What does the A/R ratio mean?
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Postmaster
Joined: Nov 2003
Posts: 3,595
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From: Utah County, UT
What does the A/R ratio mean?
Never given it much though until I started rebuild process of transmission and Turbo. Current turbo is a 1.1 AR. Does that relate to the exhaust pressure to boost pressure? ex. if the AR rating was 1 it would take 1lb exhaust pressure to make 1 lb of boost, equally 20 lbs exhaust, 20 lbs boost. Am I right in this or is the AR rating relating to something else?
Senior User
Joined: Mar 2005
Posts: 221
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From: Onalaska
The turbine housing A/R (area/radius) ratio is the area (A) of any turbine inlet scroll cross-section divided by the distance from the center of that cross-section to the center of the turbine shaft (R). For any given turbine housing, A and R vary in the same proportions, so all As divided by their corresponding Rs yield the same dividend--which is the A/R ratio.
Check here for more info:
http://www.hotrod.com/techarticles/e...bo/index1.html
Check here for more info:
http://www.hotrod.com/techarticles/e...bo/index1.html
Post Fiend
Joined: Jul 2005
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From: 21791
Lead Driver
Joined: Oct 2004
Posts: 7,413
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From: Columbia, MO
Also, both the intake and exhaust housings have an AR ratio. Most of the time, we only talk about the exhaust housing's AR though. When I upgraded my turbo bits, I noticed that the stock compressor housing is a 1.0 A/R. Stock exhaust housing is a .84 A/R. That link that strokin provided has a lot of good info.
