87 Samurai Tintop, all stock, is there enough back pressure created by the CAT to protect the valves from burning up if a free flow muffler or even no muffler is installed?

  Thanks,
               DiJiT

I don't know if this will help or not...as I don't know the answer to your question.....but I ran my 1991 Tracker with just a cat and a short tailpipe for almost half a year with no issues, and now I have a muffler and no cat.   And the motors in both vehicles are pretty similar.   My tracker sounds great...doesn't tick or rattle....doesn't burn any oil and create any smoke.

Sorry I can't help further....But I hope you can get some confidence from this anyway.

-Mooch

The only time I would worry about damaging the valves, is if you were running with no exhaust manifold all together.

I too ran a cat with a small piece of tail pipe hanging out, no problems.....just annoyingly loud.


Amilla

I asked a wheeling buddy of mine who works at the GM garage about this.

To check your back pressure on a gas engine you would remove the O2 sensor and thread in a fitting that you use a fuel/vac gauge on.  Shouldn't have no more than 3 lbs back pressure.

I asked a wheeling buddy of mine who works at the GM garage about this.

Quote

To check your back pressure on a gas engine you would remove the O2 sensor and thread in a fitting that you use a fuel/vac gauge on.  Shouldn't have no more than 3 lbs back pressure.

I did not know that, too bad the person i bought my samurai from cross threaded the O2 censor in to the header, its now in for life....

Amilla

You can buy a weld in o2 sensor bung from most supply houses. They're only a couple of sizes. Drill, weld in new threaded bung, install new sensor, so not cross thread haha, and just leave the old one in as a plug. I always put a bit of anti seize in the threads.