Cooling Upgrade - Modify Hood?

[JDMac34]

I have an idea to improve my car's cooling, but I wanted to get some expert opinions before I get to cutting. I haven't had any serious problems with cooling. The only time that it got hot was after 5 or 6 hot laps at Pitt Race (a lot of acceleration opportunities) when it was 87°F out, which I feel is reasonable. Right about the time that my oil temp gauge showed 270° was when I noticed the coolant (cylinder head) temp gauge on my dash moved higher than it usually stays. I stopped when I saw oil temps of 280° and the dash showed the needle a little over 3/4 of the way over (still short of the red). Temps got back to normal after a cool-down lap, and I understand that this is a street car that is being treated like a track car, but I'm wondering if anybody here has any suggestions for easy cooling improvements.

For context:

• Cervini Ram Air (Type 4) hood
• Boss 302 grille w/o fog lights
• Setrab 934 oil cooler w/ -12 lines
• Stock radiator
• 5w-30 Mobil1 synthetic oil <-- I'm likely going to run 5W-50 next track day
• Shifting at 7,000-7,200 RPM

I love the look of the Cervini hood, but I am concerned that it might not be helping with cooling. My main concern is that air is coming in the front holes and that the holes in the back (under the vents) aren't large enough to let enough air escape, causing a very high-pressure zone in the engine bay and reducing the airflow through the grille and into my oil cooler and radiator. Additionally, the previous owner didn't buy a new upper radiator cover when he rebuilt the car. I'm concerned that this could be another chance for air to go up and bypass the heat exchangers.

Question 1: Would getting an upper radiator cover help, or are those just cosmetic?
I've been looking on Facebook Marketplace and junkyards for that part, but might have to bite the bullet and buy a new one.

Question 2: Would opening up the vents in the rear help?
The picture below shows the small hole that I was talking about. I marked my proposed cut lines in red. This cut would allow for the full surface area of the vents to be used for airflow, not just the tiny slot.

Question 3: Should I just look for a stock hood and put Tracspec or Race Louvers vents in it?
I'm not sure if I'd have any clearance issues with the Cobra Jet intake manifold. I'm also not sure how much I trust the Cervinis hood latch strength, which this would help with.

 

[SMGDHG]

I have an idea to improve my car's cooling, but I wanted to get some expert opinions before I get to cutting. I haven't had any serious problems with cooling. The only time that it got hot was after 5 or 6 hot laps at Pitt Race (a lot of acceleration opportunities) when it was 87°F out, which I feel is reasonable. Right about the time that my oil temp gauge showed 270° was when I noticed the coolant (cylinder head) temp gauge on my dash moved higher than it usually stays. I stopped when I saw oil temps of 280° and the dash showed the needle a little over 3/4 of the way over (still short of the red). Temps got back to normal after a cool-down lap, and I understand that this is a street car that is being treated like a track car, but I'm wondering if anybody here has any suggestions for easy cooling improvements.

For context:

• Cervini Ram Air (Type 4) hood
• Boss 302 grille w/o fog lights
• Setrab 934 oil cooler w/ -12 lines
• Stock radiator
• 5w-30 Mobil1 synthetic oil <-- I'm likely going to run 5W-50 next track day
• Shifting at 7,000-7,200 RPM

I love the look of the Cervini hood, but I am concerned that it might not be helping with cooling. My main concern is that air is coming in the front holes and that the holes in the back (under the vents) aren't large enough to let enough air escape, causing a very high-pressure zone in the engine bay and reducing the airflow through the grille and into my oil cooler and radiator. Additionally, the previous owner didn't buy a new upper radiator cover when he rebuilt the car. I'm concerned that this could be another chance for air to go up and bypass the heat exchangers.

Question 1: Would getting an upper radiator cover help, or are those just cosmetic?
I've been looking on Facebook Marketplace and junkyards for that part, but might have to bite the bullet and buy a new one.

The upper radiator cover is NOT just cosmetic. The upper radiator cover helps seal the area around the coolers (radiator, ac condenser, oil cooler if installed, etc.). The air will flow in the path of least resistance; a row of stacked coolers (ac condenser, radiator, etc.) along with any obstructions downstream of those coolers represent a large amount of restriction.

If you would like to test this yourself, put your bumper back on and place a piece of paper where the radiator cover would usually go. Then, take a leaf blower, put it ~5 inches away from your oil cooler and pull the trigger. I can nearly guarantee the piece of paper you placed in the typical radiator cover location will fly up. For my car it did.

Question 2: Would opening up the vents in the rear help?
The picture below shows the small hole that I was talking about. I marked my proposed cut lines in red. This cut would allow for the full surface area of the vents to be used for airflow, not just the tiny slot.

Your cervini hood is acting as a parachute. It is doing 3 bad things:

1.) Creating drag
2.) creating lift as a result of the drag (ps do you have hood flutter?)
3.) It is feeding air into the engine bay, thereby increasing the pressure of air in the engine bay. Increased air pressure within the engine bay leads to a decrease of airflow through your radiators. Again, going back to path of least resistance. Your cervini hood is doing the exact opposite of what hood vents do. Therefore, I cannot recommend enlarging the holes as I feel this would have a negative effect on your cooling.

Question 3: Should I just look for a stock hood and put Tracspec or Race Louvers vents in it?
I'm not sure if I'd have any clearance issues with the Cobra Jet intake manifold. I'm also not sure how much I trust the Cervinis hood latch strength, which this would help with.

