Cam education please
Thread Starter
Melting Slicks
Joined: Jun 2008
Posts: 2,168
Likes: 50
From: Somerville New Jersey
Cam education please
Ok, I'm a newbie to Engine performance upgrades, I put a supercharger on my 1994 Dodge Ram P/U in 1996 and blew up the motor 3 times before I gave up so this time before I play I want to know what I'm getting in to.
I'm looking at getting a cam installed in my 2014 Stingray MN7 Premier edition. Car is currently pretty stock and 100% engine stock. I love the sound of a cammed C6 but haven't heard a C7 in person yet but I figure it'd be much the same. What am I getting in to? Pro's and con's? HP gains? Drivability issues? I'll never track the car in any way, I just want the cool sound of a cam. I'd have it all done by a professional that mostly does Corvettes but looking for some education/ advice.
Thanks!
I'm looking at getting a cam installed in my 2014 Stingray MN7 Premier edition. Car is currently pretty stock and 100% engine stock. I love the sound of a cammed C6 but haven't heard a C7 in person yet but I figure it'd be much the same. What am I getting in to? Pro's and con's? HP gains? Drivability issues? I'll never track the car in any way, I just want the cool sound of a cam. I'd have it all done by a professional that mostly does Corvettes but looking for some education/ advice.
Thanks!
Thread Starter
Melting Slicks
Joined: Jun 2008
Posts: 2,168
Likes: 50
From: Somerville New Jersey
It has crossed my mind but this car was my fathers and he wanted to do a cam before he passed and I was going to do a cam or a supercharger on my C6, so while I'd love to have a Z06 I can't get rid of this car just yet.
Race Director
Joined: Jul 2007
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From: Texas Hill Country
Thread Starter
Melting Slicks
Joined: Jun 2008
Posts: 2,168
Likes: 50
From: Somerville New Jersey
Le Mans Master
Joined: Aug 2005
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From: CA.
St. Jude Donor '13-'14-'15
NO NO-----The new LT4 with a supercharger is that---a supercharger cam and is not designed to work best on a NA motor
When it comes to cam choices on a LT1 corvette DI engine---you basically have to make a choice
To retain the AFM (4 cylinder mode} or not
If you choose to retain AFM your cam choices become very limited---There is a limit on max lift and max duration-----These cam choices are very mild but the largest of them would give you a slight lope
NOW If you choose to DELETE the AFM system the cam choices become endless---
You can install a very aggressive cam and it will sound amazing
With a cam retaining AFM you can expect only about a 35 HP gain
But with deleting AFM you can easily expect a 100 HP gain !!!
PS On any aftermarket cam on the LT1 you must also install a VVT limiter kit--to prevent piston to valve contact-----AFM deleted or not-----
When it comes to cam choices on a LT1 corvette DI engine---you basically have to make a choice
To retain the AFM (4 cylinder mode} or not
If you choose to retain AFM your cam choices become very limited---There is a limit on max lift and max duration-----These cam choices are very mild but the largest of them would give you a slight lope
NOW If you choose to DELETE the AFM system the cam choices become endless---
You can install a very aggressive cam and it will sound amazing
With a cam retaining AFM you can expect only about a 35 HP gain
But with deleting AFM you can easily expect a 100 HP gain !!!
PS On any aftermarket cam on the LT1 you must also install a VVT limiter kit--to prevent piston to valve contact-----AFM deleted or not-----
Race Director
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From: Texas Hill Country
Thread Starter
Melting Slicks
Joined: Jun 2008
Posts: 2,168
Likes: 50
From: Somerville New Jersey
Oh boy.....I used the AFM once on an 8 hour highway drive just to see what it would do for my MPG, that was 2 years ago and I'll never use it agisin as far as I'm concerned.
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Le Mans Master
Joined: May 2000
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From: Redmond WA
I just don't get the AFM hate. I only notice mine when it's on a dash setting that shows it, and it comes on pretty rarely, like decel coasting and maybe flat-line cruising at highway speeds. Why would you want to get rid of it?
