[ChevyRules]

Originally Posted by arpad_m

Two things, however. First, you pretend that there is a clear OHV to DOHC evolution and derive your point of "innovate/evolve or die" approach from it, which I don't see. These have traded blows over decades and as I said, they have both advantages and drawbacks. Incidentally, monstrosities like displacement taxes in Europe strongly favor DOHC, but one you quite simply introduce overall size or weight or material use or design complexity taxes that would then favor OHV configurations—either way, this is arbitrary and quite biased at the moment, since instead of a real world metric (such as size, weight or fuel economy), it focuses on an arbitrary sub-spec (cylinder displacement).

Also, mandated and less and less achievable fuel economy standards are clearly targeting the mandated phasing out of ICE engines, similar metrics could be devised if someone hypothetically wanted to phase out EVs (say, maximum battery size, overall powertrain weight or minimum charging time that are relentlessly made more impossible each year).

Second, cold start emissions—I will admit that I'm out of my depth here, but I could never understand why the first 10 or 15 seconds after cold starting an engine matters so much. It doesn't feel like a frequent occurrence even when multiplied by the number of vehicles on the road, considering a typical runtime per trip, and even less when considering trip interruption counts and the fact that these are typically followed by warm starts. In other words, why do the regulators care so much about cold start emissions? @Martinjlm, do you have any insights perhaps?

I will fully admit my points fully rely on rumors of Gen VI being DOHC are accurate. Hence why my initial post said if rumors are true, it would likely be due to big displacement engines having issues with cold start emissions. I am only laying out the reasons why GM would make the architecture change. Not coming here going, " DOHC is superior and OHV sucks!". it was then did the reply to my initial post went down the hand wringing route claiming it was the destruction of the industry.

If Gen VI ends up remaining OHV and can meet 2027 emission regulations, great. I am not invested in either architectures. As you say both have their pro's and con's.

And it isn't so much an OHV vs DOHC as it is displacement. It's displacement that causes the cold start emission issue. Since DOHC's can breath better, they can have a smaller displacement for a similar power output as an OHV engine that needs displacement to make power.

[m6-lt1]

Originally Posted by arpad_m

Second, cold start emissions—I will admit that I'm out of my depth here, but I could never understand why the first 10 or 15 seconds after cold starting an engine matters so much. It doesn't feel like a frequent occurrence even when multiplied by the number of vehicles on the road, considering a typical runtime per trip, and even less when considering trip interruption counts and the fact that these are typically followed by warm starts. In other words, why do the regulators care so much about cold start emissions? @Martinjlm, do you have any insights perhaps?

Not an expert on this but I know for a fact that for catalytic converters to filter out harmful emission particulates they have to be SUPER HOT. This is why they are placed where they are (as close to the engine as possible) so that they heat up faster. While I don’t have the data to back this up, I wouldn’t be surprised at all if our LT1’s put out more emissions during the first 3-5 minutes than they do during the next 30 minutes of driving.

[2023ZL1]

RUMOR IS GM'S EV BATTERY SOURCE IS THE BIG ISSUE.
NEW V8'S WITH HYBRID SYSTEMS WOULD BE FINE BY ME.

[Martinjlm]

Originally Posted by m6-lt1

Not an expert on this but I know for a fact that for catalytic converters to filter out harmful emission particulates they have to be SUPER HOT. This is why they are placed where they are (as close to the engine as possible) so that they heat up faster. While I don’t have the data to back this up, I wouldn’t be surprised at all if our LT1’s put out more emissions during the first 3-5 minutes than they do during the next 30 minutes of driving.

Nailed it.

[Martinjlm]

Originally Posted by 2023ZL1

RUMOR IS GM'S EV BATTERY SOURCE IS THE BIG ISSUE.
NEW V8'S WITH HYBRID SYSTEMS WOULD BE FINE BY ME.

GM’s battery source is GM. Honda’s battery source is also GM.

