When do I need a front mount oil cooler?

[winders]

Originally Posted by ian c2

Yeah right .
Inverted wing Scott .
Inverted wing …..

Sigh....

You don't want more air under the car....you want the air under the car moving as quickly as possible.

Think about it. There is finite space between the bottom of the car and the ground. What has to happen if there is more in that space? Pressure has to increase which means lift increases.

The last thing you want to do is introduce air under the car that was on top of the car as that increases the air pressure under the car which increases lift. Look at splitters on most any production-based race cars. The idea is keep the air hitting the front of the car from going under the car. That is why splitters stick out 4" to 6". You want smooth and fast air flow under the car. The splitter prevents the high pressure air from getting underneath the car and pretty much forces it over the top of the car.

The splitter also creates pressure on the top side of the car because of how air hits the front of the car. Any openings in the front of the car should exit above the splitter and not enter the airflow under the car. Ideally, you want the air going in the front of the car to exit the top of the car as that contributes to downforce.

You want any air forced through a front mounted cooler (oil or coolant) to come out above the car increasing the pressure above the car.

[winders]

Originally Posted by Walt Fricke

Don't lots of race cars - NASCAR, for instance, as well as Porsche factor race cars - run front spoilers which are almost on the ground? To keep air out of that space, because they want a low pressure under the front, and a higher pressure above it?

Yep!

[safe]

Originally Posted by Walt Fricke

Magnus - doesn't this through hood outlet for front center coolers mean you can't have a spare tire up front?

Yeah, no spare tire.
Which I don't need and less trunk space which is unfortunate, I drive this car to and from events and getting luggage into the rear with a cage and fixed seats is not ideal.
I actually got a flat earlier this year (think this its like the 3rd flat I have gotten in my life), but I plugged it and continued the track day.

I also like that I can get the cooler a bit higher up and away from the front so it will be less exposed if I go off in the gravel or beside the track. Not to mention speed bumps and other things on the road.
It's so high up that only 30-50% is exposed in the scoop, the rest of the scoop is blocked off.
And it looks kind of cool!

As Scott and others have stated, less air under the car is better, that was also something I had in mind. I should add a splitter (I have made one), but it is so inconvenient always hitting stuff....
Where the scoop exits the air pressure should be low and in theory it should increase downforce on the front.

If you design a new car from the ground up, you might want to introduce some air under the car and take care of it properly, but now we are talking proper Le Mans level prototype stuff.

[safe]

Originally Posted by Walt Fricke

But I can't do that on my SC race car - rules I run under don't allow it. But there is adequate room for the hot air to vent backward if you mount the cooler as far forward as you can in the valance's cutout. True, it can go under the car, affecting aero. But my class has rules which limit aero modifications anyway. And a street car's owner ought not to worry much about aero at sensible highway speeds, as long as it isn't way out of balance.

Is that your cars?
I was wondering how effective the that large whale tail on the white car is. I'm thinking of changing out my smallish whale tail for the big RSR one, I have it already, just needs some work and paint.

A street car should not worry about aero that much. I wanted good cooling and a more protected cooler, that was my primary goal.
An alternative could be to mount the cooler as I have but duct it into the wheel wells, but it would be more fabrication, cutting and welding, to the car.

[winders]

Originally Posted by safe

I also like that I can get the cooler a bit higher up and away from the front so it will be less exposed if I go off in the gravel or beside the track. Not to mention speed bumps and other things on the road.

Look here at what I did with my race car:

[winders]

Here is the splitter on and off the car:




The splitter extends well back toward the firewall. Note the diffusers.

That is with the first iteration of the vent opening in the bumper. I have since opened it up to match the opening of the ducting. The 3.6L engine in my race car puts out almost 120 HP per liter so it needs the cooling.

[safe]

That is some proper engineering and fabrication behind that Scott. Well made!

Probably more like I would do it if I would do it again, no holds bared.

I do have a duct from the cooler to the hood and ducting:ish from the valence o the cooler.




I also like to keep it sort of "period" looking, not a race car. Just a fun track day car with the goal of keeping up with newer cars. I can keep up with tricked out 964s and early stock GT3s if the drivers are like me, average....



Maybe I need to improve the aero too, but ABS brakes is what I would like to fit somehow and would improve my lap times most.

