Monty Posted January 5, 2015 Posted January 5, 2015 Full disclosure: I know some stuff about the original series of SBCs, but virtually nothing about these new engines, nor did I care till I took my old 'Vette to a dyno and was embarrassed and astounded by the power the LS street engines can produce. My question comes from an internet argument I saw sometime ago. Basically a pro-Ford guy said Chevy's new LS passenger car engines implemented (he said "copied") a lot of things that were part of Ford's NASCAR engines, most specifically the change in cylinder head design with port spacing now resembling Ford's NASCAR heads. I don't know anything about NASCAR nor do I have a dog in this fight, but I'd be curious what the better-informed on here think about the validity of this guy's claim.
Ace-Garageguy Posted January 6, 2015 Posted January 6, 2015 (edited) Here's a pretty good article on the design and development of the LS engine. http://www.netmotive.net/articles/hib/ls1c.html While the port spacing is similar to some Fords, the bore-spacing is exactly the same as the old smallblock Chebby (even though the LS was a clean-sheet-of-paper design otherwise) and the LS shares bellhousing bolt-patterns with its predecessor too. If you recall, the old big-block Chebby also used even exhaust-port spacing from the get-go. Development of the LS began as a stand-alone engine series (not based on the older design) in early 1993, and the first prototypes were running on the dynos by the spring of that year. While Ford guys may want to say the LS engine had things copied from Ford, the truth about engine design is that what makes horsepower (with decent emissions and fuel economy) is well known by ALL the competent engine designers on the planet, and combustion chamber shape and porting are the most important factors overall. Quoting now from the above-referenced article "All previous, production Chevrolet V8 heads have two distinct intake and exhaust port designs. A unique feature of the LS1 head is what GM calls "replicated" ports. Each intake port is exactly same and each exhaust port is exactly the same. This eliminates combustion inconsistencies between cylinders due to variance in port flow quality and quantity." This exact equality of each combustion and inlet-exhaust tract is critical in producing clean horsepower. And as engines these days are designed first in CAD, using state-of-the-art computer modeling (like CFD, computational fluid dynamics, to simulate gas flow through ports) with today's technology, it's fairly quick to go from computer model to running prototype, and to make development changes. The Society of Automotive Engineers (SAE, of which I'm a member) is the publisher and repository of almost everything known about internal combustion engine design, the body of knowledge is constantly being updated by papers and presentations supplied by the member engineers, and all of the research and knowledge in the field is easily accessed. It's no particular surprise, then, if more than one design team comes up with some similar solutions. Edited January 6, 2015 by Ace-Garageguy
Monty Posted January 6, 2015 Author Posted January 6, 2015 I was hoping you'd chime in because I know you've dealt with issues like this in your business. I found your commentary to be helpful because it takes on some of the ill-founded or uninformed opinions that exist on the 'net, such as the scenario I described. The linked article also makes for worthwhile reading. You gotta love it when the goals call for the new engine to be lighter, stronger, and more powerful with lower emissions, and they pull it off.
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