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Author Topic:   WATER RESTRICTORS/ hot topic here
bigcityracer
Dirt Freak

Total posts: 431
posted July 04, 2004 08:00 PM  
I've been reading up on the restrictors that go in the water neck. The only real purpose of them is make the car run hotter. I am not saying this is a fact, but it is in writting. This weekend 7-11-04 I will run with no restrictor and let you know what happens. I haven't really been running long enought in the street I have to know if it is cooler or not. I will post the temp it reaches with out the restrictor. I have heard many reasons for them. And the artical shot down most of what I heard.

turnleft43
Dirt Full Roller

Total posts: 38
posted July 04, 2004 08:49 PM  
Last friday we took the restictor out of our motor. It helped drop the temp by ten degrees. we were having some heating problems and that helped.

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 04, 2004 10:18 PM  
That is one of the false statements mentioned in the artical. the best cooling is the most free flowing. The use of restrictors increase the chances of cavitating in the water pump.

I run a stock pump with 1 to 1 pulleys.
Currantly I don't beleive I have a cooling problem. I am just looking to run as cool as possible.

racer038
Dirt Maniac

Total posts: 111
posted July 05, 2004 06:12 AM  
Stock pump, 3 core radiator, Steel fan, we had better performance using the large restrictor. When we changed to a race pump, aluminum radiator, steel fan the restrictor hurt us. Currently running without restrictor. Will be experimenting with a racing thermostadt, due to the engine not heating up enough in the lineup lanes. Don't think starting the race @ 150 degrees is wise!

Speedway65
Dirt Freak

Total posts: 344
posted July 05, 2004 07:21 AM  
READ THIS IT MAY HELP CLEAR UP SOME MISCONCEPTIONS.http://www.stewartcomponents.com/html/tech_support/techtip3.asp

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 05, 2004 10:26 AM  
interesting topic....how 'bout does heat make horsepower or does horsepower make heat?
i was always under the assumption that the restrictor's job was to slow down the flow to keep water in the radiator longer to cool it..ie a short cut to keep from changing the pulley ratio....ya' think?

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 05, 2004 01:37 PM  
I think its job is to increase block pressure.And as for the rad cap every pound increase over 15 raises the boiling point of water!

[This message has been edited by Speedway65 (edited July 05, 2004).]

36 Race Team
Dirt Full Roller

Total posts: 45
posted July 05, 2004 02:18 PM  
I've always heard the same carolina but if its in the rad longer its in your motor longer too right...not good huh!

rico 08
Dirt Forum Champ
Total posts: 1139
posted July 05, 2004 02:41 PM  
Nobody can make a blanket statement and say to run one or not,it depends on all the cooling system components.Stock type motors with smog pulleys and a stock type 4 core radiator like mine usually need a small hole restrictor(5/8),as you slow the pump down and use a better racing type radiator and pump the hole will need to be increased,depending on the combo up to no restriction.IMHO

allzway
Dirt Maniac

Total posts: 136
posted July 05, 2004 06:49 PM  
Most everyone I know has a restrictor using pretty much stock pumps.

The reason told by numerous mechanics is that it is to slow the water down long enough to allow it to be cooled in the radiator, otherwise it passes throught too fast to actually benefit from the radiator.

I certainly am no expert, but it works okay for me.

bigcityracer
Dirt Freak

Total posts: 431
posted July 05, 2004 09:52 PM  
Thermostats & Restrictors
We strongly recommend NEVER using a restrictor: they decrease coolant flow and ultimately inhibit cooling.

For applications requiring a thermostat to keep the engine at operating temperature, we recommend using a Stewart/Robertshaw high flow thermostat. This thermostat does not restrict flow when open. The Stewart/ Robertshaw thermostat enhances the performance of the cooling system, using any style of water pump. However, the Stewart Stage 1 high-flow water pump may require this thermostat to operate properly, and Stewart Stage 2, 3, and 4 water pumps simply will NOT operate with a regular thermostat because these pumps have no internal bypasses.

Stewart further modifies its thermostat by machining three 3/16" bypass holes directly in the poppet valve, which allows some coolant to bypass the thermostat even when closed. This modification does result in the engine taking slightly longer to reach operating temperature in cold weather, but it allows the thermostat to function properly when using a high flow water pump at high engine RPM.

A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures.

Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would overcome the radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool. Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it.

jay116
Dirt Freak

Total posts: 428
posted July 06, 2004 07:42 PM  
Sound like a salesman doing his job to me.

Here's a caption from my post above. copied directly from a web site.

Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it.

M1
Dirt Freak

Total posts: 257
posted July 06, 2004 09:12 PM  
blah blah blah blah!!!

I worked for a radiator manufacturer for almost 8 years, and we had a wind tunnel we tested stuff in. I use a restrictor for a reason, and its staying.

stock pump
1-1 pully's
3 core radiator
water wetter

JOB DONE!

bigcityracer
Dirt Freak

Total posts: 431
posted July 06, 2004 09:19 PM  
A wind tunnel and racecar. LOL
Your killing me SMALLS!!!! LOL

M1
Dirt Freak

Total posts: 257
posted July 07, 2004 09:22 AM  
we never put a racecar in the tunnel, we would use a 12"x12" test peice and run different rates of flow through it varying the wind speeds and different coolants.

there is a lot of variables that can differenciate the cooling systems from one another, but getting the right flow rates for the core size, fin count, and volume is easy with the right tools and equipment. Not everyone has access to those tools, so they have to go by trial an error.

BHays
Dirt Roller

Total posts: 16
posted July 07, 2004 02:14 PM  
we run a stock pump and pulleys on a .060 over block with a 22 lb cap and a 180 degree thermostat with 4 1/16th in holes drilled in the flange inside of the gasket surface ( stock thermostat) and never go over 210 degrees even on some of our 105 degree nights, oh and a stock 3 row radiator

racin2much
Dirt Full Roller

Total posts: 46
posted July 07, 2004 03:33 PM  
Same here, stock pump and pulleys, 4 core radiator, without restrictor, gets REAL hot, as in 240+, with a restrictor stays 190-200. Not sure what expert will have to tell me to take it out and make it better but still what works, I run. Never seen a thermostat that opened up and had NO restriction unless it completely disappears when open, so basically once it opens you have a restrictor, maybe larger, but still a restrictor. Unless they run their tests on my car, it doesn't apply to me and all the hype will sell me something and then I will need the pump they want to sell me with some additives and so on. Like was mentioned, trial and error is the only way to go, to many variables to just make a blanket statement.

hughes
Dirt Maniac

Total posts: 194
posted July 08, 2004 06:45 AM  
You do not a restrictor in the water neck. Look at a chevy head, then look at the head gasket. The head has these large holes inbetween each cylinder and the head gasket has a 1/4" hole. That is your restrictor. It is designed into the head gasket to restrict the flow around the cylinders. So yes, you do want to slow the water down around the cylinder, but it's not necessary to do it again at the water neck. I got the information from STEVE HENDREN in the motor section and did the checking myself. I've been running it that way for 2 years now.

mansfief
Dirt Maniac

Total posts: 128
posted July 08, 2004 11:07 AM  
Just happens that Circle Track, September issue, has a artical on this same subject.

    

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