Paralysis Through Analysis - Help Design My Cam
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On The Tree
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Paralysis Through Analysis - Help Design My Cam I am at the point in my build that I need to dial in the cam. I have been reading and talking to venders until I am blue in the face. Looking for some real world experience/opinions/results.
Combo is as follows.
377 CID (LS3 block, stock crank)
Lunati Rods and -3.2cc Weisco slugs
AFR 230 V2 heads (Big Bore 62cc)
Compression should be 11.3 to 11.5 by the time its buttoned up
Yella Terra Rockers
Fast 102 (will be Mamo Ported)
1-7/8 headers
This is going in a street driven 3400lb 3rd gen Camaro with a T56. The car will have full accessories and AC.
Requirements: (assuming tuned properly)
I was recommended a 223/234 on a 114+3 (lift @ .630” intake and .620” ext) which “should” give me what I am looking for (.5 deg overlap). However, I see lots of aftermarket cathedral guys running 227/235 ish cams with great results. The AFR heads flow a ton and I am afraid that split is too large. What I don’t find in the threads I search is how well off idle combos like these runs. I live in an area where I am bound to get stuck in traffic and hence the desire for a smooth idle, minimal overlap (to cut down stink and lope) and zero bucking or surging.
Before I order this cam, is there a better cam recipe I should consider? I don’t want to go too small on the cam if another grind will give me more power and still meet my goals.
Thanks in advance
Combo is as follows.
377 CID (LS3 block, stock crank)
Lunati Rods and -3.2cc Weisco slugs
AFR 230 V2 heads (Big Bore 62cc)
Compression should be 11.3 to 11.5 by the time its buttoned up
Yella Terra Rockers
Fast 102 (will be Mamo Ported)
1-7/8 headers
This is going in a street driven 3400lb 3rd gen Camaro with a T56. The car will have full accessories and AC.
Requirements: (assuming tuned properly)
- No surging or bucking at low RPM’s (with AC on)
- Fat powerband from idle to 6,000 rpm (don’t need a 7k screamer, but don’t need a diesel power band either)
- Minimal to zero lope and smooth idle
I was recommended a 223/234 on a 114+3 (lift @ .630” intake and .620” ext) which “should” give me what I am looking for (.5 deg overlap). However, I see lots of aftermarket cathedral guys running 227/235 ish cams with great results. The AFR heads flow a ton and I am afraid that split is too large. What I don’t find in the threads I search is how well off idle combos like these runs. I live in an area where I am bound to get stuck in traffic and hence the desire for a smooth idle, minimal overlap (to cut down stink and lope) and zero bucking or surging.
Before I order this cam, is there a better cam recipe I should consider? I don’t want to go too small on the cam if another grind will give me more power and still meet my goals.
Thanks in advance
From everything I've seen, when you have a set of heads that flow so well on the exhaust side and have bigger exhaust valves, you DO NOT NEED that much split. My heads have exceptional exhaust flow numbers and bigger exhaust valves, like the AFR heads, and I'm experiencing over scavenging due to the cam having too large a split, and being on a 110 LSA. Here is an e-mail reply I received from Brian Tooley:
Looks like classic over scavenging. The Dart heads tend to have a LOT of exhaust flow, which is the root of the issue.
We back to back tested 1 3/4" and 1 7/8" headers at TFS. On heads with stock 1.55" exhaust valves the 1 7/8" were better everywhere, the TFS heads with their 1.57" exhaust valves made about the same power with both headers and the AFR 205 heads with 1.60" exhaust valves made less power with the 1 7/8" headers.
Installing a better breathing intake like a Fast 102 would benefit.
Brian
I would say in your case, a came along the lines of a 236/240 114 LSA would work every well with your combination. If I were you, I'd give Tony Mamo a call. He designed the AFR heads and knows how to spec cams for them.
Looks like classic over scavenging. The Dart heads tend to have a LOT of exhaust flow, which is the root of the issue.
We back to back tested 1 3/4" and 1 7/8" headers at TFS. On heads with stock 1.55" exhaust valves the 1 7/8" were better everywhere, the TFS heads with their 1.57" exhaust valves made about the same power with both headers and the AFR 205 heads with 1.60" exhaust valves made less power with the 1 7/8" headers.
Installing a better breathing intake like a Fast 102 would benefit.
Brian
I would say in your case, a came along the lines of a 236/240 114 LSA would work every well with your combination. If I were you, I'd give Tony Mamo a call. He designed the AFR heads and knows how to spec cams for them.
