School me on Twins
 

I dont know much of anything about twins other then there two turbos. can someone explain how they work, why to choose specific turbos, etc, etc? i know turbo selection will probably depend on end use, as does most mods.



hopefully we can get a good thread going and it will be useful for future newbies like me that are curious about twins...

Twins compress the air in two stages because a single turbo isn't efficient at compressing the air to high ratios. Twins also give you better response for a given amount of airflow.

The air comes into the big turbo, out its compressor and into the small turbo. Then into the engine, out through the small turbo and out the big turbo.

If you want more than that, try searching on my name--I've posted more about them not too long ago.

jh

Here is something I have always wondered. Why does the big turbo feed into the smaller turbo? Shouldn't it be the other way around?

Good question! I thought I knew the answer, but as I started to type I realized I don't. :) Back to my turbo books in search of the explanation!

RJ

Wait... the big turbo feeds the small turbo?

/grabs hammer

[duhhh]

But wait, here is how I thought it works, tell me where I'm wrong:

Small turbo is on the manifold, it gets all the hot air from the engine. The small turbo then blows the air into the big turbo. The big turbo then... wait, that would mean each turbo would have its own intake.

PLEASE HELP ME UNDERSTAND!!!

Because the small one won't flow the required mass without positive pressure on it's intake

Cool Air flows from air filter.... to big (bottom) turbo ...... to small turbo...... to engine.

Hot Exhaust Air flows from engine..... to small turbo.... to big turbo.... to exhaust pipe.

Help any?

RJ

That does, thanks!

So how does it work if you have a HT3B that spins backwards?

the position/orientation of the turbo might be different, but the air still travels from air filter to big turbo (whether it spins 'forwards' or 'backwards') then to little turbo to engine. the exhaust still goes from engine to small turbo to big turbo to tailpipe.

Ok so the next question. What changes have to be made to a s300 turbo so they will fit these trucks. Just wondering what makes them so expensive.

ok now that i understand, time to start fabing [coffee]

When setting up a set of B1 B2 tiwins. Where do you get the small stuff like the cold pipe that connects to the s400 output the bands to connect the exaust, a gaskett for the botom turbo, and the oil return hose for the bottom turbo? I know most of the cold pipe is exaust tubing welded together I have that part covered and I also can build the hot pipe.

get your hands on a set of twins that some one already has working and copy them. you will most likely find the kits are expensive but worth it.

try this website www.sourceautomotive.biz