More Cam Help (LE2-383) 107* Separation?
Registered User
Joined: Feb 2008
Posts: 27
From: Detroit City
HotRod magazine (August 2008) did a comparison of a bunch of Comp Cams on a ZZ4 with AFR 195 heads as well as Vortec heads. For whatever reason than ran hydraulic flats like XE-268H-10, 280H-10, XE274H-10, 292H-10 and one hydraulic roller, the Thumpr (283THR-107 LM). The -10 means a 110 LSA, AFSAIK.
The Thumpr is a 227/241 @ 107 with .547/.531 lift with 1.6 rockers. The bottom line was that the Thumpr (107 LSA) made the highest peak torque, the highest average torque, the highest overall average power and the best average numbers between 2500 and 4500 and the best numbers from 4500 to 6500. Is the 107 LSA responsible for that? I don't know, but it is interesting.
From what I have been able to find out, the LE cams were out there and running quite a while before the Thumpr was released by Comp. I believe the LE cams are all ground by Comp.
If the LE cam really has a 107 LSA, it seems that lots of them have been run fairly successfully in EFI LT engines. Perhaps the best and brightest at Comp don't man the Tech Lines. It seems that way when I have called them.
Joe Urban
The Thumpr is a 227/241 @ 107 with .547/.531 lift with 1.6 rockers. The bottom line was that the Thumpr (107 LSA) made the highest peak torque, the highest average torque, the highest overall average power and the best average numbers between 2500 and 4500 and the best numbers from 4500 to 6500. Is the 107 LSA responsible for that? I don't know, but it is interesting.
From what I have been able to find out, the LE cams were out there and running quite a while before the Thumpr was released by Comp. I believe the LE cams are all ground by Comp.
If the LE cam really has a 107 LSA, it seems that lots of them have been run fairly successfully in EFI LT engines. Perhaps the best and brightest at Comp don't man the Tech Lines. It seems that way when I have called them.
Joe Urban
Registered User
Joined: Oct 2001
Posts: 2,525
From: SoCal
From what I have been able to find out, the LE cams were out there and running quite a while before the Thumpr was released by Comp. I believe the LE cams are all ground by Comp.
If the LE cam really has a 107 LSA, it seems that lots of them have been run fairly successfully in EFI LT engines. Perhaps the best and brightest at Comp don't man the Tech Lines. It seems that way when I have called them.
Joe Urban
If the LE cam really has a 107 LSA, it seems that lots of them have been run fairly successfully in EFI LT engines. Perhaps the best and brightest at Comp don't man the Tech Lines. It seems that way when I have called them.
Joe Urban
So Joe (Bert), by that statement, is it reasonable to assume Comp stole an idea from the BRE empire of cam design?
Registered User
Joined: Jul 2005
Posts: 35
HotRod magazine (August 2008) did a comparison of a bunch of Comp Cams on a ZZ4 with AFR 195 heads as well as Vortec heads. For whatever reason than ran hydraulic flats like XE-268H-10, 280H-10, XE274H-10, 292H-10 and one hydraulic roller, the Thumpr (283THR-107 LM). The -10 means a 110 LSA, AFSAIK.
The Thumpr is a 227/241 @ 107 with .547/.531 lift with 1.6 rockers. The bottom line was that the Thumpr (107 LSA) made the highest peak torque, the highest average torque, the highest overall average power and the best average numbers between 2500 and 4500 and the best numbers from 4500 to 6500. Is the 107 LSA responsible for that? I don't know, but it is interesting.
Joe Urban
The Thumpr is a 227/241 @ 107 with .547/.531 lift with 1.6 rockers. The bottom line was that the Thumpr (107 LSA) made the highest peak torque, the highest average torque, the highest overall average power and the best average numbers between 2500 and 4500 and the best numbers from 4500 to 6500. Is the 107 LSA responsible for that? I don't know, but it is interesting.
Joe Urban
Registered User
Joined: Feb 2008
Posts: 27
From: Detroit City
From the cams specs published in the article the aggressiveness of the flats was similar or more aggressive than the roller, which was fairly lazy.
