Why not just run an efr 9180 on the 3 rotor?

 

^ Because they cannot flow enough to support the HP needs of a 3 rotor. Ask me how I know.

Great turbo, great spool up at low RPMs, and IMO, by far the best turbo for the money for a 2 rotor. With a 3 rotor, the 9180 will support to around 550 WHP before it runs out of capability. You can go with the new 1.45 AR but then you sacrifice low end spool up. Not sure what the gains in HP would be.

Now, if you put 2 of them on a 3 rotor, they will work just fine. You then have to have an ECU that will support the configuration and you need a bunch of fabrication to piping and wastages to make it happen.

 

I guess that all depends on how much hp you want out of the build....

In my opinion a 550hp/450tq (ish) street port or maybe even hb-port 20b in an fd would be the ultimate weekend/nice evening driving street car...you'd have an amazing powerband with plenty of usuable torque and that sound....nothing beats that sound....
With a hb-port Im sure it would spool up the 1.45 no problems.

Just how I feel... everyone's always chasing the "hp" number... There's a point where more hp is useless anyways... that point when traction is no existant and stuff starts breaking (tranny )
Id much rather have a 550hp fast spooling 20b fd that is useable and fun to drive than have a 700-800+hp 20b that blows my tranny every time I pull hard in 3rd or 4th and all it's good for is showboating..

 

^ Don't disagree with you on the usefulness of 550WHP/450tg for street use. In fact, that is pretty much what I drive my car around at with it set at 12 PSI. I also am not one to chase HP and don't really care if I make 700+ HP. So, far, I've topped out at around 675 at 18 PSI and then called it a day.

I guess the point is the turbo is really undersized for a 20B. I worked directly with Borg Warner on securing a 9180 for my 3 rotor and was shocked at how small the turbo was once it arrived.

As it turns out, I asked the wrong question which was "what is the best EFR turbo for the 20B?" versus "what is the best Borg Warner turbo for a 3 rotor?". The first question (best EFR turbo) nets an answer of the 9180 but the turbo maps quickly show the 9180 is ill-fitted for use on a 20B. Marco Jorge on the forum pointed this out to me before I got the 9180 but I didn't know much about turbos then. The maps are posted in my build thread if you want to see them.

In any event, Borg Warner and Mike Franke from SE Power Systems then helped me go back to the drawing board to secure a more appropriate turbo for my application and we will be testing various ARs on the car soon and will post up the results in the build thread.

But, for all 2 rotor guys, I feel the EFR series turbos from Borg Warner are great advancements for we rotary guys. Put one of those on your 2 rotor and you'll have one fun ride.