flomulgator

So I searched for quite a while and found absolutely nothing. If something is out there that I missed please keep your flaming to a gentle slow roast.

So I know that emissions are a very tricky, touchy, and important issue in the design of our cars. Many people say because of EPA emissions and CARB that 232 hp is the most a Renesis will ever put out. But my question is, how are emissions calculated?

Thinks I can think of:
1. vol. fuel in --> vol emissions out.
2. vol. fuel in --> vol marker pollutants out.
3. vol fuel in --> unburnt fuel out
4. displacement --> vol emissions
5. total vol. emissions
6. total vol. emissions --> vol. marker emissions.

And any combination thereof. Is the Renesis unfairly screwed by its small displacement? I KNOW that a 6L supercharged 65AMG or a 8.5(?)L V-10 viper put out a hell of a lot more total emissions then the Renesis.

Alt. Q: does Mazda have to option of charging a Gas-Guzzler Tax?

ken-x8

Emissions are not calculated. They're measured. The car is run through a prescribed cycle on a chassis dyno. The exhaust is collected, and various pollutants measured. The regulation specifies grams per mile.

See

http://www.epa.gov/OMS/testproc.htm

for full details.

How do you know the AMG and Viper put out more emissions than the RX-8?

Ken

flomulgator

Apologies; I realize that I did something very bad that you pointed out. I got too slangy and informal and used the word "know" in the emotive sense rather than the literal and correct sense. I don't know. I have not quantified that nor have I read any supporting evidence to that statement.

I don't understand all of what you said, because I don't know what a "chassis dyno" is. I do understand the grams/mile thing though. However, I think something is still missing. I can't imagine that they set the standard incredibly high so that even the Veyron and (probably the worst of them all considering weight and drag) the Dodge Ram SRT-10 can pass this supposed blanket standard with ease yet the RX-8 struggles to make the same grams/mile figure as those cars.

It just seems that it has to be customized to the car, the SAE horsepower, or the displacement. I looked throught the list of PDF's and even skimmed one but didn't find anything but legal code and specifics for testing procedures.

ken-x8

So what makes you think those vehicles put out more emissions? What makes you think the Renesis struggles to meet the requirements? What are the test results for those vehicles and for the RX-8?

The law is not cusomized to the vehicle. Early regulations were written in terms of ppm, but it took a very short time for everyone to realize that made no sense. It's grams per mile, no matter what the size of the vehicle.

Ken

flomulgator

crazy.
I found this page:

http://www.epa.gov/oms/stds-ld.htm

Which also shows that anything that is considered a truck (SUV's included, I'm sure) is held to vastly different standards.

So it can just be comapred to cars. I find it still utterly amazing that vehicles that put out 700+ HP with almost half the gas mileage can still manage to put out less emissions per mile. I guess a rotary is just a dirty dirty engine. Does it have a smog recirculator or is that not possible on a rotary?

ken-x8

So are you just griping about the standards for light trucks vs cars? That's been a mjaor hole in emissions regulations. Are you aware of the huge loophole for turbocharged cars?

Where did you find emissions data for those vehicles vs the Renesis? You're making some pretty strong assertions. You need to show the numbers.

Ken

therm8

http://www.epa.gov/greenvehicles/E-D...ertible-06.htm

http://www.epa.gov/greenvehicles/E-MAZDA-RX8-06.htm

http://www.epa.gov/greenvehicles/E-HONDA-S2000-06.htm

zoom44

as im reading the thread i am going to the epa page and clicking thru to get the links and then i get to therms post and see he already posted relevant links

i wonder where the op searched?

flomulgator- a chasis dyno is a machine which a whole car can be attached to for running various tests. when people say "i went to the dyno and the car made X wheel horsepower" they mean on a chassis dyno. alternatively you can take the engine out of the car and test JUST the engine on an engine dyno.

flomulgator

dangit! forum stopped sending me emails and I missed all this! glad I checked back.

