Comp Cams tells me this cam for my setup???
Registered User
Joined: Jan 1999
Posts: 884
From: I reached back like a pimp and smacked that LS1....
The actual LSA # is insignifigant. Overlap is what needs to be considered.
A stock turbo buick cam is on a 107 LSA. But it also is 192/196 @.050 leaving it with negative 20 degrees overlap @.050.
218/218 on a 113lsa has negative 8 degrees of overlap.
My opinion on turbo cams is that overlap is not good (because at some point exhaust pressure will usually exceed intake pressure), and the way to reduce overlap and still run a decent amount of duration is to close the exhaust valve early. The cam I chose and will be installing soon is-
226 @.050 .558 lift intake
218 @.050 .542 lift exhaust
113 ICL
117 LSA
A stock turbo buick cam is on a 107 LSA. But it also is 192/196 @.050 leaving it with negative 20 degrees overlap @.050.
218/218 on a 113lsa has negative 8 degrees of overlap.
My opinion on turbo cams is that overlap is not good (because at some point exhaust pressure will usually exceed intake pressure), and the way to reduce overlap and still run a decent amount of duration is to close the exhaust valve early. The cam I chose and will be installing soon is-
226 @.050 .558 lift intake
218 @.050 .542 lift exhaust
113 ICL
117 LSA
Registered User
Joined: Jul 2001
Posts: 67
From: las vegas NV USA
There are way, way too many factors to just say things like "114 is best, or 117, or 106". Backpressure, RPM range, desired boost level, desired horsepower, A/R of turbo, location of turbo (exhaust heat as it enters housing), size of turbo, trim, head flow, cubic inches, etc. are all extremely important in determining both ICL and LSA. There is no rule of thumb with a turbo cam (or any cam really), there are just way too many variables. The only way to get the right cam is to take all of those into consideration, and only then can a cam be optimised.
As with any company, you need to talk to the right people. Call and ask for Seth or Sam. Everybody here kind of has their own specialty and those two are the turbo guys.
As with any company, you need to talk to the right people. Call and ask for Seth or Sam. Everybody here kind of has their own specialty and those two are the turbo guys.
Registered User
Joined: Jan 1999
Posts: 884
From: I reached back like a pimp and smacked that LS1....
Originally posted by cmotorsports.com
There are way, way too many factors to just say things like "114 is best, or 117, or 106". Backpressure, RPM range, desired boost level, desired horsepower, A/R of turbo, location of turbo (exhaust heat as it enters housing), size of turbo, trim, head flow, cubic inches, etc. are all extremely important in determining both ICL and LSA. There is no rule of thumb with a turbo cam (or any cam really), there are just way too many variables. The only way to get the right cam is to take all of those into consideration, and only then can a cam be optimised.
As with any company, you need to talk to the right people. Call and ask for Seth or Sam. Everybody here kind of has their own specialty and those two are the turbo guys.
There are way, way too many factors to just say things like "114 is best, or 117, or 106". Backpressure, RPM range, desired boost level, desired horsepower, A/R of turbo, location of turbo (exhaust heat as it enters housing), size of turbo, trim, head flow, cubic inches, etc. are all extremely important in determining both ICL and LSA. There is no rule of thumb with a turbo cam (or any cam really), there are just way too many variables. The only way to get the right cam is to take all of those into consideration, and only then can a cam be optimised.
As with any company, you need to talk to the right people. Call and ask for Seth or Sam. Everybody here kind of has their own specialty and those two are the turbo guys.
I agree.
Everyone tries to choose cams by duration, LSA, and lift, when those numbers should just be the result of the valve events chosen.
Registered User
Joined: Jan 1999
Posts: 884
From: I reached back like a pimp and smacked that LS1....
Originally posted by 93formula
interesting cam, did you select that or did a company do it for you, and why the 117 lsa?
interesting cam, did you select that or did a company do it for you, and why the 117 lsa?
I selected the cam.
I chose the valve events (IVO,IVC,EVO,EVC) and the duration, ICL, and LSA was the result of those numbers.
The lift was as much as I could get for that particular amount of duration.
Registered User
Joined: Mar 2002
Posts: 2,743
From: Baton Rouge, LA, USA
Originally posted by cmotorsports.com
. . . There is no rule of thumb with a turbo cam (or any cam really), . . .
. . . There is no rule of thumb with a turbo cam (or any cam really), . . .
Registered User
Joined: Feb 2002
Posts: 702
From: Houston, TX USA
Strange. The p/n is the same one that Comp recommended to me for my twin setup, but the numbers you listed are way different than mine... (the lift is for 1.5, I run 1.6)
"(Comp Cams)
The camshaft I would run with this is a custom grind camshaft. The part
number is 07-000-8, and the grind number is LT1 3421/3314 HR112. I have included the specs to the camshaft below. Now, I cannot guarantee that this camshaft will work with pump fuel, but the key is to bleed off a little bit of cylinder pressure. The camshaft you have now is doing just that (LT4 Hot Cam). With the turbo set up that you have you could make more power with more boost, however, the camshaft is not going to do anything but bleed off the boost. The motor has too much static compression to build boost and run pump fuel with a proper
camshaft designed for a turbo application.
Thanks,
Sam@compcams
SPEC CARD
PART #: 07-000-8
ENGINE: LT1/LT4
GRIND #: LT1 3421 /3314 HR112.0
GROSS VALVE LIFT .507 .502
DURATION @ .006 TAPPET LIFT
279 275
VALVE TIMING OPEN CLOSE
@ .050 INT 2 46
EXH 44 0
SPECS FOR CAM INST. @ 112 CENTERLINE
INT EXH
DURATION @ .050 228.00 224.00
LOBE LIFT .338 .335
LOBE SEPARATION 112.0
ROCKER ARM RATIO 1.50 1.50 "
That is a 228- 224 duration, and .540 - .536 lift with 1.6 rockers.
I wonder if they messed up and gave you the wrong specs for the part number.. ?
"(Comp Cams)
The camshaft I would run with this is a custom grind camshaft. The part
number is 07-000-8, and the grind number is LT1 3421/3314 HR112. I have included the specs to the camshaft below. Now, I cannot guarantee that this camshaft will work with pump fuel, but the key is to bleed off a little bit of cylinder pressure. The camshaft you have now is doing just that (LT4 Hot Cam). With the turbo set up that you have you could make more power with more boost, however, the camshaft is not going to do anything but bleed off the boost. The motor has too much static compression to build boost and run pump fuel with a proper
camshaft designed for a turbo application.
Thanks,
Sam@compcams
SPEC CARD
PART #: 07-000-8
ENGINE: LT1/LT4
GRIND #: LT1 3421 /3314 HR112.0
GROSS VALVE LIFT .507 .502
DURATION @ .006 TAPPET LIFT
279 275
VALVE TIMING OPEN CLOSE
@ .050 INT 2 46
EXH 44 0
SPECS FOR CAM INST. @ 112 CENTERLINE
INT EXH
DURATION @ .050 228.00 224.00
LOBE LIFT .338 .335
LOBE SEPARATION 112.0
ROCKER ARM RATIO 1.50 1.50 "
That is a 228- 224 duration, and .540 - .536 lift with 1.6 rockers.
I wonder if they messed up and gave you the wrong specs for the part number.. ?
Last edited by texlurch; Oct 30, 2003 at 01:04 PM.
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