Joe Urban
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Joined: Aug 2001
Posts: 1,983
From: Jacksonville,fla
[QUOTE=ENRKyle20;5422751]what exactly does the tight sla mean. QUOTE]
Anything from a 106-111 lsa would be considered a tight lobe seperation. Depending on who you talk to everything from there on would be considered a wide lsa. 112-114
Anything from a 106-111 lsa would be considered a tight lobe seperation. Depending on who you talk to everything from there on would be considered a wide lsa. 112-114
Registered User
Joined: Dec 1969
Posts: 3,499
From: PORTLAND, OR, MULTNOMAH
Just wondering: With that cam and specs, would you experience a drop in vacuum resulting in inefficiency in braking performance? Seems like you would need to get some vacuum assist and throw in some Ls1 brakes. JMHO
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Joined: Dec 2004
Posts: 968
From: Wichita, KS
I've got LS1 brakes on all corners....but there's plenty of vacuum available. You would never know by driving my car that it has a 107*lsa cam in it. It stops quite a bit better than my stock brakes did, and considerably better than my friend's bone stock '00 SS.
Registered User
Joined: Oct 2002
Posts: 969
From: Arkansas
You guys have to remember duration and lobe seperation are just a component of overlap. Overlap is the key component here anyways. A car with a 107 lobe seperation and a 112 lobe seperation can have the same idle characteristic and vacuum.
There are a few guys at comp who know what the hell there doing, but its not anyone on the tech line. They open there 300 page Comp catalog and pic a cam out that "THEY THINK" would be optimum.
The 112 Lobe seperation and EFI comment has to be the dumbest thing ever said regarding camshaft design
There are a few guys at comp who know what the hell there doing, but its not anyone on the tech line. They open there 300 page Comp catalog and pic a cam out that "THEY THINK" would be optimum.
The 112 Lobe seperation and EFI comment has to be the dumbest thing ever said regarding camshaft design
Registered User
Joined: Apr 2004
Posts: 144
From: mobile al
huh???
Comp doesn't have a clue aparently. Car runs very well 224/230 on a 107LSA ran very well on the stock tune. Got PCM4 Less to tune this camand there is still some cam surge between 1500-2500 wile cruising. But I will pay the price to destroy a heads, cam, full exhaust LS1 car
Registered User
Joined: May 2008
Posts: 116
From: Texas
Excellent article on this subject from David Vizard.
http://www.stockcarracing.com/techar...ths/index.html
http://www.stockcarracing.com/techar...ths/index.html
Registered User
Joined: Feb 2004
Posts: 1,309
From: Oshkosh, Wisconsin
I just purchased a used h/c package. Loyd did the work about 3 years ago. I got the heads with 7/16 studs, guideplates, and comp beehive springs. I also got a loyd ported intake manifold.
I have some question about the cam. Im sure its the correct/ideal cam for this package but there is some things I dont understand, mainly the lobe seperation being 107*.. I was talkin to comp cams and he said that fuel injection will not run on anything less than 112?.. hmm. Also, I told them my speca and he recomened a 242/238 @.050" cam with 113* separation.
so, if there somehting not right here or will it compute out once I know centerlines?.. I dont know the exact specs on the cam..
I dont want the cam to hold me back, I kinda feel like 236/236 might>?
the cam says LE2-383 on it. its done on a billet core.
should I just trust that its the right cam for the package?..
I have some question about the cam. Im sure its the correct/ideal cam for this package but there is some things I dont understand, mainly the lobe seperation being 107*.. I was talkin to comp cams and he said that fuel injection will not run on anything less than 112?.. hmm. Also, I told them my speca and he recomened a 242/238 @.050" cam with 113* separation.
so, if there somehting not right here or will it compute out once I know centerlines?.. I dont know the exact specs on the cam..
I dont want the cam to hold me back, I kinda feel like 236/236 might>?
the cam says LE2-383 on it. its done on a billet core.
should I just trust that its the right cam for the package?..
Thread Starter
Registered User
Joined: May 2008
Posts: 856
From: Sheboygan, WI
lol. no.. nothing like that.. I know were good bro.. were straight.. I know its a le2 cam, and I know its on a billet core. but I felt like 236 236 was no agressive enuff from the stuff comp camps told me. but we all know how smart they are. lol.
the main reason for the post was because of the 107 lobe sep. they told me it wouldnt run.. so I posted. and I got my answer.
when I said should i trust that its the correct cam for the package. I didnt mean should I trust the seller. I ment should I trust that loyd chose the correct cam for the package.
the main reason for the post was because of the 107 lobe sep. they told me it wouldnt run.. so I posted. and I got my answer.
when I said should i trust that its the correct cam for the package. I didnt mean should I trust the seller. I ment should I trust that loyd chose the correct cam for the package.