Stock turbo A/R?

[biglipzit]

What is the A/R of the compressor side of the stock T25 turbo? Is it the same A/R .60 as the T28 turbo?

[SpeedRacer1]

A/R .80

[biglipzit]

How come it is larger than the T28? I saw pics of a T25 next to a T28 and the T25 was alot smaller... Doesnt make sense to me. Can anyone explain?

[SpeedRacer1]

What part of the T25 on the left looks BIGGER?Take a look at the inlet chambers where the wheels are, the wheel on the T28 is as wide as the inlet. The T25 wheel has a metal slanted are.

A/R has nothing to do with wheel size.

[biglipzit]

ok thanks. were you refering to a picture when u mentioned the T25 on the left? lol

[SpeedRacer1]

Yes, I was the one who hosted it. Here it is again.

[HKSpeed]

what is A/R? sorry, I'm a turbo newbie.

[SpeedRacer1]

A/R is area to radius, it has to do with the housing designs. You can alter the pressure in the housings with different housings and trimmed or new wheels.

Generally smaller numbers mean faster spool, higher backpressure at high RPMs. Larger numbers mean longer spool up but better top ends.

[biglipzit]

does it mean that the T25 would have a better top end than a T28? What are the main differences between the 2?

[SpeedRacer1]

It means that if the T28 compressor wheel was the same size as the T25's compressor wheel then the T25 would have a better top end. But clearly the T28's compressor wheel is larger so it will naturally produce more power (bigger turbos = more power).

The main differences between the two turbo's are: The T28 compressor wheel is bigger.The T28 compressor housing is bigger.The T28 has a ball bearing centersection.The T28 has a cast divider between the exhaust turbine and wastegate port.