My guess is that the new engine is probably down a couple ponies from the old one. Nothing you are going to feel on the butt dyno, but obviously shows up on lap times.
Edit: Could also be that the new engine, being new, has more internal drag because the parts have not worn and the engine is not revving as fast as the older, more 'loose' engine was. That would also cost you at the end of a long straight.
2008 New England Region SCCA HS Class Champion
2008 New England Region Stirling Moss Championship co-winner.
92HS - 2007 Mazda 3s Sport Sedan -2006 Miata Wheel, 16x6.5, 15lb w/ Hoosier A6 245/45R16 (f) and 225/50R16 (r) MS Accessory Sport Shocks
Slow in - Fast out Fast in - out backwards
Last edited by PZ; 06-28-2013 at 09:00 AM.