Best cam for the job
05-07-2003, 07:48 AM
#1
Best cam for the job I'm building up an engine and I would like some feedback/suggestions on a cam choice. I'm having the heads stage 2 port and polished with a valve upgrade (2.02/1.57). All the usual bolt-ons, ported TB & MAF, MAC mid-length headers with off road Y-pipe and no cats. I plan to purchase the Comp LS1 cam kit with 26918 valve springs and 5/16" chromemoly pushrods. You can get what ever cam you choose. I just don't know which would be the best choice. It would be nice to end up with 400+ HP. A good lope would be nice but not to the point that it sounds like it is fixing to die. I plan to check valve/piston clearance, but I don't want so much lift that it would be a problem. I would greatly appreciate any input.
05-07-2003, 08:24 AM
#2
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Re: Best cam for the job 228/236 .571.602 111LSA 
If those heads your running are 5.7 (MILLED) forget about it. P/V clearance will be an issue. I had to exchange mine for 5.3 (UNMILLED) this cam however, should make some really nice power.
If those heads your running are 5.7 (MILLED) forget about it. P/V clearance will be an issue. I had to exchange mine for 5.3 (UNMILLED) this cam however, should make some really nice power.
05-07-2003, 08:41 AM
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Re: Best cam for the job Hey, when all else fails, go with tried and true... 224/224 .563 on either a 112 or 114. You should make your 400rwhp, and you should have idle quality to brag about. I'm not onboard with these 230+ duration 600+ lift cams in street cars... Idle is important to a street car, so is driveability... Bucking and surging and poor idling does not make a good street car IMHO. I know these guys are claiming "better than stock" idle on these enormous cams, and I say they are either seeing what they want to see, or they are just plain mad.
From what I read in your post, you sound to me like retaining the driveability is more important that making MAX power, with that in mind, I would shoot for a cam between 220 and 224 duration, between 525 and 560 lift, and on a 112 lsa or higher. That should give you good power, excellent street manners, and a good sound.
Just as an FYI, if you search, you will find several people making 400+ with the 224/224 .563 cam on STOCK heads.
From what I read in your post, you sound to me like retaining the driveability is more important that making MAX power, with that in mind, I would shoot for a cam between 220 and 224 duration, between 525 and 560 lift, and on a 112 lsa or higher. That should give you good power, excellent street manners, and a good sound.
Just as an FYI, if you search, you will find several people making 400+ with the 224/224 .563 cam on STOCK heads.
05-07-2003, 09:29 AM
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Re: Best cam for the job How about the speedtek F1 cam It made 390RWHP and 420RWTQ through an a4 with stock heads. Specks are 230/226 112 .591/.569 112 +2 BTW I have one for sale
05-07-2003, 01:57 PM
#6
Re: Best cam for the job There seems to alot of people using/reccomending single pattern cams over dual pattern. Do LS1 heads tend to flow that well on the exhaust side that you don't need that extra duration and lift on the exhaust side or is for other reasons?
05-07-2003, 10:44 PM
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Re: Best cam for the job Frankly, what cam have you seen anyone install in these ls1 engines that didn't make considerable power? Single pattern, traditional splits, reverse splits, 110 112 114 lsa's, 525-600 lift... They all make power. I think if you choose a cam that has a good install base (meaning a lot of people running it) and the feedback is all positive, there is nothing to worry about.
When I think about camshaft selection, there is a process of thinking my mind goes through. First, how many RPM's do you want to spin the engine up to? If you don't want to spin 6500-6800+ RPM, I see no reason going above 224 or 226 degrees of duration. Build your peak power where you plan on running the engine, don't get a cam that peaks above 7000 RPM if you know you're going to set your rev limiter at 6600.
Second, is it a 15,000 mile a year street car, or a 100 pass a year dragstrip car that gets trailered around? This is going to make a big difference in how much lift I plan on running, as well as how much lope I want. Here I'm thinking about how important idle quality is, as well as low RPM driveability, as well as valvetrain component life. Based on what these expectations are, I'm going to choose a LSA, or Overlap, and a valve lift that fits my application.
Finally if you want to get really scientific about it, there are a couple other things you should consider. You should match your cam to your cylinder head flow. To have optimized flow in your engine, there is a ratio of exhaust port flow to intake port flow that is considered ideal, generally 75%-85%. For arguments sake, let's just average it at 80%. When you have achieved this "ideal" ratio, you don't need to compensate with split durations to balance port flow. However, if you get outside this ideal flow ratio, then you should see duration growing on whichever side of the head that flows less than the ideal.
The math works out like this.. Say at a single given lift a head flows 300 on the intake and 240 on the exhaust. We'll make this our "ideal" head, just for an example.
240E/300I = 80% Pretty ideal, single pattern cam. 224/224
220E/310I = 71% Exhaust side weak, traditional split cam. 224/228
250E/285I = 88% Intake side weak, reverse split cam. 228/224
Again, these are just some random examples to show you how the theory works... I'm no cam expert, nor do I claim to be. Sorry for such a long post, but I hope it helps.
When I think about camshaft selection, there is a process of thinking my mind goes through. First, how many RPM's do you want to spin the engine up to? If you don't want to spin 6500-6800+ RPM, I see no reason going above 224 or 226 degrees of duration. Build your peak power where you plan on running the engine, don't get a cam that peaks above 7000 RPM if you know you're going to set your rev limiter at 6600.
Second, is it a 15,000 mile a year street car, or a 100 pass a year dragstrip car that gets trailered around? This is going to make a big difference in how much lift I plan on running, as well as how much lope I want. Here I'm thinking about how important idle quality is, as well as low RPM driveability, as well as valvetrain component life. Based on what these expectations are, I'm going to choose a LSA, or Overlap, and a valve lift that fits my application.
Finally if you want to get really scientific about it, there are a couple other things you should consider. You should match your cam to your cylinder head flow. To have optimized flow in your engine, there is a ratio of exhaust port flow to intake port flow that is considered ideal, generally 75%-85%. For arguments sake, let's just average it at 80%. When you have achieved this "ideal" ratio, you don't need to compensate with split durations to balance port flow. However, if you get outside this ideal flow ratio, then you should see duration growing on whichever side of the head that flows less than the ideal.
The math works out like this.. Say at a single given lift a head flows 300 on the intake and 240 on the exhaust. We'll make this our "ideal" head, just for an example.
240E/300I = 80% Pretty ideal, single pattern cam. 224/224
220E/310I = 71% Exhaust side weak, traditional split cam. 224/228
250E/285I = 88% Intake side weak, reverse split cam. 228/224
Again, these are just some random examples to show you how the theory works... I'm no cam expert, nor do I claim to be. Sorry for such a long post, but I hope it helps.
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05-07-2003, 11:03 PM
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Re: Best cam for the job
Idle is important to a street car, so is driveability... Bucking and surging and poor idling does not make a good street car IMHO. I know these guys are claiming "better than stock" idle on these enormous cams, and I say they are either seeing what they want to see, or they are just plain mad.
It really does idle nice. 'Course a fully dyno tune makes that happen.
Also .. Thru MAC headers an ORY !Cats thru an electric cutout... It sounds sweet. Just enough lope to keep em guessin'
The 224 is a fun sweet spot.
mine just has .563 lift though cause I was a pansey
05-08-2003, 11:34 AM
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Re: Best cam for the job choosing a cam has definitely been the hardest mod for me to make my mind up on.. The volume of choices alone is the reason, I'm sure. I think the BEST thing to remember is that there is no BEST anything, only a selection that most completely meets your goals and expectations.