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Last edited by davepl; Dec 26, 2016 at 02:09 PM.
Race Director
Joined: Jul 2007
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From: Texas Hill Country
I just don't get the AFM hate. I only notice mine when it's on a dash setting that shows it, and it comes on pretty rarely, like decel coasting and maybe flat-line cruising at highway speeds. Why would you want to get rid of it?
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
AFM hate comes from the lifters being crap. RPM limited, prone to failure (a lot during the DoD days) etc. AFM is not a performance feature and generally when we talk about cam swaps it isn't for low RPM MPGs. It's for moving the power curve up and higher.
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
Thanks, makes sense. I don't hate it in the stock form, but I haven't had to contend with it for mods, so that's why I'm naive about it.
Advanced
Joined: May 2014
Posts: 97
Likes: 3
OP, if you're going with a cam, the first question is whether you want to retain AFM/DOD or not, as there are significant price and power differences between AFM and non-AFM cams.
Even a baby stage 1 non-AFM cam will have significantly more aggressive lift, duration and overlap than the most aggressive AFM cams. With the non-AFM cam, you ditch the junk AFM lifters and associated plumbing and upgrade your valve springs (some guys do push rods, timing chain etc. too). So you'll have a better valve train for high rpm running, but you'll be paying for more parts (lifters, springs/retainers, valley tray, and miscellaneous at the least) and more labour vs. non-AFM. So if you're pricing it out there is definitely a parts and labour difference between the AFM and non-AFM cams. Ultimately the parts and especially labour (including tuning) cost for a cam swap is significant.
My '14 Z51 with a stage 1 Vengeance Racing non-AFM cam, ported heads and long tubes, has no drivability issues. It's a nice balanced combination with decent traction. If I did it again I wouldn't hesitate to go with a little bigger cam, although the stage 1 cam is blower friendly if I ever went that route.
Even a baby stage 1 non-AFM cam will have significantly more aggressive lift, duration and overlap than the most aggressive AFM cams. With the non-AFM cam, you ditch the junk AFM lifters and associated plumbing and upgrade your valve springs (some guys do push rods, timing chain etc. too). So you'll have a better valve train for high rpm running, but you'll be paying for more parts (lifters, springs/retainers, valley tray, and miscellaneous at the least) and more labour vs. non-AFM. So if you're pricing it out there is definitely a parts and labour difference between the AFM and non-AFM cams. Ultimately the parts and especially labour (including tuning) cost for a cam swap is significant.
My '14 Z51 with a stage 1 Vengeance Racing non-AFM cam, ported heads and long tubes, has no drivability issues. It's a nice balanced combination with decent traction. If I did it again I wouldn't hesitate to go with a little bigger cam, although the stage 1 cam is blower friendly if I ever went that route.
Melting Slicks
Joined: Sep 2009
Posts: 2,180
Likes: 233
From: Minnetrista Minnesota
OP, if you're going with a cam, the first question is whether you want to retain AFM/DOD or not, as there are significant price and power differences between AFM and non-AFM cams.
Even a baby stage 1 non-AFM cam will have significantly more aggressive lift, duration and overlap than the most aggressive AFM cams. With the non-AFM cam, you ditch the junk AFM lifters and associated plumbing and upgrade your valve springs (some guys do push rods, timing chain etc. too). So you'll have a better valve train for high rpm running, but you'll be paying for more parts (lifters, springs/retainers, valley tray, and miscellaneous at the least) and more labour vs. non-AFM. So if you're pricing it out there is definitely a parts and labour difference between the AFM and non-AFM cams. Ultimately the parts and especially labour (including tuning) cost for a cam swap is significant.
My '14 Z51 with a stage 1 Vengeance Racing non-AFM cam, ported heads and long tubes, has no drivability issues. It's a nice balanced combination with decent traction. If I did it again I wouldn't hesitate to go with a little bigger cam, although the stage 1 cam is blower friendly if I ever went that route.
