High under bonnet temps....raising rear of bonnet

[Lawbags]

Does this actually work or is it just a myth?

Like this (not my car...1st image I found)

[Ray Luxury-Yacht]

I'd imagine the high-pressure air flowing over the top of the gap creates low pressure under the bonnet hence hot air gets sucked out.

[TheEnd]

It will work, but it's mostly done for the looks, "because race car".

[kambites]

Impossible to tell from a picture it'll depend on the exact nature of the air-flow over the interface between the bonnet and the windscreen.

[Nurburgsingh]

TheEnd said:

It will work, but it's mostly done for the looks, "because bell end".

fixed that for you..

[Lawbags]

Nurburgsingh said:

TheEnd said:

It will work, but it's mostly done for the looks, "because bell end".

fixed that for you..

Yeah, but tbh, if it works, I don't really care what it looks like. I did look into a bonnet vent, but the price for one to be fitted on a carbon bonnet is stupid.

[V8RX7]

Test it with tell tales.

I suspect it doesn't work and air might come in - this can reduce the pressure differential hence LESS air flowing through the rad.

[Krikkit]

Since there's usually a high-pressure, low-flow build-up at the bottom of the windscreen (hence why inlets for heater vents are usually placed there), I doubt it.

[s p a c e m a n]

The only reason that I ever did that (and I went proper retro chav and used a stack of washers) was because the engine didn't fit, as shown by the dent in the bonnet from the inlet manifold

Think the theory is that it creates a low pressure area at the bottom of the windscreen so sucks the air out from under the bonnet, I want to see workings in a wind tunnel with smoke trails and bits of ribbon before I believe it though.

[Lawbags]

Any other suggestions for reducing under bonnet temps?

Would the less air flowing through the rad be the same id I fitted a vent?

[Chicane-UK]

Better / uprated radiator? Standalone oil cooler?

[kambites]

Lawbags said:

Any other suggestions for reducing under bonnet temps?

Would the less air flowing through the rad be the same id I fitted a vent?

If you have less air flowing through the radiator, your engine will get hotter because it's not being cooled by the radiator. If anything, you want to increase flow through the radiator.

[s p a c e m a n]

Exhaust wrap is up there although it just moves the heat further down the exhaust. Where are the cats? They cause a lot of heat so if they're up the front it doesn't help.

[Lawbags]

kambites said:

Lawbags said:

Any other suggestions for reducing under bonnet temps?

Would the less air flowing through the rad be the same id I fitted a vent?

If you have less air flowing through the radiator, your engine will get hotter because it's not being cooled by the radiator.

Yeah, that's what I mean. If it's the same, I'll scrap that idea too.

[Lawbags]

Chicane-UK said:

Better / uprated radiator? Standalone oil cooler?

The engine oil/water/egt temps are spot on, it's the under bonnet temps I want to bring down.

[kambites]

Lawbags said:

Chicane-UK said:

Better / uprated radiator? Standalone oil cooler?

The engine oil/water/egt temps are spot on, it's the under bonnet temps I want to bring down.

If the engine temperature is fine, why on earth do you want to bring down the under-bonnet temperature?

[Lawbags]

s p a c e m a n said:

Exhaust wrap is up there although it just moves the heat further down the exhaust. Where are the cats? They cause a lot of heat so if they're up the front it doesn't help.

It has no cats and I can't wrap the mani. Worth doing just the downpipe?

[GroundEffect]

NO.

The end.

[Who me ?]

Clean out cooling system ,and in meantime , keep check of engine temp on gauge, if it goes high switch on heater /on outlet of vents ( if it gets cold, stop and check water level). With things normal ,you shouldn't need to ,but an eagle eye can save £££££££ on repairs/ new engine .

[Lawbags]

kambites said:

Lawbags said:

Chicane-UK said:

Better / uprated radiator? Standalone oil cooler?

The engine oil/water/egt temps are spot on, it's the under bonnet temps I want to bring down.

If the engine temperature is fine, why on earth do you want to bring down the under-bonnet temperature?

Because it's causing the frame for the carbon bonnet to start to fracture.