Under hood heat is a big deal with these cars and I have been looking for a suitable solution and found these heat extractors on Verus Engineering website..
They are for a Honda Civic SI hood but look like they will work on the FD.
I do not care for any of the replacement vented hoods that I have see so far and I am thinking that these extractors will not only work well but may suit the lines of the car very well.
Taking the car to Sebring tomorrow so will be staring this project next week, will take pics of the process and will take temp readings of the hood under different circumstances before and after,
Dave

 

temp readings will be interesting, we did these on the Miata race car, and they didn't do anything (although on the one rainy weekend it did scoop the mud up and put it in the drivers lap, which is pretty funny)

 

——> https://www.rx7club.com/3rd-generati...-fixes-448589/

@Howard Coleman CPR Were you ever able to get follow up data?

 

I am starting this project Sunday afternoon (2/21) so will be getting back with data later this week.

 

I am interested in the results.

 

IMO, placement will be critical in their effectiveness. Too far forward, and they may not extract the hottest air. Too far rearward, and they may not work because of the higher air pressure caused by the windshield slope.

I will also be interested in the results.

 

i still run the louvers i had made for my hood. i did testing on them and found the biggest effect was at shutdown when my engine compartment used to bake. temps rose to 200 F and took over 30 minutes to normalise. temps hardly rose on shutdown w the louvers. i noticed little underhood temp change while driving the car and had temp probes in a couple of places.

since i swapped in a 153 F thermostat and and a FullFunctionEngineering water pump idler my coolant has dropped from 87 c to 67 c and opening my hood after a drive is a non event rather than opening the door to a blast furnace.

i suggest the thermostat and idler pulley and skip the louvers/vents

 

[QUOTE=Howard Coleman CPR;12456690]i still run the louvers i had made for my hood. i did testing on them and found the biggest effect was at shutdown when my engine compartment used to bake. temps rose to 200 F and took over 30 minutes to normalise. temps hardly rose on shutdown w the louvers. i noticed little underhood temp change while driving the car and had temp probes in a couple of places.

since i swapped in a 153 F thermostat and and a FullFunctionEngineering water pump idler my coolant has dropped from 87 c to 67 c and opening my hood after a drive is a non event rather than opening the door to a blast furnace.

Howard are you running your car that low? I swapped my oem thermostat back in because my car was running too cold with the mishimoto.

 

Just make sure your cooling system is running right, no need to cut up your OEM hood on your rare original R1.

 

I was thinking the same but, with all the heat generated I don't see how any form of vents can't help reduce strain on the cooling system. I would not sweat if oem was easily available. I wish someone did actual testing before with different hoods. I did some intake experiments. Just blocking the heat from the turbos in a half *** manner resulted in 10°f difference in air around the intake. A hood has to make a bigger difference than what most think.
Maybe like HC said it is more of an after shutdown thing, but even that is a nice benefit.

 

Ceramic coated downpipe also makes a massive difference in underwood temps.

Hell, just getting rid of the precat is half the battle .

Dale

 

....or even just header wrap and spray sealant.
Air movement under the hood also seemed to improve a bit when I removed emissions and things like the air pump and split-air by-pass tubing.

 

Same experience here with my vented hood. I think relatively high pressure on top of hood keeps much from venting while driving, but on shutdown/parking it made a huge difference. Before the vented hood it would take half the day to cool down, after vented hood it was just a couple hours to completely cool. In my opinion this is a worthwhile modification, just not for the reason most might think. Engine parts baking for many hours after you park doesn't help their longevity.

 

Placement near the outside edges of the hood, would, IMO, be the most efficient in extracting air while moving since the edges of the hood are in the lowest pressure areas available on top of the hood.

 

Wouldn’t ‘how’ the opening is shaped make a difference? I’m just thinking of the Mazdaspeed design. In addition to placement toward the front just aft of a SMIC, it also had the leading edge that (presumably) created low pressure at the opening...as opposed to how the OP intends to vent it.

 

IMO, it certainly would. That would, as you said, create a low pressure area behind the spoiler significantly aiding extraction.

 

Well they are on the car and I appreciate everybody's comments.
My car was not over heating, my primary interest in this was heat soak after shut down.
I managed to get them installed with a minimum of butchery and once I get a new sound blanket it will look pretty good.
These extractors were for a Honda and i was not sure how they would look but I am very happy happy with the result, they conform to the contours of the hood and did not require the removal of too much of the structural steel parts under the skin.
I am going to add some more of the bonding adhesive that attaches the skin to the frame tomorrow and after I get it cleaned up will do some more testing.
Unfortunately right now the outside temp is only about 80 degrees and in my initial testing the hood was only about 120 and 10 minutes after shutdown was down to 105, not what I expected.
I do plan on getting the down pipe coated and will add some shielding to the turbos at that time.
Next project is pillow *****.
Dave

This was my placement for the extractors

Paper patterns can move! After cutting the big opening set the extractor on the pattern and check the bolt hole alignment

Some trimming required inside

These vents are very well made.


I have not seen a replacement hood that did it for me, I like how this turned out and I think they will do exactly what I want.

 

I would be sure to seal all exposed metal edges. It’s aluminum so you don’t have to worry about rust, but you don’t want moisture infiltrating over time under paint.

 

That turned out looking ok.
fwiw, Race Louvers have done some rather interesting wind tunnel testing with their louvers. They have some good blog posts and video on youtube.
https://racelouvers.com/

 

I think it looks badass.... I still wouldn't do it, but I like it.

 

I did paint all of the edges and holes.

 

Nice job. Looks good. But im going to wager they will blow air in off the windscreen high pressure zone at speed.
i hope im wrong

 

Looks to me like he has them close enough to the sides of the hood that having more pressure at that position on top of the hood than in the engine compartment won't be the case.

Increased air pressure at speed due to the windshield angle is greatest in the center. Air-flow around the windshield reduces that pressure and so at some lateral distance from the center, pressure above the hood becomes lower than it is in the engine compartment. But air extraction at speed is not a given, so an air-flow study needs to be done to see if the vents function at speed.

 

I drove the car today and made some further tests. The extractors are pretty far forward of the windshield , don't think that inversion will be a factor. Have to wait for the rainy season to see what happens there. But I did measure the air temps and the airflow thru the extractors while it was idling with the AC on and the 2 Spal fans running.
A piece of paper over the extractors is blown upwards by outgoing air. The temp of the hood around the drivers side was about 120 with air temp coming out of the extractor about 140. Passenger side a little hotter because of the turbos, about 130 on the metal, air temp out is 140-165.
So far they seem to be working as planned with no apparent downside and they look pretty damn cool as well.
Dave

 

looks great! do a wool tuft test and see how the airflow moves at different speeds