Throttle Body By-Pass Value discussion
05-31-2014, 07:52 AM
#102
LOL....
All of this has got me thinking though that the heater re-circ path is more of a culprit than it gets credit for. The water pump, no matter the model, should be pumping water through the engine and the radiator. If the flow through the radiator is reduced, buy looping water through the heater core as opposed to the radiator (assuming the thermostat is open), then you lose cooling capacity.
Also, from the sketches, the water that goes to the heater comes off the back of the engine, as opposed to flowing across the hot half of the motor. Which means that the part of the engine that generates the most heat, is getting the least water, which will raise the temps more. Just sending additional volume through the hot side will reduce the temp of the water coming out. After all, temp is measured right at the thermostat. Now, all this may eventually overcome the cooling system, but at least it got a chance. What I would really like to know is the water temp coming out of the radiator when all of this is going on....
I think the valve is going on. A track test would be to run it open until temps start to climb, then close it most of the way and see if that cures the problem. This may not help the FI guys (OD) but may be enough for us mortals.
The premise is that more water will flow through the radiator, when the thermostat is open, if the heater loop is restricted or closed off.
I feel sorry for anyone looking for this thread where it ended up developing...
All of this has got me thinking though that the heater re-circ path is more of a culprit than it gets credit for. The water pump, no matter the model, should be pumping water through the engine and the radiator. If the flow through the radiator is reduced, buy looping water through the heater core as opposed to the radiator (assuming the thermostat is open), then you lose cooling capacity.
Also, from the sketches, the water that goes to the heater comes off the back of the engine, as opposed to flowing across the hot half of the motor. Which means that the part of the engine that generates the most heat, is getting the least water, which will raise the temps more. Just sending additional volume through the hot side will reduce the temp of the water coming out. After all, temp is measured right at the thermostat. Now, all this may eventually overcome the cooling system, but at least it got a chance. What I would really like to know is the water temp coming out of the radiator when all of this is going on....
I think the valve is going on. A track test would be to run it open until temps start to climb, then close it most of the way and see if that cures the problem. This may not help the FI guys (OD) but may be enough for us mortals.
The premise is that more water will flow through the radiator, when the thermostat is open, if the heater loop is restricted or closed off.
I feel sorry for anyone looking for this thread where it ended up developing...
05-31-2014, 10:45 AM
#103
Driving my unreliable rx8
Im pretty sure the water that goes to the combustion side of the engine first then to the heater and back to the front of the block.
That recirculated waster is bypassing the intake side.
Otherwise i agree a sensor on the bottom hose also would be your best indicator that you are maxing out the radiator.
Increasing flow to the radiator could also potentially be bad. If the water in it does not get enough time to cool off. In a double pass radiator i don't think that would be a problem though.
That recirculated waster is bypassing the intake side.
Otherwise i agree a sensor on the bottom hose also would be your best indicator that you are maxing out the radiator.
Increasing flow to the radiator could also potentially be bad. If the water in it does not get enough time to cool off. In a double pass radiator i don't think that would be a problem though.
05-31-2014, 05:45 PM
#105
Driving my unreliable rx8
I used the small supply and return hose from the throttle body to supply my heater core with water. It also acts as a restrictor that way overall flow is reduced. There is a shutoff valve for the heater core.
On the 5/8 inlet and outlet I have a hose direct with a valve. Shortly this will run into a cooler and from the cooler into my turbo.
The results; this summer highest temps have been 91F. Ft Worth area.
During the winter with them closed my engine would never get to 190 no matter how hard I ran it. Crusing down the highway it would stay at 160's with them closed. So I had to have both of them open.
So far this year summer I can not tell any differance. Crusing down the highway I have 175-180 Engine temps and my oil temps match it. If I get on it hard my oil temp(at the filter) gets up to 210, my water temps never go over 200. I see about the same with the valves open or closed.
I'll see what happens once the temps get in the 100's.
I have the CSF radiator with custom sheet metal ducting. I've removed the air filter tray. Mazmart thermostat, stock water pump. New stock style hoses that are 2 years old 6000 miles. I have a radiator(12x12x2) for the intercooler installed in front of the A/C condensor, but it is not being used yet.
My car Idles very high temp. If it is sitting still the temps will get up to 210. for oil and water
On the 5/8 inlet and outlet I have a hose direct with a valve. Shortly this will run into a cooler and from the cooler into my turbo.
The results; this summer highest temps have been 91F. Ft Worth area.
During the winter with them closed my engine would never get to 190 no matter how hard I ran it. Crusing down the highway it would stay at 160's with them closed. So I had to have both of them open.
So far this year summer I can not tell any differance. Crusing down the highway I have 175-180 Engine temps and my oil temps match it. If I get on it hard my oil temp(at the filter) gets up to 210, my water temps never go over 200. I see about the same with the valves open or closed.
I'll see what happens once the temps get in the 100's.
I have the CSF radiator with custom sheet metal ducting. I've removed the air filter tray. Mazmart thermostat, stock water pump. New stock style hoses that are 2 years old 6000 miles. I have a radiator(12x12x2) for the intercooler installed in front of the A/C condensor, but it is not being used yet.
My car Idles very high temp. If it is sitting still the temps will get up to 210. for oil and water
Last edited by logalinipoo; 05-31-2014 at 05:49 PM.
05-31-2014, 07:01 PM
#106
When the car is stationary the coolant temp is dictated by the fan settings and their flow capacity. The oil coolers only receive air flow when the car is moving.
