FI Test Pipes Questions.
 

Good day everyone. So I grabbed up a set of FI test down pipes for my G37 sedan. Because they were used I didn't have the flanges or the bolts but my installer used a liquid exhaust sealant for them in the meantime. I believe I'm experiencing a exhaust leak from them but can't be sure. I smell my exhaust even sitting at a light with the windows down. Wondering if this is the new normal sense I know the smell changes drastically with them.

The bigger question I have is I'm experiencing a rattle at cold start at at 65% of the range of throttle, almost tinty with a rasp to it. You can almost hear it under the car and I've asked my installer. He said they checked it over several times and that's the normal sound now. Wondering if this is because I don't have the flanges? Around 3200 RPM it sounds perfect little louder then the old G35 exhaust did. Planning on installing the FI cat back system in the next month.

What should I do? Leave it and see if it gets fixed when I install the Cat back? Or order the flanges and try again?

Test pipes will give you that smell.
Rattle = new installer.

Cats burn up the excess fuel, which is a normal part of the cycle. When you eliminate the catalytic converter, all of that unburnt fuel gets pushed out of the tailpipe and you can smell it.
It actually smells like the car is running rich compared to what you're used to.

Kirk B.

When you say "flange" do you mean "gasket" ?

That's how I understood it. I think he has an exhaust leak because they are not there and no amount of RTV will get it working 100% IMO. And I think the rasp it because it's just non resonated test pipes, even with the stock exhaust your going to have some.

Completely understood the more smell however I'm thinking the installer didn't do it right and I must have a leak because with the windows down sitting at a light the smell just enters the car. Rattle I'm beginning to think it was install error.

Yes I mean gasket. These are what I need to order.

G Sedan HFC/TP Gasket Hardware Kit, Fast Intentions

I don't mind rasp at all, but I'm getting a metal vibration sound at anything more then 25% throttle at any speed, louder the noise at higher RPM. It's boarder line a sound of resonator and a sound of vibration.

I've had it work just fine many times. The trick is to let it set up for longer than the instructions tell you to before you tighten everything down to spec. Most shops want to turn the cars over, so they just slap it on there, tighten everything down and give the car back.

The smell is normal, the rattle (assuming new test pipes in good condition) is not.

I have the same issue with my used FI resonated test pipes. I don't go over 50% throttle or 2600 RPM for the first 5-10 minutes of driving and it goes away once the car is warm. I suspect it's from loosened packing in the resonator. Have thought about just replacing the old resonators with a straight section, not sure they really make THAT much of a difference.

Once you delete your catalytic converters and run straight test pipes you will get the raw unburnt fuel rich smell and a raspy exhaust note it is normal. I hear more times than not people hearing rattles,ticking,etc. noises after a aftermarket exhaust is installed it is not normal. I would choose a different shop to get your exhaust installed at and try again and reinstall everything when you get your exhaust installed. You could also have different test pipes installed.

So I bought the proper gasket kit and had it installed. Sounds a lot better, still have a rasp but it's sound is coming from the exhaust tips so I think its back pressure. Will put it to the test this weekend at the track.