Tubi Test Pipe eliminates risk of fire

Hi all. If I replace the catalytic converter with a test pipe, will it eliminate the risk of fire? (I read it somewhere.) What is the disadvantage of using a test pipe? My car is an '89 328; I've owned it for 15 months but the learning curve is endless.

Thank you.

What you have been told is partially true. If you were to have an ignition failure in one bank, so only four cylinders is firing, then the unburned fuel from the non firing bank might get past to the cat and catch fire. But you would be pretty foolish to continue driving your car when it is obviously running on four cylinders, and you would also be likely to be damaging your engine with fuel washing down the cylinders in the bank not firing. Either way, this is a bit of an overblown problem. It happens, but seems remote on a properly maintained car.

The negative is that you would have to reinstall the cat periodically to pass the emmissions test. Although sometimes you can get "lucky" and it will pass without the cat, if the CO is adjusted just right.
The performance benefit is probably debatable, though you would get some more exhaust noise.

Thank you Dave. You're right, I would probably notice if my car is running only on 4-cyl, ie., sluggish RPM or won't "easily" go beyond 4k rpm.
Just the sight of a burned 328 from a cat fire
(saw it on the "other site") really scared me.
Thanks again.

Hi Ron,

Dave is correct...running an engine that's obviously running really poorly can cause more damage than just a fire, although the guy that refused to pull over and burned his car up caused about the maximun amount of damage possible short of causing a forest fire also or causing an explosion that injured bystanders . For MOST people the chance of a fire is minimal because they are cognisant of their car and how it is performing and deal with issues before the extreme worst case scenario befalls them. There is a small percentage however that can ruin a free lunch and break a steel ball as they say.

Regards, JRV

Thanks JRV.

The cats can cause a fire, even if the car is extremely well cared for. This happened to the PO of my 88 TR. He lives just a few miles from the dealer, and has EVERYTHING done to the cars, by the dealer.........he is their BEST customer. He now has a 355, F40(daily driver), and a 333sp! The fire was small, fortunately.......had the cat(s) and muffler replaced. The problem turned out to be that one of the coil wires disconnected......I check mine frequently.

After a few years of ownership, now my car, I noticed that a bank quite on me.......turned out to be no fuel to one side. It was that common fuel pump to mother board problem.........replaced the board, did some re-woring, and no problem since.

I installed test pipes last summer, and am happy I did.......even gutted the pre-cats.