Cooling. Why does it change??
05-08-2009, 07:43 PM
#16
Drifting
Patrick,
I had a Ron Davis radiator made for my motor. I also have an AC concensor between the front mounted intercooler and the larger radiator. The car runs cool with the AC off in the summer. We just found a leak in the radiator, and sent it back to Davis for repair. The stock motor mounts would colapse when on boost, and the fan was hitting the lower radiator hose causing too much flexing on top of the radiator. Sucks, but they are fixing it, and if it still leaks they offered to build me a new one at half price.
I know plenty of high powered 951's running the good ol factory radiator. I probably have just used it, and decided to replace it only if I was running hot. Now I don't know if the Davis (expensive) radiator made any difference.
Having a higher flowing water pump shouldn't make much difference. Our cars were designed very well and the factory water pump moves the water sufficiently. Your car won't run cooler if the hot water is just moving around faster. A better, larger, more efficient radiator or more air flow through the radiator is the best bet. Removing the AC condenser helps flow to the radiator. I would just see where you are utilizing the factory water pump. They are fairly cheap and work well.
I have a front mounted intercooler and added an oil cooler in the factory intercooler location.
Also, anytime you add more fuel to a fire it gets hotter. My car runs around 500whp with just 19psi on 100 octane pump. That is over twice the factory hp and uses MUCH more fuel when on boost. Things are hotter my friend. The motor is only 20% larger than the stock 2.5 configuration. Oil capacity has been increased with the additional oil cooler, and the Davis radiator is larger and thicker and has no plastic end tanks.
George
I had a Ron Davis radiator made for my motor. I also have an AC concensor between the front mounted intercooler and the larger radiator. The car runs cool with the AC off in the summer. We just found a leak in the radiator, and sent it back to Davis for repair. The stock motor mounts would colapse when on boost, and the fan was hitting the lower radiator hose causing too much flexing on top of the radiator. Sucks, but they are fixing it, and if it still leaks they offered to build me a new one at half price.
I know plenty of high powered 951's running the good ol factory radiator. I probably have just used it, and decided to replace it only if I was running hot. Now I don't know if the Davis (expensive) radiator made any difference.
Having a higher flowing water pump shouldn't make much difference. Our cars were designed very well and the factory water pump moves the water sufficiently. Your car won't run cooler if the hot water is just moving around faster. A better, larger, more efficient radiator or more air flow through the radiator is the best bet. Removing the AC condenser helps flow to the radiator. I would just see where you are utilizing the factory water pump. They are fairly cheap and work well.
I have a front mounted intercooler and added an oil cooler in the factory intercooler location.
Also, anytime you add more fuel to a fire it gets hotter. My car runs around 500whp with just 19psi on 100 octane pump. That is over twice the factory hp and uses MUCH more fuel when on boost. Things are hotter my friend. The motor is only 20% larger than the stock 2.5 configuration. Oil capacity has been increased with the additional oil cooler, and the Davis radiator is larger and thicker and has no plastic end tanks.
George
05-08-2009, 07:53 PM
#17
The Impaler
Rennlist Member
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You guys have to remember, though, that the theory of producing more heat with higher hp engines is only true if you are actually constantly using that extra horsepower. On a street engine, even if highly modified to twice the stock power, you are using more than the stock 220-250 hp for only a small fraction of the actual running time.
Also, as somebody already said, by modding via increase in thermal efficiency, you can increase the hp and actually produce less heat. Higher compression engines, for example, waste less heat into the cooling system.
Also, as somebody already said, by modding via increase in thermal efficiency, you can increase the hp and actually produce less heat. Higher compression engines, for example, waste less heat into the cooling system.
05-08-2009, 08:01 PM
#18
Drifting
Patrick,
I had a Ron Davis radiator made for my motor. I also have an AC concensor between the front mounted intercooler and the larger radiator. The car runs cool with the AC off in the summer. We just found a leak in the radiator, and sent it back to Davis for repair. The stock motor mounts would colapse when on boost, and the fan was hitting the lower radiator hose causing too much flexing on top of the radiator. Sucks, but they are fixing it, and if it still leaks they offered to build me a new one at half price.
I know plenty of high powered 951's running the good ol factory radiator. I probably have just used it, and decided to replace it only if I was running hot. Now I don't know if the Davis (expensive) radiator made any difference.
Having a higher flowing water pump shouldn't make much difference. Our cars were designed very well and the factory water pump moves the water sufficiently. Your car won't run cooler if the hot water is just moving around faster. A better, larger, more efficient radiator or more air flow through the radiator is the best bet. Removing the AC condenser helps flow to the radiator. I would just see where you are utilizing the factory water pump. They are fairly cheap and work well.