Originally I searched here @ rx8club b/c I wanted 8-specific information but found nothing on this forum. Therm8, thx for those links, that's the best yet.....but it confuses me more. All those vehicles are the same.....yet we struggle? And I go down to the Lambo Murcielago and it does horrendous yet it passes the g/mi mark? And we can't get a few more ponies? Is that a measurement of something different?

I had heard that trucks got a MPG break but didn't know about emissions. Have never heard of the turbocharger exemption. What is that? Didn't see it in the specs listed here:
http://www.epa.gov/oms/stds-ld.htm

Zoom, thanks for the info. Never done a dyno, so I was sitting there wondering "how is a chassis dyno different than a regular dyno? Do they grab a hold of the whole car, spin it, and see if it lands tire-side down?"

Or something like that.....

ken-x8

MPG and emissions breaks for trucks aren't exactly a break - more like a lack of priority 30-40 years ago when the rules were set up. In the 60s and 70s, only people who really needed trucks drove them. The smog and fuel problem was with cars. Part of the growing popularity of trucks for regular folks was that they weren't subject to emissions and gas guzzler regulations.

The turbocharger loophole was interesting. Definitely not an exemption. The EPA urban driving cycle is based on a real route through Los Angeles, later replicated in Ypsilanti. They recorded a car's speed, acceleration and braking for the route. For testing on a dynamometer, they program the car to follow what they measured, but with some simplification. A major simplification is that acceleration is limited to (IIRC) 0.25 g. For reference, when people accelerate away from a traffic light they do about 0.15 g. The acceleration limit on the dyno was because of limitations in what EPA's dyno could handle.

Turbochargers come in at high throttle. At low throttle, the engine may as well be NA. Early emissions-era (i.e., 70s and early 80s - back when they still had carburetors) turbo cars were set up so the turbo didn't kick in during any mode that happened during the EPA driving cycle. At low EPA-tested throttle, everything would be as in the Grandma model. At high power with the turbo pumping they could guzzle gas like crazy, and spew smog like crazy, but it never happened during the cycle EPA measured.

I suspect that these days, with programmed fuel injection and much more development in emissions technology, the loophole isn't quite as bad as it used to be. But the fun range of high performance cars just never gets tested.

BTW - some of my earlier posts in this thread were not worded all that politely. I misinterpreted part of what you were saying, but that's no excuse. I apologize for the rudeness.

Ken

flomulgator

Thanks, but no problem.....I'm used to people being very direct on this forum. In a way it keeps me on my toes and provides incentive for me to think before I write.

As for the turbocharger, that makes perfect sense; I even figured as much but I was thinking there was an actual legal loophole. In fact, I'm not so sure I would even call that a loophole. Sure any car can break its smog limits by hiting the loud pedal, a turbo can just do it a lot worse. I think of those tests as "how little can a car put out?" From there its just the driver's decision. So of course a SC would be worse than a TC, a 5.7L more than a 2.5L on the lower limits.

You check out Therm8's link? Those cars I pointed out came out much worse.....but I'm not sure they were measuring the same thing as g/mi. That's the problem w/ these government sites; you get either a legal code impossible PDF file, or the remove all science, add pretty colors, and add something like "GOV for KIDZ!"

Thx for the historic info, i learn something new every day here!

ken-x8

Yes - I looked at Therm8's link. Very interesting. Even more interesting was following links to the page that said what actual numbers corresponded to the 0-10 ratings. The 0-10 values are kind of a "gee whiz" presentation, exagerrating the actual gram/mile differences.

Just one of them "gov for kidz" deals.

I wouldn't expect the rotary to be a star in emissions. With only Mazda building them for cars, it just does not benefit from the collective R&D that conventional boing-boing engines get.

Ken

flomulgator

I can get behind that statement! People complain endlessly about the poor MPG, but from what I understand the Renesis is a significant advance in efficiency over the last-gen 13b, especially given it's increased power output. But that was like 10 years ago and meanwhile another several billion was collectively dumped in the V-6.