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has anyone installed a lower temperature thermostat in the lotus v8's. I had a gmc typhoon and syclone that i installed a lower thermostat in to help with detination. It has been along time ago but i believe stock was 180F so the syty board say to put in 160F. do or do not do...that is the guestion. Also what about say 2 7" fans on air inlet side of radiator to run all the time because stop and go traffic engine gets to 100C all the time. The fans move 1100cfm each and only pull 3 amps each...
 

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If you are having cooling problems you should try to find the source. If the car is overheating it is probably because the radiator is plugged up with debris. If that is the case it wouldn't matter if you removed the thermostat. As for the fans, they only run when they have to. The ECU turns them on and off at the set temperatures. Modern motors have to run at the particular temperature they were designed for. Running them too cool will only mess with the ECU and it will just try to warm it up more.
David Teitelbaum
 

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If you are having cooling problems you should try to find the source. If the car is overheating it is probably because the radiator is plugged up with debris. If that is the case it wouldn't matter if you removed the thermostat. As for the fans, they only run when they have to. The ECU turns them on and off at the set temperatures. Modern motors have to run at the particular temperature they were designed for. Running them too cool will only mess with the ECU and it will just try to warm it up more.
David Teitelbaum
Is there a way to get the ECU to turn on the fans sooner?

If normal temp is 82degC, and the fans don't come on until 100degC, that's another 30degF over normal running temp!

Why do they do that?

Higher temperature = higher pressures, which is the last thing you want in an Esprit V8 engine. If that extra pressure causes a cooling system leak, it's liable to blow the liners.

On my 91 SE, I installed a switch that allowed manual override, but it would be nice to just get the ECU to turn on the fans at say 85degC.

I would also like the coolant recirculation pump to come on after stopping the car always if possible. Soak heat is hard on an engine, and all the work has been done to provide cooling after a run, but it's practically never used because the ECU won't turn on the recirculation pump unless the engine is crazy hot (40 degF over normal temps) at shutdown.

I guess I could make a circuit with a timer that triggers the recirculation pump and radiator fans after sensing the engine is off for say 4 or 5 minutes.
 

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This is taken directly from my V8 manual...."During periods of idling or in heavy traffic, the temperature may rise to over 100ºC, but need not be of concern since the pressurized system raises the coolant boiling point to 120ºC."

I read this to mean that getting to 100ºC would be considered normal......as long as the fans kick on at that point.
 

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Yea, I've read that too.

But why would you want the extra temp and coolant system pressure of 30degf more in your system, especially if you have a V8 with the old sealant????

You have the old sealant unless you've already done a rebuild.
 

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The engine and all of the clearances inside have been designed for the temperatures the motor will operate at. The ECU is pre-programed to run the motor in the designed temperature range. Unless you are going to redesign the whole system I would not try messing with anything. If you try to "fool" the ECU it will just try compensating in some way to try keeping the motor within it's designed operating parameters. If it gets too hot there are things the ECU will do to reduce the heat load. This is all assuming the cooling system is in good operating condition. If you are very concerned about heat soak after a spirited run, drive the car easy and let it idle for a few moments before shutting it down. If the "old sealant" hasn't caused you any problems by now it probably won't unless you really cook the motor because the cooling system has problems and the motor overheats. In such a case you have more to worry about then the sealant. You will warp the heads and blow the head gaskets. If you are worrying about the circulation pump, test it and make sure that system is working as it should. BTW, the fans are not required when you are moving fast enough so turning them on at a lower temp won't do you anything unless the car is stopped or moving slowly.
David Teitelbaum
 

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Everything is working to spec on my car. I even used the V8 software to manually turn on the recirc pump to test it.

Not trying to get the car to run outside its specs, so don't worry about that.

What I want to do is keep it on the least stressed part of those specs for longevity. These cars have trouble surviving as evidence of the posts of failures. Keeping them less stressed is a good thing in my mind.
 

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I agree that things will last longer the less stress you put on them. Everything has been designed to operate together at the temperatures that will be encountered as long as everything is working properly. Keep an eye on the temp gauge and don't flog the car and everything should survive. Change the fluids regularly and service it as recommended with good parts and fluids. Test the low coolant level switch and check the coolant level, oil level and tire pressures weekly. Some have considered and installed a pre-oiler accumulator to prevent dry start-ups. Overkill in my opinion but it can't hurt except to add weight and complexity. It can also help with cooling, it adds some extra oil. There are also 2 oil coolers up front. You can put fans on them too!
David Teitelbaum
 

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For my drive home I happen to have a slow drive to my house after a fast stretch and I find that my fans kick on just as I'm shutting down in my shop. Also on the track, when I pull into the pits I like to idle a little to keep the oil flowing through the torbos for a little while as they cool and although the water temp is good as I pull in it quickly rises with the heat soak until the fanks click on in short order. For both these situations I have found that a simple fan override switch to proactively start some cooling is helpful.

For my use I just re-purposed the rear heated screen switch to turn the fans on (it's a simple tweak involving pulling the rear screen fuse and plugging in a fused lead in its place to a simple circuit that activvates the fan relay).

Knut
 

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There are also 2 oil coolers up front. You can put fans on them too!
David Teitelbaum
I did this on my V8 with a couple of Spal motorcycle fans, wired to come on with the main fans. They are very small but move a lot of air:

SPAL USA

As others have said though - the fans are really only for when the car is not moving.
 
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