This was just a thought that popped up in my head and wondering if it has ever been done. A bi-Turboed FD RX7 13b, not twin turbo, to where you have 2 turbos and one would send the air to one rotor and the other turbo send to the rotor. Good example of this is an B5 Audi S4 which one turbo sends the air to 3 cylinders and the other turbo to the other 3 cylinders.

 

So you basically need 2 intercoolers and two throttle bodies and twice the boost control? Sounds like a pretty bad idea to me and hopefully no one has put time or money into this

 

What you normally see with that sort of setup in the rotaries is 2 turbos each being fed by one rotor but they merge at the intercooler and become one from there. If I remember correctly, Howard Coleman had a pretty badass setup for a while like that.

Robert

 

been done, the Japanese were doing that in the 90's. it looks really cool, but plumbing gets kind of crazy, as you need 2 oil feeds, 2 oil drains, 4 turbo coolant lines, 2 down pipes...

they tend to use a single intercooler with either 2 inlets of a Y pipe

here is an IC from a 1st gen 12A turbo SA22C,,12A,13B,RX-7,TD-05,??????,???????? - ????!

 

^ Except that twin setup did not perform any better than a single turbo setup.

Imo there is no point in a separate turbo system per rotor on a 2 rotor motor.

 

^ Especially when you consider the advancements in turbo tech over the last couple years. A long time ago I even considered a triple turbo 3 rotor mainly because I though it might look cool. I realize now that my old thoughts and dreams were just nonsense. Lol!

 

Imo there is no point in a separate turbo system per rotor on a 2 rotor motor.

Except if they do not make a turbo big enough or you can't fit a turbo big enough so you use two smaller ones.

ie, it might be easier to fit two "1,000hp turbos" for a rotary instead of one "2,000hp turbo" and the damn rotary will still only make ~ 1,600hp.

 

ive thought about twins too, but plumbing hassle > looking cool.

plus you need to buy 2 of everything

 

It's almost as if this was done by the factory or something...,

There will be an obvious limitation with spool once you get to decent sized turbos. I can in zero way see this being advantageous. Just thinking out loud here off the cuff.

 

I assume blue tii will now bring up twin 7670s.

 

djseven I assume blue tii will now bring up twin 7670s.

Nope, we are talking about parallel twins in this thread.

If we were talking about sequential I would mention EFR 7163s

Look what you made me do!

 

Wyum made it work. Plumbing nightmare but there was definitely a cool factor.

 

here is a FEED car from 1999. personally i think that car is bad ***. 570ps@14.2 psi isn't too shabby either

 

It would be epic to see a sequential EFR Setup.

 

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I did that in 2001

 

What are you running now?

 

Soon borg warner efr.

 

I worked on a car with a bi turbo setup years ago. It spooled no faster and make no more power than a comparable sized single turbo. Was just a complex mess.

 

if you ran meth, and negated the intercooler, and used a P port motor, you could get away with pretty simple plumbing, and there would be benefit individual tuning... and it could be a pretty tight package. if you're shooting for the moon, like a 1500 hp two rotor...

 

As a general rule of thumb, anything Audi does in their production cars is a bad idea to attempt to duplicate.

 

That's not how the B5 S4 turbo system works. All the air moves through a common single throttle body and through a common manifold.

Bi-turbo and twin turbo are no different... Euro vs Japanese vernacular.

 

Oh, I thought the Bi-turbo went the other way!

 

Did everyone completely ignore this part of the OP?

this sounds like an even worse idea than just an aftermarket parallel twin setup (which would combine airflow at the IC and just run a single TB)

 

Yes, we were completely ignoring it because it was such a really really really bad idea.

Thanks for bringing it back up.

 

I will let you know for sure in a couple of months, I have a "twin single turbo kit" fitted to my car (plenty of pics on my build) it runs two KKK turbos, it is a relatively simple set up you just split the oil supply, the FD already has two oil drains and then all you need is a good manifold with a single external wastage.

I should be doing the first start up next month and tuning the month after.

the theory is that a smaller turbo will spool up faster than a larger one so two small one will create maximum boost much earlier, whether this works in practice remains to be seen but as i will be using the car for drift i am hoping it will give me a strong torque curve at low revs.




Now back to discussing what a bad idea it is