suspension doesn't have much to do with the stiffness of the chassis.
#16
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Yep, I somehow just noticed the last 2 pics in the first post and was about to say the same thing. Reducing the size of the radiator inlet is a big part of the drag reduction from an EP airdam. I just went out and measured my cutout- it's 4x18" with no mesh or ducting behind it, and my temp gauge stays pegged at 180 deg thermostat temp (I know, I need a 195... lack of research up front + begi spacer + lazy) while on track. The cutouts on the 949 cars appear to be around the same size or even smaller, plus they use different types of mesh to cut down airflow further based on track temp. With ducting, I wouldn't be surprised if 50 sq. in. or less were plenty.
Last edited by jpreston; 01-06-2014 at 12:40 AM.
#19
Senior Member
Thread Starter
Join Date: Oct 2011
Location: The Race Track & St Pete FL
Posts: 640
Total Cats: 59
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Yep, I somehow just noticed the last 2 pics in the first post and was about to say the same thing. Reducing the size of the radiator inlet is a big part of the drag reduction from an EP airdam. I just went out and measured my cutout- it's 4x18" with no mesh or ducting behind it, and my temp gauge stays pegged at 180 deg thermostat temp (I know, I need a 195... lack of research up front + begi spacer + lazy) while on track. The cutouts on the 949 cars appear to be around the same size or even smaller, plus they use different types of mesh to cut down airflow further based on track temp. With ducting, I wouldn't be surprised if 50 sq. in. or less were plenty.