Conversions & Hybrids - Will this cooling routing work?

Here is the standard LS1 cooling diagram:

http://farm3.static.flickr.com/2724/4069917747_525e10c0f0.jpg



Here is what I am considering doing.

http://farm3.static.flickr.com/2573/4069917773_ef8605aeb9.jpg

1. Eliminate all routing for heater. Not needed at present.

2. Run steam vent into top of water pump. I understand this is a common procedure. (blue line)

3. Tie expansion tank to the low pressure side of the system. This would be on the line exiting the radiator and going to the inlet for the water pump. (red line)

This is where it gets unusual:

4. I read that the Cobra R Mustangs used the overflow line from the standard radiator as a bleed line to an expansion tank by using a special cap.
What if I used a 7 LB. cap here? When the system reached 7 lbs, wouldn't the overflow become open to the expansion tank? Wouldn't it stay open as long as the system continued to run, (ie. over 7 lbs)? (orange line)


5. I would use an 18 LB cap on the expansion reservoir, with an overflow line (green line) going to a reservoir.


I understand common practice is to use the higher pressure cap on the radiator, and the lower pressure cap on the expansion tank. But I am not venting the radiator line to atmosphere, but keeping it within the pressurized system. The advantage is I can use a standard radiator without welding in new bungs.

Will this system work, including the expansion tank tied to the water pump inlet line (red line)??

My question is why use the pressure overflow at all? Bypass the throttle body, tie the steam line into the top of the water pump, block the heater ports and call it a day. This setup worked on my car all summer. Did another just like that with heat, no issues. Nearly every conversion I have seen has been done that way.

It may have worked on your car because the radiator was not lower than the motor.

When the radiator is lower than the motor, there has to be a provision to remove trapped air. Most Corvettes have an expansion tank for that reason.

My car has the radiator lower than the motor due to the layback of the radiator to allow for the cold air intake.

http://farm3.static.flickr.com/2536/4059710278_44b8b4e814.jpg

Here is a thread I made a while back. post number 9 might help. Setup your system as a closed cooling system and you should be good

http://www.ls1tech.com/forums/conversions-hybrids/806849-coolant-expansion-tank-hose-routing.html

It may have worked on your car because the radiator was not lower than the motor.

When the radiator is lower than the motor, there has to be a provision to remove trapped air. Most Corvettes have an expansion tank for that reason.

My car has the radiator lower than the motor due to the layback of the radiator to allow for the cold air intake.

http://farm3.static.flickr.com/2536/4059710278_44b8b4e814.jpg

My radiator IS lower than the motor (upper rad hose in this case) and it works fine but I'm not racing or planning to, just a fun daily. :) I've done many similar setups with laid back radiators like yours, etc and it works. The expansion tank in my current car higher than the highest point but it was like that factory. All you need is to add a bleeder screw at the highest point and get the trapped air out. In my case I just fill things from the upper rad hose, then bleed the air and I'm good. :D I'm not saying you can't do it your way and imitate the factory setup I'm just saying you are making it more complex than it NEEDS to be. If you don't want to do the air bleed thing and you don't want to (or can't) fill through the highest point then your way is necessary.

The benefits of the factory / your method are:
* once filled there is no first time bleed / burp issue
* fill from one point
* no tools required
* idiot proof

My method (aka old school):
* simple install
* space
* cheap (ultra low budget build)

BTW - Very nice chassis. :D Hopefully you can fabricate something that will be painted or polished and fit the under hood look while getting the function you are after.

I would still bypass the throttle body. I don't know if you are doing that or not.