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Please educate me


auxilary

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Can someone explain AR numbers to me? I'm getting into the turbo world, I know how the turbo works, but I need more info to learn what turbo I'll need to mate to my wankel (rotary, that is, get your minds out of the gutter). I'm swapping a 13b turbo into my Z, and the stock turbo's not going to cut my needs.

 

I just need a brief (or detailed, i favor detailed!) rundown of different trims, turbo sizes, how to calculate what's needed, and what a/r numbers represent

 

thanks!

 

(can't be ignorant if I ask, right?)

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Aux - that's a pretty tall information order.

 

A/R is the area/radius ratio of a turbine or compressor housing. In such a housing, the area/radius around the snail is a constant. Radius being the distance from the center of the housing to the center of the passage, and area is the area of the passage at the point you measure the radius. The higher the number, the greater the flow potential for that particular series of turbocharger. For a turbine, the A/R is directly related to the spoolup time, or response of the turbo.

 

I don't know anything about turbos on rotaries, but what I see people using are larger A/R turbines. As far as compressors, you need to determine your power needs and calculate the flow and boost pressure necessary to support that. Based on that and what type of driving you will do, you can then choose your turbo, both turbine and compressor.

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An S trim is a compressor wheel, and a P trim is a turbine wheel, just for starters. Make sure you don't confuse the two.

 

The advice on the turbo from Tim is good. Rotaries typically run a larger AR turbine housing then a piston engine. They have three power pulses per revolution if that helps you understand why.

 

Just so you know, N, O, P and Q trim are all turbine wheels. S and V are compressor. Also Stage III, IV, and V are turbine wheels.

 

You could probably have the stock turbo upgraded by sending it to one of the better shops, like Forced Performance. I am not sure if they do those or not. Alex on here also can build a turbo, but I don't know if he messes with those. He rebuilt one for me and did a nice job, so I would use him again.

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