View Poll Results: F-13 Cam 112 vs. 114 LSA
112 LSA Provides peak power earlier in the powerband
183
76.25%
114 LSA Provides peak power earlier in the powerband
57
23.75%
Voters: 240. You may not vote on this poll
112 vs 114 LSA - Difference?
01-07-2007, 10:18 AM
#62
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I think the answer is that the tighter LSA is going to provide better power (torque). The wider LSA is going to provide a tamer idle and better low speed driveability.
For a track only car, you will use 108-110 or thereabouts. For a DD you should use a 114. For a sometimes DD; sometimes track car you need to decide what it most important to you.
I am about to redo my 402 and will move from a 112 to a 114 LSA simply because the compromised low speed driveability is bugging me and I have way more power than my tires can use. So giving up a few ftlbs for better DD characteristics is what will float my boat. Also my track use of this car is track days on road courses and a few less hp is not a real issue. Driving and handling is.
Someone else may want that last bit of power for some track driven reason and that will cause them to not worry about some DD issues.
You need to decide what is most important to you. Dyno and Drag Time bragging rights and a wicked sound at idle leads to tighter LSAs.
Calm and collected DD and "talking quietly and carrying a big stick" folks will use wider LSAs.
Perry
For a track only car, you will use 108-110 or thereabouts. For a DD you should use a 114. For a sometimes DD; sometimes track car you need to decide what it most important to you.
I am about to redo my 402 and will move from a 112 to a 114 LSA simply because the compromised low speed driveability is bugging me and I have way more power than my tires can use. So giving up a few ftlbs for better DD characteristics is what will float my boat. Also my track use of this car is track days on road courses and a few less hp is not a real issue. Driving and handling is.
Someone else may want that last bit of power for some track driven reason and that will cause them to not worry about some DD issues.
You need to decide what is most important to you. Dyno and Drag Time bragging rights and a wicked sound at idle leads to tighter LSAs.
Calm and collected DD and "talking quietly and carrying a big stick" folks will use wider LSAs.
Perry
01-03-2008, 01:25 PM
#64
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EFFECTS OF CHANGING LOBE SEPERATION ANGLE (LSA)
Tighten (smaller LSA number)---- Widen (larger LSA number)
Moves Torque to Lower RPM ---- Raise Torque to Higher RPM
Increases Maximum Torque ---- Reduces Maximum Torque
Narrow Power band --- -------- Broadens Power Band
Builds Higher Cylinder Pressure ---- Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock ----Decrease Chance of Engine Knock
Increase Cranking Compression ---- Decrease Cranking Compression
Increase Effective Compression ----Decrease Effective Compression
Idle Vacuum is Reduced ----------- Idle Vacuum is Increased
Idle Quality Suffers ----- -------- Idle Quality Improves
Open Valve-Overlap Increases ------ Open Valve-Overlap Decreases
Closed Valve-Overlap Increases ---- Closed Valve-Overlap Decreases
Natural EGR Effect Increases ------- Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance ---- Increases Piston-to-Valve Clearance
Tighten (smaller LSA number)---- Widen (larger LSA number)
Moves Torque to Lower RPM ---- Raise Torque to Higher RPM
Increases Maximum Torque ---- Reduces Maximum Torque
Narrow Power band --- -------- Broadens Power Band
Builds Higher Cylinder Pressure ---- Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock ----Decrease Chance of Engine Knock
Increase Cranking Compression ---- Decrease Cranking Compression
Increase Effective Compression ----Decrease Effective Compression
Idle Vacuum is Reduced ----------- Idle Vacuum is Increased
Idle Quality Suffers ----- -------- Idle Quality Improves
Open Valve-Overlap Increases ------ Open Valve-Overlap Decreases
Closed Valve-Overlap Increases ---- Closed Valve-Overlap Decreases
Natural EGR Effect Increases ------- Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance ---- Increases Piston-to-Valve Clearance
01-04-2008, 05:23 AM
#65
dammit too early in the morning... clicked on the wrong one.
