installing 951 oil cooler on non-turbo
04-12-2005, 02:08 PM
#16
Three Wheelin'
The temps will probably be about the same since both coolers have a thermostat built into them to keep everything running within spec. You'll end up with added capacity but probably won't need it unless you are really ******* the car for a long time. I'm doing it just because I happen to have one.
04-12-2005, 03:57 PM
#17
Addict
Rennlist Member
Rennlist Member
Not quite. The thermostat is built into the oil cooler housing on the block. It opens when the oil in the engine is up to a certain temp.
Why I'm thinking about adding a second oil cooler to my car? Easy, when running on the track or in a HOT environment it's always good to have enough cooling capacity. The stock oil cooler is good enough for 99% of the time, but it's not that tough, nor that expensive to add another cooler to the system. Cool, thick oil is good, overheated, thin oil is bad for bearings. The thermostat will keep the temperature at the correct range.
Check out http://www.944oilcooling.com for some temperatures.
I'll take out that little bit of extra insurance.
Dal.
Why I'm thinking about adding a second oil cooler to my car? Easy, when running on the track or in a HOT environment it's always good to have enough cooling capacity. The stock oil cooler is good enough for 99% of the time, but it's not that tough, nor that expensive to add another cooler to the system. Cool, thick oil is good, overheated, thin oil is bad for bearings. The thermostat will keep the temperature at the correct range.
Check out http://www.944oilcooling.com for some temperatures.
I'll take out that little bit of extra insurance.
Dal.
Originally Posted by AznDrgn
The temps will probably be about the same since both coolers have a thermostat built into them to keep everything running within spec. You'll end up with added capacity but probably won't need it unless you are really ******* the car for a long time. I'm doing it just because I happen to have one.
04-12-2005, 08:28 PM
#20
Dal, I wasnt asking why have a cooler, I was asking why a second one. It makes far more sense to use a large single FM and delete the factory one, the seals suck, the placement sucks, and it isnt that great a cooler (though a lot better than you would think looking at where they put the thing).
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04-13-2005, 02:06 AM
#21
Race Director
"renline man..why do you ask about the temps of cars?"
because the benefits comes from verifying the actual numbers. If you've spent money on power upgrades, wouldn't you want to know what your $25k just bought you? If it's a +10hp increase, that's one thing, but if it was a +100hp increase, that's something completely different. Without the actual numbers, it's like two kids arguing whether fudge has any real chocolate in it.
Matt's right on, it's the delta-T that determines how much heat is shed through the oil-cooler. The hot oil entering the 1st cooler would be a lot higher than the surrounding air, and will shed a lot of heat. By the time it exits the 1st cooler, the delta-T will be lower and the 2nd cooler won't shed anywhere nearly as much heat as the 1st one. That's why with oil-coolers (and intercoolers), it's better to have a tall square cooler rather than a long narrow one. That's so you can spread out the hot oil across a larger area initially where it can shed the most heat. The 2nd half of a cooler won't lose as much heat as the 1st half, so you want to maximize the surface-area initially. If you're gonna be using two separate coolers, it's better to run them in parallel rather than in series...
because the benefits comes from verifying the actual numbers. If you've spent money on power upgrades, wouldn't you want to know what your $25k just bought you? If it's a +10hp increase, that's one thing, but if it was a +100hp increase, that's something completely different. Without the actual numbers, it's like two kids arguing whether fudge has any real chocolate in it.
Matt's right on, it's the delta-T that determines how much heat is shed through the oil-cooler. The hot oil entering the 1st cooler would be a lot higher than the surrounding air, and will shed a lot of heat. By the time it exits the 1st cooler, the delta-T will be lower and the 2nd cooler won't shed anywhere nearly as much heat as the 1st one. That's why with oil-coolers (and intercoolers), it's better to have a tall square cooler rather than a long narrow one. That's so you can spread out the hot oil across a larger area initially where it can shed the most heat. The 2nd half of a cooler won't lose as much heat as the 1st half, so you want to maximize the surface-area initially. If you're gonna be using two separate coolers, it's better to run them in parallel rather than in series...
Last edited by Danno; 04-13-2005 at 07:23 AM.
