Used to be w few manufacturers, avoid fibreglass if you can.

But why?

The late, great Harvey Smith did extensive testing and showed that underbonnet temperatures, especially those around the turbo and garbox, increased massively on road cars running reverse scoops.

Forget time attack, the forward scoop does the job.

 

Roger Clark do one

 

 

No, but it does scoop air into the engine, over the turbo and gearbox, which exits under the car, so keeping underbonnet temps down.

First thing I thought of when I had my FMIC, so asked Harvey.
He showed me his research. I didn't fit one.

 

Perhaps I better refit a normal scoop.
I have a RCM reverse scoop fitted.

 

Did he do any work around deleting the scoop all together? I can the rational with reverse scoops as it vents the air flow through the engine bay out the scoop, which would create an area of almost static air at the back of the engine bay. If you delete the scoop all together then you maintain the air flow through the engine bay and out through the transmission tunnel.

 

I believe he said the extra airflow via the scoop was beneficial.

It was enough for me to retain mine anyway.

One thing about harve was he didn't make pronouncements without having done the research to back them up.
Clever bloke, he was doing modifications to the turbo on his wife's Vectra when he died, it was a 1.9 diesel and the bl**dy thing was a beast.

 

So, a brief lesson in aero might be useful here. If you look at the car profile from side on, imagine how air flows around the car. Where it speeds up, the pressure drops, where it slows, the pressure rises.

You notice that on cars like the Ford RS Cosworth, the bonnet vents were nearer the front of the bonnet, same on the RS Turbo Escort. The air rushes over the front of the bonnet causing quite low pressures. On a New Age Scooby, the bonnet is pulled up at the front quite markedly, you can see it on a Blobeye at 100mph lifting the corners about 1". Far less on the Hawkeye, but that's progress.

Now, most cars have inlet grilles for the ventilation syetems at the base of the screen. This is because this is a high pressure area. The Scoop on a Scooby is at a fairly neutral pressure point. It relies more on the low pressure under the car to flow air through the intercooler than you think....

Basically, front of bonnet low pressure. Back high pressure. Screen high to low. Front of roof, low pressure (great for roof vents), rear of roof, high pressure. Back screen low pressure, top of boot lid, low pressure. For low pressure, rear higher airspeeds relative to car's actual speed. For high pressure, read air pulled along with the car.

I hope this makes sense.

A Reverse scoop will probably flow air into it, less than a normal one but still in, not out!

A Scoop probably produces minimal drag, maybe the Blob STI one a bit more, but the Hawk had the smaller one on the STi for a good reason. If you run a Blob with front mount, then a WRX scoop will be an ideal compromise aerodynamically....and front corner latches too!

 

Got mine from the USA , just got fed up cleaning the bay all the time with $hite flying thru the scoop ha ha

 

Any links ?

 

KS Tech USA
Cpl options . Brushed ally or black
Also under vent plate is separate
It’s not cheap , but it is Quality , fits like a glove lol

 

Ps
It’s called the air diverter plate you also want to purchase for underneath

 

http://www.kstech.biz/wrx-sti-hood-v...-w-black-mesh/