heat management, CF hood alternative

[John Rambo]

Will they be making a kit specifically for our cars any time soon, or do we just have to buy the s2k kit that's on their website?
Very interested in this significantly lower cost option to a vented hood for my turbo car

[mrk1]

I decided to go with a more low key approach, the goal here being vent heat when I come to a stop mostly. My car is a street car and I am seeing heat soak when there is no air coming in the front. I will make some pretty mesh inserts to finish them off.





(edit) Updated photo of mesh insert

[OkieSnuffBox]

Heat soak? What like your IATs that almost instantly drop back down within a few degrees of ambient once you start moving again?

[mrk1]

Originally Posted by OkieSnuffBox

Heat soak? What like your IATs that almost instantly drop back down within a few degrees of ambient once you start moving again?

Heat Soak is when everything under the hood rises in temp due to no air moving through the engine bay. Don't even need to look at IAT, just feel by hand. IAT vary to much by daily weather anyway.

My intercooler pipes would continue to rise in temp after coming home from a good drive, this is with the car idling and the hood closed. The temp did seem to plateau but I still saw room for improvement with simple vents.

[keen as]

Originally Posted by plucas

Fluid flow around a vehicle is very dependent on the car's design. Just because it works for one, doesn't mean it can be used as a blanket term for all vehicles. You also cannot always trust CFD or wind tunnel testing to have real world results. One big misconceptions of wind tunnels are that they reproduce what the car will see on the road or track. However, this is false. Wind tunnels only simulate the conditions on the road or track. Simulations inherently deviate from reality and it is often hard to quantify all the sources of the error. This is not to say that using wind tunnels or CFD is wrong or isn't helpful. The complete opposite is true. CFD and wind tunnels are very useful in helping design proper parts that work. However, you need to have the experience and know the theory to really understand the reality. You need to have the proper inputs (CFD) or choose the right tunnel for your needs (wind tunnel testing).

We have done CFD testing for the FT86. We do not have the funds for proper wind tunnel testing so results have not been verified by this route. However, on the track, we have seen the real word results. Also I have backed up many CFD cases to other CFD houses and windtunnels. Three examples are the ahmed model, DrivAer models, and the Perrinn LMP1. I will now get off the boring information and get to the CFD of the FT86.

Pressure Plot on the car, specifically the hood

What do the colours mean? If I remove the small black trim from the corners of the hood near the hinges. I am wondering if hot air will extract.

[plucas]

Originally Posted by keen as

What do the colours mean? If I remove the small black trim from the corners of the hood near the hinges. I am wondering if hot air will extract.

The colors just represent a scale. It could be any scalar or vector (pressure, velocity, temp, etc.). The colors in the pictures I posted are of pressure. I would not recommend removing the black trim in that area as it is higher pressure.

[Reaper]

Originally Posted by mrk1

I decided to go with a more low key approach, the goal here being vent heat when I come to a stop mostly. My car is a street car and I am seeing heat soak when there is no air coming in the front. I will make some pretty mesh

I see that creating alot of lift at speed. It may also li.jt the amount of air that can pass through the radiator since you're essentially forcing air behind it. We'll see.

[mrk1]

Originally Posted by Reaper

I see that creating alot of lift at speed. It may also li.jt the amount of air that can pass through the radiator since you're essentially forcing air behind it. We'll see.

Going to have to disagree on that one.

I am also working on a lip for the leading edge, create a low pressure pocket behind it. Reducing lift was never an intent with my vents, they are certainly no large enough.

[Reaper]

Originally Posted by mrk1

Going to have to disagree on that one.

I am also working on a lip for the leading edge, create a low pressure pocket behind it. Reducing lift was never an intent with my vents, they are certainly no large enough.

With the top of the vent higher and no gurney style wicker it might as well be a scoop. Tape some tufts to it. I can almost guarantee at speed that's a scoop and stuffs the bay with air.

[mrk1]

Originally Posted by Reaper

With the top of the vent higher and no gurney style wicker it might as well be a scoop. Tape some tufts to it. I can almost guarantee at speed that's a scoop and stuffs the bay with air.

To each there own

[Basket Case]

Does anyone foresee any issues with rain? i wold love to add the vents like the OP did, but living in Florida with all of our rain I don't think its gonna work...

[Lonewolf]

Originally Posted by Basket Case

Does anyone foresee any issues with rain? i wold love to add the vents like the OP did, but living in Florida with all of our rain I don't think its gonna work...

How about just doing mild openings for the fender vents? I've seen a few members take a dremel to the area behind the fake fender vent area and open it up a bit with some decent results.

[Big LrG]

Just out of curiosity, anyone ran at the track w/o a hood and checked the temps?

Another suggestion would be, instead of running the two vents/louvers along the side of the hood, run on at the top of the hood, cross-car. Maybe 3-4 blades of louvers in results of a "evenly" distributed extraction of heat.

[shiumai]

Have you guys removed the rubber seal between the rear of the hood and the plastic part in front of the windshield (forward of the windshield wipers)? It's been mentioned before in the past, so i assumed that it's the first thing removed by anyone looking to reduce under-hood temps.

Removing it creates a hood-width sized gap at the rear of the hood. I removed mine more than a year ago and can feel hot air venting through the gap after I've stopped the car, so at least i know it does do 'something' when stationary or in stop/go traffic. Since it looks like it's a low pressure area, i'm assuming that air is being drawn through the engine bay and out of the gap while driving. I have not noticed any hood flutter at highway speeds either.