Hey guys

I'm trying to figure out why virtually all the Japanese tuners - including the rotary masters themseves, RE Amemiya, are using the stock 20B UIM, TB, and "elbow," but then there's so much talk on the forum about them being so restrictive?

Also, any pros/cons WRT the OEM 20B TB? Say, vs. the 3rd gen TB (including a "big bore" TB available from vendors like FEED)?

Thanks!
~Ramy

 

I believe they just cut the stock 20b TB. The 20B tapers down to 2.5" OD. However it is around 3" before the bend. I am planning on welding a 3" pipe onto mine . . . as we discussed . I need to cut it back a bit further. It is around 2.75 where it is currently cut to.

 

Usually the big deal about the 20b TB vs. the FD TB is the removal of one set of butterflies. In the FD setup, (i'm sure you already know this) there is one set in the TB and one in the UIM. The 20b TB has both sets in the TB. So, just by using the FD TB you eliminate the second set. This of course is a very popular modification for FD owners.

As far as the size is concerned, Both the FD and 20b TB ports are the exact same sizes. I cant remember the numbers right now though. I have both if you'd like me to take pictures of them. I'm fairly certain it has been done before.

Keep in mind that the bolts for the elbow section are different as well. I am running the FD throttlebody and have to use the Greddy elbow for the bolts to line up. The 2.75 section has been cut off.

BTW- I have a 20b elbow that is already cut to 3" if anyone is interested.

 

Uh, no.
That first pic a custom made and welded TB adapter.


-Ted