Sport Side

iTrader: (6)

I'm lost by your comments, but heres a post by J-ROD, if you'd like to look into it a bit more. I was using it as a reference to valve event comparisons.

J-ROD writes...

marc_w

I'd just expect VERY different VE's based of the large duration...

I can't comprehend this stuff at the moment. Give me a few. Days.

mrr23

iTrader: (3)

yes.

it really depends on which side the restriction is on. intake or exhaust. would need to see the actual flow numbers for each side to determine the restricted side. using the rule of thumb you have there, the ratio is UNDER 75% most of the time. so, crutching the EXHAUST side is in order.



refer back to above. reverse split cams work best in turbo/blower applications. i worked with a company that owned ERSON CAMS from 93-98. got some good schooling there. now, working WITH vinci, i'm learning more about the latest accelereated lift technology. (it's nice knowing the right people. and no i do not work FOR them.)

here's the old adage that works best. " a motor can't get more in, if it can't get it out." basically work the exhaust first. looking at exhaust systems. there's a thing called 'scavenging effect'. as the exhaust pulses come out of each cylinder and travel down the pipes, it creates a vacuum behind it. this in turn pulls the next pulse out of the cylinder. and with it pulls more of the burnt gases with it. now, what this does with the intake side is allow for more fresh incoming mixture into the cylinder. which in turn creates more power. one to consider is that exhaust pressure built up due to exansion. the intake charge is actually smaller per square inch and needs all the help it can get to be pulled into the cylinder. intake mixture is at atmospheric pressure. exhaust isn't.

hope this helps to shed some more light as to why the split in intake vs exhaust duration is the way it is with the VHP cams. for a reference look at the c5 test car when they intalled the 047 cam in. the torque shot up dramatically. test 4 vs test 5 http://www.vincihighperformance.com/...ARPARENT2.HTML

Kano

iTrader: (3)

30 rwhp and over 100 rwtq?
seems like the time slips should be higher
he trapped higher maybe he had traction issues?
seems like it would've gained more

test 5. 12.368@111.13 with cam 342/428.1
test 4. 12.42@109.34 before cam 312.9/325.5

marc_w

Yeah, when they went with the 047 cam, they had traction problems... The reason the 055 is faster at the 60' is because it move enough lowend power upwards, so that it hooked easier.

The only thing about the dyno's - they're not all consistant... The first handfull are all 2nd gear pulls, the 047 is in 3rd and it looks to be unlocked... so with that 2,800 stall, I believe that's where you see the huge torque numbers.

Still though, the cam is very torquey.

mrr23

iTrader: (3)

yes the 047 is a street cam. design for lots of low to midrange torque. these times were on 18" BFG DRs. they are keeping this car as much a street setup as possible. if they had slicks, the car would have easily been an 11 on the 047 cam.

if the converter was locked, you would've seen even higher torque. and they don't lock the converter. when racing or at WOT, the converter isn't locked. so, why show it that way?

stealth03ss

im all about getting more area under the torque curve. my research has just begun and so far vhp sounds great....

mrr23

iTrader: (3)

also, VHP has made another cam just like the 047. same duration, just more lift. the 062. for those wanting just a little bit more.

marc_w

I'm so mad they came out with the higher lift version! I know it was an option for a while, then they took it down... I would have gone for that if it was available.

At the time I called, Roger either said they'd take a little while to make, or they'd cost a little more to make...

AHHH. What's .020 on the lift, anyway...

stealth03ss

so will the added lift move the powerband upwards at all? got your pm mark...dude, if i only had some cash