Suggestions regarding these cams with AFR 210cc heads
12-14-2012, 10:19 AM
#1
Suggestions regarding these cams with AFR 210cc heads I just purchased a set of AFR 210cc heads and I have a few cam specs and I'm trying to see what you guys think would be best for my setup/goals. My car is a 2002 WS6 with 46,000 miles on her; M6 with long tubes, true duals and SLP lid. The car has stock 3.42 gears. I'm not sure how any of these cams will react to the 3.42 gears. I'm looking for something that's going to make great power, but I don't want to sacrafice too much low end torque and I'm looking for a lot of lope. I guess if I'm shooting for a number, it would be around 430/440 rwhp with my LS6 intake. Here is what I have come up with so far. I would love to get opinions on which one you guys thing would be better.
232/236 111 LSA
230/238 111 LSA
227/231 110 LSA
232/236 111 LSA
230/238 111 LSA
227/231 110 LSA
12-14-2012, 10:25 AM
#2
were these cams spec'd out or just some off the shelf grinds?
If its a total street car, then big is not always better. I'd almsot go with the 230/238 I bet it will lope pretty hard.
If you take those cams and calculate which has the most overlap, that will tell you which one will chop the hardest
If its a total street car, then big is not always better. I'd almsot go with the 230/238 I bet it will lope pretty hard.
If you take those cams and calculate which has the most overlap, that will tell you which one will chop the hardest
12-14-2012, 10:31 AM
#3
Mamo says those heads don't like a lot of overlap (kind of like an LS3 to be honest).
Something like a 227/231 114+1 is what I'd do since you can't really fit more with PtV issues with those heads. Run them with 61cc chambers, .040" gaskets and that cam and there you go. Nice street manners and power all the way to 7k with a peak around 6300 that carries nicely out.
Something like a 227/231 114+1 is what I'd do since you can't really fit more with PtV issues with those heads. Run them with 61cc chambers, .040" gaskets and that cam and there you go. Nice street manners and power all the way to 7k with a peak around 6300 that carries nicely out.
12-14-2012, 12:35 PM
#4
were these cams spec'd out or just some off the shelf grinds?
If its a total street car, then big is not always better. I'd almsot go with the 230/238 I bet it will lope pretty hard.
If you take those cams and calculate which has the most overlap, that will tell you which one will chop the hardest
If its a total street car, then big is not always better. I'd almsot go with the 230/238 I bet it will lope pretty hard.
If you take those cams and calculate which has the most overlap, that will tell you which one will chop the hardest
It's a weekend warrior, but will see some limited strip time; not a DD. I'll be having Ed Curtis do the cam for me, so it will be a custom grind. I know the AFR heads love a 4 degree split and I've always heard that going with a 114 LSA is best, but I've seen combos with AFR heads and 110, 111 and 112 LSA cams make killer numbers and run their *** off on the street.
12-14-2012, 12:35 PM
#5
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Mamo says those heads don't like a lot of overlap (kind of like an LS3 to be honest).
Something like a 227/231 114+1 is what I'd do since you can't really fit more with PtV issues with those heads. Run them with 61cc chambers, .040" gaskets and that cam and there you go. Nice street manners and power all the way to 7k with a peak around 6300 that carries nicely out.
Something like a 227/231 114+1 is what I'd do since you can't really fit more with PtV issues with those heads. Run them with 61cc chambers, .040" gaskets and that cam and there you go. Nice street manners and power all the way to 7k with a peak around 6300 that carries nicely out.
If you want lope, you'll need overlap, and that will sacrifice both power and driveability down low in the RPM range.
12-14-2012, 01:52 PM
#6
Anything bigger than what I just said you'll need to flycut if you mill at all. That's a 227 LSL lobe on a 113 ICL and it fits with about a .025" cut with a .040 gasket. You might be able to fit a 230 or 231 in there with a 111 ICL with less of a cut or a GM MLS gasket. But it'd be realllllly close.
Just something else to think about.
Just something else to think about.
12-14-2012, 02:02 PM
#7
Anything bigger than what I just said you'll need to flycut if you mill at all. That's a 227 LSL lobe on a 113 ICL and it fits with about a .025" cut with a .040 gasket. You might be able to fit a 230 or 231 in there with a 111 ICL with less of a cut or a GM MLS gasket. But it'd be realllllly close.
Just something else to think about.
Just something else to think about.
If I do go the smaller route, I'll mill the heads as much as I can though.
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12-14-2012, 02:04 PM
#8
You'd still need to measure if you cut them down. At 66 yeah, almost anything would clear, but that's not a good way to make power.
As far as bigger cams with tighter LSAs and 66cc chambers: you won't gain a whole hell of a lot of power by trying to shoehorn in some massive cam on a tight LSA relative to a well sorted package and cam with the proper valve events and compression. Those larger cams on tighter LSAs are designed as max effort cams for stock heads. There's a reason for that: stock heads don't flow nearly as well, have weak I/E flow ratio, and don't have compression.
To make big numbers with stock heads, you have to install a big cam on a very tight ICL to make up for the lack of compression. Then to make it carry, you need both overlap and a wider exhaust duration to carry the power past peak. The overlap allows the exhaust scavenge effect to pull the intake charge into the chamber. Poor I/E flow of the stock heads requires this crutch. AFRs don't.
