| Message |
:im assuming lift .300 or .400 corresponds to higher RPM driving.
I think stock lift is .325 or so.
the .40 number was done as a *max* for higher lobe cams and to keep the data points similar. (.1, .2, .3, 4):how come the CFM goes down when going from stock to ported stock at lift .200? It drops from 95.09 to 93.12.
not sure... could be a few reasons, but i can't speculate :what else would be needed to put a ported exhaust manifold on? I'm assuming it is still ok to bolt sport 500's to the ported manifold or should the porting be matched on the turbo exhaust inlet as well?
for stock 'ported' manifolds, the ideal situation is to have them ported and opened up, then match the gaskets to the port, and match the heads to the gaskets. then do the same with the turbos.... It's a lot of work, but guaruntees no gaps or steps for smoother flow If the porting was not matched between the manifold and the turbo, would there still be benefits or would the missmatch cause too much turbulence?
exactly... the turbulance will probably cause dips in places, as you mentioned above... I'm pulling my engine again in the spring and am definately gonna start researching some DIY porting.
I've personally seen mike smiths work and it is really amazing... his attention to detail is choice.
I'm not a fan of porting stock manfolds tho. The manifolds are cast, and in general, significant amounts of material is removed from the cast manifolds. One problem is having too little wall thickness. This, on very high boost applications, can cause burn through (ie, burning a significant hole in the manifold). I also think it weakens the structural regidity of the manifold. Remeber the weight of the turbos and the exhaust is hanging on these manifolds.
Something to keep in mind. Risks versus rewards.
For the money, and going in knowing the potential of cracking or burn through, Mike Smith ported manifolds really are a fantastic deal.
If you dont want to deal with potential for future failures, then you might want to set aside some significant cash for something more 'consumer'.
"As the Z32 gets older and decreases in value it becomes affordable by lower income and often less desirable people whose tastes reflect their personality and social standing.- Marshall 17:37:05 10/10/03Petz #3
|
 |