I have a front mounted intercooler and added an oil cooler in the factory intercooler location.
Also, anytime you add more fuel to a fire it gets hotter. My car runs around 500whp with just 19psi on 100 octane pump. That is over twice the factory hp and uses MUCH more fuel when on boost. Things are hotter my friend. The motor is only 20% larger than the stock 2.5 configuration. Oil capacity has been increased with the additional oil cooler, and the Davis radiator is larger and thicker and has no plastic end tanks.
George
I had a Ron Davis radiator made for my motor. I also have an AC concensor between the front mounted intercooler and the larger radiator. The car runs cool with the AC off in the summer. We just found a leak in the radiator, and sent it back to Davis for repair. The stock motor mounts would colapse when on boost, and the fan was hitting the lower radiator hose causing too much flexing on top of the radiator. Sucks, but they are fixing it, and if it still leaks they offered to build me a new one at half price.
I know plenty of high powered 951's running the good ol factory radiator. I probably have just used it, and decided to replace it only if I was running hot. Now I don't know if the Davis (expensive) radiator made any difference.
Having a higher flowing water pump shouldn't make much difference. Our cars were designed very well and the factory water pump moves the water sufficiently. Your car won't run cooler if the hot water is just moving around faster. A better, larger, more efficient radiator or more air flow through the radiator is the best bet. Removing the AC condenser helps flow to the radiator. I would just see where you are utilizing the factory water pump. They are fairly cheap and work well.
I have a front mounted intercooler and added an oil cooler in the factory intercooler location.
Also, anytime you add more fuel to a fire it gets hotter. My car runs around 500whp with just 19psi on 100 octane pump. That is over twice the factory hp and uses MUCH more fuel when on boost. Things are hotter my friend. The motor is only 20% larger than the stock 2.5 configuration. Oil capacity has been increased with the additional oil cooler, and the Davis radiator is larger and thicker and has no plastic end tanks.
George
Remember the R&D they did on these cars. Running them at full boost for HOURS for years prior to selling them detuned to us.
The VW Phaeton W12 couldn't be sold until it could run for 24 hours at 186mph in 122 degree weather keeping the cabin at 71.6 degrees fahrenheit. Those germans know how to build fast cool cars. cool vid http://www.youtube.com/watch?v=KmGNRMOpg7E
I'm considering a W12 to replace my daily. I'm finding a few with under 50K for under 30K US. Talk about depreciation. I don't give a damn if it has big VW circles on the front rear and looking at you on the wheel. It's a Bentley more or less with VW badging.
Ot a tad, but I'm taking a break from some boring number crunching.
Regards,
George
05-08-2009, 08:23 PM
#19
Drifting
Patrick will be tracking this car. It will be running hotter. I still think the factory water pump is sufficient. Removing the heat is what's important. Just moving it through the system faster shouldn't make a difference. When we removed the thermostat in my car, it seemed to run hotter. The water was moving too fast to allow the radiator to do it's job. Then they wanted to add a restrictor to slow things down, and I just reinstalled the thermostat to allow proper warmup and allow factory restriction of water flow.
Installing the radiator next week, then going on a 500 mile trip to the mountains. I'll PM you Pat and tell you my temps on long boost runs. This will be using 91 fuel around 16 - 18 psi. My passenger will be tuning the TEC GT and we'll have good temp readings.
George
Installing the radiator next week, then going on a 500 mile trip to the mountains. I'll PM you Pat and tell you my temps on long boost runs. This will be using 91 fuel around 16 - 18 psi. My passenger will be tuning the TEC GT and we'll have good temp readings.
George
05-09-2009, 04:39 AM
#20
Rennlist Member
Thread Starter
Thanks for the various input guys. Yes it will be the track that puts the system to the test. I think the stock radiator is probably pretty good too. The plastic end tanks are good in comparison to welded alu because it won't crack in the welds like the alu ones can be prone to. Leaving you stranded without much or any warning. We have PWR not far from us and they can manufacture whatever custom rad we want. They have one that integrates the oil cooler in there too. Not sure about this. Any opinions? Broadfoot have been selling these for a while.
The issue is meant to be getting enough flow to the rear of the engine. No 4 is meant to get hotter than the rest, but how is this happening? Is the flow slowing down the further it gets from the pump? I doubt it. Is it just a matter of the water heating up the further it is from the Rad? Wonder if you couldn't duct some extra cool air back there and divert it to the rear of the engine or even have a small radiator / cooler and tap it into the rear? Crazy talk yes, lol.
btw George, do you have EGT monitoring? I thought you'd already sorted the EMS out by now or is it just some fine tuning?
