AST Deletion
 

Hey guys, I'm trying to free up some more space in the bay. I think I read that you just need two piece filler neck and an fc top for it. I searched and all I could come up with is the evans coolant debate... Anyway I'm pretty sure Rich did it so hopefully he can chime in with direct factual experience. Also are there any woes about this?

-Lance

http://www.rx7.org/Robinette/coolant_tank.htm

The only real 'woe' is that it makes burping the system a little more difficult. The AST is there to help remove bubbles from the system, so without it you need a more complete burping of the system.

Is you filler neck a one piece ? If so I may be able to help you with both pieces. I was orignally going to eliminate my AST but decided against it and have both pieces. The FC cap and neck are brand new, the thermostat housing is used. You will have to send me your t-housing in place of mine.

Lance,

I removed my AST and am running Evans. I bought the FC part from Ray at Malloy. Damian also has a couple of good posts or threads about switching to Evans and circumventing the AST.

The Evans debate is in the Single Turbo section. The only real reason I'm running Evans is b/c it provides me with a higher boiling point running a zero or low pressure cooling system - which is a plus for me. However, I know a couple of hard core track guys that running water/coolant w/o the AST also.

A

As for the parts I think I'm covered. This is all I need right (see picture)? I figure while I'm at it I might as well remove the overflow tank. Now do I just cap off this one last remaining port below the filler neck (see picture)?

I also know now I will have to burp the system if I ever do anything but as for driving my radiator is vertical (not tilted) so there should be no need for the ast anyway. The main intention was for tilted radiators if I remember correctly. Thanks guys
http://i27.photobucket.com/albums/c1...h_DSC00986.jpg

This is what mine looks like.

I recently routed the outlet that normally goes to the AST back into the bottom of the radiator. Previously I had it capped off. I haven't noticed a difference either way.

The top part that I'm using from the FC looks different from yours.

Here are some more pics in Damian's thread:
https://www.rx7club.com/showthread.p...ST+elimination
https://www.rx7club.com/showthread.p...ST+elimination

Yeah mine is the solid top... I have a koyo so I don't think I have a spot to route it to. Hell I'm gonna cap it anyways.

I'm running the same radiator and intercooler setup as you.

Why on earth would you remove the recovery tank ? You don't understand how the system works or you would never remove it.

It doesn't really have anything to do with the orientation of the radiator. Bubbles in the cooling system can cause localized boiling, thus bad for the cooling system. The AST was introduced to combat that problem. Even the old 4-rotor LeMans car had an AST. However, it is theorized that once the bubbles are removed from the system, the AST serves no purpose unless there is another source for gaseous contaminants which could cause more bubbles.

I have found removeing the temp sender on the back side of water pump housing makes it easier to get the air out of the cooling system. I have also used a hand held pump with fitting and pulled a vacumn on the cooling system.

Mine is setup exactly like gracer7's. I have the top nipple under the rad cap going to the overflow and the nipple below that going to the lower nipple on the koyo radiator.
Works great.