Turbin wheel sizing and affects on spool?

Rodram2002

Rodram2002

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May 8, 2007
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I'm wondering what the different affects are on a turbos spool, drive pressure, surge, and any other affects I left out. What happens when the turbine wheel is larger than the compressor wheel, example Silver 66 66mm compressor wheel and a 74mm turbine wheel? What about if both wheels are close in diaimter like a older 66mm turbo with a 65mm turbine wheel? And what if the turbine wheel is much smaller than the compressor like a Turbonetics T-76 that has a 68mm turbine wheel?
 
Turbonetics use some different wheels so they aren't a good comparison.
Larger turbines allow you to drive the compressor harder, with less backpressure.
 
62/65/14 spooled close to stock, but runs out of topend fast. Builds boosts around 1300rpm 50psi by 1450rpm.
64/74/14 lag pig, but pulls like a freight train. Builds boost around 1500-1600rpm. 55psi by 1700-1800rpm.

Those are my two experiences.

I had my 62/65/14 upgraded by Engineered Diesel to a 62/68/14. E.D. was putting in a 68mm turbine wheel, their new Super 62 comp. wheel, their race cover and their wastegate actuator rod.
Chris from E.D. said it should flow like a 64 but spool like a 62. I hope its the best of both worlds.
Besides it will make a bad ass top charger for my winter twins project.
 
the bigger the turbine wheel, the more lag you'll get, and the risk of compressor surge goes down, as will drive pressure.
 
Rollin Coal said:
the bigger the turbine wheel, the more lag you'll get, and the risk of compressor surge goes down, as will drive pressure.
Click to expand...

There is more of what I'm looking for, thanks!

Does anyone know much about the Turbonetics and how big of a difference they have between the compressor and turbine wheel? Their turbine wheels just seem so small.
 
it is too small, IMO turbonetics makes turbos for gassers, and not a cummins specific turbo.

from my experience, 62/65, 64/71 and 66/74 are the best combos unless you run a loose converter. i had a 66/71 w/ my stock converter, it was fun as hell to drive, put a nv4500 in the truck and below 2200 rpm if i floored it, it surged every time.
 
In general a 64/71 is supposed to be laggier but what happens if u matched it with 12mm exhaust housing or a 13ss? and then not to mention your combination isnt the same as everyone elses so it could be better or it could be worse.
 
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