Measuring radiator outlet temp is probably not sufficient when there are other hoses supplying uncooled coolant after the sensor. It likely needs to be located in the water pump face to see the true temp entering the engine.
Measuring radiator outlet temp is probably not sufficient when there are other hoses supplying uncooled coolant after the sensor. It likely needs to be located in the water pump face to see the true temp entering the engine.
06-01-2014, 09:41 AM
#107
@ Loga. You are right. I remembered wrong. The water is what keeps the cold side warm.
For the flow in the radiator... Too fast is not good, agreed. But too slow is bad too. The radiator dumps heat based on the temp difference between the water and the air. If the flow is too slow, the temp drops a lot, and less heat is rejected. So, up to a point, more flow is better, then it is not.
This is the reason for the radiator out temp sensor. If 200 degree water turns into 180 degree water, radiator is likely saturated.. If 200 degree water becomes 140 degree water, I think it could stand a little more flow. There might be a set of static tests I can run if I think about it a bit more. I kind of wish I had thought the turn on the heater the last time I was at the track, but I am not sure what that would have really meant.
For the flow in the radiator... Too fast is not good, agreed. But too slow is bad too. The radiator dumps heat based on the temp difference between the water and the air. If the flow is too slow, the temp drops a lot, and less heat is rejected. So, up to a point, more flow is better, then it is not.
This is the reason for the radiator out temp sensor. If 200 degree water turns into 180 degree water, radiator is likely saturated.. If 200 degree water becomes 140 degree water, I think it could stand a little more flow. There might be a set of static tests I can run if I think about it a bit more. I kind of wish I had thought the turn on the heater the last time I was at the track, but I am not sure what that would have really meant.
06-01-2014, 09:59 AM
#108
Driving my unreliable rx8
If you flow it through too fast then you could end up with it not getting cool enough. It takes time to reject the heat. Too fast of a movement might result in the water not cooling off.
Now that will depend on your radiator. A double pass will allow the water twice the time in the radiator and a double core will technically do the same. If you double the volume then it will flow through it at half the speed.
Now that will depend on your radiator. A double pass will allow the water twice the time in the radiator and a double core will technically do the same. If you double the volume then it will flow through it at half the speed.
06-01-2014, 10:29 AM
#109
no, no, and no, you have that all wrong but they're common misconceptions
2 pass radiator; all else being equal you are only flowing through the equivalent of 1/2 radiator flowpath (whole thing at once vs 1/2 - 1/2 in series) so the flow is going through twice as fast; high flow = turbulence, turbulence is good for heat transfer
in general faster is always better up to a point, but why have the same old argument again ... (kind of have to read the whole thing)
gutting the thermostat... - RX7Club.com
.
2 pass radiator; all else being equal you are only flowing through the equivalent of 1/2 radiator flowpath (whole thing at once vs 1/2 - 1/2 in series) so the flow is going through twice as fast; high flow = turbulence, turbulence is good for heat transfer
in general faster is always better up to a point, but why have the same old argument again ... (kind of have to read the whole thing)
gutting the thermostat... - RX7Club.com
.
Last edited by TeamRX8; 06-02-2014 at 11:01 PM.
03-03-2015, 07:59 AM
#110
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I hate to bring up shut from 8 years ago.... And sorry to say I didn't want to read all 11 pages.
But....
The coolant line runs through the throttle body mainly to keep it from icing over in the winter. Also the coolant warms up faster then the intake manifold so it does help heat the throttle body up in winter. Not noticeably though.
On the 4th generation fbodys they have dyno proven 7hp gain from stock to stock with bypass. Obviously that doesn't mean the rotary will see any power gain.
On my lt1 camaro I did the throttle body bypass like I do on every vehicle I own. Last winter when ambien temperatures dipped here below 0 and some days as low as -40 my intake manifold would look like the inside of a freezer. Front to back it would ice up, one day after work when i got home it had over 1/4 of ice on it.
Now obviously with wind hills dipping to -55 in Wisconsin last year it's a bit colder then our cars will ever see. This year it hasn't got anywhere near that cold.
Just thought I would chime in with a little info.
Also I left it that way and the ice never caused a problem except horrible fuel economy. The throttle plates themselves never iced up.
But....
The coolant line runs through the throttle body mainly to keep it from icing over in the winter. Also the coolant warms up faster then the intake manifold so it does help heat the throttle body up in winter. Not noticeably though.
On the 4th generation fbodys they have dyno proven 7hp gain from stock to stock with bypass. Obviously that doesn't mean the rotary will see any power gain.
On my lt1 camaro I did the throttle body bypass like I do on every vehicle I own. Last winter when ambien temperatures dipped here below 0 and some days as low as -40 my intake manifold would look like the inside of a freezer. Front to back it would ice up, one day after work when i got home it had over 1/4 of ice on it.
Now obviously with wind hills dipping to -55 in Wisconsin last year it's a bit colder then our cars will ever see. This year it hasn't got anywhere near that cold.
Just thought I would chime in with a little info.
Also I left it that way and the ice never caused a problem except horrible fuel economy. The throttle plates themselves never iced up.
03-08-2015, 07:30 PM
#113
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This thread was posts extracted from the DIY thread, because it was just a lot of arguing contrary to the "what belongs in the DIY section" definition. I continue moving those posts out of the DIY thread for that reason.
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