Le Mans: Prototype Class
Join Date: Oct 2009
Location: Methuen, Massachusetts
Re: Went to a new dyno and got some really WIERD numbers?
A few things to remember:
1) HP/TQ readings from the manufacturer are at the crankshaft. Dynos measure it from either the wheels or the hubs, so you have to factor in the loss of power from drivetrain loss.
2) Dynamometer manufacturers have different formulas, layouts, etc, so their HP outputs vary. Some dynos are more generous than others. I think Dynojets are fairly generous, but Dynocoms are stingy. Don't be surprised if the HP/TQ ratings differ between different shops.
3) What kind of intercooler are you running? The stock TMIC is notorious for soaking up heat from the engine (even with a fan blowing over it), which causes wildly inconsistent readings. Some MS3 owners have noticed drops of 10hp or even 20hp on subsequent runs after the first. For example, Grassroots Motorsports Magazine's Mazdaspeed3 Project Car was so inconsistent on a dyno that they had to measure performance gains in 30-70mph times until they upgraded to a CP-E FMIC.
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