Originally Posted by beast
the heat is coming from heat under the bonnet not being able to escape and hopefully by insulating the items ive listed this heat will be reflected by the paint rather than heating up the plenum and inlets.
i personally think that high inlet temp drop power on a turbo car more than an n/a car.this is just from experience of having owned a turbo car and having lost way more power on it than on any n/a car on a hot day.
think with the rx7 is that theres way more open space under the bonnet than there is on a 156 v6 and also the rx7's inlet manifold is way longer than the ones on the 156 so they have a bigger area to effectively dissipate heat more quickly
Hmm, if the inlet manifold is heated up from the air under the bonnet, then then the bonnet and all the other metalwork under the bonnet must be absolutely scorching; is this the case?
I wasn't trying to say that N/A and turbo cars suffer from ambient temperature the same, I was saying that they suffer from inlet manifold temperature the same; ie if you've got air going into the engine at 70C is doesn't matter whether thats due to a turbo, or heat soak through the intake, it still has the same effect of reducing the mass of air getting into the cyclinder.
Also, if the extra length of the intake manifold helps dissipate the heat, then that implies heat is getting out of the intake, rather than into it, so insulating it will hold it in?
PS, there may be a bit more space under an RX7 bonnet, but not a lot; and have you seen the way they arrange everything? The intake has got two turbos behind it, and intercooler to one side, and the radiator in front of it. Doh
For my RX, I'm planning to wire up a thermocouple on the intake, and put some thermal stickers around the place to see what's going on because it heat soaks like crazy. (I had a water temperature of 85C 5 hours after getting in to work this morning!) I'm convinced that the answer is to manage the general air flows under the bonnet; but that's for temperatures around 60C max. If that's the temperatures you're getting then I'd agree that insulating the intake is maybe the way to go, but if its getting to the 100C region I really don't see the underbonnet air temperatures getting that hot?