Bonnet Venting

[Beer Baron]

I have the traling edge of my bonnet raised. to be honest I have NFI how much affect it has. the bottome of the windscreen is a fairly low pressure area so it would probably not be drawing that much air though, but giving the air travelling into the engine bay a place to escpape is a good thing. plus when shit goes wrong I will know straight away as oil/coolant/bits fly onto my windcreen!

I've never had a problem with the law, but I do get countless people asking me why my bonnet doesn't shut properly, or telling me I've forogotten to shut my bonnet. one day someone will ask me about it and I will loose the plot and snap them in half. so possible jail time is something to consider before doing it. I don't think it looks bad though.

[sinistaGTR]

mine is raise a touch so my bonnet can close due to my cooler piping pretty much goin over the oil cap.

[T04GTR]

i want to try and find a huge naca duct. like inches wide. for the bonnet. would be pretty cool

[T04GTR]

[padey]

ON A TT SUPRA we did some testing at wakefield with streemers on the front bar and on the tip of the bonnet. and on the straight the ones on the grill and upper of the intercooler they were pointing forwards lol. the only thing pulling the air thru the radiator was the engine fan.

thisa was with a louverd bonnet. and a standard bonnet. and no bonnet. all made no differance to watertemp. the only thing that worked was having the intercooler cut in half so the radiatio gets its own air. and a curver partition seperating the rear of the cooler fronm the radiator area. with the cooler venting thru naca ducts on the bar.

also lifting the bonnet is a good trick. but the air doesnt go out of it. but back into the bay and pulls the air under the car.

im gonna try the same idea on my car at our next test day. cos ive got the same issue. at high speed it just gets hot. im no aero dynamacist but im learning

Did you ever get to do this on your skyline?

Just curious, because i'd like to get hot air out of my engine bay too, and wondered what affect it had on the aero.

[Scooby]

can't beat the look of naca ducts but they are designed to force air in and will increase under bonnet pressure. this means that unless there is a good path for air to evacuate from the engine bay - under the car - the pressure will reduce the amount of flow through at the front.

one reason that temps go down with a bonnet vent is that the pressure in the bay is lower and there's more flow through the rad.

i reckon the 32 GTR bonnet with naca ducts would work well - the vaccum created at the rear of the bonnet with the seal gone would pull air through the ducts and decrease the pressure in the bay. anyway it's all conjecture until you get a pressure gauge and a thermometer.

if anyone finds some nice looking naca ducts yell out.

Edited November 28, 2007 by Scooby

[R334door(s2)]

what about getting the correct sized spacers for you bonnet hinges to raise it a bit would this help the hot air escape.?

[Shaun]

Ive got an East Bear FRP bonnet on my r32 gtst (with the gtr grille). I bought it because it was the only one i found that was subdued (sp?) and didnt look like that fast and furious shit. Its also extremely functional; when the car is stationary, you can feel the hot air being forced out the vent by the clutch fan. Ive not got twin thermos and its even better with them.

The only negative is that it doesnt fit as well as id hoped (im extremely fastideous though), and the cost. It cost me $1700 unpainted, and im still trying to justify that!

Overall though im pretty happy with it. Got it from that place on Silverwater Road in Sydney (i forget the name).

Edited November 29, 2007 by Shaun

[Shaun]

Oh, i forgot to mention that my bonnet comes with a plug type thing that fits on the inside of the vent when its raining. The cost that i mentioned included the bonnet, gtr bonnet latch and the gtr grill.

Shaun.