LQ4+LS9 cam+LS3/L92 heads=win?
05-10-2015, 08:18 PM
#1
LQ4+LS9 cam+LS3/L92 heads=win? I know there are much better cams out there but this build defines "budget build". So realistically, what kind of power could I expect form a LQ4 with 823 heads and a LS9 cam? I like the idea of the LS9 because it's affordable and is a three bolt style which is vital since I need the 1x cam gear and LS2 timing cover setup. The car is a 3000lb BMW so the softer low end torque of the LS9 cam isn't of great concern.
Thoughts?
S.f.
Thoughts?
S.f.
05-10-2015, 11:36 PM
#2
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the build with the 823 has potential, but I think that cam will hold you back across the entire power band. it's designed for boost, so the overlap is very low. I doubt it will carry much at all past peak. If you really want to keep this thing cheap, I bet you could pick up a factory lS2 cam for cheap, and it would do better for you IMO for the same basic cost.
05-11-2015, 04:16 AM
#3
the build with the 823 has potential, but I think that cam will hold you back across the entire power band. it's designed for boost, so the overlap is very low. I doubt it will carry much at all past peak. If you really want to keep this thing cheap, I bet you could pick up a factory lS2 cam for cheap, and it would do better for you IMO for the same basic cost.
S.F.
05-11-2015, 07:43 AM
#4
the softer low end torque of the LS9 cam isn't of great concern.
So if you chose this cam for top end power you might be sorely dissapointed.
However the heads and displacement will help get that back, although don't expect more than around 400rwhp if that. The low end, even with a small cam, will be lazy due to the heads and low compression but you don't seem to care about that.
In the end it will be an ok setup at best, nothing to write home about though N/A. This is an ideal FI combination that will run poorly without it.
05-11-2015, 11:36 AM
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05-11-2015, 02:01 PM
#8
Alrighty then, you all shot holes through that pretty easily.... I'm open to suggestions regarding an affordable cam / springs and since I'm going to replace the valve seals on the 823's I can easily have them milled for $100 locally. Problem is, I don't know how far I could mill them withought getting PTV problems. Keep the education coming fellas, I don't have big dollars to spend so I darn sure don't have it to spend twice!
S.F.
S.F.
05-11-2015, 03:57 PM
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You're doing the right thing. Not many of us mind answering questions. We all had to learn this crap.
If memory serves, 0.030" milling will get you to 64cc, which is LS2 territory, giving you roughly 10.5:1 compression ratio. Once you are buying a cam, they pretty much all cost 300-450 new, so you can work from there. Where it gets expensive is springs and lifters as you get more and more aggressive.
So, some basics - PTV clearance is all about duration. max lift happens so far away from TDC, that you don't need to worry about it. Extra large durations - particularly overlap - will get you into PTV issues, because that's when the valves are open at TDC.
Also, the more aggressive your cam is, the more you will need additional valve train inve$tment$ to control things. If you want to keep it budget friendly, look into cam profiles that will work with your stock springs and lifters with little to no ill effects.
If your 823's are coming with the stock springs, you probably have about 0.550" max lift. If you look into cam motion drop in cams for a 6.0 or LS2, you can put one in that will deliver very good power without breaking the bank. Get an idea for these specs, and you can find similar ones from Tick, EPS, Brian Tooley, etc. Also worth getting a recommendation from Mamo.
Here is a decent start for something that will work with all stock hardware: http://www.briantooleyracing.com/btr...-camshaft.html
If you decide you want more cam, then remember as you get more aggressive, you start to need stronger spring$, lifter$, pushrod$, etc, so to keep the budget in check, keep it mild.
If memory serves, 0.030" milling will get you to 64cc, which is LS2 territory, giving you roughly 10.5:1 compression ratio. Once you are buying a cam, they pretty much all cost 300-450 new, so you can work from there. Where it gets expensive is springs and lifters as you get more and more aggressive.
So, some basics - PTV clearance is all about duration. max lift happens so far away from TDC, that you don't need to worry about it. Extra large durations - particularly overlap - will get you into PTV issues, because that's when the valves are open at TDC.
Also, the more aggressive your cam is, the more you will need additional valve train inve$tment$ to control things. If you want to keep it budget friendly, look into cam profiles that will work with your stock springs and lifters with little to no ill effects.
If your 823's are coming with the stock springs, you probably have about 0.550" max lift. If you look into cam motion drop in cams for a 6.0 or LS2, you can put one in that will deliver very good power without breaking the bank. Get an idea for these specs, and you can find similar ones from Tick, EPS, Brian Tooley, etc. Also worth getting a recommendation from Mamo.
Here is a decent start for something that will work with all stock hardware: http://www.briantooleyracing.com/btr...-camshaft.html
If you decide you want more cam, then remember as you get more aggressive, you start to need stronger spring$, lifter$, pushrod$, etc, so to keep the budget in check, keep it mild.