The issue is meant to be getting enough flow to the rear of the engine. No 4 is meant to get hotter than the rest, but how is this happening? Is the flow slowing down the further it gets from the pump? I doubt it. Is it just a matter of the water heating up the further it is from the Rad? Wonder if you couldn't duct some extra cool air back there and divert it to the rear of the engine or even have a small radiator / cooler and tap it into the rear? Crazy talk yes, lol.
btw George, do you have EGT monitoring? I thought you'd already sorted the EMS out by now or is it just some fine tuning?
05-09-2009, 09:25 AM
#21
Drifting
btw George, do you have EGT monitoring? I thought you'd already sorted the EMS out by now or is it just some fine tuning?
Patrick,
It's just fine tuning. We pulled the intake and found that the factory intake gaskets were not cut to allow full flow from the port matched intake to my 2.7 head. The stock 2.5 gasket was used and there was a big restriction because of this. The 2.7 head opening and the intake were about 25% larger than the dang gasket used. I know. **** happens. Glad I took the intake off. The car starts better, idles better, turbo spools faster, car feels stronger and we are doing some fine tuning as it's running much richer. I know, more air should lean it out, but it's not. Folks with multiple PHD's spend their lives trying to figure this stuff out. We just know the car is running richer since we now have intake gaskets matched to the intake and head. Seems counter to what you would expect.
We can monitor just about anything with the TEC GT hooked up to a laptop.
George
Patrick,
It's just fine tuning. We pulled the intake and found that the factory intake gaskets were not cut to allow full flow from the port matched intake to my 2.7 head. The stock 2.5 gasket was used and there was a big restriction because of this. The 2.7 head opening and the intake were about 25% larger than the dang gasket used. I know. **** happens. Glad I took the intake off. The car starts better, idles better, turbo spools faster, car feels stronger and we are doing some fine tuning as it's running much richer. I know, more air should lean it out, but it's not. Folks with multiple PHD's spend their lives trying to figure this stuff out. We just know the car is running richer since we now have intake gaskets matched to the intake and head. Seems counter to what you would expect.
We can monitor just about anything with the TEC GT hooked up to a laptop.
George
05-09-2009, 09:54 AM
#22
Drifting
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back to the original question .
in normal engine you put a given number of calories in per sec. on a good day 80% of them are turned into torque and 20% of them are turned into heat
if you want more torque your push the engine and end up putting more fuel in and both the 80 and 20%is bigger than it was .
all kinds of things can be done to increase thermal efficacy .. but they generally don't lead to big power .
I almost have My davis craig EWP set up the install is rather simple and it will run reverse flow for cooler head anti knock . I better get some pics ...
my hoist arrives next week .....
I think i will take temps in about 4 spots along the head then decide were to pump more water into the head ... so to get even combustion chamber temps ..
in normal engine you put a given number of calories in per sec. on a good day 80% of them are turned into torque and 20% of them are turned into heat
if you want more torque your push the engine and end up putting more fuel in and both the 80 and 20%is bigger than it was .
all kinds of things can be done to increase thermal efficacy .. but they generally don't lead to big power .
I almost have My davis craig EWP set up the install is rather simple and it will run reverse flow for cooler head anti knock . I better get some pics ...
my hoist arrives next week .....
I think i will take temps in about 4 spots along the head then decide were to pump more water into the head ... so to get even combustion chamber temps ..
05-09-2009, 09:59 AM
#23
Drifting
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if #4 is getting hot there is an issue with dormant water . #4 should be the coolest as its the first to get the coolant from the block .
the steam vent kit releases coolant out near 3 or 4 there for increasing the flow of coolent arcoss #4
the steam vent kit releases coolant out near 3 or 4 there for increasing the flow of coolent arcoss #4
05-09-2009, 11:06 AM
#24
Addict
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Gallons/minute X 500 X delta T = BTU/hr removing heat from block
film coefficient X area X delta T = btu/hr radiator heat removal
film coefficient is a function of velocity
If you pump more water, you can remove more heat.
I'm making plenty of Hp and stock cooling works for me. I added an oil cooler in series with the stock unit.
film coefficient X area X delta T = btu/hr radiator heat removal
film coefficient is a function of velocity
If you pump more water, you can remove more heat.
I'm making plenty of Hp and stock cooling works for me. I added an oil cooler in series with the stock unit.
