johnsjas

Questions for the guys with twins.

I am planning on setting my truck up with twins. I will use my super b and add a HT3B. My questions are why do they feed the larger turbo into the smaller turbo and not the other way around? Wont this overwork the smaller turbo?

inline6power

i think you might have heard wrong about some twins info. you will not find one person out there where they have a big turbo feeding a smaller one its the other way around. quick spool up of a smalle turbo to spool a big turbo for big performance. if you know someone thats got twins where the big one feeds the little one, please tell them they have a serious problem

TxDiesel007

well both turbos work in unison

as i understand they both spin at the same rate and further compress the air as it goes into the intercooler, thus denser air is higher boost, dont quote me on this, it is just my understanding "logic" as towards how it works, and if you feed the smaller charger into the larger i dont know what happens...

Rick

inline6power

you are right by saying that both turbos work in unison. as far as smaller feeding bigger, think about it , it makes sence. why would you put a set of twins on with a big turbo feeding a smaller one. its the other way around that way you get very very good spool up as well as big boost numbers from the bigger turbo. the small one spools way quicker than the big one, which in tern spools the big one up quick so you get big turbo performance but quick spool up for a small single.

johnsjas

To me it looks like the bigger turbo is feeding the smaller one.

Follow link
http://www.powerbypoole.com/images/DSCF0217.gif

The twin kit is for an HX-35 and bht3b.

The bht3b is the lower left turbo and the HX-35 is the upper right turbo, correct?

If you follow the outlet of the compressor on the ht3b it leads into the inlet on the hx-35.

The bigger turbo is feeding the smaller one.

Or am i totally confused

12valve

you are right... on the intake side...cold air...compressed air...

i think you and the other people are on a different channel... you are talking about intake, and the others about exhaust. basicly you all have it right in your mind.

for intake, it goes fist through the bigger one then the smaller one then intercooler

for exhaust it goes first through Small turbo then through the Big then downpipe.
am i wrong?

Willy91

Your right 12 valve. The larger turbo feeds air into the smaller turbo, but the exhaust gasses pass throught the smaller turbo and then to the primary.

johnsjas

Ok now that we got that cleared up wont forcing air into my super b (small) turbo hurt it? It seems to me if the drive pressure ratio is best around 40 psi I would think running it with forced air into it will hurt it.



Am I making sense?

inline6power

i am thinkin the same thing. for some reason i knew that the smaller turbo feeds the larger turbo on the exuast side but for some stupid reason i thought that it was the little one that feeds the big one on the intake side to.

paulb

In a typical twin setup it is actually easier on the top turbo, not harder. The turbos work on a pressure differential. In other words how much they have to increase the boost from the inlet side to the outlet side. For example on my twin setup with a total boost of 65psi, I am making 28psi of that on the bottom turbo, and 37psi on the top. Normally the top turbo, when used as a single would be at about 45psi. Really the only way it is harder, is that the compressor housing needs to hold the total boost. All the S300's have a very good clamping system. The snap ring used on the holset turbos, and be modified to hold better, but at moderate boost levels it would not be an issue.

Paul

inline6power

how much would upgrading to twins lower my egts. i could upgrade to the rest of the ATS kit pretty cheaply. right now with what i have in my sig, i hit 1250 with just injectors and peg 1550 really fast with all the boxes on.

johnsjas

Will the stock intercooler be able to hold the pressure of twins?

Timmay2

The big question is can the stock cooler cool the mass heat generated by twins.

inline6power

there is way less heat created by twins than almost any big single out there. thats really the purpose of twins it way lower EGTs.

Willy91

Your EGT's will drop a ton. Just my guess for you but I'd say you might lose 200-300 degrees. And with the way that twins operate they create less heat for yhe intake side