Quote:
Originally Posted by 88ls1blazer
 the LS1 block was ALWAYS over priced. an LS2 block is usually ~800 new, and an iron ~500-600 brand new, 2-300 isn't much more.
I have NO idea where you get your HP figures from but LS* guys went bottom 8's 4+ years ago on stock cranks and a stock aluminum block. I am pretty sure in a 3400+ lb F-car it takes more then 1000hp to do so. As far as a C5r block, you would be insane to spend that much for what you got.
please explain to me how NVH is better on iron? Iron is a denser material then aluminum, automatically making it a more efficient transmitter of vibrations.
So in your mind (just to clarify) this is how aluminum looks:
300% more expensive then Iron (because companies LOVE to spend obscene money on parts used to production when a cheaper alternative is available)
Iron is stonger (yes, durability on engines is at an all time high, the use of cast iron is at an all time low... connection anyone?)
an Iron liner is difficult to deal with (companies like to make their workers LESS productive right?)
the aluminum barely helps with heat because it still has an iron liner (even though the iron liner is thin enough to rapidly dissipate heat into the aluminum which then cools at an even faster rate)
And aluminum engines lose combustion efficiency (even though increasing compression ratio with less heat adds efficency when compared to a lower cylinder pressure with more heat)
Am I understanding you logic correctly? |
check the gm parts catalog for hp ratings. i accept that they're conservative...so the lsx is conservatively rated at 2500 hp. whatever an ls2 can withstand for 8.xx seconds, and lsx can handle many times more, and endure much longer. how often do those engines run and last?
the high cost of first run ls1 blocks demonstrates the difficulty in making it. ls3 heads cost $800 new, while gm's own cnc ls2 heads are $2000. lowering mfg costs account for the ls1 vs ls2 price difference. and the difference you quoted is still 50-60%. when mfg will work to cut pennies, $300 is not insignificant.
you obviously have no concept of design vs materials. engines today are designed much better captain obvious. and 99% of aluminum blocks use iron liners - you suggest that aluminum makes it durable. steel has a higher fatigue strength than aluminum - it will last
infinite cycles below ~50% yield stress. aluminum will continually lower its yield stress and fail at a predictable number of cycles. high stress parts are still steel - rods, main caps, fasteners, valvesprings etc. they use aluminum when they can get away with it. will cars today last as long as older cars?
all the ribbing designed into aluminum parts to increase strength and diffuse noise. mfg use coolant to dampen combustion noise. the lighter the part, the more noise it radiates. you'll sometimes find steel weights on suspension arms to dampen resonances. i was talking to a quiet steel rep recently, and he admitted that while the elastomer dampens high frequency noise, you still need mass to dampen low frequency noise.
the movement to aluminum in cars is a direct result of increasing minimum creature comforts, 'safety' devices, economy and size. the aluminum lobbies have a lot to do with it, as well as consumer perception.
so in my automotive engineering mind, from a material standpoint cast iron is just as viable as aluminum...just as i believe 2v are better than dohc in street cars. even aston martin says that 2v are an advantage in racing, and the ls7r wins motorsports engine of the year. a cast iron block ohv v6 imo is on par with a dohc aluminum v6.
c'mon, this is sophomore thermodynamics. even high schoolers learn that temperature and pressure are related - boyle's law. a thin section of material will conduct and transfer heat SLOWER than a thick section. and the boundary impedes heat again. compression ratios above 10.1 DO lower mechanical efficiency, but can be compensated with thermal efficiency. do you understand the distinction?