Overheating!
07-13-2008, 06:45 PM
#276
Well after a brain storming seesion with CRH and MM I think we're going to try modifying the coolant bypass sytem. As in metering he flow down for the coolant bypass.
A few people have mentioned the aspects of that in this thread.
So when I get back to Phoenix it will be on the list of things to try.
Hopefully this will allow more coolant to be sent to the radiator and not recirculated back to the engine. This should help with the "in trqaffic" overheating issue.
Seems that filling the gaps under and beside the radiator effectively helped with any freeway heat concerns.
A few people have mentioned the aspects of that in this thread.
So when I get back to Phoenix it will be on the list of things to try.
Hopefully this will allow more coolant to be sent to the radiator and not recirculated back to the engine. This should help with the "in trqaffic" overheating issue.
Seems that filling the gaps under and beside the radiator effectively helped with any freeway heat concerns.
07-16-2008, 02:42 AM
#279
Dont know if it will make any differents but this weekend had the time....and a few(more) beers.
I cut out the fake screens on the bottom of my rear bumper. My theory was maybe it would help suck out the air from the engine and bottom of my car. Painted my muffler and cleanned up the alumn. sheild.
I cut out the fake screens on the bottom of my rear bumper. My theory was maybe it would help suck out the air from the engine and bottom of my car. Painted my muffler and cleanned up the alumn. sheild.
07-16-2008, 09:22 AM
#280
Finally Boosted!!!!!!!
Its very hard for me to tell from the FSM but where does the OEM ECT sensor get its reading from? Is the sensor located in the thermostat cover, is it in the keg somewhere, where is it located?
07-16-2008, 10:27 AM
#283
Argh, I think I have a Thermostat thats not opening fully when hot.
Cuz right now, if I drive and keep my car below 3000, the engine will enver get past 94 Celsius. but if I keep it more than 4K rpm. I will see stupid temp goes up to 105 Celsius and I have to "stop" pushing the car.
grrrrrr .... it wasnt like this b4 my coolant bottle broke. probably has something to do with the overheating b4 (when the bottle broke) and messed up the thermostat or whatever.
Damn still tryign to figure how to break loose the bolt behind the thermostat housing so I can replace the damn thing ......
Cuz right now, if I drive and keep my car below 3000, the engine will enver get past 94 Celsius. but if I keep it more than 4K rpm. I will see stupid temp goes up to 105 Celsius and I have to "stop" pushing the car.
grrrrrr .... it wasnt like this b4 my coolant bottle broke. probably has something to do with the overheating b4 (when the bottle broke) and messed up the thermostat or whatever.
Damn still tryign to figure how to break loose the bolt behind the thermostat housing so I can replace the damn thing ......
07-16-2008, 10:35 AM
#284
A thermostat is flow control. It doesn't know or care about your system's "capacity".
It just regulates the quantity of water that can pass through the radiator as a function of time and temperature.
07-16-2008, 10:42 AM
#285
you have to have proper flow to have have proper use of the cooling capacity of your system.
If you put a huge *** radiator and two 55 gph electric water pumps on your car(just for a ridiculous example) and you have a thermostat that doesnt open until 200 degrees. Then the engine will run at 200 degrees. But if you replace that thermostat with a 180 degree one then it will run at 180 degrees as long as the cooling system is not overloaded.
olddragger
If you put a huge *** radiator and two 55 gph electric water pumps on your car(just for a ridiculous example) and you have a thermostat that doesnt open until 200 degrees. Then the engine will run at 200 degrees. But if you replace that thermostat with a 180 degree one then it will run at 180 degrees as long as the cooling system is not overloaded.
olddragger
07-16-2008, 10:53 AM
#287
The temperature will be regulated by the heat exchange rate of the rad, regardless of the thermo opening point.
If you put an oversized rad and pumps in, the cooling system will never stabilize.
Increasing the mass of the water system will simply change the stasis point.
If you put heat into the system faster than you can take it out (which you ALWAYS will), it will eventually overheat.
The increased mass just makes it happen later.
In the example you state above, you would actually want the thermostat to open less so that the flow through the system is slower, so that the water spends more time in the rad cooling off.
If you put an oversized rad and pumps in, the cooling system will never stabilize.
Increasing the mass of the water system will simply change the stasis point.
If you put heat into the system faster than you can take it out (which you ALWAYS will), it will eventually overheat.
The increased mass just makes it happen later.
