I was looking at some pictures of a car earlier running a single turbo setup and I noticed that they appear to have removed the AST from the water system and had a pipe running direct to the water filler bottle down infront of the wheel.
Is this a common setup and if so what are the pro's and con's for it.

Also can you run a traditional style sprung rad cap on a 13B motor on the ally header tank bit attached to the engine or will this not seal properly or just bugger up the way it works?

Thank you
Lee

 

Check the FAQs at the top of this section under 'A'. There are links regarding how to do it and some pros and cons.
FWIW, I've found it's a bit harder to burp the system when flushing and replacing coolant. But just takes a little patience. Other than that, no issues at all. I did eliminate the bypass hose from the neck to the bottom of the radiator.
And yes, you need a spring-loaded cap for this. I preferred to stay with the .9 bar version.

 

Thanks bud.. I'll check that out. what is the normal reason for removal? tidyness or to remove a few potential leak points?
Lee

 

In most cases , yes. As (IIRC) was mentioned in those links, the stock AST was prone to cracking...sometimes catastrophically. Most replace with a metal AST. Some guys just installed the FC filler neck, effectively replacing the larger AST's stagnate chamber with the smaller one created by the FC neck.
In my case, I had a good all-metal AST so failure wasn't an issue. But after installing a PFS SMIC, I learned it was designed for the trangular shape of the stock AST and it was difficult to cleanly mount my round one....so I eliminated it.
I also tapped and plugged the line from the filler neck to the bottom of the radiator since that allows coolant to by-pass the radiator.

 

When I eliminated my AST,I kept the line between the filler neck and the bottom of the radiator.To eliminate significant by pass,this pipe was fabricated with a 0.068in orifice,just like the factory AST.

 

Thanks guy's and cheers for the pics. I need to find myself and FC filler neck and cap then!

Lee

 

Just to clarify, you won't have a tube running directly to the coolant resevoir. That tube would come from the FC filler neck and would be blocked off by the pressure cap during normal operation.