Karl and all... (archive)

We are off in our power conversions. When we account for the 18% crank-wheel difference we should not be using 1.21 as a multiplier. I did the math in accounting class last night. I think using 1.21 is like a 0.74% error.

For example:

240 * .82 = 196.8
196.8 * 1.21 = 238.128

We just managed to lose 1.872hp due to math error.

To get the exact conversion for an 18% loss we need to use the multiplier of 1/.82

240 * .82 = 196.8
240 * ( 1 / .82 ) = 240

For those wondering 1 / .82 is about 1.219512195121951219512195121951...

So if we are estimating we should use 1.22:
240 * .82 = 196.8
196.8 * 1.22 = 240.096

Isn't that much better...

And the error is magnified when we modify our cars... given Karl's best no disc dyno run we should have gotten...

1st test: HP: 213.4 * ( 1 / .82 ) = about 260.2hp
TQ: 224.3 * ( 1 / .82 ) = about 273.4

So Karl I just added 8.4hp and 8.7 lb-ft to what you originally estimated. It's like a free upgrade by doing math correctly ;-)

The moral of the story is ( 1 / .82 ) or 1.22 NOT 1.21

Pat

Follow Ups:

Re: Karl and all... Roy 17:15 7/26/2000 (2)
- Yes, excellent point, but.....(m) Roy 16:24 7/27/2000 (0)
- Wild a$$ guess inside... Mike S 01:29 7/27/2000 (0)
Re: Karl and all... Karl Asseily 15:17 7/26/2000 (1)
- And then if you factor in the coreolus effect... DataDog 16:12 7/26/2000 (0)

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