nograin
02-15-2001, 03:36 PM
I know this has come up pretty often.
Last night the Phila SCCA had a guest speaker who discussed his chassis dyno.
He did not know all the different standards, sorry.
He did know that the readings from commercial chassis dynos are all relative. That is they are precise and repeatable, but the numbers will not be the same if you switch to another brand.
The brand he uses has large dia. rollers which he felt was safer than the emmissions dynos used in this area. I have his name and address if anyone wants to take their GW or other vehicle to Pottstown.
Most important, he said that the difference from engine hp, to chassis hp there is a 15 to 30 % loss. He had the opportunity to run a car whose engine had just come from an engine dyno, and the loss was 22% Large tires, large gears, etc are going to increase the losses (more friction).
There is a chassis dyno out there that will calculate flywheel hp.
The SAE chassis hp is generally refered to as Brake, or Brake Specific Hp. but it is not clear if this particular dyno meets the SEA specs for Brake hp.
Anyway, hope this is of some interest.
------------------
360 727auto-trany, NP229
body by beer (PO) :(
carries wood inside
no "wood" outside
My other car is a fish
Last night the Phila SCCA had a guest speaker who discussed his chassis dyno.
He did not know all the different standards, sorry.
He did know that the readings from commercial chassis dynos are all relative. That is they are precise and repeatable, but the numbers will not be the same if you switch to another brand.
The brand he uses has large dia. rollers which he felt was safer than the emmissions dynos used in this area. I have his name and address if anyone wants to take their GW or other vehicle to Pottstown.
Most important, he said that the difference from engine hp, to chassis hp there is a 15 to 30 % loss. He had the opportunity to run a car whose engine had just come from an engine dyno, and the loss was 22% Large tires, large gears, etc are going to increase the losses (more friction).
There is a chassis dyno out there that will calculate flywheel hp.
The SAE chassis hp is generally refered to as Brake, or Brake Specific Hp. but it is not clear if this particular dyno meets the SEA specs for Brake hp.
Anyway, hope this is of some interest.
------------------
360 727auto-trany, NP229
body by beer (PO) :(
carries wood inside
no "wood" outside
My other car is a fish