[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.

[2SS Capt]

Is the LT1 overhead cam or pushrod? I was under the impression it was a overhead cam engine...

[arpad_m]

Originally Posted by Hops

That’s a good video... how do nascar engines rev so high? I think 9k if I remember

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.

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.

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.

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.

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.

Originally Posted by 2SS Capt

Is the LT1 overhead cam or pushrod? I was under the impression it was a overhead cam engine...

It's a pushrod engine, a modernized version of the LSx. You might inadvartently think of the LGX that is a DOHC V6.

[BlaqWhole]

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.

If anything the DOHC engines might actually have poorer MPGs for what it's worth. A lot of those numbers you're talking about that gives them this or that certification are easily manipulated. And it might not really be about the engine. It could be the gear and trans ratios etc. It could be the tune. The cats...I remember Ford used to put 6 cats on the New Edge GTs. So is it a low emissions "vehicle" or a low emissions "engine"? If it is the vehicle then GM could simply slap an extra cat on it and clean the tune up and there you go.

[UnknownJinX]

Originally Posted by BlaqWhole

If anything the DOHC engines might actually have poorer MPGs for what it's worth. A lot of those numbers you're talking about that gives them this or that certification are easily manipulated. And it might not really be about the engine. It could be the gear and trans ratios etc. It could be the tune. The cats...I remember Ford used to put 6 cats on the New Edge GTs. So is it a low emissions "vehicle" or a low emissions "engine"? If it is the vehicle then GM could simply slap an extra cat on it and clean the tune up and there you go.

That's what I am thinking as well. Put on more cats and you are done, LOL.

From what I am seeing on EPA, the grams CO2 per mile is ever so slightly higher on the Mustang than the Camaro, though maybe Camaro has an edge due to the AFM(I used autos for comparison). Emission standard-wise, yeah Coyote is better, but I don't know how that's calculated.

https://www.fueleconomy.gov/feg/Find...40463&id=40325

Originally Posted by arpad_m

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.

Yeah, I don't agree with the metric at all personally, but some people love using that argument... Power per weight is a much more useful measure.

But to some fanboys, these pushrods are garbage even though some DOHC I4 engines are getting very close to LS1 weight.

[arpad_m]

Originally Posted by UnknownJinX

From what I am seeing on EPA, the grams CO2 per mile is ever so slightly higher on the Mustang than the Camaro, though maybe Camaro has an edge due to the AFM(I used autos for comparison). Emission standard-wise, yeah Coyote is better, but I don't know how that's calculated.

https://www.fueleconomy.gov/feg/Find...40463&id=40325

Can someone explain to me how this data on fueleconomy.gov can be accurate, or how to interpret it?

Specifically, the Camaro has a 16 city/27 highway mpg (5.0 gallon per 100 miles) vs the Mustang's 16/25 (5.3 gallons per 100 miles)... yet its projected 5-year fuel cost delta is $4500 vs $2500 for the Mustang, annual fuel cost $2100 vs $1700 for the Mustang etc. This makes no sense to me.

(By the way, the greenhouse gas emissions rating in this same table is 4/10 for the Camaro and 3/10 for the Mustang.)

[ChefBorOzzy]

Originally Posted by arpad_m

Can someone explain to me how this data on fueleconomy.gov can be accurate, or how to interpret it?

Specifically, the Camaro has a 16 city/27 highway mpg (5.0 gallon per 100 miles) vs the Mustang's 16/25 (5.3 gallons per 100 miles)... yet its projected 5-year fuel cost delta is $4500 vs $2500 for the Mustang, annual fuel cost $2100 vs $1700 for the Mustang etc. This makes no sense to me.

(By the way, the greenhouse gas emissions rating in this same table is 4/10 for the Camaro and 3/10 for the Mustang.)

Premium is recommended for Camaro. Regular is what is recommended for Mustang.

Fuel prices as they have it on EPA site.
Premium: $2.83
Regular: $2.17

Camaro: 15,000/20 * 2.83 = $2,1xx
Mustang: 15,000/19 *2.17 = $1,7xx

400 dollar annual difference over the course of 5 years comes out to 2k extra in fuel costs over Mustang.

Ford pretty much does this across the board from what I remember. Rate for power on 93, but fuel economy costs on the window sticker off of 87.

[Idaho2018GTPremium]

Originally Posted by ChefBorOzzy

Premium is recommended for Camaro. Regular is what is recommended for Mustang.

