My q is that when u have a cold car and thermostat is closed, wouldnt that put load on water pump. i believe that thermostat has a bypass valve but that thing is tiny.

 

it will make more problems that just that man... never race a car cold

 

The biggest problem is that you won't have oil pressure. Your car will NOT get the lubrication it needs and **** will start to break after a little while.

 

I just want to make sure that thermostat will cause a load and power loss.
Look at all kids pushing their cars to the line, they might has been loosing power that way.?

 

Dude..

The thermostat isn't a problem at all. The water pump will push water through the coolant passages until the water gets hot enough then the thermostat will open the circuit to include the radiator. It doesn't matter what revs the engine is at. and that doesn't affect horsepower whatsoever. (just the teeniest bit of parasitic drag)

The issue is a lack of lubrication.

 

the other problem because you will have oil pressure but if the thermostat is not open and the car is not at operating temperature then most of the internal parts are not going to be seated fully. metal expands when it gets hot thats why internal parts have clerances when the engine is still cold those clearances are still big.

take a piston engine for example when the car is cold you will have some amount of blow by around the pistons new or not. when the engine is warmed up the rings are expanded and the slack is taken up and no more blowby. that is also why older engines will have cold start flooding issues then be fine once they are at operating temps. because the metals expand and the combustion chamber is sealed.

never race a cold engine

 

your car will be faster cold, but you will also damage oil and water seals.

 

it will only be faster cold assuming the air is cold, if you run a car "cold" in the desert it will only be faster by a marginal amount, it depends on the ambiant air temp under the hood and coming from the intake runners

 

You need to do http://fc3spro.com/TECH/HOWTO/OTB/otb.html

and dont run it cold anyways.