What Happened to my quick 1914cc????

[Dredawg Racing]

Hi guys,
As some of you know I'm trying to get ready for Pinks All Out & I'm getting worried. I was running 12.70's to 12.90's. We raised the compression from 10.2:1 to 12.5:1, opened the manifolds up a little more & my car has slowed way down, 13.6 - 13.3 ET. We have tried tuning, change in venturi size. Any ideas or suggestions would be greatly appreciated.
Thanks,
Andre'

[mr horsepower]

Hello did you changed you cam set up and measured you dynamic cr .
if you change your  cr you need a different cam set up .

GR Henri,

[Fasterbrit]

It's possible that by opening up the manifolds a little more you have hurt port velocity and the air and fuel have slowed down on their entry into the inlet port. Sometimes bigger isn't always better. It would be worth speaking to some of the head guys on here like Jeff Denham (Ugly Duckling user name on this forum, I think...) Can't see how the extra compression would have hurt things unless the CR is now too high for your octane rating and you are mildly detonating.