Fuel prices as they have it on EPA site.
Premium: $2.83
Regular: $2.17

Camaro: 15,000/20 * 2.83 = $2,1xx
Mustang: 15,000/19 *2.17 = $1,7xx

400 dollar annual difference over the course of 5 years comes out to 2k extra in fuel costs over Mustang.

Ford pretty much does this across the board from what I remember. Rate for power on 93, but fuel economy costs on the window sticker off of 87.

I'm not disputing this, but do you have actual evidence of this practice? Just curious. For what it's worth, Car and Driver's test of the 2018 Mustang GT A10 was tested w/ regular (indicated in the testing notes), and it ran 0-60 in 3.8 sec and 1/4 mile in 12.1 @ 120 mph. That seems like 460 hp to me on regular.

[ChefBorOzzy]

Originally Posted by Idaho2018GTPremium

I'm not disputing this, but do you have actual evidence of this practice? Just curious. For what it's worth, Car and Driver's test of the 2018 Mustang GT A10 was tested w/ regular (indicated in the testing notes), and it ran 0-60 in 3.8 sec and 1/4 mile in 12.1 @ 120 mph. That seems like 460 hp to me on regular.

Here's a screenshot from Ford's website. On top of that, we already know Ford shows the fuel costs on window sticker with 87. Tricksters!

It says Regular on the sheet, but I have my doubts it ran that time on 87.

[BlaqWhole]

Originally Posted by Idaho2018GTPremium

I'm not disputing this, but do you have actual evidence of this practice? Just curious. For what it's worth, Car and Driver's test of the 2018 Mustang GT A10 was tested w/ regular (indicated in the testing notes), and it ran 0-60 in 3.8 sec and 1/4 mile in 12.1 @ 120 mph. That seems like 460 hp to me on regular.

That car is not running 12.1 with regular gas in it. And I doubt it is doing that even with high octane on anything but a fully prepped track using every trick in the book. 12.1 is a magician's run. That car is more of a mid to high 12 under anything but completely optimal settings. Why don't you trial it with yours? Run 2 full tanks of regular thru it so it switches over to the regular tune. Then run it down the quarter. Then run two tanks of 91-93 thru it so it switches to the high octane tune. Run it down the quarter again. Post the results. I doubt you'll get a 12.1 either way. But at least we'll know.

[BlaqWhole]

Originally Posted by ChefBorOzzy

Here's a screenshot from Ford's website. On top of that, we already know Ford shows the fuel costs on window sticker with 87. Tricksters!

It says Regular on the sheet, but I have my doubts it ran that time on 87.

It didn't. Because if it did then they for sure would have ran 93 thru it a few times, ran better than a 12.1, and posted that along with the 87 octane run. I mean, why nerf the car and then post the results if they could have gotten better results? Unless the switchover tune is only worth a handful of HP and has no effect on performance. Which would be funny because all the Mustang guys running high octane have basically been wasting money. LOL!!

[shaffe]

Originally Posted by BlaqWhole

If anything the DOHC engines might actually have poorer MPGs for what it's worth. A lot of those numbers you're talking about that gives them this or that certification are easily manipulated. And it might not really be about the engine. It could be the gear and trans ratios etc. It could be the tune. The cats...I remember Ford used to put 6 cats on the New Edge GTs. So is it a low emissions "vehicle" or a low emissions "engine"? If it is the vehicle then GM could simply slap an extra cat on it and clean the tune up and there you go.

So here is the thing as simple as I understand it.

For some reason smaller displacement OHC engines, can pass cold start emissions easier than larger displacement OHV engines. Why I don't know, I just remember reading the tea leaves that for the C7 Z06 they wanted to go with a modern 7.0 engine. It made the power they wanted, but it wasn't going to pass cold start emissions. So they went with boost and 6.2L

So despite the fact a OHC engine may be physically larger, something about the design allows it to be more emission friendly. why I don't know that is just what I have read.

[UnknownJinX]

If you want to talk about emissions, I wonder if the idle fuel consumption is higher with a larger displacement OHV engine than it is with a smaller displacement DOHC engine making similar peak power. There is no idle fuel consumption display on our cars.

Sent from toaster or something

[m6-lt1]

Originally Posted by UnknownJinX

If you want to talk about emissions, I wonder if the idle fuel consumption is higher with a larger displacement OHV engine than it is with a smaller displacement DOHC engine making similar peak power. There is no idle fuel consumption display on our cars.

Sent from toaster or something

I’m not 100% sure but it’s probably because you get way more control of the cam timing with a DOHC than you do with a cam in block design with VVT. My guess is the reason why EVERYONE but Gm and dodge strictly make overhead cam engines for their passenger cars is emissions.