Cheshire Cat Posted 11June, 2018 Report Share Posted 11June, 2018 Gents could you please explain me a simple thing? What functions the engine tin and shroud do? I assume that one of those functions is heat shield for the intakes. Am I correct? Link to comment Share on other sites More sharing options...
Coastr Posted 11June, 2018 Report Share Posted 11June, 2018 Not the expert, but my understanding is that the engine tin serves two purposes - it seals the engine bay so that the fresh air drawn in by the fan comes through the grill on the engine lid, and it also provides insulation against hot air from the exhaust rising up into the engine. If it isn’t there higher engine temps esp at idle would be the result. Some works race cars have no tin. the shroud just takes air from the fan and directs it over the cylinders fins Not the expert, but my understanding is that the engine tin serves two purposes - it seals the engine bay so that the fresh air drawn in by the fan comes through the grill on the engine lid, and it also provides insulation against hot air from the exhaust rising up into the engine. If it isn’t there higher engine temps esp at idle would be the result. Some works race cars have no tin. the shroud just takes air from the fan and directs it over the cylinders fins. Neither is for cooling the engine intakes as cylinder cooling is the primary purpose. The fact that the factory race cars don’t ever seem to run a cold air intake seems to indicate that intake temps were ever an issue. That also is the case on a street car because the fan creates negative pressure in the engine bay, so you never get rising hot air into the intake. You can see this looking at the heat haze on a hot day - when a hot 911 is switched off you’ll see a ton of heat radiating up out of the grill. Turn it on and that will disappear as the fan pulls in fresh air. There is enough vacuum to hold a sheet of a4 against the engine grill. Link to comment Share on other sites More sharing options...
Cheshire Cat Posted 11June, 2018 Author Report Share Posted 11June, 2018 4 hours ago, Coastr said: Not the expert, but my understanding is that the engine tin serves two purposes - it seals the engine bay so that the fresh air drawn in by the fan comes through the grill on the engine lid, and it also provides insulation against hot air from the exhaust rising up into the engine. If it isn’t there higher engine temps esp at idle would be the result. Some works race cars have no tin. the shroud just takes air from the fan and directs it over the cylinders fins Neither is for cooling the engine intakes as cylinder cooling is the primary purpose. The fact that the factory race cars don’t ever seem to run a cold air intake seems to indicate that intake temps were ever an issue. That also is the case on a street car because the fan creates negative pressure in the engine bay, so you never get rising hot air into the intake. You can see this looking at the heat haze on a hot day - when a hot 911 is switched off you’ll see a ton of heat radiating up out of the grill. Turn it on and that will disappear as the fan pulls in fresh air. There is enough vacuum to hold a sheet of a4 against the engine grill. So basically both of them (more or less) do work as a heat shield. Air intake temp is a thing to consider, have found on pelcans that the difference might be quite serious, between hot run and just run... up to 20 degreese. On Singers\Williams car they have a big solution to get a frash air from outside and to block all that hot air from the intake. Anyway, those are the high end level of engineering. But, what my purpose is - to find out, if there is any chance the additional heat shield might help to block some of hot air from the cylinders to come in to the intake? Has anyone seen or heard or done it himself? What I mean - there is a heatshield foil (heat barrier, not exactly this one, it`s just as an example), would it help if say we apply this foil on a bottom side of engine tin and shroud? Does it make any sense? Link to comment Share on other sites More sharing options...
clutch-monkey Posted 11June, 2018 Report Share Posted 11June, 2018 it would help, question would be how much- your engine bay is a pressurised airbox drawing air through your engine shroud/fan, when moving the heat soak would not be too bad. worth a try regardless imo. Link to comment Share on other sites More sharing options...
Cheshire Cat Posted 12June, 2018 Author Report Share Posted 12June, 2018 11 minutes ago, clutch-monkey said: it would help, question would be how much- your engine bay is a pressurised airbox drawing air through your engine shroud/fan, when moving the heat soak would not be too bad. worth a try regardless imo. that is exactly what I think. but, probably I am just overthinking, what if I meddle with cylinders cooling system? Lower (if it works) temps on the intake migh make higher temps on the cylinders? Again, just curious since I`m there... Link to comment Share on other sites More sharing options...
Coastr Posted 12June, 2018 Report Share Posted 12June, 2018 Heatshield on the engine tin would be easy to try. Just get an IR thermometer and test the surfaces after different types of running. You’ll soon see if you can lower temps. Easy to wire up a temp sensor in the intake as well to see if you are making a difference. It will all be about heat in traffic rather than at speed. Link to comment Share on other sites More sharing options...
Cheshire Cat Posted 12June, 2018 Author Report Share Posted 12June, 2018 55 minutes ago, Coastr said: Heatshield on the engine tin would be easy to try. Just get an IR thermometer and test the surfaces after different types of running. You’ll soon see if you can lower temps. Easy to wire up a temp sensor in the intake as well to see if you are making a difference. It will all be about heat in traffic rather than at speed. I do have a sensor but to make it work I have to put the engine back together first :)) Link to comment Share on other sites More sharing options...
clutch-monkey Posted 12June, 2018 Report Share Posted 12June, 2018 2 hours ago, Cheshire Cat said: that is exactly what I think. but, probably I am just overthinking, what if I meddle with cylinders cooling system? Lower (if it works) temps on the intake migh make higher temps on the cylinders? Again, just curious since I`m there... Like running on e85, ceramic coating pistons and chambers? back in the day some SCCA racers would set up a fine water nozzle spraying into the engine fan on hot days when racing Link to comment Share on other sites More sharing options...
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