Thread Starter
On The Tree
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From everything I've seen, when you have a set of heads that flow so well on the exhaust side and have bigger exhaust valves, you DO NOT NEED that much split. My heads have exceptional exhaust flow numbers and bigger exhaust valves, like the AFR heads, and I'm experiencing over scavenging due to the cam having too large a split, and being on a 110 LSA. Here is an e-mail reply I received from Brian Tooley:
All I'll say is that I've learned more over the past year or so than I've learned in my entire life. The single most important thing to think about when building an engine is having the right combination of parts that are spec'd to work together to achieve an end result. Too many times people pick this part, and then throw this part on it, and we'll go with this over that, and they end up with a finished product that does not produce the numbers or ET's they want. Going through one vendor is really important, I think, because you've got one hand in the pie as opposed to numerous hands. I have a lot of respect for pretty much all the big name LSx vendors on here. With that said, I'd entrust someone like Brian Tooley, Martin Smallwood, or Tony Mamo to direct my build. Do yourself a big favor and talk to Tony. He designed those heads and he flat out knows what type of cam you'll need to meet your goals.
Phoenix pointing you in the right direction. Tony is your best resource.
As a purely mental exercise...
Referring back to your OP, you are seeing great results in the 227/235 cam range - those are on 5.7L bottom ends, but also with some overlap and some revving. Overlap is power. RPM is power. A 377 is going to "absorb" some overlap, so don't be afraid of it. On a 5.7 on Tony's heads, he will typically specify 227/231-114+2, which has 1-degree overlap. A 377 should be able to idle OK and tolerate low RPM with 2-degrees
Secondly, you ARE leaving power on the table at 223 intake duration due to the 42 degree IVC. I'd recommend 45-46 degrees
Lastly, with a 3400 stall, you're designing your drivetrain for a motor that really won't come into it's own until 3000, but then COULD carry to 7K if you wanted. I wouldn't worry too much about low end TQ, because your stall will allow it to rev some.
So, here's two recommendations based on all that above:
1. 230/234-115+4. That'll give you two degrees overlap and address almost every concern. Being slightly larger than a 5.7 cam, going into a 6.2, should run similarly to a 227/231-114+2 in a 5.7. At 11.3 CR, DCR would be 8.4. You could easily bump CR to 11.6 and then be at 8.63 dynamic compression, which will still give good torque
2. 230/234-116+5. That'll give you zero degrees overlap, same DCR, etc, as option 1, but a smoother idle and tamer overall ride.
Consider doing LLSR instead of hydraulics. Cost of entry is minimal, but if you ever decide down the road to rev it, you'll have the valve train to handle it
As a purely mental exercise...
Referring back to your OP, you are seeing great results in the 227/235 cam range - those are on 5.7L bottom ends, but also with some overlap and some revving. Overlap is power. RPM is power. A 377 is going to "absorb" some overlap, so don't be afraid of it. On a 5.7 on Tony's heads, he will typically specify 227/231-114+2, which has 1-degree overlap. A 377 should be able to idle OK and tolerate low RPM with 2-degrees
Secondly, you ARE leaving power on the table at 223 intake duration due to the 42 degree IVC. I'd recommend 45-46 degrees
Lastly, with a 3400 stall, you're designing your drivetrain for a motor that really won't come into it's own until 3000, but then COULD carry to 7K if you wanted. I wouldn't worry too much about low end TQ, because your stall will allow it to rev some.
So, here's two recommendations based on all that above:
1. 230/234-115+4. That'll give you two degrees overlap and address almost every concern. Being slightly larger than a 5.7 cam, going into a 6.2, should run similarly to a 227/231-114+2 in a 5.7. At 11.3 CR, DCR would be 8.4. You could easily bump CR to 11.6 and then be at 8.63 dynamic compression, which will still give good torque
2. 230/234-116+5. That'll give you zero degrees overlap, same DCR, etc, as option 1, but a smoother idle and tamer overall ride.
Consider doing LLSR instead of hydraulics. Cost of entry is minimal, but if you ever decide down the road to rev it, you'll have the valve train to handle it
Last edited by Darth_V8r; Jul 22, 2016 at 05:35 PM. Reason: edited typo - exhaust duration supposed to be 231, not 237
Thread Starter
On The Tree
Joined: Jan 2012
Posts: 101
Likes: 10
Phoenix pointing you in the right direction. Tony is your best resource.
As a purely mental exercise...