I have a 112 and it peaks earlier in the powerband than a 114 would. It also has a slightly rougher idle. If I changed heads along with my cam, it'd be a different story but since I'm using the stock 98 heads, it's choking it a bit more than it should.
I have a 112 and it peaks earlier in the powerband than a 114 would. It also has a slightly rougher idle. If I changed heads along with my cam, it'd be a different story but since I'm using the stock 98 heads, it's choking it a bit more than it should.
02-15-2008, 01:27 PM
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and to add another postscript:
I did go from a TSP Torquer on a 112 to a 114 to gain better drivability.
It cost me 40 peak rwhp but did give me better drivability. However I also discovered a cracked MAF housing during the rebuild that likely was the cause of the bad manners. So I am probably back in the camp for the 112 even on a DD.
Perry
I did go from a TSP Torquer on a 112 to a 114 to gain better drivability.
It cost me 40 peak rwhp but did give me better drivability. However I also discovered a cracked MAF housing during the rebuild that likely was the cause of the bad manners. So I am probably back in the camp for the 112 even on a DD.
Perry
02-15-2008, 02:59 PM
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and to add another postscript:
I did go from a TSP Torquer on a 112 to a 114 to gain better drivability.
It cost me 40 peak rwhp but did give me better drivability. However I also discovered a cracked MAF housing during the rebuild that likely was the cause of the bad manners. So I am probably back in the camp for the 112 even on a DD.
Perry
I did go from a TSP Torquer on a 112 to a 114 to gain better drivability.
It cost me 40 peak rwhp but did give me better drivability. However I also discovered a cracked MAF housing during the rebuild that likely was the cause of the bad manners. So I am probably back in the camp for the 112 even on a DD.
Perry
02-15-2008, 03:54 PM
#72
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Actually I may have overstated the loss a bit but it is down from to 444 rwhp from high 480's low 490's. And yes, I admit I was a bit floored.
the area under the curve actually is very good and changed little, but the peak is down a lot. I fixed the cracked MAF by going from a ported ends MAF and put back on my stock MAF ends, so I have speculated that a portion of that peak loss is due to the added air restriction at high rpm as well as the 114 lobes.
Perry.
This is on a 402 btw.
the area under the curve actually is very good and changed little, but the peak is down a lot. I fixed the cracked MAF by going from a ported ends MAF and put back on my stock MAF ends, so I have speculated that a portion of that peak loss is due to the added air restriction at high rpm as well as the 114 lobes.
Perry.
This is on a 402 btw.
10-23-2008, 10:58 PM
#73
im no expert either, but from all i have read:
112, rougher idle, peaks earlier, more suited for manuals
114, smoother idle, peaks later, more for autos
some even go lower, i talked to someone with a 108 in their car that they took on most of if not the whole power tour(think it was VSGLS1)
better yet, PM ANY of the sponsors that sell cams, they can tell you the answer for sure. Allan at Futral really knows his stuff, he might be a good one to talk to.
112, rougher idle, peaks earlier, more suited for manuals
114, smoother idle, peaks later, more for autos
some even go lower, i talked to someone with a 108 in their car that they took on most of if not the whole power tour(think it was VSGLS1)
better yet, PM ANY of the sponsors that sell cams, they can tell you the answer for sure. Allan at Futral really knows his stuff, he might be a good one to talk to.
01-31-2010, 04:43 PM
#74
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ok sorry to bring this up from the dead guys but what is the Natrual egr effect? I can't seem to get anywhere on google about it.
04-30-2010, 10:13 AM
#75
If you haven't found it yet, and the fact that this thread has been bumped for quite a long time anyway, natural EGR is where you get exhaust gas recirculation in the intake and cylinder, naturally, not from a system. This is due to wide overlap at lower RPMs. The intake velocity is slower at lower RPMs and on an engine with a more overlap, the exhaust can remain in the cylinder or even be backed up into the intake due to more overlap at lower gas velocities. Since the intake velocity is slower, it is not as effective to push the remaining exhaust out, as well as the scavenging effect of the exhaust to pull intake in is also less, so this results in exhaust gas being recirculated, naturally.
