T4 A/R same as T3 A/R
T4 A/R same as T3 A/R
I was wondering if a .63 A/R T4 is the same or bigger then a .63 A/R T3 for the exhaust side.
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:: orion ::
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Checkered-Member
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taken from FAQQuote »A/R Ratios - Area/Radius Ratio... it describes the size of the housing. A larger a/r will make the turbo spool slower but will provide superior flow and thus more top end power. A smaller a/r does exactly the opposite, it spools the turbo quickly and provides semi-adequate flow. There are so many different a/rs out there that allow you to fine tune what you need out of a turbo. [/quote]
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C-Kwik
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Checkered-Member wrote:taken from FAQ
A/R Ratios - Area/Radius Ratio... it describes the size of the housing.
Unfortunately, this is quite wrong. While the A/R is affected by the size of the housing, it is NOT the size of the housing that it is really a reference to. The A/R really represents the size of the nozzle(the part of the turbine that air goes through before hitting the turbine wheel). A/R stands for Area/Radius. It is the Area of the nozzle in the housing divided by the radius from the center of the turbine axis to the center of the nozzle. A larger wheel will generally push the radius out further naturally. But for a given turbine and matched housing, it is generally only the area of the nozzle that differs from one A/R to the next. The Radius usually stays constant. Someone really needs to fix that FAQ. I have had to correct people on this very topic in many posts within the last month.
Orion is correct that you can NOT make a direct comparison of A/R's between different turbos. A .69 A/R on a T3 turbine is drastically different than a .69 A/R on a T4 turbine. Not to mention there are different trims available in each. Some are so different as to have a different major(outer) wheel diameter. In most cases only the minor(inner) diameter of a wheel changes with different trims.
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Checkered-Member
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