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Author Topic:   Water restrictors????
vosevichs
Member
posted June 11, 2003 02:25 PM
Can someone please explain why you use these restrictors in the thermostat housing? We put on hi flow water pumps, then use restrictors to stop the flow? Me and my friend(the driver) are arguing over the use of these.

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Scott Vosevich


towmandan
Member
posted June 11, 2003 02:30 PM
If the water passes thru the radiator to fast enough heat wont be transfered to the radiator and disapated youll just be pumping hot water thats getting even hotter...Hope this helps....Towman


vosevichs
Member
posted June 11, 2003 03:09 PM
Ok then we'll increase the airflow through the radiator to disapate more heat from the water.


vosevichs
Member
posted June 11, 2003 03:22 PM
Here's our problem. We were running a little hot 210-220 deg. So a thermostat got put in. 240 deg. puked everything out. Remove the stat. Still 240 deg. Puked everything out again. We're running an Afco aluminum radiator, 15 psi cap, stock SB water pump. We're going to clean the radiator (loaded with mud, should take care of the overheating) Use some Water Wetter. And install a 24 psi cap (should stop the puking). We are still trying to decide on restrictors.

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Scott Vosevich

[This message has been edited by vosevichs (edited June 11, 2003).]

towmandan
Member
posted June 11, 2003 03:33 PM
Ive always ran a 5/8 to 3/4s but a lot of guys just run the thermostat with the guts cut out of it to cut down the flow....Towman


rico 08
Member
posted June 11, 2003 05:28 PM
You didn't mention pulley's,if you spin the pump too fast it will cavitate and that will cause overheating too,I always ran a 5/8 restrictor with the newer(73-85)smog pulley's but they will cavitate,and the 3/4 on the older(60's-71)underdrive pulley's.


backwoodsracer
Member
posted June 11, 2003 05:44 PM
the RESTRICTOR is in the thermostat housing while using a high flow pump to create PRESSURE ......water pressure inside the block........water under pressure has a higher boiling point..... This help prevent the puking you discribe.


Eljojo
Member
posted June 11, 2003 08:24 PM
Go over to the Stewart Warner website. Them scientists ain't dirt racers, they're engineers, and guess what they say? PUT NO RESTRICTIONS IN THE COOLING SYSTEM
Dumb old me followed their suggestions and my overheating woes are just memories. But remember---they AINT DIRT RACERS
*grin*


towmandan
Member
posted June 11, 2003 11:35 PM
Backwoods brought up a very good point you can gain a lot with a good fan shroud it must fit the radiator right and take advantage of all the air you can move thru the radiator its very nice to have a car that doesnt get over 210 but it takes a little work to get it there....Towman


rocket36
Member
posted June 12, 2003 04:17 AM
the water restrictors actually hold the water in the block, to consume more heat (the water comes out of the engine at the top of the manifold) The pulley sizes will slow water flow (speed) and give it more time to cool in the radiator.
you will definitely need to slow the water pump speed down from standard because you will be reving the engine more than it would do in a street car. most guys start with a 30% reduction crank pulley.
most people seem to start at 5/8" hole restrictor and then work up or down from there (will probably take some trial and error)
The other guys are right, have a good shroud, fitting snug to the radiator core and over the fan.
I had never used a high flow water pump until my current late model engine and now I wouldn't buy anything else. the edelbrock "circle track" victor pump apears to be the best (bigger shaft & bearings) but the stewart and weiand pumps are also really good. I use a stewart with a race-mate alternator.
also check your radiator cap for leaks and have it checked to see if it holds pressure, other wise nothing else will help.
190 - 200 is a nice temp to run at most engines seem to produce the most power between 200 & 215 though this is arguable.
good luck


eborcim
Member
posted June 12, 2003 08:43 AM
We're 25% under drive on our pulleys. Radiator was really dirty, cleaned it out. Put in some Water Wetter with straight water. Used a dismantled thermostat for a restrictor. Fan shroud is tight against the radiator, and fan. Put some sheet metal along side the radiator in front. running 180 deg. just sitting there, 10 deg. less than before. Going to check the timing. We'll see what it does tommorrow night.

Thanks for all the advice.

Keep it coming if you have anything to add.

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Scott Vosevich

[This message has been edited by vosevichs (edited June 12, 2003).]

hobby9
Member
posted June 12, 2003 10:39 PM
I really try not to add my opinion on these types of posts. But, I feel froggy today. AkwardJeff told you about the only "good" reason for the restrictor. Eljojo told you to go to Stewarts to find out what the people who design cooling systems KNOW. Not what they "think", but what they KNOW! One common opinion of the restrictor is that it holds water in the block longer to get more heat out of the block. That's true. But, in a closed loop cooling system which cars have, the problem with that is that it heats the water up more. A given radiator at given air flow will only reduce the water temps by so much. So yes, your taking more heat out of the block, but your still only reducing water temp by say 40 degrees. So your water temp will rise.

