| Subject: |
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Re: Re: Re: Re: Horsepower confusion.. |
| Name: |
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Russ Roth |
| Date Posted: |
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Oct 27, 06 - 9:52 PM |
| IP Address: |
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209.102.127.189 |
| Email: |
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powwag4@pcez.com |
| Message: |
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It took me awhile to find what I was looking for but here goes. From Desktop Dynos book.
GROSS BRAKE HORSEPOWER: Describes the power output of an engine in strippped down "race ready" trim. The only drain on power from accessories comes from the oil pump, and possibly the mechanical fuel and water pumps. All other nonessential power-robbing devices have been removed, including exhaust manifolds that are usually replaced with non-muffled tubular headers. Before 1970 virtually all automakers rated their engines using this method. Beginning in the early 70's this rating method was changed to reflect a more representative power level for engines as they are operated in vehicles on the highway.
NET BRAKE HOSEPOWER: Measures the power at the flywheel when the engine is tested with all accessories attached and functioning This includes the cooling system, exhaust system including mufflers and catalytic converters (or a fixed restriction welded in the exhaust pipes to simulate the back pressure of mufflers and cats), plus fuel, oil, water and smog pumps. However, power-steering pumps and air conditioning compressors are difficult to hook up in a dyno-test environment so are often eliminated during net horsepower testing.
Having said all that, I thought some of those "accesssories" were pretty essential and not really accessories. The oil pump certainly comes to mind. But what do I know?????
RR |
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Replies:
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OIL PUMP? by MoparNorm · Oct 28, 06 - 5:11 AM
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