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Originally Posted by Hops
That’s a good video... how do nascar engines rev so high? I think 9k if I remember
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As UnknownJinX said, if they don't have to last longer than a race, pushrods can be, hm, pushed into the higher rev range. Nevertheless, the longer the mechanical activation path, the longer each rotation cycle will take, physics cannot be denied.
Quote:
Originally Posted by UnknownJinX
Power per litre also tends to be higher from the factory with DOHC engines, which is good for countries with displacement tax. In North America, it's a moot argument.
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Absolutely. I don't care much about these artificial metrics (why not power per lb/kg or power per cam then?) and could also come up with any silly random tax idea that artifically penalizes one design over another (cam count tax, valve count tax etc.). The overall dimensions and weight of pushrod engines are typically smaller, so I don't see why taxes should be assigned on the basis of internal dimensions such as displacement. Administrations may have not looked much further beyond the fact that these engines are advertised with their displacements, who knows.
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Originally Posted by Idaho2018GTPremium
How about DOHC vs pushrod on an emissions per hp basis? I'm thinking DOHC designs allow for cleaner exhaust, thus, lower emissions on a per hp basis, but I am not certain. My Gen 3 Coyote (2018 GT) is an ULEV (ultra low emissions vehicle) engine, I think the LT1 in the SS is only LEV...the design might have something to do with it.
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Hm, I'm not aware of any reason why a pushrod design would inherently lead to higher emissions, but I'd be interested as well. Jason's video above does not seem to mention this aspect.
Quote:
Originally Posted by 2SS Capt
Is the LT1 overhead cam or pushrod? I was under the impression it was a overhead cam engine...
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It's a pushrod engine, a modernized version of the LSx. You might inadvartently think of the LGX that is a DOHC V6.