How does this work?-remote thermostat housing

[Gary Allan]

Now I can see this working

and this too

But help me out on this:

I mean, one would reason that no one needs an 1 1/2" bib ..for any reason other than to fit the physical thermostat since this only has 3 - 1/2" ports otherwise. No need for 1 1/2" hoses ..nor the bibs on the rad ...or the water pump....etc

 

[heynow]

It uses a chevy small block thermostat and water neck bolted to the top. I believe it is for supercharged applications where there is no room for the stock thermostat location. I use the exact same piece on a manifold I made to run motorcycle carbs on a suzuki samurai.

 

[Gary Allan]

How does it manage the flow capacity with 3 x .5" ports instead of 1 x 1.5" port?

I see a box with 3 x .5" holes and one 1.5" flange for a normal thermostat housing. The 1.5" is easy enough to figure out, but even 3 x .5" ports can't even come close to 1 x 1.5" port. You can fit 9 .5" ports in 1 x 1.5" tube.

There's something that you're not saying here.

Someone will say the magic word(s) that turn the light bulb on

 

[Steve S]

You have to be smarter than the box too bad I am not. I wonder if you block off the intake manifold water passages and put fittings on the heads.There are pipe plugs in the Chevy heads .{ a wild assumption for its use}.

 

[Gary Allan]

I'm fine with that. It's just kinda odd that you would need such a size thermostat housing to begin with if you can get away with 1/3 the size even in a supercharged, over spec output, engine. I mean, the original jackarse that came up with the general size of a thermostat housing must have just been thinking "big" ..same with the rad bib makers ..hose guys ..water pump guru's

Good enough for me

 

[Shannow]

My guess is that there's two ports for coolant inlet, probably from each of the heads, and the third pipe is return to the water pump so that the coolant doesn't dead end at the housing and never warm up.

Smokey Yunick used to have a "Y" pipe, with a small bore pipe running from a drilling in each head, at 45 degrees into a common axial outlet (to stop the two coolant streams from fighting each other alternately)

Recommended an 11/16 restrictor. 11/16 is about the same area as two half inchers (although the bore size of the fittings will be smaller).

Should move enough water at highway speeds/loads.

 

[1040 WreckerMan]

What is your intended goal with the remote thermostat? What type of engine and what will it be used for.

Remember that in most cases the flow threw the thermostat is fairly low. The t-stat is not just open or closed, they are more of a regulating valve with a crack temp and a fully open temp.

The part you posted a pic of, at least the last one, is commonly used in blower applications for GM's. That creates special considerations.

 

[heynow]

The 1.5 inch hose and thermostat are probably overkill. They just use them because its the size that chevy has been using forever.

 

[Gary Allan]

Quote:
What is your intended goal with the remote thermostat? What type of engine and what will it be used for.


Inlet temp regulation ..but it seems that no one here does that other than OEM on some of the LS engines (?).

What a waste of material using all that un-needed rubber and metal for all these years with plus sizes of 1.25".

 

[Shannow]

Gary, come to a power station.

We do everything possible to improve suction side pressure (really lack of suction). Once the pump has hold of it, pressure side is then a balance of power loss versus cost of power.

 

[punisher]

Originally Posted By: Steve S
You have to be smarter than the box too bad I am not. I wonder if you block off the intake manifold water passages and put fittings on the heads.There are pipe plugs in the Chevy heads .{ a wild assumption for its use}.


You got it (well, there are no pipe plugs on older smallblocks, not sure about late model stuff). You have to drill the front of the head, braze on a fitting, and block off the manifold water passage. Racers did the remote thermostat/external coolant thing for years due to water distribution/flow problems with the intake manifold on smallblocks. Smallblock Fords were even worse but it was a waterpump design problem instead of a manifold problem on those.

Originally Posted By: Gary Allan
How does it manage the flow capacity with 3 x .5" ports instead of 1 x 1.5" port?


Figure that one of those holes is usually for a bypass, so you are only really getting coolant flow (when the t-stat is open) through 2 of the holes. The bypass has to be there so that as the coolant warms up it can flow to the bottom of the t-stat to open it up.

 

[Gary Allan]

Originally Posted By: Shannow
Gary, come to a power station.

We do everything possible to improve suction side pressure (really lack of suction). Once the pump has hold of it, pressure side is then a balance of power loss versus cost of power.


Well experienced (not "read") on suction head (or lack of it) in continuous loops. We'd be pushing 90 psi at one pump ..pulling way negative on the booster after (near) a quarter mile of pushme-pullyou 40% non-evaporatables through 3" pipe. It's just that regardless of our pump housing size and hp of the motor, it was always a 4x3 (or whatever).

That is, while I'm looking at it as an outlet ..it's the inlet side too. There is resistance across the rad ...but ..another day for that..

 

[Gary Allan]

Quote:
Figure that one of those holes is usually for a bypass, so you are only really getting coolant flow (when the t-stat is open) through 2 of the holes.

Yes. So it's down to a 3/4" choke for a 1.5" tube

 

[Shannow]

Originally Posted By: Gary Allan
Originally Posted By: Shannow
Gary, come to a power station.

We do everything possible to improve suction side pressure (really lack of suction). Once the pump has hold of it, pressure side is then a balance of power loss versus cost of power.


Well experienced (not "read") on suction head (or lack of it) in continuous loops. We'd be pushing 90 psi at one pump ..pulling way negative on the booster after (near) a quarter mile of pushme-pullyou 40% non-evaporatables through 3" pipe. It's just that regardless of our pump housing size and hp of the motor, it was always a 4x3 (or whatever).

That is, while I'm looking at it as an outlet ..it's the inlet side too. There is resistance across the rad ...but ..another day for that..



good thing about automotive use is that a pressurised system will add 12-15 pounds of suction pressure to the worst point in the system.

 

[Steve S]

I would say I know most about big blocks chev engined I used to take out the plugs in the heads and insert temp gauges when in my boat.

 

[NovaMan]

I never really thought about the hose diameters much, but I'm sure the thermostat itself is a much worse restriction than the enormous hoses. Perhaps that was the idea of the original design: make sure the 'stat is THE restriction.
With this design, I suspect there are a few things going on. One of them is that a 1/2" NPT port can fit bigger than a 1/2" diameter hose or tube. For example, with a 3/8" NPT to #8 AN (1/2") fitting, the IDs on each end are almost the same. So I'm going to figure a 1/2" NPT port would be about equivalent to maybe a 5/8" tube or hose. 5/8" compared to 1/2" is about half again as much cross sectional area. Now think of the size of the water passages at the front of SBC heads: on the same order of magnitude as a 5/8" hose, particularly when you consider that the passage is "cut" on the bias. Now compare two 5/8" openings to the opening of a thermostat, and I bet the 'stat is still smaller.
BUT all of that is just conjecture off the top of my head, so take it with a grain of salt.

 

[Gary Allan]

Well, chokes aren't all that big a deal. In many cases it just means a change in velocity ...but ..it's just the sizable difference between typical hose diameters and 1/2" ports. Going up 50% in diameter effectively doubles the area. So a 3/4 hose is as good as 2 1/2" hoses ..now if you've got a dinky 1.25 rad hoses ..you're almost double again.

It works and that's all that matters. Stuff gets turned around when you have pressure differential driven flows vs. flow dictated pressures.