I've got 93 R1

My engine mods:
Pettit Intake
rx7store DP
RB Dual Catback

Air pump and stock cat are still installed, and using stock ECU.

Here's the numbers for my test:
15mph
RPM: 1741
%CO2: 14.0
%O: 1.6
HC: 88 MAX, 124 MEAS
CO: 0.52 MAX, 0.00 MEAS
NO: 704 MAX, 722 MEAS

25mph
RPM: 1932
%CO2: 14.6
%O: 0.7
HC: 53 MAX, 110 MEAS
CO: 0.50 MAX, 0.04 MEAS
NO: 738 MAX, 24 MEAS


Took it to a local mechanic who said the cat and spark plugs look fine. (He's not a rotary specialist but he works on my family's cars and inspected them for free.)

From what I've read on the forums the high HC's point to a new O2 sensor among other things. The numbers aren't as high as some of the other tests I've seen posted, so it seems to be a few little things to just get me under the limit.

How can I lower the NO readings? Definitely gonna change the oil again, also.

Drove about a half hour on the freeway before the test, also.

Thanks

 

Yup - new O2 sensor and you should be find.

 

Failed the 2nd time around after new O2 sensor and another oil change. Fixed the NO but HCs are still too high.

New numbers:

15mph
RPM: 1800
%CO2: 14.0
%O: 1.6
HC: 88 MAX, 99 MEAS
CO: 0.52 MAX, 0.01 MEAS
NO: 704 MAX, 173 MEAS

25mph
RPM: 2918
%CO2: 14.6
%O: 0.7
HC: 53 MAX, 180 MEAS
CO: 0.50 MAX, 0.045 MEAS
NO: 738 MAX, 6 MEAS

The tech was familiar with FDs and told me to put back the pre-cat

Gonna change the spark plugs and try a different test station i guess.

 

got to be something else. I got my car passed with DP with almost same mods in your list.

 

How many miles on the cat converter? 80 K is about absolute max before replacement is needed.

 

well... the pre cat should help... but if you have an engine with alot of miles ( ie compression gettin kinda low) you can get a new cat n it still wont pass. fix all the upstream repairs before you go with a new catalyst otherwise ur going to be wasting ur money.

make sure you get the car nice n hot (dont overheat it tho!!!) n leave it running while you wait...

 

+1

Borrow a lower mileage cat (I'm sure there are several people in the CA area who can help) and add some denatured alcohol for the test. You should pass with flying colors.

 

I passed with a Bonez and no precat.

Just in case you can't find an OEM cat, there's another option for ya.

 

Is the air pump actually working? I have no precat and the RB dual-tip and I pass w/ no problems. So, IMO, it has to be extremely rich mixture, bad cat, or bad air pump.

 

I passed with a PFC and hi-flow cat (no air pump inlet).

Something might be not be working if the HC count is still too high.

 

+1 if the 02 didn't fix it, its pointing to the air injection system.

the stock MAIN cats are nearly bulletproof, probably the most durable part of the car

 

All I have to say is "eeewwww.....emissions....."

 

Where in the Bay Area are you located, biznerto?

 

+1 to what everone said, and also, check the ACV. I just passed this weekend with almost the exact same setup as you so its definitely possible (and my cat has 78k miles on it):

15mph
RPM: 298
%CO2: 14.0
%O2: 0.7
HC: 88 MAX, 13 MEAS
CO: 0.52 MAX, 0.14 MEAS
NO: 704 MAX, 127 MEAS

25mph
RPM: 2909
%CO2: 14.1
%O: 0.6
HC: 53 MAX, 12 MEAS
CO: 0.50 MAX, 0.05 MEAS
NO: 738 MAX, 203 MEAS

 

While we're on the subject of emissions.......

I live in Idaho, and they are pretty relaxed about emissions. (No testing required. Ever)

What can I do to my emissions to gain power and not screw things up?

I'm planning on getting a DP, but can I disconnect the EGR and/or air pump without screwing things up?

Eventually, I'll either run a muffler only, or a cat only. I don't need both to keep the noise down.

 

If you want to remove the emissions entirely then you'll need a midpipe, and then you can get rid of the airpump too. I've never heard of any power benefit of removing any other emissions components. Removing the airpump will be a very marginal gain in power (maybe 1-2hp) but will free up space in the engine bay. Midpipe will probably gain you 15hp in your current configuration, assuming you control your boost to the same psi. It'll benefit you more if you are putting out more power.

Personally, I would recommend keeping all the emissions stuff and use the cat to control noise, and get an intercooler, intake, dp, very free flowing catback (or straight pipe like you suggested), and pfc first. Even though you have no emissions testing, you'll be putting out about 100X more pollution without the cat, and you can really smell it outside the car (as in, your eyes will be watering if you stand behind...).

 

Thanks Nathan,

Does it hurt anything if I take off the air pump? I know it pumps extra air so that the exhaust will burn better. Will that effect my oxygen sensor and my air/fuel mixture?

Also, if I understand right, the EGR valve stays closed most of the time anyways, so could I just eliminate it?

 

it wont mess it up
but if you take off the air pump, you will need a different belt
or an idler pulley....

just leave it on with egr, egr just lower your exhaust temperature and airpump with the clutch off doesnt eat up any hp...

or just dont touch your car and and introduce new problems for absolutely no gain....

 

Sorry for such a late reply but I got super distracted and my car was garaged most of the winter during snowboard season.

My cat has less than 40k miles on it. I'm also not much of a mechanic but a friend who owns an FC said my air pump seems to be fine.

How much alcohol is enough if I were to go that route?

I'm currently in the 707 area code.

 

the air pump keeps the cat from melting, AND its OFF over 3000ish rpms.

the EGR system is TEENY (5mm?) it basically is just there for decoration

the restriction to HP is the cat itself, as it causes a little backpressure, and this is bad

 

FWIW, I was able to legitimately pass CA emissions (albeit barely) with a well worn motor that had 104,000+mi. (95-->100# compression ea face) and an FD main cat that had at least 150,000mi on it. I had an airpump, FD main cat, but no pre-cat for that test.

The replacement motor, a Pineapple large street port, was also able to pass the CA tests with an Air Pump and a modified FD main cat (no pre-cat). Interestingly enough, this ported motor posted numbers that were almost identical to the worn-out motor. Neither being quite as good as previous tests performed on a fresh, unported motor. Additionally, removing the pre-cat (I did it years ago) had little or no impact on the smog numbers.

The presence of EGR is inconsequential; it may be needed to pass a visual (if they can find it), but it has no functional role in the [CA] smog tests. What I have found that does make a difference for the tests is an under-driven air pump. If you have a small crank pulley and you're having problems passing, you may want to put the stocker back on for the duration. I think this might help you guys that are right on the edge for CO and/or HC's.

NOTE that it is important that everything be thoroughly warmed up immediately prior to the test. In each instance where my FD did not pass initially, the tech would let it run for 20min before retesting and it makes a difference. According to Mazda's Service Highlights publication, operation of the ACV has several modes (which will affect emissions performance) that are dependent on the operating temps and time in operation. The one time I couldn't pass smog, I replaced the O2 sensor which solved the problem.

Hope this helps someone.