Long time lurker, first time poster. I enjoy reading these forums because I am far from being an engineer (so please go easy on me). I'd like to contribute an update and follow it with a couple questions. According to multiple articles, including the one here:
https://www.hagerty.com/articles-videos ... -plane-v-8
the racecar, which must be based on at least 300 produced street cars, will have a DOHC flatplane crank V8 of 5.5L capacity. Thus, unless there is some loophole or waiver, at least some of the new cars will have a similar powertrain. Exhaust scavenging has been commonly mentioned as a reason for the switch away from a pushrod unit. This brings me to my questions.
The benefits of the pushrod seem to be many ( 1) weight 2) low COG 3) low/midrange torque 4) efficiency 5) cost 6) durability). Why would GM move away from a technology in their race car and some of their street cars if it seems to have so many benefits? Is it a combination of the importance of exhaust scavenging combined with the 5.5L displacement limit? If so, then why couldn't GM seek a waiver to run more than 5.5L of displacement in the race car as other manufacturers have done?
My other question is far more open ended. If one were to create a modern "unlimited" series a-la Can Am, would pushrods be the motor of choice due to packaging and the fact that for every additional bit of displacement one adds to an OHC engine, the additional weight and COG would be negate the additional horsepower created via better breathing? For the moderators, I would be happy to take this topic to a different forum if it is required. Thank you in advance!