Hello and happy new year!! I have my 550 at a paint shop while being out of the country. The hood needed a full sand down to metal and respray as the paint cracked around the edges... The prep work before last paint two years ago was probably not good enough. And the car has been out in real heat from the sun and some overheating. Now, it’s time to fix it. But I would also try to avoid the third and next respray if I can. So now all of a sudden, I have started to observe air outlet vents in the hood and fenders of many exotic cars... (hard to become more nerdy than that!!). But it is a fact that alot of fast cars have it and need it. I have read a few houres on the net too about people who have great success with cutting big holes in their hoods and addiing «louver grills» of all kinds of sorts.... They claim to all sorts of benefits. Like less engine coolant temp, better AC performance with colder air from the outlets, even better defrost of the windscreen and better milage... Police cars in the desert and other places where they experience real heat seen also to experience the same problem because the police sit in their cars at stand still for longer periode of time. I am not going to make any conclusions for any if of the arguments, but I doubt all these claims are false. And not one of them have a 5,5 l V12 that really drink fuel even at idle. And one fact is pretty obvious, and that is that heat rise up and not sideways. The outlet vents in the 550/575 fender vents are probably working fine when the car is moving, but when stationary or during stop and go traffic, the heat have not many places to go except through these vents and under the car to further heat up the inside of the car... The gap between the fenders and hood is very very tight and can not let the air go out... And it was around this edge that my paint cracked. It looked terrible in the end of this season. If the coolant is over 100 deg C / 210 deg F and the air just over the dark tarmac is probably 10-20 deg warmer than the outside air temp of let’s say 35-40 deg C / 110 deg F and you have 12 exhaust pipes of maybe 3-500 deg C (?) and two catalyzers hot as a burnibg pizza owen..... Then it is quite reasonable to imagine that the inside of the engine compartment is probably somewhere between 100-200 deg. C! That means we actually cook our own hardware inside the engine compartment on a hot summer day with a serious traffic jam. That is when you REALLY need the most AC you can get and it only makes it even worse as all the heat from the AC condencer in front of the radiator is also drawn into the engine comparment!! This is not good for all the electronics and rubber hoses etc. So the best thing would be to just leave the hood open. But who want to drive a Ferrari without the hood shut...? That make me considder to modify the hood before it is being painted.... Aston, Jaguar, Mercedes, Ferrari......... They have all big vents on many of their premium models. And the first series 456 (non M) did have air outlets in the hood! I believe it is not just a matter of styling. It is probably out of neccessity!! A 355 or a Diablo both have huge vents. And rain goes through and right onto te engine!! The 360 and 430 are somewhat better with the vents to the side of the rear engine hatch glass and down onto some rails which make water go down under the car instead of right into the engine. SO, how could a 550 hood be modified to get some new efficient vents to let air rise up while the car is moving slowly and even at standstill after you turn off the engine?? The hood is made of aluminium as far as I know, and the engine inlet manifold is touching the underside cover. The vents should be at the top which is toward the windscreen for max efficiency. The hood have several curves, so a flat «bolt on» grill is not very easy to fit and it might look horrible on a car like the Maranello.... The water from rain and washing the car would also go right onto the engine, which is not exactly ideal. What would you guys do? I have a few months before the car is going back on the road and a skilled aluminium welder could make some mods to let the engine compartment «breath» and dissipate the heat in a much better way that what is the current situation. Some refined «correct Ferrari look» vents could be added. But where? There are also some braces under the hood to give it strength etc. If I leave from my hotel or appartment, fit and in good shape for an important meeting down here in France, apprechiate to able to arrive in the same condition even after an houre or two in heavy traffic. Which is the reality every day. The AC should be able to keep 20 degrees inside the car with the fan speed at 2, when it is 40 degrees outside, while the engine is running at idle speed !! That is FAR away from reality now. It would make it much more plasant to operate the car and carry-ons would also be better without being warmed up. In hot climate, water is great, but in a really hot car, water become warm in a couple of minutes when left inside the car. Maybe I add a cooler too! The 550/575 race cars had huge louvers but those hoods are completely different and probably of very lightweight plastic or composite materials. I am thankful for all inputs here!! The hood is not yet painted. But prep work is done. Erik Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Would it be possible to cut openings in the rear flange, where the hood sits on, just below the wind screen? That way you don't have to ruin an otherwise perfect hood while creating openings at almost the highest point. I was thinking of a row of 20mm holes or something like that. Make them high enough so that (most) rain keeps out,
Wondering if any airflow changes would affect down force. I know that leaving the lower front cover off results in the front of the car floating above 100 MPH.
