Ever wonder why single turbo 3rd Gen RX-7s sound "rough" when idling or under slight acceleration?  The reason is the wastegate.  On the stock twin turbochargers the wastegate is internal.  Exhaust gas routed through the wastegate is still discharged down through the exhaust system.  The same theory applies for the single turbos except that the wastegate discharges to the open air.  The result:  when no or little boost is needed the exhaust is shot directly out the wastegate making the car sound "untuned" or like it has an exhaust leak. 

 

When boost is demanded by the engine, the wastegate is completely shut and the exhaust gas routed over the turbo is then discharged out to the downpipe and through the rest of the exhaust system.

http://www.catenet.net/dyno.php

Excellent page all about single turbo upgrades and the power they yield

XS Engineering TO4S

XS Engineering makes a kit for the T04S

Good for ported rotary engines

Lower high end output capable than the T04R

Capable of 430HP

GT35/40

(Courtesy of www.rpmperformancecentre.com)

These units have a T3 style base flange and the big .70 compressor cover with 4" inlet. They are available with .82 or 1.06 exhaust housings and are rated at 700hp with the 1.06 exhaust housing. Dual ball bearing internals standard.

Capable of 500+ HP

Rotary Extreme T04R

Turbo Spec

(Rotary Extreme)

Capable of 500+ HP

GReddy T-78

Full Boost attained by approx 5000 RPMs

Capable of 600+ HP

Apexi RX6

*Ever wonder how it compares to stock twins?*

RX-6 TCW76 P27 ball bearing turbocharger

Capable of 400HP

This site is meant to give information related to the 1993 (o)Mazda RX-7 Twin Turbo.  Anything from rotary engines to wiring diagrams and turbo upgrades to tuning info, this site has it all! efini 93 rx7 13b anfini Turbo RX-7 Turbo RX7 turbo rx7 rx7tt rx-7tt  As well as the Rotary Engine Pickup Truck aka REPU repu