What are the main differences in the 13B RE engine as opposed to the 13B?

Also bolt pattern for an 88 RX7 is 4x114.3 right????

 

I'm pretty sure the RE has small exhaust ports because all cosmo's were auto's and needed the extra tourqe to get around. Which is why people use RE iron's and REW housings because REW exhaust ports are larger and RE intake ports are larger.

 

Depends entirely on which 13B you're talking about. S4 and S5 are quite different.

http://fc3spro.com/TECH/SWAP/FD3S/BTvsBREW.html

This info is for the 13B-REW from the FD RX-7, but most of it also applies to the 13B-REW from the JC Comso.

4-stud is 4x114.3, 5-stud is 5x114.3.

 

93 and up RE engines use the bigger bearings in the front cover, and stationary gears, They have the biggest ports ever produced on a 13B stock, They use a sheild in the exhaust housing, front cover is a little different for the oil feed to the front turbo, Engine mounts are in a different place, it uses 2 thermostats instead of one, Oil metering pump is different, I think thats it