Quote:
Originally Posted by RalliartRsX
Spool is almost 100% dependent on turbine. Keep the turbine the same you are going to get the same (or very similar) spool no matter what sorts of billet compressor wheel you go to. Worse yet, an upgraded compressor wheel from tomei.
I agree with King; S15 turbo is junk and ass I mentioned before based off a 30 year old designed turbine wheel.
A 6758 will make 450 WHP easily and have spool characteristics which are MUCH improved on any GT2 series turbo of that era. And this doesn't even take into account boost recovery.........which almost nothing on the market (including the new GTX as the wheels are Inconel based and still almost twice as heavy than the equivalent Gamma ti EFR twheels) compares.
|
I agree with most of your statements and sentiments here, but I must correct you on your statement on spool being 100% based on the turbine. If you take a turbine wheel, let's say an old T-series like a P-trim, and you take off the shitty 60-1 compressor wheel and add a new, much higher efficiency compressor wheel to it, you actually reduce the work the turbine has to do to get the compressor to generate airflow. This means improved time-to-boost over the old junk, which translates to most people as "it spools faster". While you're not changing the rotating inertia or outright flow of the turbine, you are in fact increasing the efficiency of the entire unit.
This is how Garrett has gotten away with using the GT turbines for so long, adding more and more efficient compressor designs has made the turbo more efficient. Even Gen II Garrett GTX stuff uses GT turbine wheels. This is also why they released the GTW line, which are GTX compressors paired with old T-series turbine wheels.
Even Borgwarner has done this on their S300SXE line, using the cupped tip 76/68 S300SX turbine wheel (which is the higher flowing/slower spooling version vs the flat tipped one), which results in the 61.3mm S300SXE, which flows 78lb/min, to spool identically to the old 60lb/min S360 with the flat tipped turbine wheel. That is 30% more airflow with identical spool!