If you are serious about tracking the car, I would recommend selling the cervini hood. My recommendation is race louvers. They do more wind tunnel testing than anyone, and the owner, Al, is a fantastic resource. He would be a great person to reach out to if you'd like a 2nd opinion on the comments I made above.

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Some general questions I have for you:

1.) Where are you measuring your oil temps?
2.) Where are you measuring your coolant temps?

Bang for your buck, cost wise and time wise, I would perhaps consider ducting your radiators + coolers as opposed to buying a new hood, painting said hood and then adding the race louvers. This would be a good question for Al - ask him which he thinks would be more beneficial. Ducting your coolers would likely be the same amount of work (time wise) as getting the new hood and installing louvers, but the hood + louvers route will be much more expensive. I do however think the hood + louvers would overall be more beneficial than the ducting. You will get better cooling, a reduction in drag (more mph on the straights), and less lift at the front of the car (more confidence in high speed corners).

 

[JDMac34]

The upper radiator cover is NOT just cosmetic. The upper radiator cover helps seal the area around the coolers (radiator, ac condenser, oil cooler if installed, etc.). The air will flow in the path of least resistance; a row of stacked coolers (ac condenser, radiator, etc.) along with any obstructions downstream of those coolers represent a large amount of restriction.

If you would like to test this yourself, put your bumper back on and place a piece of paper where the radiator cover would usually go. Then, take a leaf blower, put it ~5 inches away from your oil cooler and pull the trigger. I can nearly guarantee the piece of paper you placed in the typical radiator cover location will fly up. For my car it did.

Your cervini hood is acting as a parachute. It is doing 3 bad things:

1.) Creating drag
2.) creating lift as a result of the drag (ps do you have hood flutter?)
3.) It is feeding air into the engine bay, thereby increasing the pressure of air in the engine bay. Increased air pressure within the engine bay leads to a decrease of airflow through your radiators. Again, going back to path of least resistance. Your cervini hood is doing the exact opposite of what hood vents do. Therefore, I cannot recommend enlarging the holes as I feel this would have a negative effect on your cooling.

If you are serious about tracking the car, I would recommend selling the cervini hood. My recommendation is race louvers. They do more wind tunnel testing than anyone, and the owner, Al, is a fantastic resource. He would be a great person to reach out to if you'd like a 2nd opinion on the comments I made above.




Some general questions I have for you:

1.) Where are you measuring your oil temps?
2.) Where are you measuring your coolant temps?

Bang for your buck, cost wise and time wise, I would perhaps consider ducting your radiators + coolers as opposed to buying a new hood, painting said hood and then adding the race louvers. This would be a good question for Al - ask him which he thinks would be more beneficial. Ducting your coolers would likely be the same amount of work (time wise) as getting the new hood and installing louvers, but the hood + louvers route will be much more expensive. I do however think the hood + louvers would overall be more beneficial than the ducting. You will get better cooling, a reduction in drag (more mph on the straights), and less lift at the front of the car (more confidence in high speed corners).

Thanks for the helpful reply. I'm glad to know that my theory is right, but I'm bummed that my cool-looking hood probably has as much of a negative impact as I was thinking it might. Surprisingly, I do not have any noticeable hood flutter. I was worried about that when I got the car and that wasn't ever an issue. My oil temps are being measured in the sandwich plate before they go through the cooler. The "coolant" temp that I was referring to is the factory one on the dash; which (to my knowledge) is actually measuring cylinder head temperature on my 2011 and not the actual coolant.

I see that RaceLouvers has a hood vent specific to the Cobra Jet, so that makes me feel better. By ducting, do you mean creating the side walls so that air is forced through the coolers rather than around?

 

[blacksheep-1]

Find yourself a " sacrificial" hood and have at it. There are some great vented hoods out there, but they come in 2 versions, a " race" version that's is very flimsy, not that great finish wise, but worked great, then some " carbon fiber" hoods that look great but weigh far more than a stock hood with bolt in louvers. There doesn't seem to be much middle ground on fit and finish.

 

[noldevin]

Thanks for the helpful reply. I'm glad to know that my theory is right, but I'm bummed that my cool-looking hood probably has as much of a negative impact as I was thinking it might. Surprisingly, I do not have any noticeable hood flutter. I was worried about that when I got the car and that wasn't ever an issue. My oil temps are being measured in the sandwich plate before they go through the cooler. The "coolant" temp that I was referring to is the factory one on the dash; which (to my knowledge) is actually measuring cylinder head temperature on my 2011 and not the actual coolant.

I see that RaceLouvers has a hood vent specific to the Cobra Jet, so that makes me feel better. By ducting, do you mean creating the side walls so that air is forced through the coolers rather than around?

I have their Cobra Jet hood vent. I think the regular one MIGHT clear a CJ manifold, but it would be extremely close. Glad I got the CJ specific one.

 

[JDee]

RaceLouvers center vent on a stock hood FTW. Totally cured overheating issues on my '16 track car. Don't worry about rain, I sat through a couple of gulley washers and there were no problems. You can add some side vents as well for more insurance.

 

[blacksheep-1]

RaceLouvers center vent on a stock hood FTW. Totally cured overheating issues on my '16 track car. Don't worry about rain, I sat through a couple of gulley washers and there were no problems. You can add some side vents as well for more insurance

Yes, this is the gold standard for hood vents, relatively cheap and proven to work.