"Just replacing the restrictive factory exhaust manifold should give a 20hp increase "
When I bought my Duratec plus 4 it had the full Williams Motorsport stainless manifold and exhaust/sports cat along with the ITG air filter conversion already fitted. I've had my car on a rolling road and it produced 155bhp at 6000rpm and 148lbft torque at 4800rpm.
Assuming Fords figures are correct that's a 10bhp increase only.
A few things to take into account here, I couldn't have the car tested prior to fitting so I'm not sure what figures would have been achieved in standard mode.
Not all rolling roads give similar results, as my tester said " some read high to please the client"
If you feel the car drives better than before any modification then the figures really don't matter!
I've followed this thread from the start and really enjoyed it. It would have been really interesting to have had Monty tested prior to any modification and again when completed. On the same equipment operated by the same tester under the same conditions obviously.
