UIM comparison
 

I searched several forums and found nothing re: this inquiry.

I have been seeing a lot of FD's lately using the 13bRE UIM. Does the 13bRE UIM flow any better than the 13bREW UIM with it's different design and what appears to be a larger chamber before the runners? Can anyone elaborate on the performance benefits of either and give me an idea of which would flow better?

It won't bolt to the 13b-rew lim, you would need a 13b-re lim.

Then the 13b-re lim port openings are much larger than the rew, so you would need to port the shit out of the rew runners, or fill the re lim with devcon or similar and port it down to avoid a large step change.

not worth it

Thanks.

SO I would assume with the larger runners the RE manifold would flow better, especially under boost. Would there be any benefit to using RE housings and the LIM and UIM for the upcoming build? Or is it a fairly insignificant difference in airflow?

Next time you go to rebuild grab a pair of 13bre housings and lim/uim, remove the stock exhaust sleeves, install fd sleeves.. The runners on the re are huge!

Just by swapping rotor housings you would not gain the RE's intake runners. If you swap irons you will, but you will loose the REW's mounting points. The RE mounts to the subframe in a similar fashion/location. However, I don't believe them to be the same.

Not worth it, just port your REW irons, and sell the re irons to someone with an FC.