Optimum Working temprature for CBR600f4i

[Mohammad Saad]

Hi! I have a CBR600f4i engine 2003 model. Recently I took log of engine temperature and found the average temperature to be somewhere around 104deg Celsius(220farhenite). In the middle, spikes of upto 116deg Celsius were also seen. Since we're using only distilled water without any additives(rule requirement), steam must be flowing within the circuit. I would just like to know that whether it is safe to run engine under these conditions? And if not, what else can be done to get the engine temperature under control.

Any kind of help would be appretiated.!

Thanks in advance.!

[MCoach]

Why would you say there must be steam in the circuit?

[Kareem]

I think the inlet temperature to engine is about 85 degrees and outlet is 95 degrees for CBR600.

How did you get the (104,116) degrees? did you measure it? if so under what conditions?

[apalrd]

Hi! I have a CBR600f4i engine 2003 model. Recently I took log of engine temperature and found the average temperature to be somewhere around 104deg Celsius(220farhenite). In the middle, spikes of upto 116deg Celsius were also seen. Since we're using only distilled water without any additives(rule requirement), steam must be flowing within the circuit. I would just like to know that whether it is safe to run engine under these conditions? And if not, what else can be done to get the engine temperature under control.

Any kind of help would be appretiated.!

Thanks in advance.!

A normal radiator cap will release at ~1 bar. So, the cooling system pressure will be regulated to ~1 bar gauge, as the water is heated and expands the pressure will rise and the cap will release the excess water into the overflow bottle.

This is significant because the pressure in the system when hot will always be higher than atmospheric. At 200 kPa abs pressure (1 bar + 1 bar atmospheric), the boiling point of water is ~121 deg C, which is above the 116deg C you are seeing. Thus, no boiling and no steam.

I don't think you have any problem at 116 deg C. It sounds like the system is working fine.

[Forbes]

Mohammad,

See here: http://www.engineeringtoolbox.com/boiling-point-water-d_926.html

[BillCobb]

Use OptimumWT programme from OptimumG. Also pages 891 - 892 in Race Car Vehicle Thermal Dynamics.

[Jonny Rochester]

From just minimal engine tuning experience, I would also judge 105 - 115 degreesC was a little high.

With our CBR the thermostat opens at 82deg C, which is also normal for most cars. The racing thermostat available opens at 62deg C.

The stock water temp sensor is in the thermostat housing (water outlet), and we mostly see temps under 100 deg. I have set the fans to come on when that sensor sees 95deg, and it's controlled well (we have 2 radiators, with a fan at each). When the engine is turned off
that sensor starts to see higher temps as there is no water flow.

Some ideas to help cooling: A bit more fuel helps low combustion temps, is it on the ragged edge of lean? Ignition maybe too retarded in places, that wouldn't help either.
Size of radiator? Fan shroud design?

[Mohammad Saad]

@MCoach
The fluid reservoir needs to be refilled after every run. Perhaps water in form of steam escapes through reservoir.

[Mohammad Saad]

@Kareem
Engine coolant temperature sensor gave me the readings. The temperature was measured after normal running of the car.

[Mohammad Saad]

@apalrd
Thanks for the response. Now i know this must not be a steam problem. Even if it's fine to run engine under such conditions, i would like to get it under 100deg celcius. If you have anything to help with, it would be highly appretiated.

[Mohammad Saad]

@Jonny Rochester
Yes we can try on changing mix strength and ignition timings. We're working on it. Thanks for advice.
We have a double pass radiator with dimensions of about 9"*11". Shroud leaks as of now, new design on the way.

But would like to know if somehow we fail to get the engine temprature down below 116deg, will it still be fine to run it under theses conditions?

(Not to mention that only a few spikes of 116deg were seen, the average temperature in the log was about 104deg celcius.)

[Jonny Rochester]

@MCoach
The fluid reservoir needs to be refilled after every run. Perhaps water in form of steam escapes through reservoir.

You have a problem then. You could have a blown headgasket causing an internal water loss, or your radiator cap may not be working as it should. I have the radiator cap overflow hose running all the way down inside the overflow bottle (as it is in Toyotas and other cars).
That way the engine can suck water back in and top itself up.

[Mumpitz]

If your car has only been run a few times you may just be purging air bubbles trapped on the initial fill. Is your overflow setup to siphon water back in as it cools or are you just purging out as it expands?