I ran across some cam blanks. What do you think about the following specs that I get them ground to:
Can grind up 0.430" lift on both
224deg duration for both intake and exhaust
lobe centerline at 112
intake open 0 BTDC close 44 ABDC
ehaust open 44 BBDC close 0 ATDC
This would give zero overlap, which is ideal in a turbo setup. What do you guys think?
Sounds nice, what brand are they?
-Aaron
www.TurboTechRacing.com
Performance Parts For Cavalier, Sunfire, Cobalts and More!!!
Joshua Dearman wrote:I ran across some cam blanks. What do you think about the following specs that I get them ground to:
Can grind up 0.430" lift on both
224deg duration for both intake and exhaust
lobe centerline at 112
intake open 0 BTDC close 44 ABDC
ehaust open 44 BBDC close 0 ATDC
This would give zero overlap, which is ideal in a turbo setup. What do you guys think?
0 degrees of overlap is not ideal. It is true that you want less overlap with a turbo grind than a blower or NA grind, but even turbo cams need the velocity effects provided by overlap. Just look at any 4g63t, 6g72tt, 2jz, rb26, sr20, etc aftermarket cam options, and you will notice that they still have plenty of overlap.
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"Youth in Asia"...I don't see anything wrong with that.
Also, I don't know if comp will grind their cams in only one way, but just out of curiosity, what kind of rising/falling lobe slope are you looking at as well? You can get a much larger mass of air into the cylinder with a higher slope, but you would need stronger springs to avoid float.
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"Youth in Asia"...I don't see anything wrong with that.
Comp isn't grinding them, and I'm still waiting on the 0.050" lift @ ?deg for the slope info. I'm NOT looking for a incredibly drastic deflection rate, I believe 20deg @ 0.050" is pretty standard for our motors but i could be wrong(off the top of my head). Either way, I'm going to be modeling the slope from HO cams since they work pretty well, obviously the slope will be a little faster since the lift is higher but will be increased by only what is required by the higher lift.
Whalesac....you got any good suggestions for overlap?
No.
But as an engineer, I would rather get my hands on some theory involving where I want the powerband/max power taking into account cylinder bore, stroke, static compression, boost pressure and head flow, instead of just guessing. I'm sure if you called up comp, crane, HKS or whoever, they might provide insight. If I WERE to guess though, I would go with 10-15deg BTDC and ATDC since you have a good amount of duration on both cams. You could always dial it in from there with adjustable cam gears. Just my $.02.
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"Youth in Asia"...I don't see anything wrong with that.
tell comp what you want and have them grind them for you. they have a nifty sheet you fill out and bam life's good
I can talk to comp but they dont have the blanks, they discontinued them so trying to get info out of them might be harder but I'll give it a shot.
well i got a call in...we'll see what they say.
