While it isn't advisable to run a street car with no catalytic converter, you would need the spacer with a 90 degree bend in it. The rear O2 sensor is a snug fit anyway and there is little to no room to add a simple spacer. You would be better served with something like this:

 

 

I have tried 90% spacers as well as a harness with a capacitor and resistor being in place. I have a friend that says a 45% offset will work. I also have an Ultragauge that I monitor the O2 voltages with. I am thinking there is both a range that the ECU looks for and also a time interval of the range under WOT. The harness I spoke of works very well with warmer weather and after the engine temps are at operating range. It is under WOT when cold that a CEL will come on regardless of the spacer that is why I am thinking there is a time interval involved as well.

I have an OEM section that I install come vehicle inspection time

 

 

I have had codes thrown with the 90.

 

 

 

So,
is there an answer to this?

Would something like this work?
https://www.ebay.com/itm/45-Degree-C...-/263680812262

Or something like this?
https://www.bimmerworld.com/Oxygen-S...r-E36-MZ3.html

I've read some stuff about a slight loss of torque after de-catting,
is that true?

I've heard some people say that the exhaust sound may become raspy and hollow sounding, but I'd guess it depends on what the system is.

This one sounds damn good imho:

 

A 200 high flow cat also has a nice sound.

 

this high flow cat appears to be want I'm looking for. I'm putting in a careless down pipe and I'm relocating the cat under the car. I'm doing this for several reasons, one being to install the high flow cat.
What is a 200 high flow cat?

 

Quick Google search found it, 200 "cell" high flow cat 👍

 

Yeah, I looked up the high flow cat too --- a little surprised they can be had for so inexpensive.

But will they work?

Or will they throw a CEL?

Even some of the big name headers with a sports cat have had problems with their aftermarket cats triggering CEL.

 

Does anyone stateside do up something similar with a stock cat like 1320 did with their Tom-Cat?

https://www.1320.co.uk/the-tom-cat-f...peed-manifolds

It has been proven effective with many good reports.

Alternatively,
back to the spacer/simulator thingies...

...a trusted NAM member said one of these:

https://www.summitracing.com/parts/v...BoCvlUQAvD_BwE

...worked well in his application:

https://www.northamericanmotoring.co...ml#post3971756

.

 

 

 

Interested in sound clips as well as I live in Florida with no emissions laws...

As for heat shields, honestly, you can get away without them on a catless car because the heat is much lower. A catalytic converter works on the principle that it gets insanely hot to burn any residual combustible gases in the exhaust. THAT is majority of what the heatshields are for. By removing the cats, you reduce temp greatly in that area. Now, that being said, if there are brake/fuel lines in close proximity, you'd still want heat shields for that reason.

In terms of experience, I had a BMW X5M and I installed catless downpipes (twin turbo V8, turbos in the Vee and cats RIGHT behind them against the firewall). The underhood temps dropped dramatically just by doing this, it was unbelievable.

I don't have experience with the O2 spacers, but I'd be curious to their effectiveness, this would make me much more interested in getting a header or punching out the stock cat...

 

currently out of town, its actually not that loud at all having a 1 ball mod.. no droning on the interstate. I'll get one as soon as I get back Home this sun.
As far as the heat shield goes, I took the rivets out and did a little bending and put it back on