Notice some writeups now state LS2 "estimated" horsepower is 400.

Also, 6500 rpm redline, max power at 6000 rpm, 10.9 compression ratio, sounds more like an LS6 than an LS1 to me. But now there's more....

The webcast talked of 13% more valve lift. From the current LS1 lift of .500 that's .565, or more than the current 405 HP LS6 lift of .551.

What sealed it for me was a calculation of the compression ratio. Since compression ratio is cylinder volume at BDC (bottom dead center) divided by cylinder volume at TDC (top dead center). From the bore, stroke and 10.5 compression ratio, the volume at TDC can be determined for the existing LS6. With this same volume, and a bored engine to 4.00, the compression ratio is 10.9

Thus, I am convinced that the LS2 is an upgraded LS6. For reasons stated in this forum, GM wants to be politically correct and not show higher HP at this time, as Z06's are still on the dealer's lots. Besides, why argue with success. Its easy for GM to use the same LS6 heads, increase valve lift slightly, and increase the bore and reduce inlet and exhaust restrictions.

My esimate of the actual power rating: lower restriction inlet and higher valve lift, add about 3%, less exhaust backpressure, add 2%, increased displacement, add 5%, same inlet valve size (2") with higher flows probably reduces volumetric efficiency, deduct 2%.

Bottom line- Expected LS2 output of 440 HP.

 

$40Hp uncapped sounds good to me. :cheers:

 

I like your thinking ;) I have posted that I believe the published LS2 numbers are 5 to 10% below what is going to be delivered. If somebody could nail down the specs of the cam(actual life, durations, lobe seperations), we could definately make a good argument for the actual power based on current numbers for the LS1/LS6 motors.

I doubt the increase in exhaust flow is worth mentioning, since it is extremely small and totally offset by the increase in displacement. I think aftermarket long tubes will still be a desired mod for this motor(even the new cats can be relocated to the collector of a ceramic coated header).

Todd

 

I think the cam is where the ls2 is losing power. It may be more aggresive than the ls1 cam but the motor also has more cubes which make the cam milder.

 

Gee, I came to the same conclusion but used a different method. I used Engine Analyzer, a software engine dyno. It's fairly accurate. I got about 443 hp in corked up mode simulating a stock LS2 in a C6 as I possibly could. But with just minor stuff, this engine will clear 500 hp with bolt-ons.

Chris

 

As far as back pressure, I will guess that the C6 exhaust has less that the Z06: after all, 8 (yes, that's right!!) 90 degree bends have been eliminated due by the new muffler configuration. The new engine also uses two main cats, just like '02+ Z06s.

As far as power output, I think it is really 400. Peak Hp occurs at 6,000 versus 6100 in the Z. If you raise the redline 100 rpm on the LS2 (assuming the cam is specd accordingly, that would yield 406 HP...just like the Z. This is seriously dumbed-down, of course. What this really tells me, combined with the more complex analysis above, is that the LS2 is de-rated. GM has left plenty of potential for future bumps in there. There is an easy 25-30 RWHP in there with minor flow mods...more with a cam and heads. I also think there is serious potential for the LS7, especially if displacement goes to 6.3 or 7.0L.

Guess we'll just have to see what the dyno says. We know the driveline well: it chews up 50HP at 6,000 rpm. So if people are getting 350RWHP, then its 400 crank. Any RWHP on top of that is gravy.

 

Well, the '04 Z06 is getting 365 hp to the rear wheels bone stock so that puts crank hp at 420 hp approx. That means that the current Z06 is underrated by 20 hp. Now the C6 LS2 engine has better flowing intake, better flowing heads with more efficient combutstion chambers, much better flowing exhaust, better flowing headers, higher compression ration and more displacement. If you add all that up, I can easily see the LS2 making 30 to 50 more hp over the LS6 engine. That would put it right around 470 hp at the crank and 400 hp at the rear wheels. Don't be surprised when the first C6 vettes to hit the dyno put 390+ to the rear wheels. GM has severly underated this engine. A clue is they made the manual transmission standard. The automatic requires them to do all sorts of mean tricks to limit power so that the engine won't exceed the transmissions rated max torque capacity, particulary while shifting.

But until the cars go up for sale and someone puts one on the dyno, it's all just speculation. Although if someone could get me actual cam specs and flow numbers for the heads and intake specs and flow numbers for the exhaust, I could run it through Engine Analyzer and get pretty damn close to the actual output. :yesnod:


[Modified by bluemax750, 5:33 AM 1/8/2004]

 

Well it's nice to see that all the experts are coming out of the woodwork to tell us how much power the LS2 really has.

As far as the cam specs and head flow numbers are concerned, hell, they're all over the internet. GM wanted to make sure all that data is out so our hundred dollar PC-based engine simulation programs will agree with their dynos and supercomputer based engine simulation programs.

Duke


[Modified by SWCDuke, 11:56 PM 1/7/2004]

 

Duke,

Maybe you could produce some of the internet links of the LS2 specifics that are "all over the internet." I did a search and went through the first couple hundred results for LS2 engine and most of it relates to the POS Saturn LS2 model.

Todd

 

Yeah, since you've seen them, supply the info for us.

Don't spout off about stuff like this and not be expected to pony up the info. :nono:

 

I was being facetious! Guess I should have added the ;) . Other than the high level data released by GM such as bore, stroke, CR, etc. - the data on the spec tables - nobody outside GMPT knows ANYTHING about the internal details such as valve timing, port flow, exhaust backpressure, etc.

I find it amusing that the rocket scientist wannabes are speculating about "how much horsepower" the C2 has and running PC simulations and hyping the results. You can't run a valid simulation unless you know something about the internal details and even then the results are subject to error.

PC simulation programs are great, but their value is in comparing various configurations, which will generally tell you which is best for your requirements, but they aren't that accurate when it comes to predicting exact values.

Chances are the LS2 is rated fairly IAW SAE J1349, and the peak RWHP numbers that we will eventually see will show it very close, but slightly below the LS6, however, the torque bandwidth will be broader, so it will make more average power below about 4500 revs and more average power over the entire rev range.

Duke

 

Well, call it whatever you want but this is one fact that is very hard to deny.

Bored LS1/LS6 motors respond much better than stroked LS1/LS6 motors because the CC can be modified more and unshroud the valves. Done deal in the factory LS2 motor. #2: The new lift numbers for the LS2(done from the 13% increase stated) are basically identical to the LS6 cam(.551/.547, 204/218 on a 117.5 LSA). If the duration of the new LS2 cam is bascially the same as the LS6 cam, with the better flowing induction and LS2 heads, the LS2 is going to make more power than the LS6. Then you throw in a reduction in exhuast restrictions and you have the basis for my prediction GM powertrain is purposely de-rating the LS2 to keep current Z06 prospective buyers interested.

The Corvette has been the horsepower King with in GM for many, many years and now we have a LS6 motor in a Caddy(Dave Hill himself said this would NEVER happen when the LS6/Z06 combo was announced) at 400 horsepower(but the exhaust is better, less U-bends and the rest is the same basically, so why not 405hp??) and the new C6 is at 400 as well....This leaves the current top performance Vette as the remaining King. Well, IMO, the 400hp rating is enough to attrack the buyers GM wants without alienating the Z06. However, when the C6 is released and somebody throughs one on a dyno, the real truth will be known. I can eat all these words at that time.:smash:

Right now, it is just friendly speculation:yesnod:

Todd

 

I am from the future!! although your prediction was a justly one I have traveled back in time to tell you that you were a little off on the HP prediction. lol just a bored time traveler

 

Ibtl

 

True, but the LS2s are still gettin' it done.