Question about cam advance.
08-21-2008, 11:04 AM
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Question about cam advance. Have a question about cam advance. I was wondering if you advance a cam two degrees (double roller chain) what difference does it make in the IVC. My cam has a IVC of 53. Which might be a little late. Seems to lack low end torque a little. I would like to get some torque back.
08-21-2008, 03:01 PM
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Some looks but no responses. I've been kicking around some new cam specs based on some past combos. I'm trying to figure out some valve events on a new cam I thought about. I tried the spreed sheet but I don't have excel. XER or XFI
dur.050 238/242
lsa 112
installed at 110 lobe sep.(+2)
16 degress overlap
Should be good N/A and 200 shot.
Motor is 12/1 comp speed inc 348
Maybe Predator or Pat G can chime in.
dur.050 238/242
lsa 112
installed at 110 lobe sep.(+2)
16 degress overlap
Should be good N/A and 200 shot.
Motor is 12/1 comp speed inc 348
Maybe Predator or Pat G can chime in.
Last edited by LS1 BU; 08-23-2008 at 06:24 PM.
08-21-2008, 06:27 PM
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IMO rather go with a smaller duration cam, if your concerned about low end power.
however the exhaust opening sooner should be good on spray if you were to install that cam at 108 ICL.
however the exhaust opening sooner should be good on spray if you were to install that cam at 108 ICL.
08-23-2008, 11:28 AM
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Just trying to get a 12 comp motor to run on pump gas and make good tq. My last cam which was on the limit of running on pump gas had a IVC of 47 degrees. My current cam has a IVC of 53 which makes it run on pump gas but lost power down low. Just trying to find a happy medium. The cam that I speced is XER
238/242
.6xx/.6xx
intake center line 110(+2)
lobe sep 112
16 degrees overlap
IVC of 49 degrees.
I think this cam should be a good na/nos cam.
238/242
.6xx/.6xx
intake center line 110(+2)
lobe sep 112
16 degrees overlap
IVC of 49 degrees.
I think this cam should be a good na/nos cam.
08-23-2008, 02:24 PM
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Have a question about cam advance. I was wondering if you advance a cam two degrees (double roller chain) what difference does it make in the IVC. My cam has a IVC of 53. Which might be a little late. Seems to lack low end torque a little. I would like to get some torque back.
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08-23-2008, 03:06 PM
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238/242 112+4 you want, which I get IVC of 47*(will vary on certain lobes/cam companys). And you want to move your rpm sooner I take it. I would use a smaller cam IMO, and tighten up the LDA. You can try speeding the cam up more 2* that will help a little, (cam is BIG), but the intake mainfold has alot to do where the motor peaks also.
08-23-2008, 03:16 PM
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Just trying to make good low end power My last cam had a IVC of 47 degrees but it would not run on straight 93 octane. After we pulled a little timing and added fuel it would run fine. Unless hot outside. It would get some knock. Current cam has a IVC of 53 and runs on 93. When I swaped cams I lost 14 rwtq at peak and alot under the curve. 4000-5000 area. Just trying to get some of the power back and run on 93 octane. That's why I went with 2 advance to get the IVC of 49
Current cam is 240/244 LSK lobes.
lobe sep 113.5
intake centerline 113.0
with IVC 53
15 degress overlap.
Previous cam is LSK/XER
235/240
lobe sep 111
intake centerline 109.5
15 degrees overlap
IVC of 47
Current cam is 240/244 LSK lobes.
lobe sep 113.5
intake centerline 113.0
with IVC 53
15 degress overlap.
Previous cam is LSK/XER
235/240
lobe sep 111
intake centerline 109.5
15 degrees overlap
IVC of 47
08-23-2008, 03:23 PM
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Just trying to make good low end power My last cam had a IVC of 47 degrees but it would not run on straight 93 octane. After we pulled a little timing and added fuel it would run fine. Unless hot outside. It would get some knock. Current cam has a IVC of 53 and runs on 93. When I swaped cams I lost 14 rwtq at peak and alot under the curve. 4000-5000 area. Just trying to get some of the power back and run on 93 octane. That's why I went with 2 advance to get the IVC of 49
Current cam is 240/244 LSK lobes.
lobe sep 113.5
intake centerline 113.0
with IVC 53
15 degress overlap.
Previous cam is LSK/XER
235/240
lobe sep 111
intake centerline 109.5
15 degrees overlap
IVC of 47
Current cam is 240/244 LSK lobes.
lobe sep 113.5
intake centerline 113.0
with IVC 53
15 degress overlap.
Previous cam is LSK/XER
235/240
lobe sep 111
intake centerline 109.5
15 degrees overlap
IVC of 47
08-23-2008, 03:36 PM
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I shift a 7000 rpm and rev to 7300. That's not an issue. Just trying to close the intake valve a little sooner to get dcr back to where it should be. I don't have the formula to figure it out. I have a 12/1 compression motor with the cams that i have run. I estimate my compression with new cam specd at IVC of 49 should put me in the 8.80-8.90 area. That should work on 93 octane.
08-23-2008, 06:04 PM
#14
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I shift a 7000 rpm and rev to 7300. That's not an issue. Just trying to close the intake valve a little sooner to get dcr back to where it should be. I don't have the formula to figure it out. I have a 12/1 compression motor with the cams that i have run. I estimate my compression with new cam specd at IVC of 49 should put me in the 8.80-8.90 area. That should work on 93 octane.
08-23-2008, 06:19 PM
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I was running a tr6 when both setups were tuned N/A. I would switch over to a tr7 plug for N/A with new cam. I think the Tr6 might be a little hot.
08-24-2008, 03:54 AM
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47.5 IVC
08-24-2008, 10:17 AM
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Hey predator can you help me figure out DCR with cam setup. Motor is 348 at 12/1 static compression. Still not sure which lobe I would run. I've run LSK lobes and XER lobes. Don't have experience with XFI lobes. I have springs setup to run LSK lobes. Just have heard that they are hard on valvetrain parts. My heads are ET 215 heads.
. AT the same time I swaped cams had my fast 90/90 ported and went from macs to hooker 1 7/8 long tubes. I only picked up 6 hp up to and lost alot down low. I think the cam I specd should be a happy medium between the two and run on pump gas.
Current cam is 240/244 LSK lobes.
lobe sep 113.5
intake centerline 113.0
with IVC 53
15 degress overlap
Last cam is
235/240
lobe sep 111
intake centerline 109.5
15 degrees overlap
IVC of 47
new cam
238/242
.6xx/.6xx
intake center line 110(+2)
lobe sep 112
16 degrees overlap
IVC of 49 degrees.
I think this cam should be a good na/nos cam
new specd cam
. AT the same time I swaped cams had my fast 90/90 ported and went from macs to hooker 1 7/8 long tubes. I only picked up 6 hp up to and lost alot down low. I think the cam I specd should be a happy medium between the two and run on pump gas.
Current cam is 240/244 LSK lobes.
lobe sep 113.5
intake centerline 113.0
with IVC 53
15 degress overlap
Last cam is
235/240
lobe sep 111
intake centerline 109.5
15 degrees overlap
IVC of 47
new cam
238/242
.6xx/.6xx
intake center line 110(+2)
lobe sep 112
16 degrees overlap
IVC of 49 degrees.
I think this cam should be a good na/nos cam
new specd cam
