I purchased a set of used Helix non-resonated test pipes from a fellow forum member. I'm not sure exactly for how long, but they were installed on his car for some time.

Now I've read that when you first install test pipes, you will smell unburnt fuel quite prominently for several hundred miles. I'm wondering if this will still be present in test pipes that have already been used? Does the smell go away afer the ECU relearns proper A/F ratio, or is it something inside the new test pipes reacting to the exhaust gasses that causes the smell?

 

The test pipe smell never really goes away totally. Your stock cats are design to catch unburnt fuel and burn it up. Well now that you have test pipes which is basically a straight pipe. Your unburnt fuel doesn't get burnt and it runs through your test pipes into your exhaust system. It burns up the unburnt fuel constantly even after the old fuel is burnt up. Your going to have to deal with it when having test pipes or get high flow cats!

 

A lot of threads report that the smell almost went away after a few hundred miles of driving though.. or is it just the unburnt fuel killing the sense of smell of the drivers in the threads that I've seen?

 

they will still smell. its just a matter of getting use to it.
i have 5k miles on my res. test pipes and i really only notice the smell when i stand behind the car or get something outta the trunk.

 

At first you notice it big time from inside the car a little, with the windows down you can tell a little still, then if you stand behind your car you'll notice it alot more. To be honest I can't speak on others behave but at first you notice it then after I'll say a month you'll barely notice it. It will always be there and I've had my test pipes before X-Mas, so go figure!

 

My theory is that the car will adjust the AF ratio when you change your cats, but it wil take the computer a while to change it so that it isn't running as rich. So even if their used, the smell isn't from the test pipes burning in so to say, but its more from unburned fuel.

 

So how bad is the smell REALLY? I mean does it punch you in the nose when you turn the key, or is it kind of like hmm something smells a little funky, but you can't quite put your finger on it? How bad is it when say, you're sitting at a stoplight with the windows down? Windows up?

Just trying to get a feel for these things before I take the time to install them.

 

Depends which way the wind is blowing. If you're sitting at a light with the windows down and the wind is blowing just right, you definitely get a good dose. I never really mined the smell, but some people that ride in my car complain. If you put the A/C on recirculate w/ the windows up, you won't smell it.

 

It smells and also burns your eyes, lol.

 

The oil film on new pipes will burn off just like a new exhaust.
The unburnt fuel smell won't go a way PERIOD, the computer can't/won't "fix" the smell.
This is the facts!!!

 

It will never go away but Jimmy Cracked Corn and I Don't Give a Damn.

 

I have the same problem, I figure it would exit through the exhaust tips and not from underneath the car where I can smell. Maybe I have an exhaust leak?

 

Thanks for the description, that was very helpful!

 

my teg did'nt have a cat and it was not very pleasing.. girls don't like it for sure..

on a turbo car i notice even when catless the smell is not as bad..