Thanks Adam..we are excited as well, not sure what all your changing with the valve job'd head your getting, but would be interesting to see what real world gain we can see. It's a 30-40cfm increase...and we think the budget head can be done, actually worked on this towards the end of the day. We just did a head for a customer, ported, guides, stock valves and GSC beehive, and it made me think how it was kinda of a cool low budget deal. And he had about $15-1550 into it with shipping.





And seriously, thanks to all of you. The direction is very welcomed. Again, we are going to do only something that all can enjoy, nothing to technical..technical material becomes debatable material...and that turns most off.

 

30-40cfm with just a valve job is a very nice increase IMO!

 

First off, I love the budget idea. I'm sure a good majority of us are on somewhat of a budget when it comes to our cars and shelling out for a built CNCd race head is kind of hard to do. It's like having wine taste on a beer budget..

As I have been looking into what all I can do with my head to gain more top-end power I have come across a lot of new things that I have questions about. You answered one of them earlier about the oversized valves. I haven't been able to find much that makes me think paying for oversized valves is a worthwhile investment and if there are cars making 900hp+ on stock valves then I'd say I'll be just fine! lol.

A couple questions I do have though are on porting.. I am wanting as much top-end power as I can get out of my build, thus I will be going with the Kelford 280s most likely, which are an 11.5/11.0mm lift. I have been told by a very intelligent board member that anything with a lift above 10.5mm will be pointless because the stock ported head cannot flow beyond that rate. Now will this mean that if I go with anything above that 10.5mm lift I'll ultimately see minimal gains if any until I port my head? At the same time, I have also been told that since I am just running a standard GT3582R there's no need for me to port my head until I am running something a little bigger like a 37R or equivalent, I'm guessing the cost to power ratio just isn't worth it? Do you find this to be true? I have always figured that the main key to making power is how well your head flows.

I think you guys could easily do several tech articles on helping to clear up some of the many questions that daily consumers would have. I'd say several good topics have already been brought up. There's so many questions I have about what valvetrain to go with and for what cams and if porting my head will result in noticeable gains for what I'm going for ultimately. It shouldn't be hard to come up with something to put on a page and I also agree with your original post about how flow testing numbers to me individually are meaningless unless you're going to compare to competitors in the same article and try to explain what it all means to the consumer.

/end novel!

 

What are the differences on a street car on conservative boost when using stock (or stock-sized) valves in a ported head vs oversized valves.

Basically data to support/falsify:

IMHO a really good head can be put together for a great price with porting, valve job, stock valves (back-cut exhaust valves), and simple beehive springs like the GSC 5039 or FP ones that use the stock retainers. On a stock-frame turbo, this is the way to go.

On a big turbo w/ tubular manifold, larger-than-stock valves and extra-beefy valvesprings improve performance and justify the cost of a whole new set of valves when building a head.

 

Head looks great! Can't wait to put it back together and beat my stock clutch into submission. I guess we'll see how much power it makes at about 16psi til I get my Exedy.

 

How about velocity vs flow specifically on the Evo head. And maybe about how the exhaust valves are too big