Choosing Your Compressor Wheel
If you have a hard time deciding which compressor wheel to use on your turbo, here are some tips for you which might help you decide. We’re mainly going to compare the compressor wheels based on their blade count and will compare between 11-blade and 6+6 blade here, however, blade shapes such as cut back blades and extended tips will also impact turbo performance on a slight scale. Cut back blades spools faster than normal blades but you lose some power over it. Extended tips generate more air flow because of its higher blades, capturing more air volume into the engine.
Aside from the blade shapes, blade count has bigger influence on the performance. A 11-blade compressor wheel spools faster than 6+6 blade wheel as it has 11 major blades and thus the air fills up the compressor housing faster, it boosts more efficiently but maxes out sooner too, meaning it peaks at less boost, therefore comparing to 6+6, 11-blade wheel makes less power. Also keep in mind that due to having 11 major blades, it weighs more than a 6+6 blade.
A 11-blade wheel tends to surge more because when it tries to push more air at lower boost level, the air isn’t able to escape fast enough on the exhaust side of the turbo when the compressor side continues to compress air in the engine, however, using a bigger sized turbine wheel will recompense the condition.
A 6+6 blade wheel has 6 major blades and 6 minor blades, that’s why it’s lighter since more materials were taken out during machining. In comparison to a 11-blade wheel, overall a 6+6 blade wheel flows in more air and boosts at higher level to make more power due to more room in between the blades to allow more air to enter. It also has less surging problem than a 11-blade wheel.
Choosing compressor wheel depends how you use your vehicle, a 11-blade wheel will be more suitable for daily drive and for street use, but if you are modifying it for a race or you intend to go with more horsepower then definitely go with a 6+6 blade compressor wheel.