LS6-LS2 comparison
Thread Starter
Melting Slicks
Joined: Jul 2003
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From: Albuquerque New Mexico
LS6-LS2 comparison
I just happened to be thinking about it today and wondered to myself; If the LS6 had a 5.7 liter displacement and produced 405 HP then why does the LS2 with a 6.0 liter displacement only produce 400 HP? I know of course that the LS2 produces HP and torque over a broader range than the LS6. I also understand of course that when the C6 coupe was introduced in 2005 it would not have sat at all well with some if the new base model suddenly featured as much or more HP than the more expensive Z06 model of the previous year. That should have become a non issue in 2006 though, since after all the 2001 Z06 only had 385 HP and was raised to 405 HP the next year.
So again, why doesn't the larger displacement LS2 produce more HP than the LS6? Is the LS3 simply an addressing of that issue? The LS3 of course is an even larger displacement. Also does the LS3 feature the 3 valve head design that was discussed around the time of the C6's introduction?
I'm just wondering and figure there are enough better informed members here that could enlighten me.
So again, why doesn't the larger displacement LS2 produce more HP than the LS6? Is the LS3 simply an addressing of that issue? The LS3 of course is an even larger displacement. Also does the LS3 feature the 3 valve head design that was discussed around the time of the C6's introduction?
I'm just wondering and figure there are enough better informed members here that could enlighten me.
Instructor
Joined: Mar 2006
Posts: 147
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From: Snohomish WA
The LS2 does not produce more power over the entire rpm range. Actually, the LS6 was under rated by GM. GMHTP magazine took one and put it on the engine dyno and got 425hp out of it at the flywheel. Everyone always talks about how the C5Z was lighter and had better gearing for the reason it out performs the C6 but no one ever mentions that it put out more power too. Now for a good source on LS6 info go to Corvette Action Center. It has way better info than you will find on this site and I do not mean that in a bad way. And before you start flaming me, the LS2 is a good motor but everyone thinks that 18 cubic inches will make it a world beater. Its not that much really. As for the LS3, that engine is something very special and we are just seeing its first year application. Could we see 450-475hp from the factory?
Instructor
Joined: Mar 2006
Posts: 147
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From: Snohomish WA
And to clarify what I meant by power range, dyno graphs don't mean squat because of variable. What does mean something is timeslips. I have yet to see the C6 fast time threads get close to the C5Z fast times in stock form. This is not a slap on the LS2 but rather someone who believe the LS6 is better. As for the LS3, it has L92 heads and they are not 3valves per cylinder. But they are very similar to the LS7's and flow better than the LS6 version which the LS2 even used.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
The LS2 has the same smaller cam as the 01 LS6 that had 385 HP. There is your answer. The 02 up LS6 had a hotter cam to get 405 hp and they will beat stock C6's, equal drivers, every time. The C5Z's are lighter than C6's and they have a hotter cam.
Thread Starter
Melting Slicks
Joined: Jul 2003
Posts: 2,010
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From: Albuquerque New Mexico
The point of my question got completely missed here. First of all I [U]never[U] said that the LS2 produced more power than the LS6 at any point. What I said was that it produces HP and torque (400 HP/400ft lbs) over a broader range. I also wasn't here to start a pissing contest over which is better or debate over which is faster, a C6 or a C5 Z06. I know that there is more to speed than HP or torque. There are lots of factors such as gearing, CD and weight. All I wanted to know was what differeneces there were that caused one engine to make more HP over another engine. And yes .3 liters is very little difference in displacement. At least Joe G was able to provide more insight and information. I never have expected the C6 with an LS2 to be a world beater. You've got a C5 Z06 and you love it. I get that. Good for you.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
The LS6 and LS2 motors have differnt Computers too.
The LS2 computer system has torque managment, which can not be turned off. Good tuners have made changes so it does not come on as frequently. and a few tuners have been able to make the perimeters so high that the TQ mang will not come on.
But stock for stock.
There have been several ppl who have changed the LS2 motor to run with the LS6 ( LS1 ) compture, put in a good cam, and the LS2 came alive.
