Emissions problem

[torresmd]

OK so I just bought my 930 slantnose and went to get it registered here in Arizona and failed emissions. Well to my surprise the car does not have a cat so it failed miserably.
Here is what the mods are when I bought the car:
Carerra Cams
Garrett Turbo
BTR dual exhaust no cat

I noticed that the O2 sensor is not connected.

So here is my problem, I took the car to a shop who was going to just place a cat on for me and make some adjustments to try to get the car to pass. They called me and said they would not be able to do this since it has a garrett turbo. Different connections.

So what are my options?

My future plans were going to be B&B headers, aftermarket exhaust undecided which brand. So will my aftermarket exhaust work with a garrett turbo or not. I am just very confused right now. So I guess first thing is first. Pass emissions. How i don't know. Change the turbo? then what? Help!!
Thanks,
Steve

[A930Rocket]

Get a used cat and swap the flanges on it so it will fit the garrett. Any other exhasut and you'll have to do the same.

BTW, isn't GHL located in Arizona? I'd go with them on your headers and muffler first. Your close by and service is excellent (I'm a happy customer).

[spuggy]

Originally Posted by torresmd

OK so I just bought my 930 slantnose and went to get it registered here in Arizona and failed emissions. Well to my surprise the car does not have a cat so it failed miserably.

My '78 RoW has never had a cat fitted. It passed the post-registration emissions check in WA after the engine swap (but is exempt from the bi-annual due to age). When I took it to the UK, it passed an inspection there - including the (age-related) emissions portion.

In fact, last dyno guy I used remarked on the gas analyzer output, saying "clean running motor - may be using a lot of fuel, but it's burning it all, nothing wasted".

Without the cat. Just a data point.

Depending on the emissions standards you have to meet, your car may simply be set too rich at idle...

Factory spec gives 2-4% CO2 for a pre-81 930/60, or 2-3 %/1.5-2.5% CO2 for US engine types, depending on year/model.

I find my car runs much better when warming up, or part-throttle driving, at about 3.0 %, but would probably exceed my state's HC limit at anything over 3.25%.

There could be some other issue - like a tough (or non age-related) emissions standard that really needs a cat to pass. Or something that needs to be addressed that's making it not pass.

I'd advise an fuelling/ignition check/tuneup, set the idle CO2 to the low end - say, 1.5% - and drive around carefully off-boost until the motor is good and hot - you may find it'll just sail through the emissions check like that. (Or you may be better off simply connecting the O2 sensor and making sure that that is all working correctly)

Then just richen it up on a gas analyzer until it runs right when warming up and doesn't surge part-throttle under load. Which is where it's running efficiently, and is somewhere around 3.0% on my motor.

If the AZ rolling road test is like the WA one, they'll tell you to shift up if you're making more than 3,000 RPM at the test speed in the gear they originally asked you to be in - so as far as I understand it, idle mixture adjustment is pretty much the only thing in the picture sub-3000 RPM off-boost...

Which would all be a lot less hassle than getting an inspection-only exhaust system, no?

If there's any kind of special flagging that goes on in your state for multiple fails, you maybe want to take it to a shop that knows 930's and has a gas analyzer - for their advice. This free advice may be worth what you paid for it.

[icemann427]

Steve,

I live in Tucson and had a catalyst/muffler combo made just for the annual emission's test in case you want to borrow it. It bolts up to the turbo flange so you would have to remove your aftermarket muffler to use it. It comes with the air pump tie in pipe, too, so you can plug your hose right into it. My car is an 87' so I would guess your 86' system might be the same.

As well, before you go to emissions, go to your local Pcar mechanic and have him lean it down for you while on his diagnostic machine. The combo of the two should get you passed without problem.

Geoff

[torresmd]

Originally Posted by icemann427

Steve,

I live in Tucson and had a catalyst/muffler combo made just for the annual emission's test in case you want to borrow it. It bolts up to the turbo flange so you would have to remove your aftermarket muffler to use it. It comes with the air pump tie in pipe, too, so you can plug your hose right into it. My car is an 87' so I would guess your 86' system might be the same.

As well, before you go to emissions, go to your local Pcar mechanic and have him lean it down for you while on his diagnostic machine. The combo of the two should get you passed without problem.

Geoff

Just sent you a PM!

[Craig 930 RS]

What icemann said - just don't get on the boost much when she is leaned out -

[ZLP]

You don't need a cat, etc. I left you a vm.