Test Pipes (FAQ)

From Zwiki

Contents 1 General 1.1 What are test pipes? 1.2 Isn't that illegal? 1.3 What else are they called? 1.4 Who makes them for the 350Z/G35? 1.5 Non-Resonated Pipes 1.6 Resonated Pipes 1.7 Potential weight savings? 2 Installation 2.1 Is it hard to install myself? 2.2 Can I install them with my stock exhaust? 3 Sound 3.1 Will my stock exhaust be louder? 3.2 Raspiness? What causes it? Will i have rasp if....? 4 Maintenance 4.1 Will i get a CEL light if i use test pipes? high flow cats? 4.2 Lean/Rich with test pipes? 4.3 Want to get rid of the SES light after removing your cats?

General

What are test pipes?

They are metal pipes that replace the OEM catalytic converters. The biggest restriction in the exhaust system is the cats, and by replacing them with a straight through pipe, you will free up the exhaust drastically.

Test pipes are typically made from steel or stainless steel, although there are a few companies offering titanium versions.

Isn't that illegal?

Yes. That is why they are always labeled "race/track use only"

What else are they called?

The most common term used in the Z/G community is test pipe. however, there are several equally valid names for these such as, cat delete pipes, down pipes, race pipes, etc..

Who makes them for the 350Z/G35?

See our extensive list here: Test Pipes

Non-Resonated Pipes

Resonated Pipes

Potential weight savings?

Installation

Is it hard to install myself?

Are you good in a garage? It took me 2.5 hours the first time.. now i can do it in about an hour.. There are 4 bolts that are very difficult to remove (upper bolts near engine)

Can I install them with my stock exhaust?

Yes. I have stock exhaust with test pipes.

Sound

Will my stock exhaust be louder?

Yes. If you go with straight pipes, your exhaust will be louder and there will be a strong raspy noise around 3500 RPM. You can go with resonated test pipes and 90% chance will eliminated the raspy noise. I found that different combinations of exhaust react different to test pipes.

Raspiness? What causes it? Will i have rasp if....?

There are a few different reasons for rasp. One of the reasons is proper backpressure (i'll elaborate on that as well). Another reason is the bends and shapes of the part, this contributes to how it will sound. And one more reason is what the material it is made out of is. Yet another reason for the exhaust sounding raspy is how the muffler muffles the exhaust. And of course, all of this together contributes to how it will sound.

Maintenance

Will i get a CEL light if i use test pipes? high flow cats?

You may with test pipes, however, there are some options you can use that will trick the ECU into thinking that everything is fine with the O2 sensors. I'll elaborate on what you can use in the next paragraph. High-flow catalytic-converters should not set off a CEL, but if it does, I recommend checking to make sure it is installed properly first, and then try the following if it does not work.

Lean/Rich with test pipes?

Usually the engine will lean out when you modify any part that increases air flow. "Lean" means that there is more air flow at a given load than what the ECU is supplying fuel for, so there is more air than the ECU thinks there is, and the ECU isn't adjusting injector duty cycle (how much fuel is being used), therefore, your combustion chamber and piston cycle is not being as efficient as it could be.

Want to get rid of the SES light after removing your cats?

MIL eliminators or the Help! method here: Tutorial:Stop_CEL_With_Test_Pipes