Welen XLR8 Performance skrev:<!--quoteo(post=498547:date=12 Aug 2008, 14:04:35:name=Atec)--><div class='quotetop'>QUOTE(Atec 4 12 Aug 2008, 14:04:35) <a href="index.php?act=findpost&pid=498547"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec--><!--quoteo(post=498536:date=12 Aug 2008, 13:09:43:name=Welen XLR8 Performance)--><div class='quotetop'>QUOTE(Welen XLR8 Performance 4 12 Aug 2008, 13:09:43) <a href="index.php?act=findpost&pid=498536"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec-->I don get this? "it will reach peak torque earlier but at higher rpm " Maybe I'am missing something..
I think that exhaust gas reversation goes back in to the intake runner is more an effekt of the cams rather then the head design. Look at saab or volvos that has pretty small turbos and extream back pressures so they can spool the turbo and keep emissions down.. (thats why they get away with turboheaders that has terrible flow) They can have a peak boost at maby 0.7bar and 5 bar of backpressure.. To have them chiped is not a good ide..
Haha, Im sorry I rewrote the sentence now so it is more understandable lol...
Yes you are right, the camprofile is everything, but you can also configure the valves, valveseats and some of the intake/exhaust chanels to prevent the reverse flow.
A good example on cams, our custom stage 1 cams used here has a slight different profile than the stock R cams, to prevent reversation, but are limited by the slipper type rocker arms.
But you cannot compare a volvo head with this, remeber the volvo only need cams/head to flow 5-6000rpm, and that is easy to do with a mild cam.
here we need flow past 9000 + unough boost to make power and a fairly good powerband to do trackdays. three things into one make compromizes you know

well well, about my own project blockbuster..
The blockbuster car have rollertype rockers that made it possible for us to make a "square" cam that have wide duration but still can fight the reversation.
I just got the shipping number for the last parts I needed to start assemble it btw...

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Sure a to small turbo makes peak tourqe earlier but it also makes peak boost earlyer.. It would have been intresting to see a log on backpressure boost tourqe and hp. That turbo is fore sure on the small side.. But if you have gone with a bigger one that keeps the tourqe flat at that tourqe level it would have maked a ton more power. But i would have taken alot longer to spool also so it is a trade of between powerband and peak hp..
I did not compare the volvo heads and honda heads flow wise.. Just how you can make the cams work with no reversation and high backpressure. To adress these things with the head design is to fix it in the wrong end but Iám sure it helps some but If it is even worth it?... Well that is what all head porters argue about..
If you design the heads valves, valveseats and some of the intake/exhaust chanels to prevent the reverse flow I´m sure it is a tradeof of power.
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It is not a trade of power infact to eliminate reverse intakeflow is a powergainer, or else we would not have done it.
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Andreas T. Fjeldstad
[i]In-tec motorsport Norge[/i]