The making of the Treadstone EFR Turbine housing
The engineers at Borg Warner analyzed every component of a turbocharger and re-engineered the entire unit with the latest technology. We feel that this technology and latest advancement in materials will lead the way of the turbo aftermarket to come. Some key features of these turbo’s are below……- CNC Forged Mill Billet Compressor Wheels
- 347 Cast Stainless Turbine Housings
- Integrated Compressor Recirculation Valve
- Dual Row Ceramic Ball Bearings
- Titanium Aluminized Turbine Wheels (50% lighter than the Inconel)
- Integrated electronic boost controller
Borg Warner has a wide array of turbine wheel selections, ranging from 55, 58, 64, 70, 74 and 80mm. This measurement is the inducer(exhaust gasses enter), and is the largest part of the wheel. Other manufactures such as Precision, Turbonetics and Garrett will denote exducer diameters in there sales, ranging from 49, 54, 57, 62, 65 and 68mm trims. These sizes of turbine wheels are the most popular for single turbo applications ranging from 300 to 1000hp, or twin turbo applications up to 2000HP.
Turbo Comparisons:
The chart below shows inducer and exducer measurements for the EFR range. For example, the ever so popular Precision 6262, one of the first main stream turbo’s utilizing a billet compressor wheel to hit the aftermarket that was a pretty big hit. The 6262 denotation from precision means 62mm compressor inducer, with 82 exducer and 62mm turbine reducer, hence 6262.
The 8374EFR has a compressor inducer of 62mm and Exducer of 83mm, almost exactly the same as the Precision compressor wheel. The 8374EFR has a turbine exducer of 64, 2mm bigger than the 62 from precision. This slightly larger turbine wheel, is closer related to the 65mm turbine wheel from Precision/Turbonetics. The 6265 combination has been more popular lately for guys wanting to push the envelope of the 62mm compressor wheel, making this very similar size to the 8374EFR. Being that the Borg Warner's turbine wheels are made from Titanium and are half the weight of Turbonetics, Precision or Garrets Inconel wheels, you can afford to have a slightly bigger turbine wheel, it will spool up quicker because of the reduced inertia and at the same time eat more exhaust gasses. Turbine wheels are the main factor in limiting HP, so with the same size compressor wheel, the Borg Warner units are able to support more HP than their competitors, while spooling the same, if not quicker!
However, when you use the large T3 .83 Borg Warner turbine housing in
combination with a small 64mm Borg Warner turbine wheel, your combination is far
from optimized, and spool time will suffer greatly due to the difference in turbine
housing and wheel combo. Going with a twin scroll housing will help, but your
combination is still not optimized for that particular housing/wheel combo.
Turbine Housing Optimization Optimization of turbine wheel to turbine lies within the actual distance from the
tip of the turbine wheel, to the tongue of the turbine housing, this is known as optimizing.
Manufactures have different clearances for this optimization and is somewhat of a closely
guarded secret, and is not advertised by any manufacture to the public. This measurement
can easily be measured when taking a turbo apart or showing a cross sectional view
below.
With our design, we optimized our .86 turbine housing around the 70mm EFR
Turbine wheel, while still being able to machine it for the 74 and the 64 wheels. This
housing will fall into the mainstream T3 turbine housing range, and be similar for turbine
wheels of 57, 62 and 65 from the Precision and Turbonetics, as well as the GT30 and
GT35 turbine wheels from Garrett. We feel this is the middle of the road size housing
Borg Warner didn’t make, and our housing will fill in the gaps that Borg Warner left
open. This turbine housing will be optimized on the EFR range of turbo’s, with power
ranges from 300 to 750hp.
