In a message dated 9/3/2005 11:19:15 AM Eastern Daylight Time,
lors01@msn.com writes:
Just read the Car & Driver article on long term test of RX-8.
They saw the same long break-in period on the engine that I did.
Compression was terrific from first run on but the power increased slowly over
time. The CD car was significantly faster in the 1/4 mile after 40,000
miles than when new. I still don't know why this should be. The
slightly wider side seals and exhaust shield on the rotors would
not seem like they would cause this much
difference.
After a race engine rebuild the pros run in on the dyno for several hours.
I just do an hour at fast idle (3,000 RPM) before using the engine hard. The
engine runs best about the third weekend, because the sealing just keeps getting
better to about then. A street engine will take much longer. Best sealing would
be (my guess) after 6 months of gentle driving.
The best ever power will be much further down the road. The sealing goes
away a bit, but as the seals loose height, and spring tension, and the scrapers
edges wear a bit flatter and become less effiecient, the total rotational drag
goes down.
Say it takes 5 foot pounds to rotate the new engine without plugs. The
60,000 mile engine will take less than 2 foot pounds. A 3 foot pound improvement
over new.
3 pounds times best power RPM (8,500 RPM) = 25,500/5252= 4 free
HP less a very small amount for slightly poorer sealing.
A worn out ring package in a Miata (or any) engine will not seal like a new
engine, but will always produce more power. The Formula Vees get 60+ HP from a
stock (all stock pieces)
40 HP 1200CC VW motor. Formula Ford (1600CC) stock parts puts out over
100HP.
Drag elimination is the secret.
Lynn E. Hanover