Question about LSA
04-05-2009, 09:23 PM
#27
Depending on what lobes Patrick uses, I've seen him and Predator Z both spec a 224 XFI intake (comes in around 226 when cut) and a 230 XE-R on 111 LSA before. Would be a great cam for your goals and pull well past the peak. You don't have to have lots of duration to make power over 6000 rpms, and you can't have lots of duration if you want power under 4000 rpms.
04-05-2009, 09:27 PM
#28
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You probably don't want to go much larger than what you started with then. As a matter of fact, less is more as far a torque is concerned.
Depending on what lobes Patrick uses, I've seen him and Predator Z both spec a 224 XFI intake (comes in around 226 when cut) and a 230 XE-R on 111 LSA before. Would be a great cam for your goals and pull well past the peak. You don't have to have lots of duration to make power over 6000 rpms, and you can't have lots of duration if you want power under 4000 rpms.
Depending on what lobes Patrick uses, I've seen him and Predator Z both spec a 224 XFI intake (comes in around 226 when cut) and a 230 XE-R on 111 LSA before. Would be a great cam for your goals and pull well past the peak. You don't have to have lots of duration to make power over 6000 rpms, and you can't have lots of duration if you want power under 4000 rpms.
Basically id like to have something around 230 232 around a 110. Something that is really torquey and sounds nasty
04-06-2009, 06:31 AM
#29
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I had Predator-Z spec my cam. Plenty of TQ all the way across, and the car pulls insanely. This is with just a LS6 Intake and 853 heads. In the next 2 weeks, i will be adding heads and a Fast setup.
04-06-2009, 12:14 PM
#31
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Zach:
228/230 .588/.592 112 +2 LSA..
That is probably not a bad choice for your current application (stock heads).
If chop is what you want, with 5 degrees of overlap you should be happy.
From my experience once you get past ~6 degrees of overlap, you really will not get the full benefits of that additional overlap without steeping up your compression ratio (I.E. heads).
For example I am currently running a 228/232 110+2 on a 62cc head. My Hp peaks at ~6000rpms..but carries to ~6400rpms before slowly falling. But without the additional CR, I am not sure you could carry the power peak to your satisfaction.
A lot of the Torque gains from the higher overlap cams are being aided by a higher CR head and more efficient exhaust ports. On stock heads many are making lots of power with far less overlap.
Just some additional thoughts for you. There is always a 'sweet spot' you have to hit once you start bumping up cam duration/overlap.
Good luck.
..WeathermanShawn..
228/230 .588/.592 112 +2 LSA..
That is probably not a bad choice for your current application (stock heads).
If chop is what you want, with 5 degrees of overlap you should be happy.
From my experience once you get past ~6 degrees of overlap, you really will not get the full benefits of that additional overlap without steeping up your compression ratio (I.E. heads).
For example I am currently running a 228/232 110+2 on a 62cc head. My Hp peaks at ~6000rpms..but carries to ~6400rpms before slowly falling. But without the additional CR, I am not sure you could carry the power peak to your satisfaction.
A lot of the Torque gains from the higher overlap cams are being aided by a higher CR head and more efficient exhaust ports. On stock heads many are making lots of power with far less overlap.
Just some additional thoughts for you. There is always a 'sweet spot' you have to hit once you start bumping up cam duration/overlap.
Good luck.
..WeathermanShawn..
04-06-2009, 12:44 PM
#32
This thread has some great info, but I was wondering why stock cams are~ 117-120 LSA and run out of steam at 6000 rmp. From what I have read in all of the cam threads in the last few months that I have tried to figure out what to get is the higher LSA's will put you higher in the RPM range and the lower LSA's get you there with less RPM's. You would think they would pull to 7000k easy with a 121 lsa, LOL. Is it true that the Higher the LSA the easier it is on the idle, especially with an auto trans?
04-06-2009, 01:49 PM
#33
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Beedo:
I use the "DCR Calculator" published by Pat Kelly. If you run a Timing & Overlap calculation on a stock LS1 cam: 119/209 119+4 LSA..
What you get is still a fairly low Intake Valve Closing (IVC) of ~34.5 degrees.
A 228/230 112+2 cam has an IVC of ~44 degrees.
The later IVC's and additional lift from the added duration is why a cam with an IV of 34 will poop out early, and one with 44 degrees will hit 6600 RPM's.
But you are right, there are many ways to manipulate the valve timing events..LSA are overlap are just a piece of a much bigger puzzle.
Hope that clarifies.
..WeathermanShawn..
I use the "DCR Calculator" published by Pat Kelly. If you run a Timing & Overlap calculation on a stock LS1 cam: 119/209 119+4 LSA..
What you get is still a fairly low Intake Valve Closing (IVC) of ~34.5 degrees.
A 228/230 112+2 cam has an IVC of ~44 degrees.
The later IVC's and additional lift from the added duration is why a cam with an IV of 34 will poop out early, and one with 44 degrees will hit 6600 RPM's.
But you are right, there are many ways to manipulate the valve timing events..LSA are overlap are just a piece of a much bigger puzzle.
Hope that clarifies.
..WeathermanShawn..
04-06-2009, 04:27 PM
#34
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Zach:
228/230 .588/.592 112 +2 LSA..
That is probably not a bad choice for your current application (stock heads).
If chop is what you want, with 5 degrees of overlap you should be happy.
From my experience once you get past ~6 degrees of overlap, you really will not get the full benefits of that additional overlap without steeping up your compression ratio (I.E. heads).
For example I am currently running a 228/232 110+2 on a 62cc head. My Hp peaks at ~6000rpms..but carries to ~6400rpms before slowly falling. But without the additional CR, I am not sure you could carry the power peak to your satisfaction.
A lot of the Torque gains from the higher overlap cams are being aided by a higher CR head and more efficient exhaust ports. On stock heads many are making lots of power with far less overlap.
Just some additional thoughts for you. There is always a 'sweet spot' you have to hit once you start bumping up cam duration/overlap.
Good luck.
..WeathermanShawn..
228/230 .588/.592 112 +2 LSA..
That is probably not a bad choice for your current application (stock heads).
If chop is what you want, with 5 degrees of overlap you should be happy.
From my experience once you get past ~6 degrees of overlap, you really will not get the full benefits of that additional overlap without steeping up your compression ratio (I.E. heads).
For example I am currently running a 228/232 110+2 on a 62cc head. My Hp peaks at ~6000rpms..but carries to ~6400rpms before slowly falling. But without the additional CR, I am not sure you could carry the power peak to your satisfaction.
A lot of the Torque gains from the higher overlap cams are being aided by a higher CR head and more efficient exhaust ports. On stock heads many are making lots of power with far less overlap.
Just some additional thoughts for you. There is always a 'sweet spot' you have to hit once you start bumping up cam duration/overlap.
Good luck.
..WeathermanShawn..
