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Discussion Starter #1
I asked this in another thread, but it wasn't answered. So I will ask again here. What is the real rating of the LS2 motor? The picture below shows it at 395 HP where as I thought it was suppose to be 400. Many have claimed even the 400 was underrated and the real # was somewhere between 407-412. I don't want to compare the LS2 to the LS3. I just want to know facts about the LS2 only. Does anyone know the truth behind this picture?


 

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Better be 400... or else Mike is gonna have to bust a cap:thumbsup:
 

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Discussion Starter #3
TO be honest if it were only 395 I certainly wouldn't loose any sleep over 5HP, but I would like to know the facts.
 

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Hmm...GM Powertrain's website has a PDF you can download with the 2007 Corvette LS2's powerband graph and it shows 400/400.

Link here: http://media.gm.com/us/powertrain/en/product_services/2007/HPT Library/Gen IV/Gen IV Car/2007_60L_LS2_corvette.pdf

Perhaps the difference is that the LS2 is not SAE J1349 certified as some of the newer engines (such as the LS7) are. However, if in fact it really is being underrated at 400 horsepower (as GM has tended to do with most of its engines), then perhaps there is another explanation for the 395 number.

BTW, here is the link to all of the 2007 GM engines. If you click on the link in the "PL" (Plot) column, it will take you to the graph.
 

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The chart showing the LS2 producing 400 HP is based on the old SAE guidelines. The latest chart showing the LS2 at 395 HP (a comparison with the new LS3 at rated at 430 and 436 HP) is based on the latest SAE guidelines used to rate the LS3. Gm engineers at the Bash confirmed the LS2 rates at 395 HP under the latest standards (testing must be witnessed by an independent certified engineer and the test engine must be equipped exactly as it will be sold in the car).
 

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The chart showing the LS2 producing 400 HP is based on the old SAE guidelines. The latest chart showing the LS2 at 395 HP (a comparison with the new LS3 at rated at 430 and 436 HP) is based on the latest SAE guidelines used to rate the LS3. Gm engineers at the Bash confirmed the LS2 rates at 395 HP under the latest standards (testing must be witnessed by an independent certified engineer and the test engine must be equipped exactly as it will be sold in the car).
A-ha...makes sense. The only part that I was surprised about was that folks thought the LS2 was underrated at 400, when in fact it was slightly overrated. Oh well. But I did have the theory about the SAE certified horsepower being the difference:
Hmm...GM Powertrain's website has a PDF you can download with the 2007 Corvette LS2's powerband graph and it shows 400/400.

Link here: http://media.gm.com/us/powertrain/en/product_services/2007/HPT Library/Gen IV/Gen IV Car/2007_60L_LS2_corvette.pdf

Perhaps the difference is that the LS2 is not SAE J1349 certified as some of the newer engines (such as the LS7) are. However, if in fact it really is being underrated at 400 horsepower (as GM has tended to do with most of its engines), then perhaps there is another explanation for the 395 number.

BTW, here is the link to all of the 2007 GM engines. If you click on the link in the "PL" (Plot) column, it will take you to the graph.
 

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I thought the LS2 made 409hp under its original testing procedures.
 

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I thought the LS2 made 409hp under its original testing procedures.
I'm just guessing here, but maybe it's 395 as installed in the car and 409 in not quite that form. I know that Toyota, for example, was running less oil than recommended in their engines for horsepower testing under the less-stringent old rules so there would be less internal resistance. I'm not saying that GM did that, but maybe it's some sort of similar factor.

At any rate, 436 certified horsepower is pretty great. The irony that it's one more than the legendary 427/435 of 1967 isn't lost on me (even though the numbers aren't really comparable).
 

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I read somewhere in a Corvette book that the LS6 made a actually 400hp, but they rated it at 405hp, and the LS2 actually made 409, but was rated at 400 under the old SAE testing procedures. I'll go through my books to see if I can find it.

Anyway, 436hp should give us a hope of a sub 4-sec 0-60 time. IIRC a British mag got a 3.9 time on a C6, but one time is awfully rare.
 

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It's not a big deal, 395 vs 400, at least for me. I for one can't tell the difference between 5 or even 10bhp. Might be a marketing ploy to make the LS3 look even better. Then again, it's already better so what's another 5 hp? Saw the LS6 vs LS2 graph as well which shows the LS2 to be the stronger engine but on the road, the C5Z dominates (due to other factors as well) meaning the LS6 via dyno and track was the stonger engine.
 

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The engineer at the bash said the LS2 data was taken from the Trailblazer SS not the Corvette.
Well then I think that's our answer, someone said that in the last thread too.

It doesn't really make sense for the LS2 to make less with the new testing procedures. If anyone remembers, the LS7 was rated 500 old, and 505 new, but the torque went from 475 to 470. Weird that the LS2 would do the opposite, but then again the ambiguity of never stating an exact horsepower number throws a bag of wrenches in the mix. :huh:
 

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The engineer at the bash said the LS2 data was taken from the Trailblazer SS not the Corvette.
If this is true, then why compare the new LS3 Vette engine with the LS2 in the Trailblazer SS?? Marketing is my guess.
 

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The engineer at the bash said the LS2 data was taken from the Trailblazer SS not the Corvette.
I was at the BB and asked several engineers as to why the LS2 was rated at 395 vs the advertised 400 HP. Most of the engineers did not know but tried their best to come up with an answer. One particular engineer said the old 400 HP rating was not based on SAE standards but the rating used in the LS2 vs both LS3 configurations was based on the same SAE standards. Hence the only conclusion I can draw from this is the relative difference in HP of 35-41 between the LS2 and LS3 is accurate. If you consider the increased displacement, better ports, better head design, larger valves, improved intake, different Cam profile etc, it makes sense to me. I also spent a good amount of time with two of GM's test drivers who's job was to drive the LS3 mules. They both echoed that the LS3 was a lot stronger then the LS2 and the difference was quite noticeable. Neither of them new the answer on the 395 HP rating for the LS2 as compared to its old "400 HP" rating.
 

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15% or 18%

If you beleive there is a 15% driveline loss 576hp or if you beleive there is an 18% driveline loss 591hp:huh:


:cheers:
 

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As long as it's still 4.1 secs to 0-60 with Z51, there should not be any argument.
 

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Bone stock on a Dynojet w/CF: SAE smooting:5
2005 C6 Corvette
350 rwhp 426.8 crank hp

360 rwto /devide by .82 for 18% driveline loss A4 Auto = 439.0 crank torque

It's fast, and going to be a lot FASTER very soooon! 395hp Hmphhhh..:lookinup:
 

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15% loss is not accurate, and 18% is just plain silly. It's less than that for sure.
 
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