In the example you state above, you would actually want the thermostat to open less so that the flow through the system is slower, so that the water spends more time in the rad cooling off.
07-16-2008, 11:03 AM
#289
Finally Boosted!!!!!!!
So whats the optimal cruise (70mph) temp?
I have been anywhere between 195 and 205 for the last month or so. I have the BHR radiator and the RE-medy water pump.
I have been anywhere between 195 and 205 for the last month or so. I have the BHR radiator and the RE-medy water pump.
07-16-2008, 11:15 AM
#291
good discussion and I think we are agreeing without realizing it.
target cooling requires the right flow within a system that has the right heat exchange capacity for the results desired. too restrictive of a thermostat is not good, not enough restriction is also not good. too much heat exchange capacity is not good, too little is also not good.
It has to be a balanced system--and system is the key word.
OD
target cooling requires the right flow within a system that has the right heat exchange capacity for the results desired. too restrictive of a thermostat is not good, not enough restriction is also not good. too much heat exchange capacity is not good, too little is also not good.
It has to be a balanced system--and system is the key word.
OD
07-16-2008, 12:11 PM
#293
And that is where the problem lies because there is no such thing.
The engine will always be able to put more heat into the cooling system at some point.
If you go small, it takes less to overheat, but it is easier to reject the heat.
If you go big, it takes longer to overheat (but you still will eventually) and much longer to dissipate that heat.
Create a system that "balances" at cruise and it will overheat during burst loads.
Make a system that can maintain proper temps under hard stop-n-go and it will overheat at cruise.
Almost all of the energy produced by the Renesis is released as heat. Its amazing that the thing moves the car at all.
The big variable is ambient conditions.
In 90% or better of the operating conditions out there, the latent heat capacity of the ambient air is sufficient to pull heat out of the system at a rate greater than it is generated.
As the humidity drops and the temperatures go up, that balance point takes a steep dive. Unbelievably steep.
Just a 15% increase in relative humidity translates to a nearly 50% increase in cooling efficiency.
Out here, where the ambient temp is often above 110° and the RH is below 6%, our cooling system is working like it would in Georgia on a 200° day, of which (I presume) you have very few.
The engine will always be able to put more heat into the cooling system at some point.
If you go small, it takes less to overheat, but it is easier to reject the heat.
If you go big, it takes longer to overheat (but you still will eventually) and much longer to dissipate that heat.
Create a system that "balances" at cruise and it will overheat during burst loads.
Make a system that can maintain proper temps under hard stop-n-go and it will overheat at cruise.
Almost all of the energy produced by the Renesis is released as heat. Its amazing that the thing moves the car at all.
The big variable is ambient conditions.
In 90% or better of the operating conditions out there, the latent heat capacity of the ambient air is sufficient to pull heat out of the system at a rate greater than it is generated.
As the humidity drops and the temperatures go up, that balance point takes a steep dive. Unbelievably steep.
Just a 15% increase in relative humidity translates to a nearly 50% increase in cooling efficiency.
Out here, where the ambient temp is often above 110° and the RH is below 6%, our cooling system is working like it would in Georgia on a 200° day, of which (I presume) you have very few.
07-16-2008, 01:11 PM
#294
I just came back from Sears with some Craftsman sockets.
I wonder should I just go get like a big tool set like this one instead of keep buying parts from here and there
http://www.sears.com/shc/s/p_10153_1...000P?adCell=A3
2 Problems with getting the set
- there're tons of 12 pt or 8 pt sockets in the set which I probably never need. All this car need is a 6 pt socket, right ?
- Plus I already have some of the sockets in the set in my garage (Duralast, Powerbuild, Husky, etc)
it will be great if I can sell my old sockets/tools on ebay. but I doubt anyone gonna buy it. Aye
Oh Hey, the manual saids to replace the O-Ring (No. 6), but I cant find the part in the service manual. how come ?
Last edited by nycgps; 07-16-2008 at 01:28 PM.
07-16-2008, 03:57 PM
#296
2005 Ti Gray RX-8 - SOLD
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-C
07-16-2008, 04:23 PM
#298
2005 Ti Gray RX-8 - SOLD
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Out comes the sub-box.....
wait, what is the weight of water again, 8 lbs/gal? Crap, we'll have to go with a smaller tank! Just fill up water the same time as the oil.....and the gas!!!! Argg!!!
wait, what is the weight of water again, 8 lbs/gal? Crap, we'll have to go with a smaller tank! Just fill up water the same time as the oil.....and the gas!!!! Argg!!!