Seriously. Besides protection of the underside (especially for some of the poorly routed hoses), I made sure to put that cover back on before my trip to Monterey.
I guess the wall there is to reduce the risk of vapour from possibly leaking fuel and oil from the engine...?! Isn’t that where the air to the cabin goes in and to the hester fan? Might be more engine noise aswell. Many new cars today have big vent just under the rear end of the hood. I was actually thinking a very wide opening parallell to the lip in front of that top lip of the hood. Something that would not make a big difference to the design. Just make it slightly more «racing».
you have to have underside panel, it applies to most performance car. it is there to prevent air coming back into the engine compartment, and pressurize it. how air move through radiator is by pressure delta front and rear of radiator. so lower pressure in engine compartment helps with radiators efficiency, it helps draw air across radiator fins. make sure you install hood vents at lowest pressure area of the hood (towards outside), as it helps draw out the hot air in engine compartment. do NOT install vents anywhere near windshield/center area, as it is a high pressure area. it will just force air back into the engine compartment. That's where you put intake. hood vents also helps with aero. Hood area is huge, so even a small vents lowers front end lift. most track guys/gals in socal use them: http://trackspecmotorsports.com/
in one of op's picture, the Mercedes SUV. that is NOT where you want to put a vent. many cars use that area for cabin intake, and install cabin filter there. note wheel well is a high pressure area, so venting it out is always a good idea, but isn't easy to do on a street car. one big negative with vents is rain intrusion....... no big deal if you don't drive in rain.... but something to think about.....
Image Unavailable, Please Login this is a general idea. it depends a lot of hood side profile also. but the general triangular shape of low pressure are is correct. you want vents behind radiator for obvious reason. where Ferrari 550/575 air intake area isn't exactly high pressure area. but the scoop helps a ton. it also helps if you install a tiny gurney flap on leading edge of vents. it creates a low pressure area over the vent.
From the yelo550 thread a few years back. https://www.ferrarichat.com/forum/attachments/img_1223-jpg.2097335/
Interesting input here. I remember some Mustangs or Corvettes from the 60/70s had big opening in the hood just in front of the wind screen because it is believe to give a good effect for feeding the engine with cold air since it is a pressure area in front of the wind screen. It is a bit odd since the air is supposed to go into the engine compartment through the radiator and possibly flow through and out somewhere... I had a look at a 550 today, and it is not easy to make a good vent hole.... I checked the plate in front of the windshield wipers like Bart (Franschman) over here suggested. This profile consist of two plates pressed into each other and to drill here seems like a pain and possibly will damage the paint and corrotion protection.
Erik- You need to get the belly pan back on her before fiddling with the airflow. Once you do that, you can baseline whether you actually have a problem or not. Stock Maranellos generally do not have a problem with battery life if well maintained.
My belly pan (the big cover under the engine?) on the 550 have always been on. It was the 456 that never had one! But it is sold years ago. What I said was that I never had any stability problems without the cover on that car. And it never overheat either although I never had it in real heat down in southern Europe like with my 550. The 456 had the openings in the hood as the front bumper and good was from the old 456 while the rest of the car was a 456M. Perviously an accident car. The problems with the 456M was that the lights were never properly adjusted so the hood touched the lights when I opened the hood. And the window gap was not really good. Other than that, the 456 was very good!
