On Tue, Jan 04, 2000 at 01:42:04PM -0500, SS454454@aol.com wrote:
> I totally agreaa with you Rob. Also, don't forget the (very mislead) people
> in the Speed Shops that will actually tell you that a K&N Filter (10hp) +
> Headers (15hp) + CatBack (10hp) + Chip (10hp) + Pulleys (10hp) + MSD (5hp) =
> 60hp. It just doesn't work that way. (Maybe 35-40hp...but not 60hp)
In fact, it gets even worse!
When a manufacturer makes a "15 horsepower!" claim, that means their product
adds 15 horsepower to _some part_ of the horsepower curve. Horsepower is
dependent on RPM, and when the automaker says "This engine makes 250
horsepower", that's a peak figure.
When an aftermarket manufacturer says "My product makes 15 horsepower!",
that's the peak _difference_ between the old horsepower curve and the
new horsepower curve. So if you peak 250 hp at 4000 RPM, you might still
peak 250 HP at 4000 RPM-- but the 175 hp the truck delivered at 2000 RPM
may now be 190 HP at 2000 RPM.
So 250 + 15 = 253, or 255, or maybe 260 or perhaps even 245! But rarely
does 250 + 15 = 255 when adding horsepower numbers.j
So not only are modifications not cumulative because two modifications may
exploit parts of the same horsepower gain (headers and exhaust, for example),
but they're even more not cumulative because they may be changing different
parts of the horsepower curve.
Moral of the story: Never buy a product based on claims of how many
horsepower it makes. There's enough people out there doing it. Find
someone who did and test his vehicle instead of making the same mistake. :)
-- --J.D. Forinash (foxtrot@cc.gatech.edu) / '69 Coronet 440, yellow, 318 The more you learn, the better your / '70 Fury III 'vert, mostly white, 318 luck gets. / '99 Dakota R/T 15.601 @ 85.57 The Golden Tornado goes to the Gator Bowl again! Next victim: Miami
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