06-12-2013, 07:27 PM | #15 | |
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06-12-2013, 07:31 PM | #16 | |
Drives: 2015 Z/28 #533 Join Date: Jul 2012
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06-12-2013, 07:41 PM | #17 | |
Drives: 2011 SS/RS LS3 Join Date: Oct 2010
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06-12-2013, 07:44 PM | #18 |
Drives: Toyota Join Date: Jun 2013
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You probably did not read the posts above or you would have seen that I already answered this. Drag racing has rules that work against any V8 overhead cam cars. In fact, if you read the rules, they prohibit overhead cams in the pro classes. Sort of hard to compete when the rules won't allow it. If you took one of those push rod engines and designed the same engine with an double overhead cam, it would produce more HP and dominate the drag racing class. That's why they don't allow them.
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06-12-2013, 07:46 PM | #19 | |
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06-12-2013, 07:47 PM | #20 | |
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06-12-2013, 07:50 PM | #21 | |
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I change my statement above to say no car on Earth beside GM and Dodge uses push rods. And I still stand by my statement that the pushrod motor is obsolete and does not match up with the overhead cam in performance with the same cubic inches. It is not even close. |
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06-12-2013, 07:54 PM | #22 | |
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06-12-2013, 07:55 PM | #23 | |
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What advantage does smaller displacement give you? There are so many other factors that matter in the real world to the performance of a motor that a push rod motor is superior. Cost Weight Packaging Fuel economy Weight distribution Power throughout the powerband How are all these trumped by displacement when it has no bad impact on weight and fuel economy? |
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06-12-2013, 07:58 PM | #24 |
Drives: Toyota Join Date: Jun 2013
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They are wider because they are using 4 valves per cylinder and two cams per head, which is a much better design than 2 values per cylinder and one cam way down in the block and connected to the values with lifters, pushrods, and rocker arms (lots of valve train wasted energy). I don't think the overhead cam engine is limited on cubic inches. Ford just did not design the coyote to be a large displacement engine. Ford used to have a 427 big block overhead cam engine way back in '60's as a special race engine, so overhead cam motors can have large displacement.
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06-12-2013, 07:58 PM | #25 | |
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The bigger motor when compared to the smaller motor has the same peak hp and more throughout the entire powerband than just at a very few rpm at the top and yet still manages to consume no more fuel with larger displacement and weight less. |
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06-12-2013, 08:01 PM | #26 | |
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The LS3 produces more peak hp and more through the powerband and thus has less moving parts. With a disadvantage of 2 valves per cylinder and no VVT like the coyote. What's better about that? Why focus on displacement? Why aren't you saying wow the LS3 produces more hp with 2 less valves per cylinder? The coyote needs 2 more valves per cylinder and two cams and yet still 6 hp short of the LS3 even with VVT that the LS3 doesn't have. Then with all that crap the motor has packaging problems compared to the LS3 and all those extra parts on top of the motor effect handling negatively compared to one cam low in the block. |
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06-12-2013, 08:06 PM | #27 | |
Drives: Toyota Join Date: Jun 2013
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I don't just care about displacement, but as someone above pointed out, there is no substitute for displacement for making power, all things being equal. I am amazed that anyone would think the pushrod motor is a better motor for performance from a design standpoint than an overhead cam. I wonder why all performance motorcycles use overhead cams if the overhead cam has all of the disadvantages that you cite above. I also wonder why the most fuel efficient small cars use overhead cams if the motors weigh more and get less fuel economy than a pushrod motor. I think people on websites become fans of something even when logic and facts say otherwise. After all, I am on a Chevrolet forum. In short, nothing you wrote above is true and you should know that. |
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06-12-2013, 08:11 PM | #28 | |
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The coyote makes 420 hp compared to 426 hp for the LS3. 426 > 420 hp. Thus the LS3 has better performance. Everything I wrote is true. The coyote motor weights 430 lbs. The LS3 weights 418 lbs. The LS3 is a lighter motor. Having the weight down low in the block like the LS3 has a handling advantage and having the weight up high like in the overhead cam coyote has a handling disadvantage. The coyote motor is larger physically and thus uses more space in the engine compartment. The LS3 is able to fit in much smaller spaces. What have I said that is false? I think people get brainwashed into thinking a particular motor is a better design and more advanced without actually doing some research and thinking for themselves. |
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