VP Needs More HP!

[geardys]

porting heads is never going to hurt power output if it's done properly.

yeah i agree. but its not going to be good if ur got a std cam and massive intake and exhaust ports. ur going to rob the lower end of the power range.

now the polishing, the reason for polishing is it creates a shine(and this is the important part) reflective surface which helps to keep the heat in the exhaust gases. a smooth surface also helps to stop carbon buildup which leads to detonation from hot spots etc. you could take this one step further and get special heat refective coating (like HPC)

so polishing the ports and head has nothing to do with air swirl and fuel Atomisation????

 

[Immortality]

yeah i agree. but its not going to be good if ur got a std cam and massive intake and exhaust ports. ur going to rob the lower end of the power range.





so polishing the ports and head has nothing to do with air swirl and fuel Atomisation????

porting doesn't mean that your going to have "huge" ports. swirl comes from port bias, which is where you increase the size of the port more on one side then the other, normally the longer side of the port has more material removed from the area around the bowl and valve guide following the natural flow path. swirl leads to good mixture distribution. in a fuel injected engine good fuel atomisation comes from the injector spray patern and fuel pressure. a good book to read about porting and it's benefits (although it's for chevy engines many of the same theories apply to any small block V8 engine) is "how to build chevy small blocks on a budget" by David Vizard. has a very good section on porting, pocket porting. swirl and mixture distribution

 

[nathans1987]

if its just been rebuilt i would supercharge. i like the idea of eaton m112 or m120(if its out yet, same as m112 but more efficiant apparently) it gives heeaps of torque and power idol-5800(where ever it revs too) or a turbo/centrifugal if you want more power aboue 3000-3500rpm turbos and centrifugal make more power but only in upper range. root(m112) type also makes fuel compsumption better.

 

[ghd1996]

Thanks guys, all the info has been very helpful. I have done some of my own homework and I like the idea of supercharging as "$$ vs performance", but I would rather strengthen/work the motor to get my performance. A little old skool I know, but I also dont want alarm bells going off when the law pops the bonnet and sees a nasty big blower hanging off the motor :whistling So I've been told to go a "roller cam setup" over "hydraulic cam setup" whats the difference?? :bang:

 

[xcop5l]

theres less friction in a hydrolic cam setup.
and theres also less loss of lift from the cam.

it would also make a difference if you ran roller rockers with the roller cam

 

[Immortality]

with roller cams you can have more aggresive opening and closing ramps, thats basically how fast the valve opens. with roller cams the valve stays at it's maximum lift just a little longer then the equivalent hydraulic setup. there is definitly a power advantage to the roller setup alhtough it's a lot more expensive. definitly get roller rockers with that and i'd also suggest getting K liners fited to the valve guides to reduce wear there as high lift fast opening/closing valves to tend to wear out the valve guides faster etc