Darwantae951

I need inspection, too Danny! I'll soon have the lindsey 3" with XR-1 and no cat...maybe I should get Lindsey's sport 3" cat. Either way keep us updated (at least the Texans out here) as to what you do to get her to pass!

-Darwin

Jeff N.

My 90 BMW 535i has passed Wa state emissions with no cat. Rolling road test. Car's has a modded engine, chip, MAF conversion.

I think the key is a good tune and a stoich mixture at idle and low speed throttle. As far as I know, they never check at WOT.

Ian Carr

My car passed CT emissions with no cat... one of the limits was 1500, my car was 1495 LOL

Keithr726

My smog is coming up in october, I think. I bought the car last year a week after it was smogged so I may have to do it this year. If I do, I'm going to have a shop install a SFR or lindsey exhaust with removable cat and sell my bursh testpipe.

944Fest (aka Dan P)

Yes, I researched this option, but it kind of sucks dealing with the bureaucrats in Columbus. 2 years ago I tried, but my car was not on their "collector" list. Other guys I know who went this route years ago told tales of having to document it's rarity, so it fits in the collector category, mail off forms and then wait a month, and then no more 944Fest plates, etc. The e-check is FREE so it can't hurt to try. I'd rather lean out my mafterburner 10 or 20% just for the roller test, and then click it back to rocket mode. There really is no "easy" solution, but your suggestion is definately the default option. Any suggestions where to set the tune would help.

danny951

Someone mentioned reducing the timing.. this can be done with most aftermarket chips as well as stock chips, correct? using the gas quality selector on the DME? How exactly does this help me with emissions though? (I really don't know)

lee101315

What do you guys plan to do about NoX? You can lean out the mixture as much as you please, if your state is sniffing for NoX... YOU WILL NOT PASS WITHOUT A CAT.

944Fest (aka Dan P)

My concern exactly. I have heard of car passing without a cat, how did they do it?

lee101315

Some states do not test for NoX, only HC and Co.

Cory9584

I think nox goes down when you retard the timing

lee101315

Sure, ignition timing helps. If you lower the coolant/cylinder temp, it will also go down. The point is, when a car has a defective cat ( read defective, not gutted ) NoX readings can be up to 1500ppm higher.

Adjusting the ignition timing and lowering the coolant temp would help a car that was on the borderline for NoX emissions, but it will not compensate for a test pipe.

Some states only test HC and CO, I hear about people in the midwest claiming to pass emissions with no cat. I dont hear anyone from NJ or CA claiming that.

Cory9584

i got by in jersey with another car that had a gutted cat. I retarded the timing to the point the car had no power at all for the test

Laust Pedersen

In CA we have a visual inspection as well where they (should) look for the presence of a CAT.

But what is the talk about “leaning out”. The Motronic should be in closed loop mode under testing and therefore automatically adjust to stoichiometric AFR.

Laust

lee101315

Thats probably because the car was equipped with an EGR system.

Although anything is possible, I would like to see a 951, gutted cat, pass state inspection on the rollers. At idle, you may get away with no cat but probably not on under a load at 25- 50mph

cpt_koolbeenz

I passed in CO with NoX, HC, and CO without cat. No dyno though...