I am in the process of buying a 95 RX-7Beast. Can anyone tell me what in the "Blue Hell" a Y-Pipe does? And what the AST is used for and WHY does or need to be removed? All inquiries welcome.....Nap 2002.

 

>>Can anyone tell me what in the "Blue Hell" a Y-Pipe does? <<

The "Y" pipe ia a Y shaped pipe that collects the intake air from the two turbos and feeds into the intecooler. the early version had a rubber connector between the Y and the PLASTIC intercooler pipe, both of which are prone to splitting/breaking and leaking boost - the Latter "EFINI" version is all Aluminum has a larger ID for better flow and uses a flanged & Bolted conection an easy Bolt in Upgrade


>>And what the AST is used for and WHY does or need to be removed? All inquiries welcome.....Nap 2002.<<

The AST (Air Seperation Tank) serves the simple function of removing potentially harmful Air Bubbles from the coolant (hence it name) the problem is that the OEM unit is a two piece plastic casting that is prone to splitting along the seam causing almost instant loss of all coolant it is a good idea to replace the OEM unit with an aftermarket Aluminum or SS unit. There is some debate as to wether or not it is needed at all , however in my opinion MAZDA would not have spent the $$ to design it into the system if it wasn't needed.

 

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He basically got it all...end of story. Be careful though, the aluminum y-pipe will not work with most aftermarket smic (stock mount intercoolers).

 

Here's a recycled pic from an earlier post that shows the y-pipe in the upper right, along with the rubber coupler that splits. (Ignore the "this and this" arrows.)

13-240D = Y-pipe
13-247 = rubber coupler

 

THANKS FELLAS FOR YOUR HELP. THAT INFO, PLUS MORE SOUNDS LIKE THAT WILL ALMOST DEFINATELY IMPROVE HP. THANKS AGAIN!
-BIG NAPO.

 

I have heard of a 1 psi increase in boost after installing the y pipe (better air flow). the AST will not increase hp but engine life.