04-28-2005, 05:51 PM
#23
Rennlist Member
Sorry for bringing this one back from the grave.
Joe,
Here are two pictures I promised a couple weeks ago.
http://forums.rennlist.com/upload/oil_cooler_1a.jpg
http://forums.rennlist.com/upload/oil_cooler_2a.jpg
The passenger side cooler is the factory 951 cooler set on its side. The other cooler is the setup that Terry Morris (KISS) puts together. I had him make custom oil lines to fit my arrangement.
As far as one large cooler, vs two smaller ones, versus in series or in parallel: optimizing a heat exchanger is not always intuitive, and it requires either educated assumptions or measured data to determine heat transfer coefficients. To really analyze the oil cooling system, you would have to get into pressure drops, flow velocities, boundary layer characteristics, fouling resistance, film coefficients of the fluids, etc to determine the most efficient oil cooler setup/design.
There are some pressure drop concerns with running two small coolers in series (with the associated hoses and fittings), instead of a single large cooler with equal surface area. Running two coolers in parallel will split the flow and reduce flow velocity, so heat transfer would actually be lower as/if oil flow becomes more laminar, and the fouling will increase, compared to a single or in-series arrangement.
None of us easily have the capability for that kind of analysis, so other than buying a whole bunch of different coolers, ducts, and hoses, and running a series of tests, determining which setup is best is only a guess.
With all things being equal, surface area is surface area. So more surface area, the more heat transfer capacity a cooler has. External shape is generally important for maximizing the air flow and velocity across the coils/tubes/fins. Internal coil/tube/fin cross sections are designed for surface contact area and flow patterns of the fluid (oil).
But we dont really care that much about efficiency anyway. It doesnt cost us much money to oversize the cooler (initial capital) and we are not worried about energy costs for long term operation (we throw the heat away).
In a nut shell, there are a lot of ways to skin a cat. I wont argue with anyone on which cooler or arrangement is the best, because I have not done the calcs or the tests to prove one way or another. What I can tell you is that airflow across the cooler is critical. Put them where they get the best flow.
Joe,
Here are two pictures I promised a couple weeks ago.
http://forums.rennlist.com/upload/oil_cooler_1a.jpg
http://forums.rennlist.com/upload/oil_cooler_2a.jpg
The passenger side cooler is the factory 951 cooler set on its side. The other cooler is the setup that Terry Morris (KISS) puts together. I had him make custom oil lines to fit my arrangement.
As far as one large cooler, vs two smaller ones, versus in series or in parallel: optimizing a heat exchanger is not always intuitive, and it requires either educated assumptions or measured data to determine heat transfer coefficients. To really analyze the oil cooling system, you would have to get into pressure drops, flow velocities, boundary layer characteristics, fouling resistance, film coefficients of the fluids, etc to determine the most efficient oil cooler setup/design.
There are some pressure drop concerns with running two small coolers in series (with the associated hoses and fittings), instead of a single large cooler with equal surface area. Running two coolers in parallel will split the flow and reduce flow velocity, so heat transfer would actually be lower as/if oil flow becomes more laminar, and the fouling will increase, compared to a single or in-series arrangement.
None of us easily have the capability for that kind of analysis, so other than buying a whole bunch of different coolers, ducts, and hoses, and running a series of tests, determining which setup is best is only a guess.
With all things being equal, surface area is surface area. So more surface area, the more heat transfer capacity a cooler has. External shape is generally important for maximizing the air flow and velocity across the coils/tubes/fins. Internal coil/tube/fin cross sections are designed for surface contact area and flow patterns of the fluid (oil).
But we dont really care that much about efficiency anyway. It doesnt cost us much money to oversize the cooler (initial capital) and we are not worried about energy costs for long term operation (we throw the heat away).
In a nut shell, there are a lot of ways to skin a cat. I wont argue with anyone on which cooler or arrangement is the best, because I have not done the calcs or the tests to prove one way or another. What I can tell you is that airflow across the cooler is critical. Put them where they get the best flow.
04-28-2005, 11:35 PM
#24
Race Car
Thread Starter
thanks jim. good info there