[ian c2]

A bit rough as it was done by thumb on an iPhone , but this is what I was referring to .

[ian c2]

And here is how it was done on my car

[stownsen914]

Re: air under the car - I'll paraphrase Joseph Katz, an aerodynamicist who did the aero on at least one IMSA championship car - air under the car can be a good thing if it's carefully controlled. i.e. flat bottoms, diffusers, and wind tunnel time. In some cases you can even feed under-car aero with an enlarged opening incorporated into the front splitter/bumper.

Without those things, or when rules prevent, you're better off keeping as much air out from under the car as possible with a low spoiler/splitter. And hot air is worse than ambient temp air.

[safe]

Originally Posted by ian c2

And here is how it was done on my car

Why haven't you ducted it under the car if its so good with extra air under and why do you have a splitter at all?

[ian c2]

My car is now just a shell .

Air under the car is good if you use it correctly , and as I said earlier the engine at the rear doesn’t help , but that’s not to say it cannot be usable.
It would take a lot of work and If people don’t want to this that’s fine .
I’ll probably bleed some off for brake and cooler airflow , but the main thing is to keep the car looking like original panels on top .
I’m looking at the theory of a low drag smooth body , with downforce pulling rather than pushing …
I don’t come here to argue , especially when the info to support this is so readily available.
(Some people on here will even argue with you when you are agreeing with them )

[winders]

As I said, production-based race cars, or those with a production silhouette, do not direct additional air under the car. If you look at most GT cars, they do their best to keep out from under the car. Yes, even the cars with front and rear diffusers and otherwise flat bottoms. They have low splitters at the front and vents to evacuate air from the wheels wells all in an effort to keep the pressure lower under the car.

Cars that have full length underbody tunnels and diffusers benefit from directed airflow but still seem to do what they can to prevent adding air underneath the car. Instead, they use that directed airflow to manage what is there.

I am unable to think of a production-based race car that directs airflow from on top of the car (air above the front splitter) to underneath the car.

[ian c2]

[stownsen914]

If you are building DIY under-body aero, you'd probably REALLY want to know what you are doing if you want to "feed" it with a raised front. Some of the older prototypes had such setups, and a few supercars did too. With a good dose of CFD or wind tunnel time probably it should be possible. Modern aero rules for most sanctioning bodies are pretty restrictive with what's allowed. It may not even be allowed anymore. When I flat bottomed my 914 and put large rear diffuser on it, I decided to keep my limitations in mind. Low front splitter for me.

[winders]

Originally Posted by ian c2

Production-based race car.....not street cars. Street cars have different parameters to work within. You don't see a splitter 1 to 3 inches off the ground on a street car. Since a street car, even an Enzo, is going to have a lot of air going underneath it compared to production-based race car, it makes sense to control and direct where that air is going.

Did the racing version of the Enzo have that setup? Have any off the Ferrari hypercar race cars had that center air-feed to the undertray?

[ian c2]

I think the mc12 Maserati built on the enoz (ish) used it , but not 100% and I’m on my phone .
Earlier you seemed rather adamant that it couldn’t be done and would never work . Period .
Now it seems you do ?

[winders]

Originally Posted by ian c2

I think the mc12 Maserati built on the enoz (ish) used it , but not 100% and I’m on my phone .
Earlier you seemed rather adamant that it couldn’t be done and would never work . Period .
Now it seems you do ?

I said "production-base race cars". Again, race cars have a whole different environment to run in.

A street car has to have a lot more ground clearance than a race car so splitters and other methods race cars use to keep air from getting underneath the car don't work nearly as well or at all.

I can't find a photo of the Enzo FXX race car under tray....but I can see that the Maserati MC12 race car does what it can to keep air on top of the car from going underneath:

[ian c2]

Sigh

[winders]

Go ahead and sigh.....you are the one that is exasperating here. Just because you found a dated supercar that was trying to emulate F1 cars does not mean you are right.

Look at the 2021 GT3 Cup car design:



It has a cooler in the front that exits out over the hood. The splitter keeps air from going under the car and creates a high pressure area at the splitter/bumper intersection. The air coming out over the hood instead of below the car or in the front truck area improves downforce as well.

The bottomline here is that an old air-cooled 911 does not want bumper mounted oil cooler air dumped underneath the car if reducing front lift is the goal. I don't care what you have under the car in regards to diffusers.