Even a baby stage 1 non-AFM cam will have significantly more aggressive lift, duration and overlap than the most aggressive AFM cams. With the non-AFM cam, you ditch the junk AFM lifters and associated plumbing and upgrade your valve springs (some guys do push rods, timing chain etc. too). So you'll have a better valve train for high rpm running, but you'll be paying for more parts (lifters, springs/retainers, valley tray, and miscellaneous at the least) and more labour vs. non-AFM. So if you're pricing it out there is definitely a parts and labour difference between the AFM and non-AFM cams. Ultimately the parts and especially labour (including tuning) cost for a cam swap is significant.
My '14 Z51 with a stage 1 Vengeance Racing non-AFM cam, ported heads and long tubes, has no drivability issues. It's a nice balanced combination with decent traction. If I did it again I wouldn't hesitate to go with a little bigger cam, although the stage 1 cam is blower friendly if I ever went that route.
Advanced
Joined: May 2014
Posts: 97
Likes: 3
That is exactly the set up I am thinking about. Already have long tubes and ported intake and TB. Did you get dyno numbers with this set-up. Would love to see your dyno sheet and results. Seems like some of the cam results I have seen on the LT1 sacrifice low end torque for high RPM horsepower,
Racer
Joined: Feb 2009
Posts: 309
Likes: 61
From: Palm Beach
I just don't get the AFM hate. I only notice mine when it's on a dash setting that shows it, and it comes on pretty rarely, like decel coasting and maybe flat-line cruising at highway speeds. Why would you want to get rid of it?
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Racer
Joined: Feb 2009
Posts: 309
Likes: 61
From: Palm Beach
I just don't get the AFM hate. I only notice mine when it's on a dash setting that shows it, and it comes on pretty rarely, like decel coasting and maybe flat-line cruising at highway speeds. Why would you want to get rid of it?
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Also the Z06 has no lope. At least none to speak of. Blower cams don't like a lot of overlap.
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Drifting
Joined: Jun 2016
Posts: 1,744
Likes: 234
I don't mind the sound of someone else's lumpy cam, I'll admit that, but they're like babies... nice to play with, but a lot of work to live with. I just don't want to live with annoying cold starts, poor driveability, and so on. If someone respected offered a cam+tune that retained stock driving manners, I'd probably look at it. I just don't know of any.
Race Director
Joined: Jul 2007
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From: Texas Hill Country
Lope is based on overlap. You can only change overlap with dual overhead cams. The small block Chevy is an overhead valve setup or cam in block setup.
Overlap is a function of valve events, namely the relationship between when the intake valve opens and when the exhaust valve closes. The more degrees that the intake opens before the exhaust closes the more overlap you have and the more lope you will have at idle. Overlap is ground into the cam with OHV applications. DOHC allows you to move the exhaust and intake cam lobes independently and create or remove overlap as needed.
To add: All you can do with the tune on an OHV car is destabilize the idle, which is not the same thing as lope, it's just running like crap.
Last edited by Higgs Boson; Dec 30, 2016 at 10:59 PM.
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
Higgs, on a DFI motor where you control both the injection time and the spark (but not the valve events) do you think you could replicate a lumpy cam in software, or would it just sound like nonsense?
Between the IAC, timing, and injection events you could "start" an ignition event sooner, then later, basically do the opposite of what idle stabilization does to -prevent- lumpy idles.
Still might just sound like crap. But if you could get a -rhythm- going, and no just random misfires, maybe it'd work. But I think they rhythm part is key, if you know what I mean. Not just unstable, but rhythmically so.
Between the IAC, timing, and injection events you could "start" an ignition event sooner, then later, basically do the opposite of what idle stabilization does to -prevent- lumpy idles.
Still might just sound like crap. But if you could get a -rhythm- going, and no just random misfires, maybe it'd work. But I think they rhythm part is key, if you know what I mean. Not just unstable, but rhythmically so.
Last edited by davepl; Dec 31, 2016 at 03:13 PM.