Referring back to your OP, you are seeing great results in the 227/235 cam range - those are on 5.7L bottom ends, but also with some overlap and some revving. Overlap is power. RPM is power. A 377 is going to "absorb" some overlap, so don't be afraid of it. On a 5.7 on Tony's heads, he will typically specify 227/237-114+2, which has 1-degree overlap. A 377 should be able to idle OK and tolerate low RPM with 2-degrees
Secondly, you ARE leaving power on the table at 223 intake duration due to the 42 degree IVC. I'd recommend 45-46 degrees
Lastly, with a 3400 stall, you're designing your drivetrain for a motor that really won't come into it's own until 3000, but then COULD carry to 7K if you wanted. I wouldn't worry too much about low end TQ, because your stall will allow it to rev some.
So, here's two recommendations based on all that above:
1. 230/234-115+4. That'll give you two degrees overlap and address almost every concern. Being slightly larger than a 5.7 cam, going into a 6.2, should run similarly to a 227/231-114+2 in a 5.7. At 11.3 CR, DCR would be 8.4. You could easily bump CR to 11.6 and then be at 8.63 dynamic compression, which will still give good torque
2. 230/234-116+5. That'll give you zero degrees overlap, same DCR, etc, as option 1, but a smoother idle and tamer overall ride.
Consider doing LLSR instead of hydraulics. Cost of entry is minimal, but if you ever decide down the road to rev it, you'll have the valve train to handle it
As a purely mental exercise...
Referring back to your OP, you are seeing great results in the 227/235 cam range - those are on 5.7L bottom ends, but also with some overlap and some revving. Overlap is power. RPM is power. A 377 is going to "absorb" some overlap, so don't be afraid of it. On a 5.7 on Tony's heads, he will typically specify 227/237-114+2, which has 1-degree overlap. A 377 should be able to idle OK and tolerate low RPM with 2-degrees
Secondly, you ARE leaving power on the table at 223 intake duration due to the 42 degree IVC. I'd recommend 45-46 degrees
Lastly, with a 3400 stall, you're designing your drivetrain for a motor that really won't come into it's own until 3000, but then COULD carry to 7K if you wanted. I wouldn't worry too much about low end TQ, because your stall will allow it to rev some.
So, here's two recommendations based on all that above:
1. 230/234-115+4. That'll give you two degrees overlap and address almost every concern. Being slightly larger than a 5.7 cam, going into a 6.2, should run similarly to a 227/231-114+2 in a 5.7. At 11.3 CR, DCR would be 8.4. You could easily bump CR to 11.6 and then be at 8.63 dynamic compression, which will still give good torque
2. 230/234-116+5. That'll give you zero degrees overlap, same DCR, etc, as option 1, but a smoother idle and tamer overall ride.
Consider doing LLSR instead of hydraulics. Cost of entry is minimal, but if you ever decide down the road to rev it, you'll have the valve train to handle it
I went with the larger motor so that I could get away with a smaller cam and less overlap, yet still make power, as you mentioned. Interesting point on the IVC. Is the 45 to 46 range considered ideal for this type of powerband? I only ask because I was recommended 43 IVC and 54 on EO.
No stall here. 6 speed with 3.42 gears. I thought about the LLSR option but I had already purchased Johnson link bars.
Good feedback. Appreciate it.
I went with the larger motor so that I could get away with a smaller cam and less overlap, yet still make power, as you mentioned. Interesting point on the IVC. Is the 45 to 46 range considered ideal for this type of powerband? I only ask because I was recommended 43 IVC and 54 on EO.
No stall here. 6 speed with 3.42 gears. I thought about the LLSR option but I had already purchased Johnson link bars.
I went with the larger motor so that I could get away with a smaller cam and less overlap, yet still make power, as you mentioned. Interesting point on the IVC. Is the 45 to 46 range considered ideal for this type of powerband? I only ask because I was recommended 43 IVC and 54 on EO.
No stall here. 6 speed with 3.42 gears. I thought about the LLSR option but I had already purchased Johnson link bars.
Old cam was 7.5 overlap and current cam is 11 overlap, and I'm still on stock gears. Off idle isn't *too* bad, but it is an issue. I actually NEED some rear gear
to get out of that off idle region quicker, so you're instincts are valid there. I still think 2 degrees of overlap will run fine for you, but I can understand wanting 0 for good measure. Especially if you're planning to run 6th gear at 1100 rpm. Even at 11 degrees overlap, once I get above 1500 rpm, it smooths out.For some reason, I looked at your 3400 lb weight and read as stall speed. my bad.
Johnson lifters are very good. i doubt you'll have any buyers remorse over them.
