Where should these hood vents go?

[BruceH]

I'm thinking of adding some vents to pull heat out of the engine bay. I have a set of used GT500 vents but I'm not real sure where they would go.

I'd think they would need to be toward the rear in order to work. I'm certainly not set on using them. If I did there would probably be a functional hood scoop going on too.

 

[skwerl]

You need to consider not only where they will draw the most heat/air, but also where they will cause the least amount of hassle when water drips through them. I think that's why the new GT hood vents are located where they are. Water drips between the heads and strut towers. On the GT500 the water drips in front of the engine.

 

[claudermilk]

I think that's why the new GT hood vents are located where they are. Water drips between the heads and strut towers.

Nope. The water is routed to drip directly on top of the stock airbox and fuse box. You would have thought that Ford would route the water to drop through a harmless open space, but no.

 

[AlbertD]

At every stop light I can see a ton of heat coming out of mine at the factory location.

 

[ford20]

I know that with the Tiger Racing Hood people aren't really seeing too much difficulty with water dripping onto the engine. I would go with the stock location for the GT500 but that is just me. I would figure out where the end the of the fan shroud is and tape a line form there. At least you know than that anything closer to the edge of the hood would be useless. Too far back and you begin to reduce the effectiveness of them as the air stacks up against the windshield.

IDK if you would be able to find an aerodynamic testing of the FR500S or the FR500C or even the regular GT's so you would be able to see how the airflows over the car to really tell where to place them.

Thinking about it, looking at the Tiger racing hood for the 05-09 would tell you where the best are to place them probably is because it would show you how far not to go back and how far forward you can go.

 

[mavisky]

You want them where they'll evacuate the most air. It shouldn't be a surprise that the area occupied by the belts between the radiator fan and the engine block is one of the warmer areas outside of the actual headers. It's also an area where the incoming air into the engine bay suddenly meets a solid obstruction and is looking for a way out. It can either route around the engine to the sides and down, go under the engine, or in the case of every properly vented hood out there, up and out of the engine bay through the vent above it. This not only reduces temps, but also reduces underhood pressure and drag which can lead to aerodynamic lift at speed.

When I cut the hood for my GT500 vent in my SN95 I placed it as close to this location as possible.

 

[stkjock]

Bruce - the stock GT500 location???


I know you're a big believer in Ford's engineers, they must have had reason for placing them where they are. I know I see heat rise from mine

 

[lito]

The thing is that they wont be as effective as designed in the original hoods, you wont have the forward hump that generate the low pressure area to suck air from the inside, while moving, they can actually make the inverse effect in the way they would end being angled.

 

[stkjock]

ahh, good point, I forgot that the GT500 hood has that raise area.

 

[mavisky]

The thing is that they wont be as effective as designed in the original hoods, you wont have the forward hump that generate the low pressure area to suck air from the inside, while moving, they can actually make the inverse effect in the way they would end being angled.

This is absolutely true, and it really surprised me to see that Ford did away with it in the 2010+ cars. Perhaps (and I haven't done the measurements) there's enough pressure inside the engine compartment to overcome the high pressure on the hood surface and they've deemed that to be "good enough".

 

[skwerl]

This is absolutely true, and it really surprised me to see that Ford did away with it in the 2010+ cars. Perhaps (and I haven't done the measurements) there's enough pressure inside the engine compartment to overcome the high pressure on the hood surface and they've deemed that to be "good enough".

My '14 has about twice the open grill area of my '09 Bullitt. There is a crap ton of air flow through the grill compared to my last car.

 

[bobbaloo]

I used these locations and they seem to work real well with the m90 2.49 pulley and 12% od pulley , it was making a lot of underhood heat , these seemed to help alot , since these pics were taken the a/c has been deleted and I have had no issues with heat or with hood baffling . After you cut the holes in your hood you can reinforce the hood sub-structure with 1/8" perforated metal and pop rivets , this will give you the option to make your vents removable , pop on home made trim rings to retain the hood insulation , or hang drip trays if you desire . I've never had the need for drip trays as I believe dynamic tension prevents rain water from dripping in . with the engine running and the car in motion its a non issue as it expels any surface water once you get to speed .

 

[lito]

This is absolutely true, and it really surprised me to see that Ford did away with it in the 2010+ cars. Perhaps (and I haven't done the measurements) there's enough pressure inside the engine compartment to overcome the high pressure on the hood surface and they've deemed that to be "good enough".

The vent design is completely different, the hood is "flat" but the vent is not so a low pressure area will be generated at speed (plus the possible discussed underhood pressure). The 07-09 vents are "flat" so they required a previous hump for that.

No aerodynamicist so take all these with a huge chunk of salt, lol. But from the basic side of how it works, looks to be that way and consistent with what Ford did in both cases.

13+ look to be different functionality oriented, more underhood heat than the GT500s were they look more radiator/HE flow improvement oriented.

With the ones that Bruce has, I would personally save all the hassle and skip it, doesnt matter if you get to see heat when stopped, they should actually work once you are on the move and then, I am not so sure they will. But again, what do I know.

 

[BruceH]

The vent design is completely different, the hood is "flat" but the vent is not so a low pressure area will be generated at speed (plus the possible discussed underhood pressure). The 07-09 vents are "flat" so they required a previous hump for that.

No aerodynamicist so take all these with a huge chunk of salt, lol. But from the basic side of how it works, looks to be that way and consistent with what Ford did in both cases.

13+ look to be different functionality oriented, more underhood heat than the GT500s were they look more radiator/HE flow improvement oriented.

With the ones that Bruce has, I would personally save all the hassle and skip it, doesnt matter if you get to see heat when stopped, they should actually work once you are on the move and then, I am not so sure they will. But again, what do I know.

I'm sitting on the fence about cutting my hood. Just looking for some little things to help. Now that I think about it as long as I run e85 it doesn't matter. It's cool enough around here for 9 months out of the year that it won't matter with gas during that time either.

 

[Razorbed]

Bruce, what about the MMD 2013+ Style hood vents?
They mount where the Saleen have theirs so it should work...

 

[mavisky]

I'm sitting on the fence about cutting my hood. Just looking for some little things to help. Now that I think about it as long as I run e85 it doesn't matter. It's cool enough around here for 9 months out of the year that it won't matter with gas during that time either.

I'll tell you that it was one of the scariest mods I've ever done to a car, right up there with cutting fender and mounting flares on my old autocross car.

 

[BruceH]

That is a thought. I'm not committed to using the vents I have. I do think that vents will help and if done right they won't look bad.

I used these locations and they seem to work real well with the m90 2.49 pulley and 12% od pulley , it was making a lot of underhood heat , these seemed to help alot , since these pics were taken the a/c has been deleted and I have had no issues with heat or with hood baffling . After you cut the holes in your hood you can reinforce the hood sub-structure with 1/8" perforated metal and pop rivets , this will give you the option to make your vents removable , pop on home made trim rings to retain the hood insulation , or hang drip trays if you desire . I've never had the need for drip trays as I believe dynamic tension prevents rain water from dripping in . with the engine running and the car in motion its a non issue as it expels any surface water once you get to speed .

Bruce, what about the MMD 2013+ Style hood vents?
They mount where the Saleen have theirs so it should work...