LS1 not as efficiant as the LS2????
11-09-2006, 09:15 PM
#1
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LS1 not as efficiant as the LS2???? taken from GM high performance
"The new, 6.0-liter LS2 taps into a pair of proven winners in the breathing department: the Corvette Z06-derived LS6 cylinder heads. Compared to the standard LS1 heads, the LS6-style lungs feature raised intake ports and a combustion chamber design with unshrouded valves. This design, GM claims, when combined with the engine's flat-top pistons, produces a more efficient swirl of the air/fuel mixture. This efficiency allows a higher, 10.9:1 compression ratio--vs. 10.1:1 on the LS1 and 10.5:1 on the LS6--helping the engine attain 400 horsepower and, we're told, better fuel economy than the smaller-displacement LS1. "
Ooooooooooooooh, is this last sentence true, is this cube per cube and how efficiant is it compared to the LS1 IF so????
"The new, 6.0-liter LS2 taps into a pair of proven winners in the breathing department: the Corvette Z06-derived LS6 cylinder heads. Compared to the standard LS1 heads, the LS6-style lungs feature raised intake ports and a combustion chamber design with unshrouded valves. This design, GM claims, when combined with the engine's flat-top pistons, produces a more efficient swirl of the air/fuel mixture. This efficiency allows a higher, 10.9:1 compression ratio--vs. 10.1:1 on the LS1 and 10.5:1 on the LS6--helping the engine attain 400 horsepower and, we're told, better fuel economy than the smaller-displacement LS1. "
Ooooooooooooooh, is this last sentence true, is this cube per cube and how efficiant is it compared to the LS1 IF so????
11-10-2006, 12:24 AM
#5
Of course with better flowing heads and flat top pistons you will have more power and better efficiency than an LS1. Also, let's remind ourselves that the 10.1:1 SCR on the LS1 is not the max that the motor can handle. The LS2 can run a higher SCR, sure, but what about the DCR? This gives us no details about the cam, which will dictate what the DCR is in the engine and therefore, how powerful/efficient it can be. I can run 14:1 SCR all day long if my cam has a late enough IVC to produce a reasonable DCR.
Last edited by ArcticZ28; 11-10-2006 at 12:29 AM.
11-10-2006, 08:43 AM
#6
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If they are saying a 6.0 is more efficiant than a 5.7, then, that is interesting, and by how much? My thinking was/is that bigger heads do not always mean better fuel economy, so what was/is it? compression? intake? cam? D, all the above?
11-10-2006, 01:15 PM
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They could make that claim and base it entirely off the fact that the LS2 has more compression, and there would be some truth in it.
The simplified equations from Thermo for efficiency of a IC engine all revolve around compression as the single most important parameter.
Ben T.
The simplified equations from Thermo for efficiency of a IC engine all revolve around compression as the single most important parameter.
Ben T.
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11-10-2006, 05:37 PM
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Since the LS1 is 346 CID and the LS2 is 364 CID (18 CID difference), that calculates to the LS2 having about 5% more displacement. Now factor in that the 243 castings are probably a bit more efficient and the compression ratio is a bit higher for the LS2. If the mass/weight of the vehicle is the same and is driven in a very controlled manner like the EPA mileage test, it could be possible to have a marginally higher MPG figure (let's say .3 MPG) and the claim would be true.
Steve
Steve
