mark kibort

Funny, Mark A and i have been talking about this . I just saw my plan for this kind of mod that will increase frontal downforce yesterday. its on a viper or if you want something that will look real cool and not disrupt the lines of the car, look at an Austin Martin Vanquish. there are two long rectangle filled with diamond shape screens holes it looks TRICK! would work great on our cars. for racers, the intake to the radiator , flows right back down to the bottom of the car. if it could run out the hood, that would help. (plus cooler engine temps)

Mk

hacker-pschorr

The Vanquish has ducts going from the exhaust manifolds to the hood vents. You can see them in the last picture sticking up next to the left throttle body.

Two Aston hood vents:

Nicole

You say you did this to reduce temps at low speeds. Did you have an overheating problem?

You're not in Texas or Soudi Arabia, so I'm very surprised to hear that... a properly maintained 928 should do well in stop and go in England without such tricks.

sublimate

The cross brace would look great on a 928. Very curvy like the bodywork.
The plain round bar has always look too, well, plain to me.

SharkSkin

Erik,

Do you have a side view? It's hard to tell from those pics how useful that setup would be for driving vs. letting the heat from the exhaust manifold heat out after shutdown.... Maybe it's supposed to serve both purposes?

drnick

mark i agree about the radiator airflow going out the hood rather than under the car potentialy giving more downforce but i think the aston martin screens are placed to far back to usefully achieve this. it looks like on the racing car they have gone for six ducts placed well forward.

nicole, its not actualy an overheating 'problem' as such but a combination of factors. on most days across here in sunny england ambient temps are much lower than texas and saudi but now and again during the summer months you can get some properly hot weather and its on these days that my fans really battle to lower the engine temp. and the reason they struggle, apart from the high ambient temps is due to the fact that they are not ducted like the S4 to draw air from across the entire surface of the rad, instead they are two small fans mounted directly to the radiator surface.

dont forget the car was originaly an 86 with an engine driven fan for cooling - long since departed. im sure i can improve the fan installation to combat the heat more effectively and as a part of this i also wanted to aid heat evacuation, and i didnt mind cutting the bonnet on my aleady much modified 928. dont get me wrong, for a nice stock car i think this would definitely be the wrong aproach to cooling, but for a pseudo racer...

Vilhuer

Strosek placed their vents little further back. They rarely did anything for purely esthetical reasons. Not sure if there is some science behind this placement.

drnick

placed back there you will also be venting heat from the exhaust manifolds that tracks up from the side of the engine block. i wanted to vent the radiator airflow more than release heat trapped back there over the heads. i suppose one potential advantage of the rearward placement id that it might help cool the intake manifold?

ibkevin

Here's a good read...

jorj7

Nick,

I cut some slits in my hood last year to help get the heat out from under the hood. I was
going to put them behind the radiator, but Marc T. advised me to move them further back,
about even with the rear of the wheel well. This would allow the most hot air out.
Here is a photo of Bill B helping me put the hood on:



Here is a shot with the hood closed:


Here is a shot of the underside of the hood. I removed the hoodliner to help air flow:


And here is a shot of the car at the last ORR:


I did seem to help keep the engine cooler. By the way, the hood was donated
by Beth and repainted to match my car.

hacker-pschorr

Dave,
Those are what I found doing a GIS. I did not find a good side view showing exactly where they go.

SharkSkin

Thanks anyway.... I think those are supposed to be "pretty" shots -- and they are -- but I'm always curious about the details...

heinrich

I like those slits.

drnick

george, those are some neat cutouts - i was surprised by how thick the bonnet aluminium was! from all the pics i looked at and things i read it seems like your placement is ideal in some senses ie its the highest point underhood where hot air will collect and you will be evacuating hot air from the exhaust manifold as well. if i could, and i might yet, i would find some additional vents to place back there as well - maybe the mesh screens like on the aston.

when i looked under the bonnet and tried to picture the airflow it seemed as if the flow might be somewhat restricted by the actual engine to any venting point rearward, hence my choice of placement. im taking a drive today so i will see how it performs on the road.

fabric

Thanks for the link, the last bit, while not exactly germane to this thread, may be of interest to other S4+ owners: