Detailed Camshaft Selection Question
01-26-2017, 12:35 PM
#1
Detailed Camshaft Selection Question
Preface:
I have done some research on this topic, and have found mixed results and opinions. I am looking for facts and in depth explanation if any knowledgeable individuals are willing to provide it or possibly point me in the correct direction. (dyno sheets and time slips illustrating responses would also be greatly appreciated)
On to the question:
In my specific case, I have a bone stock '02 z06, and I have an end goal of a Cam/blower/meth setup in the 600-650 rwhp range. As of right now, I do not quite have the funds for the blower, but would like some extra power for the upcoming car season and could probably swing a cam and headers. My question is, in a nutshell, will the car make power safely and reliably with a "blower cam", but without a blower? Also, will a typical "NA cam" make power safely and reliably with a blower? What EXACTLY is it about big NA cams with large amounts of overlap that limits performance with a centrifugal supercharger setup? As a mechanical engineering student, I am looking for science and details if possible. I would like to get over the 400rwhp mark with the cam only setup, have a nice, choppy idle, and be able the throw a blower on a year or two down the road without swapping cams again. Is this possible? If so, any cam recommendations? Thanks in advance.
I have done some research on this topic, and have found mixed results and opinions. I am looking for facts and in depth explanation if any knowledgeable individuals are willing to provide it or possibly point me in the correct direction. (dyno sheets and time slips illustrating responses would also be greatly appreciated)
On to the question:
In my specific case, I have a bone stock '02 z06, and I have an end goal of a Cam/blower/meth setup in the 600-650 rwhp range. As of right now, I do not quite have the funds for the blower, but would like some extra power for the upcoming car season and could probably swing a cam and headers. My question is, in a nutshell, will the car make power safely and reliably with a "blower cam", but without a blower? Also, will a typical "NA cam" make power safely and reliably with a blower? What EXACTLY is it about big NA cams with large amounts of overlap that limits performance with a centrifugal supercharger setup? As a mechanical engineering student, I am looking for science and details if possible. I would like to get over the 400rwhp mark with the cam only setup, have a nice, choppy idle, and be able the throw a blower on a year or two down the road without swapping cams again. Is this possible? If so, any cam recommendations? Thanks in advance.
01-26-2017, 02:29 PM
#2
I was in about the same situation as you. Bone stock z06 2001. I installed a cam and headers with regards of installing a blower down the road. I bought a vengeance blower cam and did the installed and tune and it made 420@400
And now just installed a v3ti blower on my car. Haven't tuned it yet
And now just installed a v3ti blower on my car. Haven't tuned it yet
01-26-2017, 03:43 PM
#3
I was in about the same situation as you. Bone stock z06 2001. I installed a cam and headers with regards of installing a blower down the road. I bought a vengeance blower cam and did the installed and tune and it made 420@400
And now just installed a v3ti blower on my car. Haven't tuned it yet
And now just installed a v3ti blower on my car. Haven't tuned it yet
01-26-2017, 05:28 PM
#5
Melting Slicks
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St. Jude Donor '15-'16-'17-'18
Bret would be a good one to talk with on this regarding the science behind it.
Cam and headers you shouldn't have an issue making 400rwhp. There are guys in here running radical NA cams with a blower and still make good power. Of course there is some power left on the table, but if the sound is a selling point go for it. I run Arun's Jam Cam. I think it sounds great, drives great, and makes power everywhere. Good Luck! Hopefully some of the heavy hitters chime in.
Cam and headers you shouldn't have an issue making 400rwhp. There are guys in here running radical NA cams with a blower and still make good power. Of course there is some power left on the table, but if the sound is a selling point go for it. I run Arun's Jam Cam. I think it sounds great, drives great, and makes power everywhere. Good Luck! Hopefully some of the heavy hitters chime in.
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z06tolbs (01-29-2017)
01-29-2017, 08:36 AM
#6
Melting Slicks
As others have largely said, you're way over thinking it.
If you want a lopey cam...just buy a lopey cam. At some stage yes there may be slightly better options in terms of power...but I'm sure every other aspect of the build wont be fully optimised.
And if there ever was a serious concern about losing boost from a cam with too much overlap.....just spin the blower harder. But I suspect few these days use such cams, especially as there is no need when the head flow is very efficient.
So it really is a non-issue.
If you want a lopey cam...just buy a lopey cam. At some stage yes there may be slightly better options in terms of power...but I'm sure every other aspect of the build wont be fully optimised.
And if there ever was a serious concern about losing boost from a cam with too much overlap.....just spin the blower harder. But I suspect few these days use such cams, especially as there is no need when the head flow is very efficient.
So it really is a non-issue.
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z06tolbs (01-29-2017)
01-29-2017, 09:37 PM
#7
ISIS SUCKS FAT CHOAD
Learn what happens with engine power out put and how changing the valves events affects your engines Efficiency and induction system as you change the Intake Valve Opening (IVO) Intake Valve Closing (IVC) Exhaust Valve Opening (EVO) and Exhaust Valve Closing (EVC) points.
Let the duration Lobe Separation Angle, Intake Centerline and Lift end up where they end up.
Unfortunately a lot of learning this stuff comes down to entrusting people who have done it and or testing various camshafts yourself (which can be very expensive)
The good news is guys like Brian Tooley and even Bret (who was mentioned in here) have a lot of experience with what works.
There is no black magic to picking a good camshaft. The information you need to know is out there. If you research and ask the right questions you can become proficient at selecting a good camshaft. (Becoming proficient probably won't happen over night though)
Good luck man!
Let the duration Lobe Separation Angle, Intake Centerline and Lift end up where they end up.
Unfortunately a lot of learning this stuff comes down to entrusting people who have done it and or testing various camshafts yourself (which can be very expensive)
The good news is guys like Brian Tooley and even Bret (who was mentioned in here) have a lot of experience with what works.
There is no black magic to picking a good camshaft. The information you need to know is out there. If you research and ask the right questions you can become proficient at selecting a good camshaft. (Becoming proficient probably won't happen over night though)
Good luck man!
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z06tolbs (01-29-2017)
01-29-2017, 10:03 PM
#8
Bret would be a good one to talk with on this regarding the science behind it.
Cam and headers you shouldn't have an issue making 400rwhp. There are guys in here running radical NA cams with a blower and still make good power. Of course there is some power left on the table, but if the sound is a selling point go for it. I run Arun's Jam Cam. I think it sounds great, drives great, and makes power everywhere. Good Luck! Hopefully some of the heavy hitters chime in.
Cam and headers you shouldn't have an issue making 400rwhp. There are guys in here running radical NA cams with a blower and still make good power. Of course there is some power left on the table, but if the sound is a selling point go for it. I run Arun's Jam Cam. I think it sounds great, drives great, and makes power everywhere. Good Luck! Hopefully some of the heavy hitters chime in.
01-31-2017, 07:51 AM
#10
Burning Brakes
[QUOTE=z06tolbs;1593954181]Preface:
My question is, in a nutshell, will the car make power safely and reliably with a "blower cam", but without a blower? Also, will a typical "NA cam" make power safely and reliably with a blower? What EXACTLY is it about big NA cams with large amounts of overlap that limits performance with a centrifugal supercharger setup?
I agree w MVP about learning what the parameters effect, but not so much with worrying about the LSA,lift,ect.
Generally speaking, the duration will determine where your torque peak occurs. More duration moves that up, and the higher your torue peak, the more HP you will make since HP is a function of RPM
Lift is good stuff. Generally again, more is better. But the real world limitation has to do with physics. Higher lift stresses the valve train, especilly as RPM increases. Boost can make this worse.
Overlap is needed with NA to help the induction system when it is relying on atmospheric pressure.It is less important when you have positive manifold pressure. Overlap is a funtion of duration and Lobe separation, is is what typicaly give the choppy idle sound we all love. The downside is that excessive overlap bleeds off cylinder pressure. When you have high compression this is nesssesary, conversely with very large cams you NEED compression to make them work. A 12:1 engine with a short cam will tend to detonate, whereas a 8:1 engine with big cam will barely run.
So again generally, blower and turbo specific cams have historically been wider LSA with less overlap to avoid bleeding off boost. Keep in mind boost is a untion of restriction- for a given drive ratio you will see a higher boost with a short duration small port engine and lower figures with a large cam/larrge prt/valve/ lift engine. But since its all about airflow, the larger version will usually make more power with a lower boost reading.
If you have a limited capacity supercharger that may not work. [I was one of the first customers for the B&M mini blower in the early 80s] But with a 6-71 it was a different story- a big duration cam killed off enough low end for it to hook up and made much more power on the top end.
So, my take is that if you put in a blower specific cam you will be not really be optimised for NA. If you go for the choppy idle big cam, it may not be optimised for boost- but if the blower can be spun more, its all good. And we know which one will sound cooler.
My question is, in a nutshell, will the car make power safely and reliably with a "blower cam", but without a blower? Also, will a typical "NA cam" make power safely and reliably with a blower? What EXACTLY is it about big NA cams with large amounts of overlap that limits performance with a centrifugal supercharger setup?
I agree w MVP about learning what the parameters effect, but not so much with worrying about the LSA,lift,ect.
Generally speaking, the duration will determine where your torque peak occurs. More duration moves that up, and the higher your torue peak, the more HP you will make since HP is a function of RPM
Lift is good stuff. Generally again, more is better. But the real world limitation has to do with physics. Higher lift stresses the valve train, especilly as RPM increases. Boost can make this worse.
Overlap is needed with NA to help the induction system when it is relying on atmospheric pressure.It is less important when you have positive manifold pressure. Overlap is a funtion of duration and Lobe separation, is is what typicaly give the choppy idle sound we all love. The downside is that excessive overlap bleeds off cylinder pressure. When you have high compression this is nesssesary, conversely with very large cams you NEED compression to make them work. A 12:1 engine with a short cam will tend to detonate, whereas a 8:1 engine with big cam will barely run.
So again generally, blower and turbo specific cams have historically been wider LSA with less overlap to avoid bleeding off boost. Keep in mind boost is a untion of restriction- for a given drive ratio you will see a higher boost with a short duration small port engine and lower figures with a large cam/larrge prt/valve/ lift engine. But since its all about airflow, the larger version will usually make more power with a lower boost reading.
If you have a limited capacity supercharger that may not work. [I was one of the first customers for the B&M mini blower in the early 80s] But with a 6-71 it was a different story- a big duration cam killed off enough low end for it to hook up and made much more power on the top end.
So, my take is that if you put in a blower specific cam you will be not really be optimised for NA. If you go for the choppy idle big cam, it may not be optimised for boost- but if the blower can be spun more, its all good. And we know which one will sound cooler.