Aero, air flow, and oil cooler efficiency - thinking time....

[KC Wildcat]

Here is an idea, and come to think of it, something I have not seen....if you are kicking around the idea of a reverse tilt on the radiator - why not just graft a whole coupe front end on a roadster? That would give you give you the reverse tilt, the hood opening, a tilt front end, and a lot slicker, more aero front. I am not sure about the proportions, I know the coupe wheelbase is 5" longer, but you might be able to make it work....and it would certainly be unique!

[DealsGapCobra]

Don't bother with the strakes unless you like the looks, they will be non-functional.

As stated earlier, aerodynamic flow can be very complicated and often very hard to visualize. On the other hand, one of the easiest to visualize is a pitot intake which is pretty much what you have for your oil cooler. They are well behaved so you have very little (I doubt it is even measurable) to gain with exterior modifications. I would add the ducting from the hose to the cooler first.

Thumper, supersonic airflow follows completely different rules than subsonic. For a Mach 2 jet to have the intake running as designed it is necessary to dump unneeded air, otherwise the intake will "unstart" and the desired complex shock wave structure will be replaced by a single bow shock which is much less efficient. What you have described is true but not applicable to this discussion...unless his car is really, really fast.

[Jack Wojack]

Chepsk8, like Ron and others have said; I would add ducting from the hose to the cooler first. That by itself will maximize the efficiency of your cooler. I think the exhaust from your radiator is blowing through that opening between your hose and the cooler and diverting that air stream down rather than through the cooler.

With that big air dam (I Like) in front you're creating significant negative pressure under the car and the exhaust from the radiator and cooler are going to seek that negative pressure. I don't think you need any exhaust ducting.

Jack

[Chepsk8]

More good ideas, and a plan is hatching with the improved ducting.

Good thoughts Jack, I will wwork on that idea.

Now, let me ask about a separate areo/undercar pressure occurence on my car:

I had an issue with the trans heating up, and actually pushing a little but of trans oil (ATF) through the shifter and into the interior area (no boot at the time, but did have a plate and gasket on the shifter to keep out most, but it seeped around anyway). The fluid would find it's way onto the dashboard via interior air currents at high speed. I still have a windshield.

So, do I still have some high pressure under the car by the transmission?

Some extra notes:

I have since added a vent tube to the transmission via the shift plate, no more mess. The shifter now has a boot to seal it off. I also have the rear diffuser, but no clue if it does anything.

[Dan Babb]

Sounds like the aero mods you have made reduced the flow of air that used to go through the trans tunnel....so now it's heating up.

Hard for you to test that out now that you have the mods in place though...right?


Wonder how much fluid you lost?
Have you topped it off since it happened?

Maybe you were seeping a little at a time and didn't notice. Then it got low enough that the fluid in there heated up and compounded the issue?

Do they make such a thing as a trans cooler for a manual transmission?

[Chepsk8]

So basically the overall goal of creating low pressure under the car by getting all the air out has worked. But now I am dealing with the after-effects of the areo package, and having to identify and fix them one at a time..

What a great lesson in Areo, and how all things inter-relate!

[Chepsk8]

May have found the inner panel vibrating cause. While changinh tires and checking the car out, I found the driver's "Elephant Ear" panel was only held on with one rivet, and positioned at an angle that could let alot of air into the area. All fixed now, so I'll have to wait for the next track day to see if this was the culprit.

[Someday I Suppose]

Dan, just thining on the duct work, Earl sells a plastic boot for the oil cooler opening to run ducting. If you got two of them, one for the opening, and then one as a shroud around the cooler itself and ran the duct between them I would think you would be pretty effecient in making sure the air coming into the opening is going through the cooler.

Google Image Result for http://www.cobraearl.com/ProdPics/OilCoolerDucts4.jpg

[Chepsk8]

Scott,

Already have one in the body opening, but a second at the cooler could be an alternate to sheet metal

[Thumper135]

If I’m looking at your cooler picture correctly, I think I’m see it mounted just behind the “X” member, Do you have a better picture of this and measurements on the cooler itself, height, width, and thickness? I was looking at my frame and trying to come up with a good solution to all of this, and was thinking of possibly laying it down at an angle to allow ducting directly into the cooler from the front opening and maybe a little short piece of duct on the back side to help get rid of the air somewhere besides letting it blow onto the already hot engine. I’m working on an idea now and would like a better idea as to what your cooler is like.

[KC Wildcat]

Ah Chepsk8, you are learning the ripple effect. Cars are a complex machine composed of interrelated and interacting systems. A seemingly simple change can not only alter the local system, but can effect other systems. That is why I preach to people to develop as comprehensive a build plan as possible. No you will not find everything, but you thing through and research things, you can minimize the risk of the ripple effect.

It seems you have done a good job of reducing airflow under the car, Now you need to focus on managing it. I am sure someone makes a manual transmission cooler. Something else to consider, your rear end. No, not what you are sitting on, but the differential. Is that going to be the next wave in the ripple? I know that some race cars have differential coolers. I am getting way out of my league here, beyond knowing race teams have used them. My guess would be for trans or rear diff, it is a couple of threaded ports, an electric pump, some tubing and a generic cooler. Of course, then you have to manage. airflow to those coolers

You might reach out to Rich Miglori, he has done a lot of stuff like that with his racing GTM.

Good luck

[McMahonRacing]

how about trying this ....

coolant 200f
oil 230 in the pan
ambient 90 + f
538hp/502ftlbs

oil cooler in the std location, brake ducts in the std location ... additional tow/diverter bar weled directlt off the 4" mains - supports splitter - oil cooler ( mesh covered) - sway bar and doubles as a tow point .....

[CraigS]

Since you mentioned windshield, I'll bring up Fast Freddy. He has mini plastic windscreens which I remember got him a lap time reduction of more than a second compared to a stock w/s.
Fast Freddie's Fabrications

Call him for the exact number. I think some planning/fabricateing could make you windshield reasonably quick detachable.