Most of the time it looks (really) cheap. Either execution, style choosen....and most certainly, even if the style choosen is really clean....it just doesn't suit the car. The 90s V12's just aren't aggressive enough to suit vents. -- The Saurus 550 has it implemented well (though personally I'd have the vents flush with the rest of the bonnet, like on the 599XX). It works well on the Saurus 550 because it's got a more aggressive body, which in turns works out well with it's stripped out interior. I'd still change more things to create my personal itteration of a Marenello ''GTO'' but it's a good start... Image Unavailable, Please Login
I agree. The 456/550/575 cars are really elegant without too much racing like stuff and I like that. It is just that the heat won’t come out if there are no holes where the heat can escape.... It would be very interesting to measure the heat inside the engine compartment with a cheap digital thermometer while driving on a hot summer day. Not possible where I have the car as the snow and ice is still on the ground for 5 months... But maybe in other places of the world. Anyone up for a little experimenting? Let the engine warm up, go for a little drive. Highway speed and stop and go traffic for a a while and then just leave the car idling in the burning sun for 30 minutes or more. Just like when you are stuck in a real traffic jam! Write down the temps of the coolant and inside the engine compartment at each driving condition. And then open the hood and let the engine room ventilate and see if there is any difference.... it would be interesting. Position the sensor somewhere around the brake booster. Possibly let the AC blow to keep the car cool inside aswell to furter make as much heat as possible and see how high it goes. I feel the AC is working significantly better when the car is moving. Probably because the compressor spins faster and the condenser get much better cooling when the car is moving than what the fans can cool. Also measure the voltage. With cold engine and when everything is working under maximun load and heat. We noticed that there is a tall rubber seal across the engine compartment just in front of the wipers. If taken off, there will be a slight gap there between where that seal sit and the hood itself. Maybe that would be a small and easy way to improve the cooling? But personally, I don’t like to remove something that is there from the factory, as it is there for a reason. This would be most interesting to test on a 550 but could well be done on a 575 for comparison purposes. The 575 have a better working cooling system. Erik
Erik- That is a high pressure area generated by the windshield. You will get airflow into the engine compartment, not out of it. Here is an L-88 Corvette hood as an example. Image Unavailable, Please Login
what Taz said. that area close to center / windshield is a high pressure area - as long as the car is moving. if the car is sitting in traffic. removing the hood (or raise rear of hood up) will help with engine cooling. But that's kind of missing the point. fan is for cooling at low speed. at high speed (anything over say 60mph) it does not serve any function. radiator air flow works by pressure delta front to rear of radiator. idea is to raise air pressure before radiator, and lower air pressure behind radiator. anything you do to raise engine compart's air pressure makes the radiator less efficient. you want vents at low pressure area of the hood.
this is for a Miata, but general idea is similar. negative number means low pressure. Image Unavailable, Please Login
I agree on that argumentation. However, the problem will never occur while the car is moving at a speed of about 40-50 kph as the wind is «servere» even that slow. About those American designed are scoop with intake from behind... The area in the front of the car and the size og the grill + of course the speed the car is travelling would determine if the air is going in or out of that air scoop... if the engine compartment is «over charged» by the air forced into it, then I bet the air would go out at the back through that scoop and not the opposite way. Most flow design that I can think of, would make a vacuum on the back side of a vent like that because there is a massive amount of air flyvinge over the scoop....? Are there any proof with scientific test that air is actually flowing inside the engine compartment (to feed the engine with fresh air) or is it just a myth? Maybe a temperature sensitive system would be better? A flap that opens up when the engine compartment reach a temp of let’s say 100 degrees ? A little bit like the air flaps in the front bumper of an F12 to cool the brakes. In Paris, lots of cars drive around with their hood just a little bit open during really hot days. Cars that have small engines and no AC. Here we are talking about a car with an engine compartment almost full to the edge, a pretty serious fuel consumption even at idle, and an AC condenser/radiator in front of the main radiator. And on my car, a huge almost black hood. I bet I can cook an egg or maybe a pizza on that hood during seriously hot days in city traffic.
Image Unavailable, Please Login Maybe buy a bonnet/hood from ebay, make the vents ''deeper'' (if possible), perhaps some ducting from the radiator to the new, deeper, vents so the air can go through the rad quicker and find it's exit as well... And a better radiator? I think it would be the cleanest way of doing it.
I like your initiative! The curves in the hood of the 550/575 is different from the 456 so might not be as easy to fit? Another option would be to buy an extra 550 hood and make the modifications to that instead. That way it would be possible to experiment and if one fails, it is not the end of the world. It just became quite expencive... But what is more expencive is to own a car that you eventualy end up selling because it can’t work satisfactory on a really hot summer day. I have tested three 550s, and all have the same problem. They just run very hot and I am not comfortable driving a car that you constantly need to follow the engine temperature. It is a bit stressful... I found a C-class worth probably not more than 5.000 euro today. It had an effective heat escape grill.... Image Unavailable, Please Login
