Both the elegant design and the simplicity in the maintenance of the Weber 48 IDA Carburetor have proven to be compelling reasons as to why the Weber name has remained so popular over the years.
This Weber 48 IDA unit is primarily suited for various race applications because of its simplicity, compactness, tunability and excellent float bowl design. As applied to a Mazda rotary engine, the carburetor exhibits a variety of good characteristics. However, in a stock or street-ported engine this carburetor's lack of a choke system can make cold-starts difficult, even in warm climates.
The Weber carburetor is well suited for a number of Mazda rotary engine applications, including:
12A Street Port Engine
13B Street Port (4-port) Engine
12A Bridge Port
12A Peripheral Port Engine
(We do not recommend this carburetor for us on a 12A stock port engine.)
It may be necessary to change the jetting, emulsion tubes, venturis, etc.., in order to tune the carburetor to match the performance requirements of your specific application. We offer the appropriate Weber components to properly tune the carb for these applications. Follow this link for a listing of tuning recommendations for various rotary engine applications. (PDF) Use of this carburetor requires the use of a fuel pump that delivers 4.5 PSI.
Peripheral Port Engine Application
The one application where this carburetor performs best is on a 12A peripheral ported engine. Here, its relatively small size is compensated by the excellent breathing capability of the porting on the engine. For even a greater performance increase, we have found that using a RB-modified 51 IDA unit on a 12A peripheral port engine, power can be increased by 10HP to approximately 280 HP.
This unit is sold as configured by Weber and Racing Beat has performed no modifications to this unit. Requires the use of two (2) base gaskets, additionally, optional phenolic spacers available if needed.
The selection of an appropriate intake system requires that many factors be taken into consideration. Various intake systems yield different performance characteristics based upon specific engine, exhaust, and drive line selections. Due to the complexities associated with these configurations, it is difficult to determine exact power gains for specific applications. Use this intake reference guide (PDF) for performance comparisons between the Weber and Holley Intake systems that we offer.