K Series remote thermostat.
Discussion
I used a VVC in my kit car.
I understood that part of the problems of cooling the K engine was because the 'stat was in the inlet side of the cooling system. Such that in steady state light throttle running, the engine wasn't developing a lot of heat and the water was circulating with a fair proportion going via the bypass not the radiator.
When the throttle is opened wide, the engine temperature climbs, the water temp rises and eventually the 'stat opens more. This has taken a bit more time than on most cars because the higher temp water has to go all round the bypass circuit to heat the 'stat at the water inlet instead of the exit.
When the stat opens, water cooler than the engine is let in from the radiator circuit, which doesn't get a chance to mix in with the hotter bypass water as the mixing point is right by no1 cylinder. The cooler water hits the hot engine all of a rush and that part of the engine suffers a thermal ramp.
I was also told that this was far worse on rear engine applications (like my GTM) as the radiator is further from the engine, so I fitted the QED item. I was also told that the K series was more sensitive than most to abuse by running from cold. So I never gave it full throttle or more than 4000 until I knew the oils was up to temp. I didn't have any HGF problems with my 143VVC and it did mostly track and motorway miles.
I also believe that a relatively small number of VVC powered Caterhams had HGF problems. Probably due to a very simple cooling circuit.
I understood that part of the problems of cooling the K engine was because the 'stat was in the inlet side of the cooling system. Such that in steady state light throttle running, the engine wasn't developing a lot of heat and the water was circulating with a fair proportion going via the bypass not the radiator.
When the throttle is opened wide, the engine temperature climbs, the water temp rises and eventually the 'stat opens more. This has taken a bit more time than on most cars because the higher temp water has to go all round the bypass circuit to heat the 'stat at the water inlet instead of the exit.
When the stat opens, water cooler than the engine is let in from the radiator circuit, which doesn't get a chance to mix in with the hotter bypass water as the mixing point is right by no1 cylinder. The cooler water hits the hot engine all of a rush and that part of the engine suffers a thermal ramp.
I was also told that this was far worse on rear engine applications (like my GTM) as the radiator is further from the engine, so I fitted the QED item. I was also told that the K series was more sensitive than most to abuse by running from cold. So I never gave it full throttle or more than 4000 until I knew the oils was up to temp. I didn't have any HGF problems with my 143VVC and it did mostly track and motorway miles.
I also believe that a relatively small number of VVC powered Caterhams had HGF problems. Probably due to a very simple cooling circuit.
Paul Drawmer said:
I used a VVC in my kit car.
I understood that part of the problems of cooling the K engine was because the 'stat was in the inlet side of the cooling system. Such that in steady state light throttle running, the engine wasn't developing a lot of heat and the water was circulating with a fair proportion going via the bypass not the radiator.
When the throttle is opened wide, the engine temperature climbs, the water temp rises and eventually the 'stat opens more. This has taken a bit more time than on most cars because the higher temp water has to go all round the bypass circuit to heat the 'stat at the water inlet instead of the exit.
This is exactly what the PRT fixes, it opens under pressure as well as temperature so even with a cold engine it will open if the engine is run at high RPM, preventing localized overheating and cycling of the thermostat.I understood that part of the problems of cooling the K engine was because the 'stat was in the inlet side of the cooling system. Such that in steady state light throttle running, the engine wasn't developing a lot of heat and the water was circulating with a fair proportion going via the bypass not the radiator.
When the throttle is opened wide, the engine temperature climbs, the water temp rises and eventually the 'stat opens more. This has taken a bit more time than on most cars because the higher temp water has to go all round the bypass circuit to heat the 'stat at the water inlet instead of the exit.
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