I see this diagram everywhere for the FC. Anything similar for the FB out there? Wondering where the low and high pressure areas along the hood line are.

Thanks

 

 

Thanks! I can't really see the low pressure areas well, but it's pretty cool pic!

 

Here's a pic from a French brochure. The site I got it from is long gone.

 

What's interesting is that as soon as you raise the headlamps, it all changes. Way back when, I tested this by adding coat hanger wires from the front turn indicators which extended about a foot into the airflow at the front of the car and then attached paper mache streamers to the ends. The airflow was nice and smooth up the hood and along the windscreen smoothly flowing around and above the rear view mirrors until the headlights went up - at which point the air then flowed directly up the hood and straight over the top of the car.

Surprised to see this airflow characteristic, you can test this yourself by raising and lowering your headlamps during light rain and watch where the water beads off of your windscreen.

I'd also be curious to see the same pressure mapping of a Mariah rear hatch, as I lost about 1-2mpg after I added the hatch. That rear glass keeps the airflow attached beyond the roofline and to the back of the car, and the hatch creates a lot of turbulence.

 

I have wanted this info for years! Thanks for asking, thanks for sharing!

 

That’s what I’m talkin about! Thanks a lot!

I wanted to vent some air from under the hood. I run a OEM style CF hood with the OEM latch at the center Around 150mph the corners of the hood raise up about an inch! I’m afraid my OEM hood latch is going to let the hood go one of these days. Instead of pinning the hood down (I hate hood pins). I’d like to try and vent the pressure trapped under the hood.

Just like the FC obviously venting the back of the hood is a bad idea! Cutting hole behind the radiator area seems ideal. Don’t know if I can bring myself to that either. Hmm…

 

There is a thread on here somewhere where a guy made a real nice vent just behind the radiator. He basically cut a big U shape (with the open part of the U facing the windshield) dropped it down a couple of inches and inserted screen material. Really well done and would vent in the proper area. If you could find that thread it may be what you are looking for. Does your hood have the inner bracing? If so, it gets more complicated.

 

It was Steve84GSTII or some such user name with the vented radiator.

 

Something like this?

 

No head lamps to worry about, but I don't have any room to go under the hood line. Engine bay is pretty cramped.

If anything I'd have to just cut a hole behind the radiator. Not very excited about that concept either. May have to run pins.

Thanks all!

 

^ this one == ultimate baddassery ^

 

Really? I think it looks like the hood has some sort of bumpy STD.

 

i'm not sure what the hood does @150mph, but at 60, if its not latched it'll just hover about 1-2" open, the air pushing it down and the air pushing it up balance out.

not like an Rx2 where the hood skin pops off...

 

The one with the black hood was the one I was referring to. (At least it is done in the same manner). It should resolve your hood lifting problem, should help the handling at high speed and reduce the under hood temps. You would only have to have an inch or two of under hood space to make it work.

 

I wonder what the aero profile would look like with the rear of the hood jacked up an inch or so...

 

Hot dogs on the hood...

 

Well its just that sometimes in hot weather, mainly stop/start driving, I will drive around with the hood popped in my '85 fb to help ventilation (and try to save my paint from turbo and exhaust heat) and have noticed that once out on the freeway with a good head of speed up, the hood will levitate up maybe an inch or two more from where it was already sitting on top of the latch, and just stay there hovering really steady, and not move till i slow down and then it will gently sit itself back on the latch again. It finds its own equilibrium

 

If you want to cut that nice CF hood up I'll buy it and give you a couple of stock ones to cut.

 

At 100-115 mph on the track the hood on my sa was open about 5"-6" because I didn't push it down enough for the latch to catch all the way. I had to pull in to the pit lane because I was black flagged. My passenger thought it was quite funny.

 

Do 130 mph with the sunroof open. Just do it and see what happens, my passenger thought that was funny too lmao

 

if you spin the car out around 100mph with the windows down the rear hatch glass pops off