| that have been machined to allow fitment of the 76-trim GT28 10-blade turbine wheel. The housing is slightly smaller in volume than the 5-bolt .64 A/R housing that most people are using on the GT2860RS. The difference in the housing and extra blade on the turbine wheel is primarily accounting for the spoolup response of the compressor. The term "A/R" has nothing to do with compressor or turbine. A/R is short for area/radius. It is a ratio of the cross-sectional area of the turbine housing divided by the radial distance from the center of the wheel to the center of the area in the scroll. This ratio is constant at any degree of measurement you take it from and it directly relates to the velocity of the exhaust gases at the nozzle within the housing. Consider the turbine housing like a funnel. The lower the A/R, the bigger the difference in area at the inlet vs. the outlet. Forcing gases through this "funnel" is going to produce higher gas velocity at the nozzle. The nozzle is an integral component of the turbine housing: this is the end of the funnel that directs gases into the blade tips of the turbine wheel. My housing is accelerating the exhaust gases more and impinging that gasflow onto a turbine with one additional blade. Even considering that this setup will inherently produce more backpressure on the engine, it isn't so much that it has become detrimental to making torque/power at higher RPM. I am making more peak power and peak torque than Dee's or Seb's setup, but with a healthy improvement in bottom end and midrange performance. Again, it is a fine balance of parts coming together that makes this possible.
[ ashspecz.com ]
[ agpowers@bellsouth.net ] Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the tailor.
Albert Einstein
|