For SCCA T1 racing:
an Stock LS6 with stock air box, stock headers, stock cats, but X and straight pipes after the cats. Running on 100 octane can be tuned to 380-385 rwhp. The LS2 with the same set up was running 380-390 rwhp.
The LS2 can come alive, just need to find the right tunner.
The LS2 computer system has torque managment, which can not be turned off. Good tuners have made changes so it does not come on as frequently. and a few tuners have been able to make the perimeters so high that the TQ mang will not come on.
But stock for stock.
There have been several ppl who have changed the LS2 motor to run with the LS6 ( LS1 ) compture, put in a good cam, and the LS2 came alive.
For SCCA T1 racing:
an Stock LS6 with stock air box, stock headers, stock cats, but X and straight pipes after the cats. Running on 100 octane can be tuned to 380-385 rwhp. The LS2 with the same set up was running 380-390 rwhp.
The LS2 can come alive, just need to find the right tunner.
Safety Car
Joined: Jun 2004
Posts: 3,563
Likes: 2
From: Dallas Tx
A big factor in the HP calculation is RPM. On a dyno, HP is not actually measured. The dyno measures torque, then calculated HP using RPM. The LS6 had a number of things that made it rev higher faster. Cam, hollow/hollow sodium filled valves ... Being able to rev higher faster, puts up a bigger hp number.
Combine that with a lighter car, lighter wheels, lightweight supercar tires... and the LS6 in a C5Z felt like a rocket ship.
I needed a new vette in Aug of 04. I test drove a new 05 LS2 C6 when it first came out, one of the first ones the dealer had. That was nice. Then took a spin in an 04 C5Z, holy crap this thing is an animal. Motor revved to the moon, exhaust had a nice growl, *** end sliding around at will ... Got back in the C6, just to be sure, hmm can't hardly hear it run. Nice car, but the excitement level is too different worlds.
The C5Z went home with me and the LS6 remains my favorite motor to date. That motor revved so fast the tach couldn't even keep up with it.
Combine that with a lighter car, lighter wheels, lightweight supercar tires... and the LS6 in a C5Z felt like a rocket ship.
I needed a new vette in Aug of 04. I test drove a new 05 LS2 C6 when it first came out, one of the first ones the dealer had. That was nice. Then took a spin in an 04 C5Z, holy crap this thing is an animal. Motor revved to the moon, exhaust had a nice growl, *** end sliding around at will ... Got back in the C6, just to be sure, hmm can't hardly hear it run. Nice car, but the excitement level is too different worlds.
The C5Z went home with me and the LS6 remains my favorite motor to date. That motor revved so fast the tach couldn't even keep up with it.
Team Owner
Joined: Mar 2001
Posts: 25,889
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From: Virginia Beach
CI 3-5-6-7-8 Veteran
^ It's been covered... smaller cam out of the '01Z and invasive torque management.
Throw a cam, headers, and a FAST 90/90 on an LS2 and they make serious power... more than the LS6 w/ the same mods.
But weight is also important... the C5Z weighs less and has lighter rotating mass... the wheels w/ SC tires are very light.
Throw a cam, headers, and a FAST 90/90 on an LS2 and they make serious power... more than the LS6 w/ the same mods.
But weight is also important... the C5Z weighs less and has lighter rotating mass... the wheels w/ SC tires are very light.
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Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
^ It's been covered... smaller cam out of the '01Z and invasive torque management.
Throw a cam, headers, and a FAST 90/90 on an LS2 and they make serious power... more than the LS6 w/ the same mods.
But weight is also important... the C5Z weighs less and has lighter rotating mass... the wheels w/ SC tires are very light.
Throw a cam, headers, and a FAST 90/90 on an LS2 and they make serious power... more than the LS6 w/ the same mods.
But weight is also important... the C5Z weighs less and has lighter rotating mass... the wheels w/ SC tires are very light.
I also personally find the LS2 computer much easier to tune. There's actually much fewer tables to deal with, but sometimes less is more! The faster computer does a better job catching and holding a good idle even with my G5x3 cam.
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
I also personally find the LS2 computer much easier to tune. There's actually much fewer tables to deal with, but sometimes less is more! The faster computer does a better job catching and holding a good idle even with my G5x3 cam.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
My fancy new street wheels with my Supercar runflats are 60 lbs!!
