did anyone knows if 13B RE(cosmos) inport, is bigger than 13B(fd3s) inside the housing? I have noticed that at the outside side is a quite bigger, but someone told me that the inside side is the same thing.Is that correct?

My plan used to be 13b-RE but after looking at the lower intake manifold and comparing some things, I noticed that the intake came into the engine at an angle. Like this \| instead of -| making the port look much larger than it really is. It indeed might be slightly larger, but I don't think it is worth it at all, having to buy special mounts and so on.

The RE intake runners are much larger than the REW. But the ports are smaller in the RE.

Keep in mind the 13B-REW was the highest output 2 rotor engine, and was the engine in mazda's flagship sports car. If the RE engine block was superior to the REW, it would have been in the rx7.



Just because the port is bigger doesnt mean its better. Smaller ports/runners have better port velocity, which helps fuel atomization and engine VE. In addition, the runners are a big large for the port timing/area on stock form, so theres room for increasing port timing and area without needing to increase runner size.

Your answers were very enlighting.I'm very grateful !

There is no superior or inferior in that comparison. Just two engines optimised for different platforms.



The REW is just a glorified S5 TII running twice the boost... Not the holy grail some make it to be.

The REW has a better oiling system stock than the "race" parts available for the other engines. The machining on the rotors is superior to the previous engines, and the block was reinforced in all the problem areas. The corner seal springs were updated for the REW, which became almost standard practice to use those springs when rebuilding earlier engines. The intake runners were angled to raise the manifold flange on the block, which allowed more clearance for the turbos. The wear coating on the rotor housings was improved, which required only 2 oil injectors, vs the 4 in previous engines.



The RE was the step between s5 and REW. But its still a lot closer to a S5 block than it is to an REW.

All that improving and the engine can only make 65k without shitting an apex?



The RE may be closer to the S5, but it isnt glorified at all like the REW. People need to stop that nonsense.



I have no money to make by my statements. Im not selling RE adaptor mounts...

I sell the REW mounts because its a more common engine in the US(you dont have to import it from japan), and because its a superior block.



The REW block is not at fault for the reliability issues the FD is known for. The engine bay is cramped, and the radiator is too small, even for stock output. In addition, it runs speed density fuel management. It has no way to compensate for a change in airflow if the boost does not change. And we all know that can change over the lifespan of the engine, but the ecu was never designed to compensate. And the stock twins keep tons of heat in the engine and engine bay, which has to be dealt with.



The problem with turbo rotaries, and especially FD's is its too easy to make power without supporting mods to make it reliable. How many FD's do you see making 1.5-2 times stock output running a koyo radiator, which only has about a 20% improvement in cooling capacity. Where do you think the rest of the excess heat is going? Right into important engine parts that need their temperature kept in check to keep the car reliable.



In addition, how many of those blown engines do you think can be attributed to tuning errors. Its well known that standalones dont compensate for changes in weather like the stock ecu does. Mada engineers spent a considerable amount of time tuning the car to run properly in every reasonable weather pattern. Most standalones dont have more than a few hours of tuning put into them, and I bet there isnt a tuner in the rotary community who has anywhere near the training or experience in engine management mazda engineers do, save one or two shops.