I have a 1982 RX-7 GS with Racing Beat single pipe exhaust system and of course the Dellorto Intake system, and Fuel Pump kit. The exhaust system includes header, Power-Pulse pre-silencer and muffler. The engine is otherwise completely stock.

My experience with this intake system has been largely favorable. With the exception of the icing problem, I love this system. However now that I only drive the car on nice days, icing isn't an issue any more. This car used to be my daily driver and as long as you were driving "normally" and kept the engine under 4K RPM, mileage was identical to the stock system. Between 4K and 6.5K RPM is where the engine really puts on the power (along with mileage reduction J ). It's a huge power increase over stock (50% according to RB) and the sound is great without being too loud.

Throttle response is a bit choppy when the engine is cold. Especially when the carb and intake manifold are cold. It's not nearly as smooth as the stock system. However, once the carb and manifold warm up, the response is nearly as smooth as stock. Perhaps a bit less so under 4K RPM and much more so above that. It's also a bit more abrupt between throttle on/off. The power increase more than offsets any smoothness in low-end response.

Other than adjusting the idle mixture, I have not changed any of the settings on the carburetor. Racing Beat did a good job in making a system that worked out of the box. Speaking of the idle mixture, the carb is fairly sensitive to this adjustment. I did have some trouble with the engine hesitating/stumbling upon hitting the throttle. It turned out that the idle mixture was set too lean. Opening the adjustment screws 1/2 turn at a time slowly (starting from 2 turns out) improved things. Even 1/4 of a turn can make a difference between an occasional stumble and good throttle response.