[BiturboS4] SAE vs. DIN

Edwards, Dave Dave_Edwards at iOra.com
Wed May 22 18:59:09 EDT 2002

The whole of Europe (that includes the UK) is supposed to be using Watts
now. Certainly the German manufacturers will quote kilowatts but usually add
the PS (DIN hp) in parenthesis whilst people get used to it. Similarly
torque is quoted in Nm, sometimes with the imperial units for reference.

Of course the UK (like the US) is still hanging on to imperial units. UK
cars will be quoted in bhp for years to come. However there's rumour that
we'll start using kilometres on our road signs soon. We'll be using Euros


Message: 4
From: Noah Ward <nward at printcafe.com>
To: S4 group <biturbos4 at audifans.com>
Date: Tue, 21 May 2002 14:09:23 -0400
Subject: [BiturboS4] SAE vs. DIN

There are several specifications of horsepower and how it is to be measured
Engine manufacturers must base their claims of power upon the standard
selected by the country in which the claim is being made. In the US, the
standards body for engine power is the Society of Automotive Engineers
(SAE). So all power claims in the US are measured in SAE horsepower. Other
countries have their own standards bodies which create their own definitions
of power. As I recall, Japan uses JIS and the European Community uses ISO
(and I think Germany used to use DIN). Each standards body's specification
dictates what the designator is to be (e.g hp, BHP, etc.) as well as what
must be included in the measurement. For example, the SAE may specify that
water pump power losses must be included but not exhaust stream losses, and
the ISO may specify that it's measurement be in Watts instead of horsepower.

Also, specifications change: US "Brake" horsepower (abbreviated "Bhp") was
measured at the point of output, with no load from a chassis or
power-robbing accessories and with fuel and ignition operations under ideal
conditions. Often called "SAE gross" horsepower, this figure was often used
for advertising purposes prior to 1971.


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