http://www.corvetteactioncenter.com/forums/c4-corvette-zr-1/14104-demise-lt5-engine.html
I'd say they chose right, do you not remember that the ZR1 also cost as much as a current Z06?
Too bad they didn't stick with that LT5...
The contrast between the Gen III [LS1/LS6 engine] and the LT5 engine is striking. The LT5 is both taller and wider, as a result of its double overhead-cam cylinder heads and its complex intake manifold. It became apparent that the next generation Corvette, if it were designed solely around the Gen III small block, could be significantly smaller and lighter than if it had to accommodate the LT5 engine.
Studies based on a large population of modern cars have given us the standard relationship between engine weight and total vehicle weight. Increasing an engine's weight by one pound means that the total car's weight will likely increase by two pounds. We estimated that taking 80 lbs out of the Corvette's engine would allow us to remove another 80 lbs from the chassis. In the case of the Gen III, reducing the engine's length would also contribute significant savings. Weight reduction of this magnitude is only possible when you're designing a car from scratch.
The planned future LT5 engine, with its even more complex valve train, would have been 205 lbs heavier than the aluminum Gen III. Thus a Corvette designed around the Gen III aluminum engine would weigh around 405 pounds less than the same car designed to use the LT5. As a result, the LT5 engine would have had to generate 55 hp more than the Gen III, simply to compensate for the heavier car. With the Gen III generating 405 net hp and the future LT5 estimated at 475 net hp, the effective power gain would have been a mere 15 horsepower. And, given an estimated $25,000 price premium for the LT5 engine, the cost of this small increment of power is astronomical.
The Corvette had reached a crossroads. We could design the C5 around the LT5 engine or we could design a smaller, lighter car that was fitted like a glove around the Gen III small block. By opting for the smaller package, we could achieve ZR-1 performance at the price of a standard Corvette. This was too important an opportunity to ignore. As we explored it further, we convinced ourselves and Chevrolet that this was the right strategy for the next generation Corvette. This, however left us with the conundrum that the far-superior Gen III might seem, to the consumer, to be low tech.
The Gen III uses computer management to control fuel and timing, providing smoothness, high power, and efficiency -- a very high-tech feature, but eariler forms of control -- such as the four-valve combustion chamber -- were what the public perceived as modern technology. We knew that the Gen III LS1 would do just fine without these older features, as they came at such a high price, in terms of size, weight, and complexity. Like the consumer, we had been accepting the notion that complexity was good. Yet, here was one case where just the opposite was occurring. The simple solution was almost as powerful, and it was smaller, lighter, cheaper, and more fuel-efficient. Whether it was considered high-tech or not, the Gen III was the better engine. So, in the end, the only logical choice was to back the Gen III small block as the Corvette's engine of the future -- even if it's roots dated back almost 50 years.
Yeah, but the S63 is a 550 hp engine, BMW will be getting LT1 numbers out of the new M3 next year with a turbo inline 6, which will be considerably lighter.
Considerably lighter? I doubt it.
I am all for this new engine and its incremental improvements. It will likely be very robust like all Chevy small blocks and I doubt that mpg number is correct.
There is no doubt GM took the right path by sticking to a lighter motor, and I'm happy to see now that they have no increased the engine weight, I just think a lot of enthusiasts were expecting a LIGHTER motor this time
http://www.corvetteactioncenter.com/forums/c4-corvette-zr-1/14104-demise-lt5-engine.html
I'd say they chose right, do you not remember that the ZR1 also cost as much as a current Z06?
I feel dumb for not knowing that.
The 90's "LT1" was named after the 70's "LT-1" so I guess GM just loves recycling numbers
I just expected more gains out of going DI.
After all, the 5.0 in the Mustang is making close to 450 horses without DI.
Lighter? Show me the proof, cause right now no one really knows how much this engine weighs, or what BMW engine will weight. LS1 was 409 pounds, which is VERY light.
Yeah but German Engines cost 3-4 times the price of this one. Heck most 4 cyl German engines cost on par with new LS3. M54 from E46 was 375+lbs (add Turbo to that). VERY small difference.
I remember in the early 2000s one of the LOWEST end German 8 cylinders (W8 in the Passat) was 25-30k new. And we are talking worse performance, PITA to work on, not great reliability amongst many other things. I won't even get into the fact that they are a nightmare/expensive to modify.
Germans have a LOT to learn still cause frankly they still haven't learned anything from their WW2 engineering failures.
For now, I suggest they get the basics right.....like say, making a badge that doesn't chip and peels off within 5 years of ownership (BMW).
:biggrin:
Please don't compare an overpriced, overly complex for no apparent reason, overly PITA to work on, overly expensive to maintain and fix German engines.
Considerably lighter? I doubt it.
I am all for this new engine and its incremental improvements. It will likely be very robust like all Chevy small blocks and I doubt that mpg number is correct.
That's also DOHC. I can see the reasoning in saying 'you can't compare HP:L of a DOHC engine.'
I can also see the reasoning in asking why the hell GM is still making a pushrod motor, though. Yeah, yeah, it's lightweight and shit.
...the Ford is 430lbs. The Nissan V6 I mentioned is about 320, I think, without VVT (not sure how much that adds).
These aluminum V8's aren't really that special in the weight category unless you're comparing them to old iron engines of similar displacement.
Oh, and the weights I'm listing are actually complete engines...kind of sick of Corvette guys talking about their 350lb aluminum engine...uh, dude, you need to include more than just the long block and intake. I've seen complete LS1's listed as high as 500lbs or so. I'd bet an LS3 is low 400's at best.
I think the numbers reported must be deliberately low.
If they were well past 450hp in 2007 with this DI "LT1", then they are surely well past that today.
I just wonder why it wasn't put in a vehicle long ago?
I think the numbers reported must be deliberately low.
If they were well past 450hp in 2007 with this DI "LT1", then they are surely well past that today.
I just wonder why it wasn't put in a vehicle long ago?
D/I motors have been having a hard time running without clogging up the intake valves. Audi/VW seen to be really bad with many others like lexus 2.5 having issues as well. Lexus has DUAL injection on their 3.5motor.
I have not seen any major reports about this being a big issue on the GM D/I 6cyl and 4cyl but the V8 is a whole other monster esp since it will be used in performance cars and large trucks. No room for major wide failure there.
Hard to believe they are at the same point as they were in 2007 with this engine.
Yes, the new M3 engine based on the N55 will be considerably lighter then the S63. The link compares it to the 4.4 liter Twin Turbo V8, which is either the N63 or S63 depending on if you're going for the performance variant or not.
The link states it's 40 lbs lighter then the BMW twin turbo V8, big deal. I'm saying the next M3's engine will have a similar hp/tq rating as the LT1 and it'll be considerably lighter then that tt V8 as well.
Why does DI clog intake valves? I would think it would be the opposite, since all that comes through the intake is air.
Or is that the issue? No solvent (gasoline) to dissolve carbon, perhaps? Which I'm assuming would get there from valve overlap?:hmm:
Even if that's optimistic, I would think 400hp+ is reasonable to expect out of a ~5L V8. But at engines of this size, I think arguing over an extra liter is splitting hairs.
That's fine, but my points still stand. You can't compare the 2.