Steam Tube Question
Thread Starter
Racer
Joined: Jun 2004
Posts: 281
Likes: 3
From: Nashville TN
Steam Tube Question
I am putting a LS3 in my 02 Z06. I didn't get the front steam tube with the motor and the back two are blocked off. What would be the appropriate steam tube to use - would the one from a LS3 C6 work?
Any other applications have these tubes? I need one to finish engine assembly
Any other applications have these tubes? I need one to finish engine assembly
Burning Brakes
Joined: Jul 2011
Posts: 1,097
Likes: 111
From: Fredericksburg Virginia
Thread Starter
Racer
Joined: Jun 2004
Posts: 281
Likes: 3
From: Nashville TN
The rear is already blocked from the factory. I didn't know if the ls3 tube would have fitment issues on a C5 or if the gen3 stuff would clear the intake. Mind posting some pictures of the tubing you have ran?
Drifting
Joined: Apr 2010
Posts: 1,262
Likes: 122
From: Vetteville Tennessee
I guess everyone has their own opinions about the rear steam ports. Early in the C5's life people reported issues with #7 cylinder not cooling. When I added intake and heads I opened up the rears with a the same tube used on the front (just turned it around) and ran the line against the firewall and under the coolant reservoir teed it to the front tube and off to the radiator. This definitely helped burping the system and in my mine prevents steam pockets. But then again, it's one mans opinion. 
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Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
I always wondered if you are better of without them. My thought process is that the coolant comes into the front of the block, flows to the back and up through the head as it passes. Then forward through the head and out to the pump. So if some of the coolant is diverted at the rear of the head is this a good thing or a bad thing? I would think you want more coolant flow through the head. However, some of the big racers use aftermarket systems that have pipes connected at all four locations.
Drifting
Joined: May 2007
Posts: 1,547
Likes: 210
From: Huntersville, NC
If you think of the location as a high point vent, then having the back two not connected makes sense. Once you vent the air space the cooling system is happy. Park the car on an incline facing up hill and the front "steam line" crossover is the highest point point on the engine from a cooling system perspective. I think that's why that is the best place to burp the engine. When you disconnect the line from the TB to remove the intake, you only get a small dribble, you don't drain the reservoir, which tells me this is really a high point in the system
Team Owner
Joined: May 2001
Posts: 36,836
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
More options. Make your own lines and route them where you want:
www.wegnerautomotive.com/
Click on "GM GENIII/IV LS"
www.wegnerautomotive.com/
Click on "GM GENIII/IV LS"
Melting Slicks
Joined: Dec 2004
Posts: 3,120
Likes: 119
St. Jude Donor '10
I have seen plenty of situations personally where the "highest point" doesnt always get the air pockets out. Why do you think even LT1 cars had the crossover tubes in the back of their heads? The LS is no different. There is a study from an aussie company on tech even about it. Let me see if I can find it.
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
Originally Posted by Pratt & Miller
(Pratt & Miller Engineering New Hudson Michigan) and Dr. Jamie Meyer (head of GM Performance) both say that the rear two should stay blocked off.
I used to advocate having fittings that went to -4an on all 4 steam vents feeding into a coolant swirl pot, which then drained back into the lower hose or return heater line... this is a setup that was used successfully by a few race teams, but it looks like this was a band-aid once I got 'real' information from REAL race teams.
The issue is not flow - the coolant passages flow plenty - it's pressure.* When driven hard, engines need coolant pressure to "scrape" the steam bubbles that form on hot spots in the head off the wall of the passage.* With all 4 ports open, there's not enough pressure locally (in the head) to promote proper heat transfer unless you run your overall coolant pressure extremely high (30psi or so).* Indy and F1 cars run MUCH higher than that, due to higher hp/liter (heat concentration).
The proper setup all my LSx racers are using is, assuming the top of your radiator is below the steam vent port:
*The rear vents blocked off, the front tee'd (LS6-style).
*Radiator cap replaced with "open" cap (free flow through radiator overflow port)
*Steam vent tee and radiator "overflow"/free flow feeding into coolant swirl pot (aka expansion tank)
*Swirl pot has pressurized radiator cap, bottom drains to non-thermostat-controlled water pump return
I used to advocate having fittings that went to -4an on all 4 steam vents feeding into a coolant swirl pot, which then drained back into the lower hose or return heater line... this is a setup that was used successfully by a few race teams, but it looks like this was a band-aid once I got 'real' information from REAL race teams.
The issue is not flow - the coolant passages flow plenty - it's pressure.* When driven hard, engines need coolant pressure to "scrape" the steam bubbles that form on hot spots in the head off the wall of the passage.* With all 4 ports open, there's not enough pressure locally (in the head) to promote proper heat transfer unless you run your overall coolant pressure extremely high (30psi or so).* Indy and F1 cars run MUCH higher than that, due to higher hp/liter (heat concentration).
The proper setup all my LSx racers are using is, assuming the top of your radiator is below the steam vent port:
*The rear vents blocked off, the front tee'd (LS6-style).
*Radiator cap replaced with "open" cap (free flow through radiator overflow port)
*Steam vent tee and radiator "overflow"/free flow feeding into coolant swirl pot (aka expansion tank)
*Swirl pot has pressurized radiator cap, bottom drains to non-thermostat-controlled water pump return
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
Wait! NO! Not yet. I want to read the article from the Aussie first!
Melting Slicks
Joined: Dec 2004
Posts: 3,120
Likes: 119
St. Jude Donor '10
http://ls1tech.com/forums/forced-ind...4-why-7-a.html
There is one
http://ls1tech.com/forums/generation...-hp-setup.html
Another one
If there are others i remember, ill post em up.
There is one
http://ls1tech.com/forums/generation...-hp-setup.html
Another one
If there are others i remember, ill post em up.
Melting Slicks
Joined: Dec 2004
Posts: 3,120
Likes: 119
St. Jude Donor '10
Wegner makes more race engines than Pratt and Miller do, and there is a reason they machine them. Also Kurt Urban uses them so much, he has his own kit. Doesnt really seem like snake oil.