[R50 Nick]

Quote: Originally Posted by MINIMANIAUK (original)

You keep mentioning polished heads ,do you mean ported and polished?
Different cams give different results and the 4-5 bhp is a generalisation, the cam is very dependant and the flow of the head- the standard head does not flow fantastically ,hence the large airflow gains possible, with smaller ports the port velocity is high and maximum torque is at a reduced rpm thats what the designers wanted.
The high lift flow with cams is compromised by the limitation of the valves and head ,so the size of the ports has to be done , with the cam lift /duration in mind ,stock or performance.
large ports on the head give high rpm gains and maximise cylinder filling,and extraction(with a manifold) provided the cam is correct with the head flow ,keeping the maximum torque ,rpm as low as possible
It ultimately depends on what usage the car is for road or track and in this respect the head/cam combination and CR is tailored to the rpm range the cars is to be used , whatever the set up you have used doesnt sound good to me ,as a 6 bhp gain with way over 20% flow increase looks like the cam is working against the head configuration .
Have we done dyno runs -yes
am i going to give you the data -no
Should you wish I have a ported /polished head here with stock valve size ,skimmed for increased CR -for use with stock cam -PM me for a price
or I also have a large valve version with race cam and springs for high rpm car let me know
or I have a large valve head with fast road cam using stock springs

I also have in stock a cryo intake kit and cryo fuel bar -probably cheaper than the fuel cooler you are using -not tested as yet so I cant give you numbers
A

I wouldn't pay too much attention to his words, he is the one he thinks he knows everything! Exactly the same in NAM I don't know what he is aiming at, but he is not that convincing! cheers