Originally Posted by B8
Originally Posted by Tony Turbo
Originally Posted by B8
Why? all because of a poorly manufactured Valve.
Nice one Vulcan
Sorry to hear that Andy
Vulcan strike again
Ah shit happens I suppose Tony. Boundarys cant be pushed without an element of risk.
One things for sure if/when Im having a head worked again, I'll be sure to find out who the Valve manufacturers are.
Back on topic:
Cylinder head developments article in PF looked good, prices appeared to be very reasonable aswell. Pics look good Johnny. Nice
Turboboss again pics look good nice work
I must say Im well impressed with Puma Racings web site specificaly the technical info & his straight talking no noncense aproach, there are a lot of parallels between both his and my own tuners 'tuning principles & idealoligies'
pumaracing designs his own valves for maximum flow they are not your normal stainless steel crap which end up destroying the valve inserts. if you are aftera cvh head he is the only man to see.
i remember speaking to andy weston about fitting 45mm inlet valves to a cvh head and his words to me was it cant be done. dave baker does'nt talk bull shit,you tell him waht you want and he will tell you how to achieve it.he is a master engine builder who pays so much attention to detail... here is a little editorial from david baker about flow rates, he was explaning why some zvh dont rev check in the techical essay archive under turbos engines dont rev true or false,with the help of his bv head and the addition of newman custom cam i hope to have built one of the most powerfull zvh powered cars in the country. sorry for going a bit off the topic but if you want a modified cvh head contact david baker, he is now taking new orders
As a rough guide, and std flow varies quite a bit from head to head (as of course does flow after modification depending on the skill of the modifier) they flow (or can be made to flow) as follows.
Std CVH - 140/145 cfm
Ported std valve CVH - 160/170 cfm
Std Zetec - 170/175 cfm
Ultimate Ported 45mm BV CVH - 180/190 cfm
Ported std valve Zetec - 190/200 cfm
Ported 33.5mm BV Zetec 210/220 cfm
By ported I mean by an expert with a flowbench who's put a lot of R&D time into it and not by someone with a flapwheel and more optimism than expertise.
As you can see a well ported CVH, especially BV CVH will match a std Zetec and get close to a fairly well ported std valve Zetec. However even a BV Zetec isn't going to turn a 2.1 bottom end into any sort of rev monster without using cams and turbos that are just not going to be very road driveable.
According to Ford my 2.0 Focus ESP produces peak power at only 5750 rpm and I have no reason to doubt that from how it drives. Increase the size of the bottom end a bit, drop the CR to 8:1, make the air go through an intercooler and several feet of plumbing before it even reaches the inlet manifold and that rpm would drop a lot further still. Adding the turbo won't alter any of this.
If high rpm for its own sake is a specific target for someone then tune a N/A engine with throttle bodies and cams or build a turbo one with a smaller bottom end. Personally I'm not sure what the big deal with high rpm is provided the car is geared correctly for its power output.