RotorMotor

iTrader: (5)

So i'm up for smog again, and i take my FD into the local smog shop. Everything seemed fine to me so i wasnt too worried. After the test they tell me that my car didn't pass because the CO2 emissions were "too low." I was like WTF wouldnt the ywant them as low as possible? So the guy said that maybe i was cheating and "venting" the exhaust, or that i have a leak in my exhaust system and im sucking in fresh air. I took it home and checked everything out... nothin except a very small rust hole in the muffler (i still have stock everything). So what do i do now... CA wont let me pass untill i pollute more??? Anyone run into this problem? The guy mentioned that my exhaust was somehow getting diluted, and i was like dude it has an airpump which is meant to do exactly that, but he just told me that i wouldnt pass untill my CO2 was higher. So now I'm $35 poored and cant register my car. Any ideas on what to do now? By the way (i dont know if anyone would have any old CA smog checks to compare to) but my CO2 output was 6.8%. Thanks

r0t0r-rooter

Hmm.... I think you need this exhaust system:
https://www.rx7club.com/forum/showth...hreadid=173925

No holes/leaks

RotorMotor

iTrader: (5)

see the thig is i checked for leaks and didnt find any...

rynberg

I would like to hear the smog guy explain how a leak in the exhaust can SUCK in air when you have exhaust gases shooting down the pipe at several feet/minute. You just got ripped off and I would report the smog shop.

You cannot have emissions that are too low to pass, that's BS. If you wait until I get home from work, I'll post my CO2 numbers I just got on my smog last week (I passed BTW).

EDIT: Actually, Rotor-motor, give me a PM. Depending on where you are in the Bay Area, I can direct to a competent smog shop....

RotorMotor

iTrader: (5)

i dont know.. he said its CA law and i believe that much. ive taken other cars to this place and have never been ripped off so i dont see why they would completely BS me. its just the stupidest thing ive ever heard of and im really stumped as to what to do

Kento

take it to another smog shop...

I also would like the shop proprietor (or someone knowledgeable in smog check requirements, if for some inane reason this is true) explain to me how low CO2 levels by themselves could possibly signal a "venting of exhaust" or cheating.

GlassHouseRX7

Move to Ohio, no one cares

rynberg

Ah, but the problem is no one cares to move to Ohio!

r0t0r-rooter

I was gonna say "good kill" until I remembered that the great powers that be which bless us daily with the wonder that is the Forum originate from Columbus, OH....

rynberg

Haha, I grew up in Michigan and lived 5 years in Indiana before moving out here 5 years ago. I still have a right to dig on the midwest, but if any of you Cali-born guys start in.....

Nathan Kwok

The guy is right about the CO2 levels but the reason is probably due to his own incompetance and not the hole in your muffler. He could have the signal wire messed up reading the wrong RPM, therefore your CO2 levels aren't corresponding to the correct RPM (this has happened before), he could also have not attached the sensor properly, causing it to read ambient air. However, I'd go ahead and replace your muffler, I mean, if its rusted so badly it has a hole in it, come on man, get that fixed! The idea behind CO2 levels is at a given RPM, the level of CO2 being put out should be relatively constant no matter how much the car is polluting. CO2 emissions are a function of how much gas is being burned, the only way to reduce it is to run leaner or not combust all the gasoline. If you run learner, you can only lower CO2 levels slightly, as most cars are already tuned for as low CO2 emissions as possible (ie good gas mileage), this includes the RX-7, despite our rich A/F ratios. Therefore the only way to seriously lower CO2 emissions is to simply not burn the gas completely, in which case your HC emissions will be off the scale. Therefore, CO2 emissions are used as a litmus for "cheating" by purposely diluting the exhaust (ie rerouting some of it). Of course, the smog guy can do this cheat for you by improper placement of the sensor so it picks up ambient air. I'd make sure you don't have any exhaust leaks, fix the muffler, and take it back and make sure the RPM signal is correct and that the sensor is attached properly.

rynberg

Thanks for the good info Nathan. Having grown up in an area where half the people didn't even run cats, the whole emissions thing is new to me.....

BTW, here's the numbers for my recently passed smog test. Mods were as in my sig, except on the stock ecu.

at 725/2600 rpm:

CO2 (%): 13.4/9.6
O2 (%): 1.9/7.0
HC (PPM): 26/5
CO (%): 0.00/0.00

RotorMotor

iTrader: (5)

yeah im gonna take it to another shop tomorow...things dont add up. as for the muffler ive been meaning to replace it ever since i bought the car but i keep diverting money to other areas of the car. i've been thinking about the racing beat dual.... rynberg: you have one, are you happy with it? anyone else? i know there are tons of posts on this already, ill go look now... but if you've got one are you satisfied with it after hearing others?

JeffShoots

An FD owner in Ca without a P.O. Box in the northern side of Ca

Do I have to spell it out to you? Or was that plain enough.

RotorMotor

iTrader: (5)

WTF? youll have to spell it out for me... i have no idea what you are talking about... is this even a reply to this post

James Paventi

iTrader: (34)

I bought my RB dual, mild steel used (16K+ miles) for $250 on this forum. I was hoping for a quiet muffler with a slight performance improvement. This is exactly that. The muffler is hard to notice while cruising on a level road, has an authoritative rrrrrrrr under slight acceleration and a raspy amplified version of the stock whoosh. That last part would be my only complaint.

Oh, the Dual polished 3" (I think) tips look great!

I don't have any dyno numbers, but I believe RB claims around 15HP. If you don't care about noise there are plenty of other mufflers out there that lean toward performance over comfort.

RotorMotor

iTrader: (5)

noise is definately an issue for me... i really dont have any desire for a loud car... i mean, do we really need to attract attention to our FD's by making them loud as hell? i dont know... really loud mufflers are... well... kind of rice. like this completely stock civic i saw today with something like a yuban coffee can attached to the back (you could hear it from like a mile away), and a huge silver wing. thats it, just a completely stock automatic civic with a huge wing and exhaust.... it even had hubcaps!!! frankly, i actually like seeing this sort of thing i was laughin about it all day! Anyway, my point is theres no need to show off in your FD with a loud exhaust... the car already shows it self off. Now if you have a 20B under the hood thats a different story... you need the loudest exhaust possible

Johnsrx7

If noise is a problem, then get a Racing Beat dual tip or an M2 dual tip, they are very stock looking, give a good increase in power with a slightly louder exhaut note than stock.

James Paventi

iTrader: (34)

Don't know about the M2, but the Racing beat has the tips in the stock location. The only difference is that they are about twice as big. From a distance you can't tell ... but up close they look Uh Hu Uh Hu good

spooledUP7

I have the m2 exhaust and it is great. I like it more than the RB because I think it looks better. The tips on the RB have some sort of chromesexual sheeth around them while the m2 has two solid looking tips.
The only problem is finding a store that has the m2 in stock.