How Many have welded in Catalytic Converters on their SSI's

[Vincent Hill]

I am Welding in 2 small Magna Flow Metallic Catalytic Converters into my 1974 Style SSI's With the O2 sensor I think this should allow it to pass emissions anywhere except California. I cut the ends off which make them about 7 inches long and hopefully will fit. Anyone else do this?

[e p slick]

I just went the other way. Bought a used 993 cat and gutted it. Saved my original for every 2 year smog check. Nice results with eliminated weight and better throttle response. Save the TUNAFISH!

Greenie EPS

[jpnovak]

I know that Ben (M&K Exhaust) made a custom set not long ago.

I have considered doing the same thing. Today's modern, high-flow cats are Worlds better than what was available even 10 years ago. There would be no reduction in flow but sound control would be better.

[Vincent Hill]

Originally Posted by jpnovak

I know that Ben (M&K Exhaust) made a custom set not long ago.

I have considered doing the same thing. Today's modern, high-flow cats are Worlds better than what was available even 10 years ago. There would be no reduction in flow but sound control would be better.

THE Winner! I am Hoping that it lowers the Sound a Little myself. I am using 300 Hole cats and on the Mini Cooper "S" WHen I did the same thing it quited down the Sound a LOT more than I expected. When I get this done I will Post some Pics!

For the Guy with the 993, I already had a 1976 so I was Limited to 1983 and got the deal on a 1982 and took it!

[911pcars]

You'd have more flexibility with bolt-on flanges, yes? I assume this is allowed by the feds.

Sherwood

[darrin]

If I recall correctly from a prior thread, the underlying problem here is that the cats will be sitting adjacent to the cylinder heads and will be transferring a LOT of heat to this sensitive part of the engine. While this arrangement may well allow one to pass emissions tests, it is likely not an ideal permanent install solution unless the heat issue is properly addressed.

[911pcars]

Originally Posted by darrin

If I recall correctly from a prior thread, the underlying problem here is that the cats will be sitting adjacent to the cylinder heads and will be transferring a LOT of heat to this sensitive part of the engine. While this arrangement may well allow one to pass emissions tests, it is likely not an ideal permanent install solution unless the heat issue is properly addressed.

We've got a few sets of these remaining (NLA):


Send me a PM if interested.

Sherwood
Seine Systems

[Vincent Hill]

Originally Posted by 911pcars

We've got a few sets of these remaining (NLA):


Send me a PM if interested.

Sherwood
Seine Systems

Looks Good! Have you seen my thread about your Shifter modification?? You guys have allowed Porsche Owners to shift like Normal People! Thank You I Just realized that NLA (No Longer Available) Thank you for letting me get a set and putting them to some Very good USE!

This is also the reason I used the Off Set spun Cats so that they would be Lower in the Airstream and at the Back of the Engine. Somehow I would think that 2 Small Cats would produce less heat than the one Large on on the left side of the engine along with the reduced Back Pressure of no longer having a cross over pipe using the 2 in and 2 out Muffler. I remember the "Thermo Destroyers" produced a lot of heat also and helped destroy more than a few engines. I may have to make up 2 Heat Shields that would clamp over the top of the Cats to deflect that part of the heat Away from the lower Valve cover. I have sent a PM

Nothing like solving problems Before the Fact!

[MBAtarga]

I thought consensus was that the SC's don't have any problems passing emissions w/o the cat? I recall that's what John Walker has stated anyway.

[Vincent Hill]

Originally Posted by MBAtarga

I thought consensus was that the SC's don't have any problems passing emissions w/o the cat? I recall that's what John Walker has stated anyway.

I can always cut it out and have a tube welded in but my feeling is that it will need the Cat because they use a Dyno and the Sniffer! I do not think the performance will be effected and the Extra Heat no more than what the large Cat is already producing. In reading the report on my car before I bought it, it was always failing inspection the First time. I tuned it up and it passed the first time and I hope to keep it that way! Yes, I am adding 4 pounds (2 on each side) but other than at Idle and not moving, the cats hangine down should run fairly cool and sitting still during testing when they get hotter is only better for emissions.

I think / Hope this all works out because changing exhaust is not my idea of FUN! (At least doing it more than ONCE)

[Scott R]

I just went though this nightmare with my SC. I did not need a cat in the end to pass emissions on the rolling dyno test. And our test is very strict here in Denver.