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TECH Fanatic
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Posts: 1,845
Likes: 255
From: Coast of San Mateo County Between Pacifica & HMB
NA up to 6500 RPM with AFR Cathedral Heads 4* extra exhaust
Split is the optimal. I like Darth's first choice out of his two.
My .02 would be 227*/231* LSA 114*+3* .620"/.600"
on the small side to 231*/235* LSA 115* +4* .620"/.600
on the large side, still a stock stroke we are talking about.
Either of these would drive very docile at idle & part throttle
And the head flow combined with a MAMOFIED FAST 102
would have Phenominal throttle response and peak
6200-6500 and carry to 7000 RPM.
All this said contact Tony since he designed you're heads
and is porting you're FAST.
Split is the optimal. I like Darth's first choice out of his two.
My .02 would be 227*/231* LSA 114*+3* .620"/.600"
on the small side to 231*/235* LSA 115* +4* .620"/.600
on the large side, still a stock stroke we are talking about.
Either of these would drive very docile at idle & part throttle
And the head flow combined with a MAMOFIED FAST 102
would have Phenominal throttle response and peak
6200-6500 and carry to 7000 RPM.
All this said contact Tony since he designed you're heads
and is porting you're FAST.
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Verdad Gallardo TECH Fanatic
Joined: Aug 2009
Posts: 1,845
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From: Coast of San Mateo County Between Pacifica & HMB
[QUOTE=Darth_V8r;19333838]Phoenix pointing you in the right direction. Tony is your best resource.
"On a 5.7 on Tony's heads, he will typically specify 227/237-114+2,"
Darth I believe you mean Tony typically specs "227/231"
114+2 with his heads on a 5.7
"On a 5.7 on Tony's heads, he will typically specify 227/237-114+2,"
Darth I believe you mean Tony typically specs "227/231"
114+2 with his heads on a 5.7
[QUOTE=NAVYBLUE210;19334316]
That's what I was thinking too.
That's what I was thinking too.
Thread Starter
On The Tree
Joined: Jan 2012
Posts: 101
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NA up to 6500 RPM with AFR Cathedral Heads 4* extra exhaust
Split is the optimal. I like Darth's first choice out of his two.
My .02 would be 227*/231* LSA 114*+3* .620"/.600"
on the small side to 231*/235* LSA 115* +4* .620"/.600
on the large side, still a stock stroke we are talking about.
Either of these would drive very docile at idle & part throttle
And the head flow combined with a MAMOFIED FAST 102
would have Phenominal throttle response and peak
6200-6500 and carry to 7000 RPM.
All this said contact Tony since he designed you're heads
and is porting you're FAST.
Split is the optimal. I like Darth's first choice out of his two.
My .02 would be 227*/231* LSA 114*+3* .620"/.600"
on the small side to 231*/235* LSA 115* +4* .620"/.600
on the large side, still a stock stroke we are talking about.
Either of these would drive very docile at idle & part throttle
And the head flow combined with a MAMOFIED FAST 102
would have Phenominal throttle response and peak
6200-6500 and carry to 7000 RPM.
All this said contact Tony since he designed you're heads
and is porting you're FAST.
You're making the right choice talking to him. He knows those AFR heads better than anyone and knows how to cam an application using them to achieve the best results.
Yes, you're correct. it was a typo. Previous post edited for clarification.
Last edited by Darth_V8r; Jul 22, 2016 at 05:37 PM. Reason: Added comment that previous post was edited
Weird. My 229/236 112+2 made pretty good power with some used AFR 205's...
Must've been unicorn blood on the lobes.
Oh, and the numbers in sig were with "over-scavenging" TSP 1 7/8" with true duals as well....
Must've been unicorn blood on the lobes.
Oh, and the numbers in sig were with "over-scavenging" TSP 1 7/8" with true duals as well....
yeah, personally I would run a bigger cam, but he said he wanted to keep it on the smaller side. If it were mine I'd go 234/240
Thread Starter
On The Tree
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I was able to speak to Tony this weekend and he was able to help me dial in the rest of my build. I scrapped the AFR 230’s and will be going with his MMS235’s. They are just a better product, period. As for the cam, we settled on a 227/231 on a 114+3 with .614”/.610” lift. This should give me the low RPM behavior I am looking for yet not run out of breath at 6500 rpm. I am not sure if the aftermarket cam makers are really aware of how efficient aftermarket cathedral heads are, especially on the exhaust side. They seem to have the OEM heads and square ports down pat, but are knowledge limited on aftermarket cathedrals, hence the weird recommendations I was getting. I’m not passing judgment, I just feel that my intuition has been validated.