RX7Club.com - Mazda RX7 Forum - 3rd gen 13b and 2nd gen 13b?

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3rd gen 13b and 2nd gen 13b?

What are the exact differences in a 13b for a Fd and a 13b for a fc? I know when you buy them you specify, but is it posiable to switch out engine cores (bolt pattern, internal specs, etc..?)

There are 4 unique 13B's for FC's, and one for FD's. The FD version is similar to the 89-91 turbo FC engine, but not the same either. Motor mounts, ports, water pump housing, things like that changed. There would be no advantage to an FD block over an 89-91 FC block except a bit larger ports on the FD. The rotors are the same compression ratio and therefore can make the same amount of power...it's all about what goes on top of the block to run the engine.

Quote:

Originally posted by hypntyz7
There are 4 unique 13B's for FC's, and one for FD's. The FD version is similar to the 89-91 turbo FC engine, but not the same either. Motor mounts, ports, water pump housing, things like that changed. There would be no advantage to an FD block over an 89-91 FC block except a bit larger ports on the FD. The rotors are the same compression ratio and therefore can make the same amount of power...it's all about what goes on top of the block to run the engine.

There is a huge difference between the FD block and the turbo FC block. The FD is a over all stronger block casting wise and shares very few parts from a FC 370 block. As for putting a FD engine in a FC it would be easer to put a 390 RE motor in. Have the advantages to the FD engine and the easiness of mounting plus the cas vs the triggers.