Fitting under tray to stop air pressure under bonnet?

[spartacus]

Following on from the chin spoiler thread, I was lying under the car today measuring the width of the area where the old spoiler was fitted and started to ponder with the notion of fitting an aluminium under tray effectively sealing off the front part of the engine bay where the air is getting forced in.

I think this is a common practice on many high performance cars to completely panel underneath to induce downforce.

Can anyone give me any reasons why this would be a bad idea in the case of the Cebera?

[GreenV8S]

I think the lower tray would help reduce drag under the car but not do much for the lift. You best bet to drop the pressure under the bonnet is to lower the pressure under the car by putting a splitter or air damn in front of the lower openings.

[spartacus]

Any other opinions?

[350matt]

I'd agree with Pete, It probably won't reduce lift but should definitly reduce drag.

now whether it'll stop the bonnet flapping about I'm not sure, worth a go surely?

Matt

[spartacus]

Sound like a case of "suck it and see".
One snag might be how far the front suspension wishbones travel downwards when the front suspension is at the top of its travel, I suspect they will interfere with a panel that is flush with the front chin.

[jonnyw]

I don't think that the Cerb sits close enough to the floor to warrant the total undertray and therfore rather than suck it down it could well do the opposite and create a windtunnel and positive pressure rather than the Bernoulli effect??


I reckon a front spolier is probably the better route and the Carbon one I saw on the racer that Andy at APM is building looks pretty good.

[cerber450]

Would this effect the cooling when your stuck in traffic? Just thinking that the only place cooler air will come from is the radiator area and that will be hotter than the air underneath.....possibly?????

Just a thought!

[cerealsurfer]

Carbon Cerbie had a carbon splitter attached to his car, plans were to go into production but never followed up on it as it was not on my priority list....

Just checked his web site... you can see it here....

www.carboncerbie.com/underconstruction.htm

no need to re-invent the wheel...... I guess

And he may be able to inform us of it's effectiveness at reducing air pressure under the bonnet as he has had it attached to his car has had it attached for a while.

[spartacus]

cerealsurfer said:

Carbon Cerbie had a carbon splitter attached to his car, plans were to go into production but never followed up on it as it was not on my priority list.... Just checked his web site... you can see it here.... www.carboncerbie.com/underconstruction.htm no need to re-invent the wheel...... I guess And he may be able to inform us of it's effectiveness at reducing air pressure under the bonnet as he has had it attached to his car has had it attached for a while.

I have tried to contact Carboncerbie through his site, but never get any reply, looks the site has not been updated for years.

[cerber450]

spartacus said:

cerealsurfer said: Carbon Cerbie had a carbon splitter attached to his car, plans were to go into production but never followed up on it as it was not on my priority list.... Just checked his web site... you can see it here.... www.carboncerbie.com/underconstruction.htm no need to re-invent the wheel...... I guess And he may be able to inform us of it's effectiveness at reducing air pressure under the bonnet as he has had it attached to his car has had it attached for a while. I have tried to contact Carboncerbie through his site, but never get any reply, looks the site has not been updated for years.

Heres his profile try that www.pistonheads.co.uk/gassing/profile.asp?h=0&memberId=33126!

I know he is very busy these days. I got mine from him and its the same as is on the black one at andys (APM).

Al is great with these things but yes a busy man and hard to get a hold of!

[slinky]

Thinking about the flappy bonnet thing, could a low pressure area above the trailing edge of the bonnet be sucking it up, rather than (or in addition to) high pressure in the under bonnet area?

slinky

[spartacus]

slinky said:

Thinking about the flappy bonnet thing, could a low pressure area above the trailing edge of the bonnet be sucking it up, rather than (or in addition to) high pressure in the under bonnet area? slinky

Could be, anyone got a wind tunnel?

[GreenV8S]

I expect there will be a huge low pressure area over the front and middle of the bonnet, and a smaller high pressure zone centered in the middle of the windscreen pushing the back down slightly.