Cyphear

I'm looking to buy a corvette which I would supercharge, and I am trying to decide if I want an LS2 or LS3. Amazingly, I couldn't find any threads about this.

I know the LS3 is a little bigger and badder, but it runs a bit higher compression ratio (10.9 vs. EDITED, I was wrong: 10.7). Do you need to run slightly less boost with an LS3 to keep it from detonating?

If anyone knows of any safe horsepower limits with or without water injection of the LS2 or LS3, that would be helpful. I think 550 to 600 whp would be a good number.

I know the LS3 is a little rarer, so if you think they are much more expensive to replace, that information would be helpful as well.

Thanks in advance!

EDIT: Is it just me, or do the LS3's sound a little meaner? To me, a LS2 sounds kind of like an LS1, and a LS3 sounds a little meaner and lopey, like a LS6/7.

JoesC5

Don't know where you are getting your info, but the LS2 has 10.87:1 compression ratio. The LS3 is less with 10.7:1 ratio.

The LS3 has a stronger block, stronger rod bolts, much better flowing heads.

In my opinion, the LS3 is the better choice for supercharging.

Cyphear

Thanks! I googled LS3 compression ratio, and the first link implied it was 11.3, but once you clicked the link the data was in a chart and showed 10.7:1, as you've stated.

That right there pretty much answers my question.

Anyone know what the safe limits (or records) are with and without water injection?

old motorhead

All else being equal, you can get to your power goals with less boost if you start with an LS3. Less boost = less heat which can equal a longer engine life. A few extra cubes don't hurt the quest either.

JoesC5

Don't know what the "safe" limits are, but a friend has a LS3 with a maggie, cam and long tubes, He's running 6-6.5 pounds of boost(no injection) and with a safe tune for 91 octane is getting around 554 RWHP. Tuned for 93 octane, he was seeing 604 RWHP. He feels comfortable with that, but he is not interested in pushing it further.

bradc6

665 rwhp with my LS2.

http://forums.corvetteforum.com/c6-t...a-vortech.html

old motorhead

That's a pretty good illustration of what can be done with an LS3 and mild boost. I have a similar set up on my LS3. 2 more psi and I'm at 672rwhp. It's been running that way for over a year. I've had drivetrain troubles, but the motor has held up fine. I'm guessing the same set up on an LS2 would be 50+ hp less.

Cyphear

Thanks for the info guys. This is helpful.

With water/meth injection?

TrenAman

LS3 640rwhp rounded up to 7#'s boost, but I also have damn near everything else possible done to my car to get those #'s.. through an A6..

old motorhead

I've considered adding meth, but haven't pulled the trigger on it.

tpereira

LS2 seems to handle boost well... 11psi

0EG@EnglandGreen

LS2 with A&A Vortech + Headers (automatic)


LS2 with A&A Vortech + Headers (manual)


LS2 with A&A Vortech + Meth/Heads/Cam/Headers (manual)


LS3 with EnglandGreen Havoc cam + A&A Vortech/Headers - stock heads, no methanol injection (manual)


LS2 with EnglandGreen Whiplash cam + A&A Vortech/Meth/Heads/Headers (manual)


The LS3 makes power with less parts and at a lower cost.

Stephen

JoesC5

I might add that the 2009 & 2010 LS3 blocks are stronger then the 2008 LS3 blocks. Around 20% stronger in the main bearing webs.

PowerLabs

They use the same crankshaft and have the same firing sequence and will thus sound identical through the same exhaust. For that matter, an LS1 will sound the same as an LS2 or an LS3 or an LS6 through the same headers and exhaust. You are hearing these different engines in different cars with completely different exhaust systems and attributing the sound to the engine, which is wrong.
Also not sure where you got your comp. ratio info from. The LS3 is lower compression, as others have pointed out.

Both engines work great. If you ruin an LS3, the engine block costs 500 bucks more; it is not any more rare; both are readily available for anyone with a little $$$ to spend. The LS3 IS the better engine, with better flowing heads and a little more CuIn, but they both work great, and the money you save by going with an LS2 could go towards headers, a cam, methanol injection, etc...
My LS2 made 597RWHP / 517RWTQ with nothing but a base A&A supercharger kit, headers and a tankfull of 93 octane. I was extremely happy with it.

Cyphear

Thanks for the input. It sounds like you guys are making gobs of power on either block.

I think that bore has something to do with the exhaust sound. The head design definitely does have something to do with the sound (think LS1 vs a modular motor). Having said that, I don't really care enough to argue about it.

PowerLabs

You realize the bore on an LS3 is exactly 1.4% bigger, right? You think you can hear that through the exhaust?

Cyphear

6162/5967 = 1.033, but I think bore has some effect on engine sound, but maybe it's corresponding change in camshaft profile? Bore may be unnoticeable on a LS2 vs. LS3, but I felt like they sounded slightly different when comparing them on youtube. It probably has a lot to do with the headers/exhaust, as you mentioned.

LedfootLarry

[QUOTE=Cyphear;1574728445]6162/5967 = 1.033, but I think bore has some effect on engine sound, but maybe it's corresponding change in camshaft profile? Bore may be unnoticeable on a LS2 vs. LS3, but I felt like they sounded slightly different when comparing them on youtube. It probably has a lot to do with the headers/exhaust, as you mentioned.[/QUO
Are you basing your purchase on the sound of the engine , because the sound will vary , depending on exhaust system & camshaft selected, I would buy the ls2

b16gsr

wowsa digging up a 2 year old thread, he now has a z06 btw

winters97gt

Holy hell batman!