[Gen6cyl]

Maybe my favorite car was my 06 Acura rsx-s. Running the k20 from 6k to 8.3k rpm is something that was great. Stock it would run 145 mph and had no over driven gears. Surely and engine like that could do good with emissions if run below 6k rpm.

[arpad_m]

Originally Posted by m6-lt1

Not an expert on this but I know for a fact that for catalytic converters to filter out harmful emission particulates they have to be SUPER HOT. This is why they are placed where they are (as close to the engine as possible) so that they heat up faster. While I don’t have the data to back this up, I wouldn’t be surprised at all if our LT1’s put out more emissions during the first 3-5 minutes than they do during the next 30 minutes of driving.

Originally Posted by Martinjlm

Nailed it.

I see. Are there any actual numbers anywhere to help me to put this into perspective? What little I've found online indicates that moderns cats typically come up to max efficiency temperature (300 °C/570 °F+) after the first minute and half, two minutes.

[DaveC113]

I think cats need to be warm enough to be effective in 60 seconds. IMO this isn't enough time and mfg'ers have to do too much to achieve this for what it's worth. There gets to be too much gas in the oil, some engines need an air pump and the location of the cats needs to be very close to the motor.

[Casper the friendly G]

Originally Posted by 2023ZL1

RUMOR IS GM'S EV BATTERY SOURCE IS THE BIG ISSUE.
NEW V8'S WITH HYBRID SYSTEMS WOULD BE FINE BY ME.

Most of resources to make the batteries come from African mines under the control of China via child slave labor....sad. Thats the problem...the US would be and is to dependent on China now. EVs will never work out in the near future...watch and see. ICE ain't going nowhere!

[LT4Greg]

I agree Casper!

[Alan47717]

Originally Posted by m6-lt1

Not an expert on this but I know for a fact that for catalytic converters to filter out harmful emission particulates they have to be SUPER HOT. This is why they are placed where they are (as close to the engine as possible) so that they heat up faster. While I don’t have the data to back this up, I wouldn’t be surprised at all if our LT1’s put out more emissions during the first 3-5 minutes than they do during the next 30 minutes of driving.

Of course it's dependent on how cold the cold start is, but it's probably a lot longer than thirty minutes. And it isn't just the total emissions. Getting the converters "lit" is one of the most significant factors in converter life expectancy. Therefore, smaller displacement to get the same power results in less excess cold start fueling and so on.

[Number 3]

Originally Posted by Casper the friendly G

Most of resources to make the batteries come from African mines under the control of China via child slave labor....sad. Thats the problem...the US would be and is to dependent on China now. EVs will never work out in the near future...watch and see. ICE ain't going nowhere!

Your post reminds me of the Mony Python Holy Grail, sorry.

https://www.bing.com/videos/search?q...6FORM%3DHDRSC3

I'm not dead. I'm getting better.

As for mines and pictures of the children? Well if you have something valuable that can be dug out of the ground by child labor, it's going to be dug out of the ground by children to make someone some money.

But simple sloothing would indicate the largest supplier of Lithium is actually Australia not Africa with Chile second (laregest known reserves). But if you are anti EV, the pictures of the kids makes a better narrative. Pretty sure the largest producer has child labor laws like we do.

https://www.worldatlas.com/articles/...the-world.html

[Joshinator99]

Originally Posted by Number 3

Your post reminds me of the Mony Python Holy Grail, sorry.

https://www.bing.com/videos/search?q...6FORM%3DHDRSC3

I'm not dead. I'm getting better.

As for mines and pictures of the children? Well if you have something valuable that can be dug out of the ground by child labor, it's going to be dug out of the ground by children to make someone some money.

But simple sloothing would indicate the largest supplier of Lithium is actually Australia not Africa with Chile second (laregest known reserves). But if you are anti EV, the pictures of the kids makes a better narrative. Pretty sure the largest producer has child labor laws like we do.

https://www.worldatlas.com/articles/...the-world.html

Believe the OP was referring to Cobalt being mined by children in the African mines, not Lithium. There was a big news story that broke recently about it.

[Gen6cyl]

Maybe it's time for electric pre heated cars.