All of that said, the single best thing you can do to get your car to run cool is to put a real good shroud system on. I'd venture to bet that 75% or racers don't use they're radiators full cooling capacity. Look at Late Models or even Winston Cup cars. They get enough cooling air through those little holes in the grill. A good shroud systme will work assuming that your fan is in the right position, water pump is good, your engine doesn't have a problem, etc...

Randy

MiPinto6
Member
posted June 13, 2003 04:18 PM
One other thing you can do is hang a piece of plastic from the bottom of the radiator to stall the air going under the chassis. This will give your fan/shroud system a chance to pull it thruogh.


courtjester
Member
posted June 16, 2003 05:27 PM
went from a six blade fan to a four blade and lost 20 degrees.


vosevichs
Member
posted June 17, 2003 10:43 AM
It didn't overheat this weekend. Ran around 220 deg. I think I can still get it a little cooler. Going to replace the flex fan with a steel fan.


ratracer10
Member
posted June 19, 2003 01:30 PM
i knew it! ratracer is an engineer! i'm an engineer too......of the southern variety though......lmao!

you forgot to mention one of the variables.....spinning the water pump at an rpm that is higher than it is "engineered" to operate can cause the pump to cavitate or shear/flatten the impeller blades and that throws a monkey wrench into the engineering.

fastow
Member
posted June 19, 2003 11:09 PM
i'm not an engineer but i do work on a variety of different pumps for a living. and they're heaps bigger than the one on the front of an engine.
if you disassemble a stock pump you will notice that the impellor is nothing more than a piece of pressed up tin. as most of us have pointed out a reduction in pump rpm is beneficial this is predominantly because of the simple impellor design. most of the aftermarket "race" water pumps have a cast or machined impellor with proper vane design.
these pumps are far more efficient and are capable of pumping at both high and low rpms. as someone mentioned, it is a closed circuit system so it just pushes the water around in circles, this obviously places the pump under continuous positive head pressure.
The water restrictor thing is something that Smokey Yunick came up with years ago and has obviously proven its use. it might not be the ideal way of doing it, but as most of us are not engineers and don't have access to the required info or technology to do otherwise, it is probably the best method. and i bet there have been just as many races won with engines using water restrictors as there have been without.


ratracer10
Member
posted June 20, 2003 11:35 AM
ratracer, we use underdrive crank pulleys to slow the water pump down, not to speed it up. i'm surprised no one has mentioned a water pump driven at too high of rpm's will rob horsepower. another reason to use an underdrive pulley. there is no reason to spin the water pump any faster than what's neccesary to circulate the coolant and keep the engine cool. if i can get by a smaller crank pulley, it'll make more power as long as the engine isn't melting down.

also, my ford motorsport water pump has restrictors built into it. i'm goin' with the ford engineers on this one.

rico 08
Member
posted June 20, 2003 12:28 PM
I'm with outlaw,if i took out the restictor on mine it would be like nuclear meltdown,my theory is the restrictor gets you to that sweet spot that is optimum cooland speed and every engine/combination will be a little different,Wes,i changed the pump on my dad's 351W and man do they have alot of bolts and different sizes too,also a cast pump bolted to an aluminum housing didn't seem right to me,i like the chevy fout bolts,cast on cast.(couldn't resist!)


fastow
Member
posted June 21, 2003 01:52 AM
i have seen this too. i didn't realise it at the time until someone pointed it out to me.
good point if you are having trouble with belts coming off.


rico 08
Member
posted June 21, 2003 12:49 PM
The smooth belts work better,i like the DAYCO belts,they seem to stay with you,don't use GATES belts,they are designed not to slip and will climb the pulley and fly off.


hesseracing
Member
posted June 26, 2003 12:40 PM
u said u had a flex fan on. get that off and get a plastic one that most race catalogs sell for around $20. that will help alot. the higher the rpm the flatter the flex fan gets meaning less air pull. also as one other racer said put a dam under the rad. out towards the nose. my wifes car was running hot and putting a piece of sheet metal from under the rad out forward and bending 2 inches of the front edge dropped the temp by 20 deg. two wires hold the lead edges and when time to load onto trailer just bungee up to nose for clearance.


PEDDLER
Member
posted June 26, 2003 06:53 PM
We've talked pulley size, restrictors, water pumps, coolant flow, belt speed, fan shrouds and a variaty of other things.

One of the most simple and most overlooked problems, especially with belts just circling the pump and crank is.

BELT SLIPAGE.

cobb
Member
posted July 13, 2003 12:00 AM
forget restrictors-go to advance and buy a 160 thermostat-they work.you trust them to drive your family across country.works greatforus with a good radiator and shroud with a 50% reduction crank pully. even at 7000


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