riffman12

So I recently bought a '86 951 from AZ and now need to get the registration in California.

PO has the cats (main and mini wastegate cat) taken out and replaced with straight piping. Claims he is going to send me the cat that he still has but I am becoming skeptical.

My question is, can I just order something like this?

http://www.magnaflow.com/02catalytic...niversal=36106

And have it welded in to the main pipe to pass smog OK? Does it matter that I won't have the mini wastegate cat?

Already 8 days into my 20 days allowed to get it registered here in CA. Starting to panic a bit

Thank you for your help.

Mike

doabarrelroll

Mine passed with a hot swappable cat. I think it all depends on where you get it smogged. Some places will fail you for a dual port wastegate or anything modified.

LUCKY DAVE

Mine passes with a bolt in aftermarket cat that replaces the test pipe.
If they even ask (doubtful, none of the smog guys have any idea what a 25 year old Porsche is supposed to look like) just tell them that the stock part is NLA.

riffman12

hmm so even if the wastegate pipe bypasses the cat completely it will pass the sniffer?

I guess the wastegate won't be opening on the smog roller...? Unless it's leaky

Brantley

I just passed CA smog today (on my 2nd try). Car is all stock though with original exhaust and cat. Failed the first time possibly due to custom chips causing the car to run rich. Removed the custom chips (weltmeister) and put the stock ones back in. Also, replaced the spark plugs, wires and new O2 sensor and passed. Barely passed the 15 MPH rolling test for HC. Max is 115 ppm and measured was 115 ppm.

The visual test will be fine. They don't know what the stock exhaust should look like so that won't be an issue. Agree... I don't think much will be passing the wastegate. So, get the best / biggest cat you can get on there. Get it really warm by driving around for 20 minutes before the test. Leave your car idling while waiting for the test to keep it warm.

In a previous 951, I passed with a fabspeed downpipe with an SFR drop-in cat. So, it is doable.

Good luck! Let us know how it goes.

Tom M'Guinn

I did pass previously with a small bolt in cat, but subsequently learned it was not technically compliant with the CA rules. The tech who tested the car was fine with it, and the emissions were well within spec, but I wanted to make sure my set up met the letter of the law, so that I didn't have to rely on which tech I got. So I switched to the DEC factory replacement cat, which meets all current CA requirements. See details here:

https://rennlist.com/forums/944-turb...g-success.html

URG8RB8

If you are in the Bay Area PM me, I have a lead that will help you.

riffman12

I believe that magnaflow cat is California legal, and seems to be much cheaper than the DEC units?

Is there a reason for this? Is the DEC a lot better? Am I better off trying to buy someone's factory cat?

Tom M'Guinn

I'd be hesitant to buy a used cat. Most are 25+ years old and not as effective as they once were. There may be a weld-in cat that meets all CA requirements and is cheaper than the DEC. The DEC is a factory replacement from down pipe to muffler and is clearly designed to meet the regs and look the part...

PEvans

It depends a little on where you are. Some localities (AQMDs) have more restrictive limits. If you are in a built-up area that is you, and the limits are a little hard to get under with a 951.

Given that you have to put in a new cat I would do the DEC. Follow Tom's thread including the fix to get it to fit. It will fit and you will pass. You can screw around with alternatives forever, and then you get to do it all over again in two years.

I bought a used OEM cat as a backup. I have no idea how it would actually perform. They are better and as new would last longer than the DECs but I don't think a used OEM is a realistic first option today. I figure if I have to someday I can drop it in to (maybe) pass a test.

pozican

Went through this last February in LA.

You've linked the cat I used. One shop told me it wouldn't fit, the next shop told me that they couldn't put it in because of a "modified exhaust" (they were talking about the wastegate bypass), and the last shop ended up having to mount it at a 45 degree angle so it would fit. I think our cars originally had oval shaped cats instead of oblong like this.

Anyway, no inspector ever checked the numbers on the bottom of the cat, only the paperwork that it passed emissions. Getting through the visual inspection required some smooth talking. Be prepared.

V2Rocket

Use that Magnaflow or the equivalent Walker piece. Print out that whole webpage and highlight the 944 turbo part and take that whole thing with you to the smog test, along with receipts etc.

There should be a model number on the cat, have it installed so that the number is visible from below or the side.

riffman12

I'm having it installed by a reputable shop that says they can assure it has the correct EO# and such. Don't think my smog tech will care too much...I hope not because the car has B&B headers haha

PEvans

The requirements for entry in this business are not high. I had a tech ready to fail my '86 on a visual when it still had its original cat (I halted the test and went elsewhere). Smog checks ought to be a minor inconvenience, but for 951s in CA they are like passing the bar. For me, anything that adds "hope" to all the other variables is unwise.

riffman12

success!

I passed with the Magnaflow cat...but just barely. My NOx levels were pretty close to the limit.

Related: When my car is getting up to full operating temp I am experiencing a climbing high idle. Max of ~1500 RPM.

I'm assuming this has something to do with the high NOx. Any thoughts? Just a vaccum leak? O2 sensor?