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Why are the Horsepower ratings at 5k on chevy`s site????

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Old 07-24-2008 | 10:12 PM
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GMRULZ's Avatar
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Why are the Horsepower ratings at 5k on chevy`s site????

I don`t understand every car I`ve ever seen is rated at redline. LS3 redine is 6500-6600 I beleive so what gives? Misprint on the site or waiting to post numbers at redline at a later date? It seems to me it must be a misprint as 422 puts it close to the Vette rating of 430 at 6500 I beleive.

Could someone in the know please answer this? Scott?
Old 07-24-2008 | 10:20 PM
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Usually hp peaks a bit before redline. In the Corvettes LS3, peak hp comes at 5900 RPM, peak TQ at 4600 RPM.
Old 07-25-2008 | 12:51 AM
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Horsepower is calculated as (torque*rpm)/5250. If the right combination of torque and rpm to create the peak hp happens before redline then that's what it is.

As CLEAN was saying, the hp peak for the LS3 is at 5900rpm and then starts to drop towards redline:
http://media.gm.com/us/powertrain/en...bination_n.pdf

Last edited by ImportedRoomate; 07-25-2008 at 12:55 AM.
Old 07-25-2008 | 12:56 AM
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5250? Wasn't it 5252? Whatever. I want to see what the numbers are at 2500rpm.
That's a little more important to me than peak power.
Old 07-25-2008 | 01:00 AM
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Originally Posted by DAKMOR
5250? Wasn't it 5252? Whatever. I want to see what the numbers are at 2500rpm.
That's a little more important to me than peak power.
I'm assuming you mean the torque numbers? If so, I'm w/ you, but I would imagine that the graph provided would give you a pretty accurate reading.
Old 07-25-2008 | 01:09 AM
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I think it's a typo IMO. Unless they have changed the cam and other valvetrain items from the LS3 in the C6 there is no way this thing puts down 422hp at 5000 rpm if it redlines near 6600.
Old 07-25-2008 | 04:17 AM
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Originally Posted by DAKMOR
5250? Wasn't it 5252? Whatever. I want to see what the numbers are at 2500rpm.
That's a little more important to me than peak power.
why 2500? for a split second in first gear only? if you mean 2500 because of daily city driving, then looking at what it makes at WOT at that RPM is useless if your wondering about part throttle characteristics. I'd be more interested in what it makes from 4500-6500 range.
Old 07-25-2008 | 07:00 AM
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Torque for around town cruising.
Old 07-25-2008 | 07:50 AM
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It requires 443 lb/ft of torque @ 5000 rpm to make 422 HP @ 5000 rpm (TQ = HP / rpm * 5252). Given that the LS3 in the Camaro is listed at making a peak of 408 lb/ft @ 4500 rpm, it is obvious that something is amiss.
Old 07-25-2008 | 08:12 AM
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Originally Posted by Bob Cosby
It requires 443 lb/ft of torque @ 5000 rpm to make 422 HP @ 5000 rpm (TQ = HP / rpm * 5252). Given that the LS3 in the Camaro is listed at making a peak of 408 lb/ft @ 4500 rpm, it is obvious that something is amiss.
Math is a great thing, isn't it?

Is it possible we're seeing some traditional GM underrating of the Camaro?
Old 07-25-2008 | 08:30 AM
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Originally Posted by Bob Cosby
It requires 443 lb/ft of torque @ 5000 rpm to make 422 HP @ 5000 rpm (TQ = HP / rpm * 5252). Given that the LS3 in the Camaro is listed at making a peak of 408 lb/ft @ 4500 rpm, it is obvious that something is amiss.
That makes sense Bob. I could see the 422hp at 5800 since peak for the LS3 Vette is 5900 and peak torque is a 100 rpm higher also on the Vette. Using the Formula it would take 382tq to make 422hp at 5800rpm which seems like a logical drop off from 408tq after 4500rpm. This is a drop of 408tq-382tq=26tq drop. This is of course assuming the peak torque number is correct at 4500rpm.

Looking at my dyno graph of my stock LS2 it drops 22tq from peak at 4500rpm to 5800rpm. So it looks like they may have a misprint and that 5000rpm peak hp should possibly be 5800rpm peak hp on the camaro. 8`s and 0`s kinda look a lot alike, so I say typo..Note: this is purely conjecture on my part....

Last edited by GMRULZ; 07-25-2008 at 08:32 AM.
Old 07-25-2008 | 10:32 AM
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1967 - two of the big block 427 engine options were the L71 and L88...

If I recall correctly, Chevy showed these specs for the engines:

L71 - HP 435@5,800
L88- HP 430@4,600

Now if Chevy didn't want a bunch of L88's on the streets back then, do you think listing the specs like that, making it radio and heater delete, and charging somewhere around a grand more for the L88 would help?

They didn't mention how much the L88 "woke up" over 6,000 RPM. The engine made the stated HP at the stated RPM...

Is GM listing the HP on the SS Camaro under the LS3 in a 'vette? Has that ever happened before?
Old 07-25-2008 | 10:50 AM
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Originally Posted by IZ28
Torque for around town cruising.
You often drive at WOT lugging the engine in a high gear cruising around at 2500rpm? Your bearings must love you. Ever thought of getting a diesel?
Old 07-25-2008 | 10:57 AM
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Originally Posted by 1fastdog
Is GM listing the HP on the SS Camaro under the LS3 in a 'vette? Has that ever happened before?
So you're saying that if we put one of these on a dyno, we might be pleasantly suprised?
Old 07-25-2008 | 11:33 AM
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Heh...

I'll laugh for a year if they pulled the L-88 stunt again...

Scratch that...

"YEARS". I'd laugh for years.



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