"Test Pipe" Performance Improvements?

[RRoller123]

Has anyone replaced their catalytic converter with a "test pipe", and can you describe any performance improvements or other changes in engine behavior? Assuming all other systems are functioning nominally, do you get any real gain in performance by doing this?

Thanks for sharing any info on this!

Pete

[81SPIDERMATT]

mine seemed peppier ... but I also increased air flow and put on a better muffler (or so I was told) at the same time I deleted my cat .... I have heard it is a cheap and effective way to get a little extra juice

[RRoller123]

That's what I was thinking too. Really easy, so if it makes a significant difference it makes sense.

Anyone else?

[joelittel]

Mine felt a little peppier too. I noticed a more sporty feel to my acceleration as soon as I opened it up. It's not going to blow your doors off, but it will be more fun to drive.

[toyfiats]

Has anyone replaced their catalytic converter with a "test pipe", and can you describe any performance improvements or other changes in engine behavior? Assuming all other systems are functioning nominally, do you get any real gain in performance by doing this?

Thanks for sharing any info on this!

Pete

The difference between the USA-spec FI Spiders (102hp) and the Euro-spec Pininfarina Spiders (105hp) is only 3hp, with the main difference between the two systems being that the euro cars did not come with a catalytic converter. Assuming yours is still functioning and isn't plugged at all (if its original that's doubtful) you'll gain all of 3hp at the most. It will certainly sound different, but I doubt anyone can feel that small of a real performance difference.

[RRoller123]

Thanks for the info! It also weighs a lot more than the pipe and the cat support system rattles at ~4500-5000 rpms, which drives me crazy. I think it is going. My MA insp people never look for it. But I will save it in the attic just in case....

[narfire]

I didn't notice any difference really after swapping out the cat. I did notice a difference after spending a ton of $$ on the engine though.

[donm]

I had my cat replaced by a muffler shop a few years ago when I bought the car because the welds were broken and it was leaking. The guy pointed out to me the difference between the old style cats like our cars had and the newer style which is more of a flow though design.

The newer style is a honeycomb design and is much less restrictive. I decided to go with it so it wouldn't be a potential reason to flunk my car during the yearly inspections we have here. If the car came with one, technically it must be present or they can flunk you. And also, just in case at some point in the future MA might require emission inspections even for older cars like ours.

[TX82FIAT]

As others have pointed out the old CAT's have a shelf live and often become partially restricted so it feels like the gains are substantial when you put a test pipe on. New CATs are much better. With that said, i took mine off and have a straight back 2.25 system with a resonator and a muffler (no CAT). I think the exhast being opened up with the larger pipes gave me about 5 - 7 hp. I can't really tell because I changed a bunch of things at once.

[redcars]

On my FI 82 I replaced my newer high flow cat with a 2" test pipe. The exhaust is stock front with assa center and rear mufflers. I did not notice any difference in performance. I you want an improvement from exhaust go with a 2.25" system all the way. Don't expect much more that a 5% increase without other work.

[RRoller123]

Thanks for all the info, folks.

[DanD]

I think you would find that all the improvement is in the last 500 RPMs to redline. It doesn't make much difference until you are pushing a lot of flow, and at that time, you will see an improvement.

[RRoller123]

Thanks, not the way I drive it, so I will leave the Cat in. I don't believe it is blocked. But I will get the DAMNED RATTLES out of the support system fer sher...

[bobplyler]

I put one in when the car was about 1-2 years old. Didn't notice any real performance difference, but the cat rattle stopped.

[RRoller123]

I pull away from my favorite Friday night cruise, where the American iron actually loves my Spider and I get many complements and have great friends and conversations! I show it off, run it up through 2nd and 3rd from the stop light at the end of the driveway, and it does that damned noise at about 4500-5000 and I am totally embarrassed. LOL One way or the other, it must stop.