Restrictor in lieu of thermostat
05-09-2006, 10:51 AM
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Restrictor in lieu of thermostat Our engine builder delivered our LS1 with just a 5/16" opening in the restrictor he installed in place of the thermostat. Seems small to me.
The water temp climbs to 240 when we start working the motor, then drops right back to 200 when at cruise or idle. Your thoughts? Thanks in advance.
The water temp climbs to 240 when we start working the motor, then drops right back to 200 when at cruise or idle. Your thoughts? Thanks in advance.
05-09-2006, 03:37 PM
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Yeah, we're old aircooled vw guys, but like I said, it seems like too small an opening to me, when I compare that to an open thermostat. Yet this is the way we received our engine from the builder.
What size would you suggest?
What size would you suggest?
.........thats nutz.
05-09-2006, 03:44 PM
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I don't know the builder, the car owner traded for it, I'm just trying to learn how to make it work. Seems like a running temp of about 210 is the consensus for LS1's. I'm old school, I guess, cuz my 5.7 Buick/sbc runs only about 195 going 80 uphill, full a/c, 110 ambient.
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05-09-2006, 07:44 PM
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Originally Posted by nobrakes
My understanding is that the thermostat could fail during a race and cost time and damage.
05-09-2006, 09:41 PM
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A few years ago I changed the stock thermostat to a 160 stat. The water temperature immediately dropped a few degrees so I figured if I took the guts out of the 160 stat and put the empty thermostat body back in the temp might drop a few degrees more. WRONG! With the guts removed the larger opening in the 160 stat allowed the water to flow through the system too fast. The water never spent enough time in the radiator to get cooled down. If you take the stat out completely it would probably be even worse. The water flow has to be restricted enough so that the water is FORCED to spend enough time in the radiator in order that the water can be cooled down. If the water is moving too fast the radiator doesn't have enough time to do it's job.
05-09-2006, 10:27 PM
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My understanding is that thermostats fail closed, and that has been my experience with both GM and Fomoco products. That's why we want to use a restrictor instead. I know there are special fail open thermostats, but we don't need one since it's an off-road racecar. Plus enlarging a hole is cheaper than getting a thermostat. And we are cheap!
I know we need some restriction. Heck, even old Ford flatheads needed restriction of the water flow.
I know we need some restriction. Heck, even old Ford flatheads needed restriction of the water flow.
