I have an interesting question. Compared to a set of 6.1 OEM heads... Does an improved intake runner design (maybe even with a larger valve) really matter on a car that is supercharged? The air/fuel is now being forced in at a high speed under boost pressure... NOT negative pressure as in normally aspirated and bottle fed cars. Is a ported/polished intake with/without a larger valve necessary? Now I can easily see the need for larger exhaust valve with ported exhaust runners. ..
Are you asking about cost? If you consider the system as a whole, improved efficiency at the heads means you need less blower or visa versa. right?
The cam profile would have more of positive/negative effect. Actually my cam is designed for a SC. I guess it's been almost 2 years since it was designed, so others have similar grinds now. I do have larger valves also. The intake side doesn't need to be open as long being it's FI. The exhaust needs to be open longer to scavange the extra intake charge created by the SC. The higher LSA keeps the intake and exhaust centerlines further apart, which will create better vacuum and idle, which also can effect torgue, but if your boosted, torque is not an issue. That's why a tighter LSA is more often used for NA. Say in our cars, a 112 or 113. I had a 110 in my H/C LS1 Z28. Some feel a lot of head work on a boosted motor is really not that necessary in a car that is more used for street. Just turn up the boost a little. My SC cam .609/.598 235/248 116 LSA If you've heard my car run, you'd think the LSA was tighter, still pretty lumpy.
Cost is the side effect here. Less cost due to required work on the exhaust side only. I think increasing boost is not really to defeat losses in the intake path. just more pressure n the cylinder. I figured it was mostly in the cam, but as you say there is not much need for a lot of intake valve. When the intake valve opens, the cylinder comes up to pressure equalibrium with the boost pressure rather rapidly. I don't think the amount of boost is really to overcome intake losses though. Increase in boost is actually becaue you wnat more mixture pressure in the cylinder for more power.
I think what everyone is missing here is, are we talking about a street/strip car, or a race car? Most are talking about race heads on street cars. Isn't needed.
I agree with Hal. Unless its a HARDCORE track terror, you will never benefit from a race style head with a blower. Stock heads have advanced lightyears from the old muscle car era. Years ago, Tim Palmer ran EIGHTS with untouched Ford OEM crappy "B" heads and cams on his 98 Cobra w/ a big ass turbo. Modern OEM heads flow pretty damn good IMO.
Yes... I am discussing "Hot Street" and some strip application. Not a dedicated track/strip car. I know there will be some benefit for a hardcore track terror machine. ..