That's why a lot of cam only setups have the mountain top peak... ramps up quickly at 4000 to 5000 and then falls off quickly again. The tight LSA/ICL causes that as does a late IVO and early IVC. This builds compression in a very narrow part of the power band. The added exhaust duration and overlap allows it to continue on past peak so you can actually use the cam in a race.
The cam I provided above doesn't need overlap or a wide exhaust split to make power. The heads come with compression, so you don't need to build it in the valve events. Instead, you can shoot for an early IVO and later IVC (both which would kill torque on stock heads) and make power that carries high into the RPM range because of the valve events. The cam is able to keep the intake charge coming in because the valve is held open for a much longer period of the combustion cycle (relative to duration). And because the AFR (or any aftermarket casting) has great I/E ratio, so you don't need overlap to pull the intake charge through the exhaust to create power. Cams like that create tabletop torque (albiet maybe a little lower in peak), but pull cleanly upto 7000-7200 with no drop off.
This is based on what I've seen in dynos and from my discussions from the cam gurus around. I'm just throwing that out there because you might gain a little peak torque or peak HP with a much more rowdy cam, but the difference in drivability is pretty big for 5-10HP. And the way you cam stock or stock ported heads and aftermarket castings is different. Not saying you can't go either way. Good heads make good power regardless. But there are tradeoffs you make with stock or stock ported heads that you don't need to make with high flow aftermarket castings...
As far as bigger cams with tighter LSAs and 66cc chambers: you won't gain a whole hell of a lot of power by trying to shoehorn in some massive cam on a tight LSA relative to a well sorted package and cam with the proper valve events and compression. Those larger cams on tighter LSAs are designed as max effort cams for stock heads. There's a reason for that: stock heads don't flow nearly as well, have weak I/E flow ratio, and don't have compression.
To make big numbers with stock heads, you have to install a big cam on a very tight ICL to make up for the lack of compression. Then to make it carry, you need both overlap and a wider exhaust duration to carry the power past peak. The overlap allows the exhaust scavenge effect to pull the intake charge into the chamber. Poor I/E flow of the stock heads requires this crutch. AFRs don't.
That's why a lot of cam only setups have the mountain top peak... ramps up quickly at 4000 to 5000 and then falls off quickly again. The tight LSA/ICL causes that as does a late IVO and early IVC. This builds compression in a very narrow part of the power band. The added exhaust duration and overlap allows it to continue on past peak so you can actually use the cam in a race.
The cam I provided above doesn't need overlap or a wide exhaust split to make power. The heads come with compression, so you don't need to build it in the valve events. Instead, you can shoot for an early IVO and later IVC (both which would kill torque on stock heads) and make power that carries high into the RPM range because of the valve events. The cam is able to keep the intake charge coming in because the valve is held open for a much longer period of the combustion cycle (relative to duration). And because the AFR (or any aftermarket casting) has great I/E ratio, so you don't need overlap to pull the intake charge through the exhaust to create power. Cams like that create tabletop torque (albiet maybe a little lower in peak), but pull cleanly upto 7000-7200 with no drop off.
This is based on what I've seen in dynos and from my discussions from the cam gurus around. I'm just throwing that out there because you might gain a little peak torque or peak HP with a much more rowdy cam, but the difference in drivability is pretty big for 5-10HP. And the way you cam stock or stock ported heads and aftermarket castings is different. Not saying you can't go either way. Good heads make good power regardless. But there are tradeoffs you make with stock or stock ported heads that you don't need to make with high flow aftermarket castings...
Last edited by JakeFusion; 12-14-2012 at 02:16 PM.
12-14-2012, 04:57 PM
#9
Whats more important to you, hitting the 430-440 rwhp or having a shitload of lowend/useable power? The first 2 look pretty big if your looking for all that lowend torque. Id say 223/227-224/228 for a shitload of torque. Not sure on LSA but I think those could still peak at 6,000-6,100 RPMS. The fast would help it carry power more up top to possibly hit the higher rwhp numbers but for a street beast you cant be too worried about that, I know Im not.
12-14-2012, 05:07 PM
#10
First of all you have a lot of $$ tied up in your heads already. Don't let it go to waste by mismatching the cam. If you are already talking with Ed Curtis about the combo then don't waste your time on here trying to get suggestions. He has tons of experience with AFR heads and knows what he is doing. Let him get your combo setup for you and you will be very happy when it is all said and done. He will make sure the right combination of head chamber CC, compression, and camshaft specs is done to achieve what you are after.
12-14-2012, 06:09 PM
#11
FYI there's also a 225, 229, and 233 LSL lobes to choose from. You'll also want to go with a 110 or 111 lsa and 2-3 degrees of advance if you go with the 66cc chambers to keep the DCR at 8+ . Going with a 62cc chambers will bump your DCR up about .4 .
12-15-2012, 09:57 AM
#12
I will mill the heads; how much, I don't know. That will depend on my conversation with Ed. I think going with something in the 227/231 ballpark would be best. That, by no means, is not a "big" cam. It will still provide me with great low end torque and carrry till 6500 rpm's. I've seen lots of dyno graphs of all kinds of setups using Ed's cams and they all seem to make great low end torque; even the bigger cams. Dr. Whigam on here is running Ed's 229/236 112 LSA cam using AFR heads that were milled down to 59cc and he had enough clearance. Whatever cam Ed thinks will be best, that is what I'll go with and I'll then mill the heads accordingly.
