New Product: All-Alluminum Replacement Coolant Reservoir
07-01-2013, 10:31 PM
#77
Rennlist Member
OEM pressure is 13 psi. Raising the cap pressure to 16 raises the coolant boiling point by 48 degrees. Raising it to 20 psi raises the boiling point another 12 degrees. Odd that its not anywhere near a linear progression. This info comes from Carl... http://www.928motorsports.com/parts/radcap.php
Was just curious if anyone had tried the higher psi cap. Looks like 16 psi might be a nice compromise. Tis a good point about the hoses likely being a weak link in a higher pressure system. The radiator and expansion tank can take it, but what about the hoses...
Was just curious if anyone had tried the higher psi cap. Looks like 16 psi might be a nice compromise. Tis a good point about the hoses likely being a weak link in a higher pressure system. The radiator and expansion tank can take it, but what about the hoses...
07-01-2013, 10:43 PM
#78
Former Sponsor
OEM pressure is 13 psi. Raising the cap pressure to 16 raises the coolant boiling point by 48 degrees. Raising it to 20 psi raises the boiling point another 12 degrees. Odd that its not anywhere near a linear progression. This info comes from Carl... http://www.928motorsports.com/parts/radcap.php
Was just curious if anyone had tried the higher psi cap. Looks like 16 psi might be a nice compromise. Tis a good point about the hoses likely being a weak link in a higher pressure system. The radiator and expansion tank can take it, but what about the hoses...
Was just curious if anyone had tried the higher psi cap. Looks like 16 psi might be a nice compromise. Tis a good point about the hoses likely being a weak link in a higher pressure system. The radiator and expansion tank can take it, but what about the hoses...
07-01-2013, 10:50 PM
#79
Rennlist Member
Greg, under racing conditions, things get a little hotter than when just puttering around town. Happens when running the car above 5k rpms for extended periods of time. Also, the stock set up has the AC condenser right in front of the radiator, substantially reducing the air flow over the radiator. I'm deleting my AC when I do the radiator so that's less of a concern for me, personally. Lastly, I intend to pursue adding a power adder, likely a mid or rear mount turbo, which will introduce even more heat into the system.
07-01-2013, 10:52 PM
#80
Team Owner
FWIW the cooling systems on the BMW engined MK III Range Rovers 2003 to 2005, run at 215F thus the coolant bottle cap is set to run quite a bit higher than the 928 system .
this results in exploding coolant bottles,
and hoses blowing off and the radiator end tanks rupturing,
as well as the other systems being cooled by the engine have a reduced service life.
I did a mod to my 2005 RR and replaced the water pump with a machined version that will accept the thermostat from a BMW M60 engine this is a non electric version and runs at 185 F, now the whole drive line is running cooler and I expect the life to be extended quite a bit
this results in exploding coolant bottles,
and hoses blowing off and the radiator end tanks rupturing,
as well as the other systems being cooled by the engine have a reduced service life.
I did a mod to my 2005 RR and replaced the water pump with a machined version that will accept the thermostat from a BMW M60 engine this is a non electric version and runs at 185 F, now the whole drive line is running cooler and I expect the life to be extended quite a bit
07-01-2013, 10:58 PM
#81
Rennlist Member
FWIW the cooling systems on the BMW engined MK III Range Rovers 2003 to 2005, run at 215F thus the coolant bottle cap is set to run quite a bit higher than the 928 system .
this results in exploding coolant bottles,
and hoses blowing off and the radiator end tanks rupturing,
as well as the other systems being cooled by the engine have a reduced service life.
I did a mod to my 2005 RR and replaced the water pump with a machined version that will accept the thermostat from a BMW M60 engine this is a non electric version and runs at 185 F, now the whole drive line is running cooler and I expect the life to be extended quite a bit
this results in exploding coolant bottles,
and hoses blowing off and the radiator end tanks rupturing,
as well as the other systems being cooled by the engine have a reduced service life.
I did a mod to my 2005 RR and replaced the water pump with a machined version that will accept the thermostat from a BMW M60 engine this is a non electric version and runs at 185 F, now the whole drive line is running cooler and I expect the life to be extended quite a bit
07-01-2013, 11:01 PM
#82
Three Wheelin'
If Mike removes his condenser does it make sense to keep the aux fan in front of the radiator? If his '88 is like my '85, where the aux fan kicks on if the temp gets too high, maybe removing the condenser and keeping the aux fan is the way to go???
