hiya,

several ?s here.

1 what does the air pump do on these cars?? can i remove/run w/o it w/o hurting anything.

2 on turbo cars there looks like there is a bleeder on the main air hose from the air box to the turbocharger what does it do and what is it fer? (yes, it is OEM)

3 do i need a certen kind of hose for the one mentioned above or could i get any air tight hose/pie to work?

4 i'm thinking of running straight pipe back from the precat. on my exaust system to an ebay muffler, will this be enough back presure

thats it

peace

Gear Grinder

 

I'll answer #4 since i dont have any stock intake parts.
you dont need backpressure after the turbo at all. but that setup would be very loud most likely.

 

ebay muffler will not cut it with a rotary engine. rotaries produce an amazing amount of heat, and will burn up mufflers if they are not packed with high quality materials. canister mufflers are just unbearably loud.
i would suggest going with a nice racing beat or hks muffler, or something similar.

 

I believe on a turbo II the only thing the air pump does is pump air to the exhaust or silencer...the only downside to removal should be premature cat failure and/or failing a smog test if you have to have one.

My car is N/A so the only hose I have from the Intake is the hose to the Bypass Air Control Valve, this valve regulates air bypassing the TB to maintain idle speed. I believe it's just above the turbo on the UIM of a Turbo II....but, what do I know, my car is N/A.

 

#1 The airpump on turbo models are in place to reduce emissions. They pump air into the (big) main cat, to further break down carbon and fuel going thru the exhaust. If you remove it, you're cat will burn thru, so if you remove the airpump you need something in place of the main cat soon.

#2 This hose is for the stock air bypass valve. It works like a blow off valve, but rather then "blow"ing off the air, it "bypass's" the air into the intake stream, at a point before the turbo, rather then after it. Without this line, you need a one-way check valve, to prevent a big vacuum leak. ALSO, if you remove this, you will hit a mega-rich point on the fuel map, causing flames and backfiring and stuff on decel.

#3 You would probably want the same kind of line that was originally there. (3/4"? vacuum hose, L shapes, 90*? !THIS IS ALL GUESSING BESIDES THE L!)

#4 A straight pipe is not a good idea. Neither is an ebay muffler. You want a quality muffler, capable of maintaining much higher heat then usual piston motors present. Like something from Racing Beat, Corksport, GReddy, etc. A straight pipe should be replaced (which also replaces the main cat, hopefully) with something like a Borla XR-1 to reduce noise.


For #4, if you want quality and performance, you would go with something like the entire Racing Beat turboback system. If you are doing all this after-cat stuff...why not get rid of the restrictions up front too?

If you go with the Racing Beat, theres no need for any external-brand silencing. If you go with something like Corksport, you basically NEED something like a Borla XR-1.

 

You need a very tight pre-formed bend to fit. I ended up sticking with the stock one because I couldn't find a replacement to suit.

With a turbo you want as little exhaust restriction as possible. Getting rid of the pre-cat would be an excellent start. Only use mufflers packed with steel wool, not fibreglass.