Engine bay heat

[Grandad]

Hi
To get heat out of the engine bay do we need a bonnet scoop to get air into the engine bay, or bonnet louvres to suck air out of the engine bay?
Thanks
Stephen

[roverspeed]

You don't need either unless the car is overheating.

You can remove some of the weather strip of the top of the firewall which will let hot air out up over the windscreen.

Or you can to the bonnet riser mod, but everyone will tell you that your bonnet is open.

If you are doing track days, get an oil cooler fitted to keep your oil temps down rather than chopping up your bonnet.

All imo

[dylan0451]

with regards to airflow, since the 5 has an undertray as well i'd want to add aft facing louvres, or raise the back edge of the bonnet as mentioned to increase airflow in one direction. oil cooler (with a thermostat?) sounds like a good investment regardless - was looking at the mx5parts one if it wasn't for the reviews stating it's only a partial kit

i have exhaust wrap at the moment and it reduces underbonnet temps by quite a margin

i know manifold manufacturers invalidate warranties if any kind of thermal insulation is used - something to do with a combination of the iron content in the material seperating under thermal cycling and the wrap holding moisture and rotting the manifold

no idea whether this is more apparent on higher exh temp FI'd engines with higher Fe content manifolds, but the best (not cheap) would be an inside + out ceramic coating

http://www.camcoat.u-net.com/Exhtprices2002.htm

Edited by dylan0451 on Tuesday 19th January 13:20

[Phil @ P5]

Regulate engine temperatures with a water radiator and oil cooler; don't turn it into a Beetle engine.....

Ceramic coating will help, but that's more to do with keeping the energy in the exhaust than keeping the bay cooler.

Phil

[dylan0451]

i was thinking along the lines of that ceramic coating apparently reduces radiant heat by 30% while keeping the manifold material sandwiched between the 2 layers at a coolet temp - stopping the manifold breakdown by either super high temps and/or moisture/rusting

which would then allow you to wrap up the ceramic coated manifold (even turbo) once its fully cured without fear of damaging it, dramatically reducing under bonnet temps and prolonging the life of the turbo/manifold etc.

doing that and fitting a coolant reroute to a cooling system in good condition would possibly negate the need for any extra airflow mods ?