BTW Mike, I haven't had AC since I reinstalled the engine, I have new parts for a rebuild but just haven't gotten around to it, so long story short I pulled the compressor last weekend as it was just dead weight. I think you'll like the space it gives in the engine bay and weight it removes
BTW Mike, I haven't had AC since I reinstalled the engine, I have new parts for a rebuild but just haven't gotten around to it, so long story short I pulled the compressor last weekend as it was just dead weight. I think you'll like the space it gives in the engine bay and weight it removes
07-01-2013, 11:31 PM
#84
Three Wheelin'
How are the dual fans controlled? Can you lower the temp sensors on the fans to come on sooner so the radiator doesn't get as heat soaked? I have two seperate sensors for the electric fans, one in the radiator at the return hose, and the other tied to the aux fan circuit as I removed the aux fan unit. Something like that might help?
(Maybe you want to start a new thread to get some feedback, or did I miss it). Sorry Carl.
(Maybe you want to start a new thread to get some feedback, or did I miss it). Sorry Carl.
07-01-2013, 11:44 PM
#85
Rennlist Member
How are the dual fans controlled? Can you lower the temp sensors on the fans to come on sooner so the radiator doesn't get as heat soaked? I have two seperate sensors for the electric fans, one in the radiator at the return hose, and the other tied to the aux fan circuit as I removed the aux fan unit. Something like that might help?
(Maybe you want to start a new thread to get some feedback, or did I miss it). Sorry Carl.
(Maybe you want to start a new thread to get some feedback, or did I miss it). Sorry Carl.
07-02-2013, 07:50 AM
#86
Three Wheelin'
I'm guessing the system functions similar to mine then. If you haven't already done so I would check/change the temp sensors and then do some field testing before adding a manual switch. The last thing you need to think about while driving at speed is how hot your car is. Remove the condeser, install the new rad, run waterwetter, and then give it a good hard run on a hot day. If you find you still have a problem, then you have another problem...
07-02-2013, 10:33 AM
#87
Developer
Thread Starter
What I say about a 20 psi cap is written on this page:
http://www.928motorsports.com/parts/radcap.php
In short, I recommend them for 32v motors that are raced, or supercharged engines that are raced.
Making more HP makes more heat, more heat equals hotter exhaust valve seats - which contributes the largest amount of localized heat to the head.
The increase in pressure is a safety precaution to avoid boiling the coolant in the head near those exhaust valve seats. Some "head gasket failures" on race engines are simply a symptom of the primary issue - coolant boiling in the heads that blows those head gaskets.
All that being said - on a stock 32v 928, I would stick with the stock cap. Taking a stock system up to 20 psi will likely crack the plastic heater valve at the back of the motor, and may cause damage to plastic end tanks of stock radiators.
Unless you have a real reason to increase the pressure n your system (racing, supercharging, etc) I wouldn't recommend it.
http://www.928motorsports.com/parts/radcap.php
In short, I recommend them for 32v motors that are raced, or supercharged engines that are raced.
Making more HP makes more heat, more heat equals hotter exhaust valve seats - which contributes the largest amount of localized heat to the head.
The increase in pressure is a safety precaution to avoid boiling the coolant in the head near those exhaust valve seats. Some "head gasket failures" on race engines are simply a symptom of the primary issue - coolant boiling in the heads that blows those head gaskets.
All that being said - on a stock 32v 928, I would stick with the stock cap. Taking a stock system up to 20 psi will likely crack the plastic heater valve at the back of the motor, and may cause damage to plastic end tanks of stock radiators.
Unless you have a real reason to increase the pressure n your system (racing, supercharging, etc) I wouldn't recommend it.
07-02-2013, 11:20 AM
#88
Racer
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('AC on' switch turns both fans on)
07-02-2013, 02:28 PM
#89
Former Sponsor
Greg, under racing conditions, things get a little hotter than when just puttering around town. Happens when running the car above 5k rpms for extended periods of time. Also, the stock set up has the AC condenser right in front of the radiator, substantially reducing the air flow over the radiator. I'm deleting my AC when I do the radiator so that's less of a concern for me, personally. Lastly, I intend to pursue adding a power adder, likely a mid or rear mount turbo, which will introduce even more heat into the system.
Last edited by GregBBRD; 07-02-2013 at 02:54 PM.
07-02-2013, 02:44 PM
#90
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Yea but Greg it is so much more exciting to HAVE to remove the cap just to check fluid levels when hot or very hot.....reminds you of "old Faithful " Pretty much assures that you WILL be adding coolant