Why do older Z's ( and soon, new ones) have to have TT's? Why not just one big one? Just curious, because I think that they use the twin turbos out of tradition.

correct me if i'm wrong

 

There are definite benefits to using two small turbos as opposed to one large one. I think the main benefit is that small ones spool up faster and therefore exhibit reduced turbo lag, making for smoother power bands.

BTW...where did you hear that there will "new ones"?

 

Two types of TT sort of. Bi turbo means two (usually smaller) turbos running seperatly feeding each half of an engine so they can spool up faster. The other twin turbo set up can have one smaller and one larger turbo. They are sequential (one after the other), the smaller spools up first and feeds the larger giving more power.

I had an Audi S4 that was Bi-turbo, helping reduce the lag, but in terms of out-right tuning, usually short of a TT set up. (although i still had 330hp and 380tq)

 

 

He refers to most likely, the Skyline. Another reason there is no single turbo for the Z is space. It's tough to fit all the plumbing with twins. A single turbo, as tuners have found out, is impossible to jam in the engine bay.

 

Not trying to jack the thread, but how does a single turbo get powered in a V application. Do you have to plumb both sides to the turbo, or would you leave one side "open" and the other side powering the turbo. Neither sounds good to me.

 

I read somewhere on this forum that they might be making a TT 350Z soon as an upgraded model...maybe it was BS

In any case there are already kits out there to my knowledge that are TT (I think greddy has one, not sure.)

 

Hey, not to be a dink, but I think ya got that backwards. Im pretty sure Bi-turbo means that they do not both run at the same time, for example, a small turbo for low rpm and then the big turbo kicking in at the higher rpm band. I was under the impression that a twin turbo setup runs both turbs at the same time, feeding half the engine each.

I could be very wrong, but in the interest of education, anyone else have any idea what the definition of each is??

BTW, S4's are SICK when modded up.

 

bi-turbo is two smaller independent turbos (aka my S4) or Audi is pulling mind games on me (although i think the 300zx was similar and called twin turbo).

 

I believe JeepRage is right.

 

If you had room one turbo would be fine. Doing one side only...you're kidding, right?

 

yeah, bi's feed together, twin is sequential.

I think they get plumbed together with a turbo manifold, though Im sketchy how that works.

a turbo application is not the same as NA. backpressure isnt a concern. the turbo is creating as much backpressure as it possibly can. what happens after that doesnt matter as far as 1 or 2 pipes, you just need enough piping to fit all the additional exhaust.

 

IIRC from a friend of mine who owns a speed shop and drives an Audi S4, BITurbo is nothing more than Audi's way of saying "twin turbo". I don't think it pertains to a specific setup (two turbos boosting in parallel vs. sequentially). Don't quote me on that though-it's been a while since I've talked to him.

Jeeprage pretty much said it. Twin turbos are just a way to reduce lag by using a small turbo down low and then using a big turbo up high (sequentially). As far as when both turbos boost in parallel, each to a bank (V engines only), I'm not sure why but maybe something to do with boosting 3 cylinders vs. 6 cylinders as a load for each turbo? Anyone here in mechanics? Volumetric efficiency?

 

From what I've seen, there is no naming standard for turbos. Bi-turbo, twin-turbo; they can mean the same thing (usually two independent turbos boosting into the same intake manifold).

From what I remember, it seems like sequential turbo's (a small one for low boost that @ certain RPMS gets bypassed and the exhaust goes to power a bigger one) were always specifically noted as such. I think the Supra and RX-7 had twin sequential turbos.

The downside to running a single turbo off one side of a V engine is that you are only getting 1/2 the exhaust gasses to power the turbo but you are still boosting the intake which is feeding all six cylinders. This means that you will either need to use a very small turbo to avoid lag and just have very low boost (probably not worth the effort) or you need to figure out how to pipe in the exhaust gasses from the other side of the engine. In the Z, I think it was easier to use two turbos than it was to try and pipe the exhaust gasses from one side to the other.

-D'oh!

 

bi turbo=twin turbo. Like the z32. Both turbos at the same time (2 chicks at the same time )

sequential=2nd turbo comes in on preset RPM. MKIV has sequential twin turbos.

Single turbos are better on straight 6 like the poopra. Personally I like the z32 design better (twin throttle bodies) v6