Going back to CIS, and setting the mixture up it passed fine in the end with the SSI's installed. The interesting part is that I was counting on failing and then returning with the original exhaust installed. Turned out it didn't need it.

[911pcars]

Vincent,
Thanks for your comments, and thanks for the product push. Yes, I've been following that thread for awhile. Glad to hear you and many others are satisfied.

Converters must be up to temp for them to operate as designed. Thus, each should operate in the same temp. range as a single cat. However, with two cats there may be less exhaust restriction resulting in a little more usable torque, but maybe not. Yes, I would suggest additional heat barriers/shields to prevent cat heat from marginalizing the cooling system.

If your inspector performs a typical visual test, you should have a cat-like installation. It depends on the thoroughness of the inspection. The suggestion for bolt-on flanges is to provide an easier transition from cat to no cat, etc. Cutting and rewelding every couple of years can be tiresome and eventually w/insufficient metal to join.

Sherwood

[steve911T]

Vincent, does DC still make you go through emissions on an '82? In Maryland, I think that you get off at 25 years or older. In the county on the eastern shore where I live, I do not have to put anything through the emissions test. On my 89, the cat is hollowed but I do have a back up if and when they come to get me. Steve

[Vincent Hill]

Thanks Sherwood! Yes, Seine allowed me AND My wife to Totally enjoy this Car. I had Never heard of it and I am sure others had not either. or knew exactly what it does and for so few and small Parts who KNEW how valuable they really are! Now they Do Know!

Second, My feeling that Heat is how the Cat works and sitting Still on a Dyno it should work very well, while out on the road it should be cooler and put less heat on the engine. I feel that with your SHield and a Shield Directly Over the Top of the Cat and being at the Rear of the car where the Airflow exits I should be OK.

Steve, YES, Every 2 Years! Even my Old BMW 320I Is tested! right down to the Gas Cap! My Feeling is with the SPec Sheet I can see if this will immediately Pass Inspection (Which I think it will between this and the O2 sensor along with the Fact that I am Splitting the readings.

[midnight911]

mine's not SSI but has the magnaflow cats. I'm in OR and passed emission, going in the line with the car really hot. I don't think the first fail was anything to do with the cats...

[Vincent Hill]

Very nice work Midnight! Talk about having everything at the Back of the car, you have it. I hope mine turns out as nice. I decided to put it all in and IF an SC Does not need one then I really will be OK.

[JJ 911SC]

Originally Posted by Vincent Hill

...Steve, YES, Every 2 Years! Even my Old BMW 320I Is tested! right down to the Gas Cap! ...

Here, we are exempt if the car was not fitted originaly with an ODB.

There is a few house for sale down the street, bring a winter coat

[Vincent Hill]

Originally Posted by JJ 911SC

Here, we are exempt if the car was not fitted originaly with an ODB.

There is a few house for sale down the street, bring a winter coat

I have a Friend that lives in Uxbridge, I am afraid that the Service at the Restaurants is soo bad that it feels like Discrimination back in the 60's here in the USA but they treat everyone that way! I do like driving there. Everyone moving along seriously and not running into everyone! I am From Toledo Ohio Originally so I KNOW Cold. I am actually moving to where I see most of the canadian Plates! Florida

[JJ 911SC]

Originally Posted by Vincent Hill

... I am actually moving to where I see most of the Canadian Plates! Florida

Vincent

As soon as my wife stop buying toys; Das Babe, scissor lift and the latest, Stress Less coach and chair (it better work because after I saw the bill I need to be de-stress...) you will see my plate down South

Here is my plate for the Odyssey:



New Avatar:

[Drdogface]

Originally Posted by MBAtarga

I thought consensus was that the SC's don't have any problems passing emissions w/o the cat? I recall that's what John Walker has stated anyway.

My SC does fine w/o the cat and w/o the belt on the smog pump. Love to put SSI's on so this thread is of great interest to me. In Ca., however, it needs to pass the visual and likely SSI's won't even though the exhaust will be clean. Makes no sense but it's Govt. so.....

If anyone is really up on Ca. smog rules/visual, etc. that can shed some light on this issue I'd sure like to hear it.

Edit: Just took a look at the Magnaflow web site and it looks, at first glance, as if they make one for Ca.