3" Exhaust on V6?

[Phoenixx]

Someone told me not to go over 3" for backpressure reasons but i found a SLP Loudmouth CatBack really really cheap, only problem is its a 3" would this be okay to do without having to worry about messin up my car? Thanks In Advance for Any Advice!

[MunsonGTA]

i wouldn't use it but it's up to you really. i doubt it'll hurt your motor. it's going to most likely sounds like crap though. it's a v8 exhaust being put on a v6 car. it's not going to give your car a rumble or anything. your exhaust will sound somewhat like it does now, only ALOT louder.

[ConElite]

An old system out of a TA or Z28 would do good. and cheap plus it flows more than stock. 3" is to big if u ask me.

[Christopherrr]

You'll hate the sound from it without headers, ypipe and some head work if no cam. 3.8's are raspy muffled...open it up and it'll sound like a cat out of hell.

[Z Ya Later]

Get a used stock V8 cat-back. I run the Loudmouth on my Z and it is what it says it is...loud. Without a V8 breathing through it, you will hate the sound.

[Injuneer]

A modern fuel injected engine does NOT need "backpressure". It was a problem with a carb'd engine, because reducing back pressure does improve breathing, and that means you have to adjust the A/F mix on the carb to avoid leaning it out and losing HP. But a modern electronic fuel injection system makes those adjustments for you.

That said, if 3" catbacks are fine for 300-400HP setups, you probably aren't going to see much improvement in performance on a V6. But it won't "hurt" performance. Backpressure is a myth.

[Joe 1320]

A 3" exhaust on a V6 will give it a hollow drone, you will likely hate the sound. My GN requires uses two inline Walker Ultra Stainless mufflers to try and cut the cruise drone. Even with that it can get on your nerves. I've had several exhaust systems, the 3" single is the one that made it start to drone.
The best V6 exhaust sound I've heard was a Borla Muffler back system. It is not the 3" adjustable cat back, it's a simple muffler and tailpipes originally made for the 93-94 Z28 as well as the V6. i've got one on mine and it doesn't produce the typical V6 growl, it sounds very much like a stockish Z28.

[ConElite]

A modern fuel injected engine does NOT need "backpressure". It was a problem with a carb'd engine, because reducing back pressure does improve breathing, and that means you have to adjust the A/F mix on the carb to avoid leaning it out and losing HP. But a modern electronic fuel injection system makes those adjustments for you.

That said, if 3" catbacks are fine for 300-400HP setups, you probably aren't going to see much improvement in performance on a V6. But it won't "hurt" performance. Backpressure is a myth.

If thats true then why does the New ZO6's have that butterfly valve in the exhaust that stays closed during take off and opens up when the car is up to speed? Also, just 2 days ago I installed an off-road pipe on my buddies SVT Focus and the low end torque was lower but top end was greater. Does that not have anything to do with backpressure?

[Craig 94 TA GT]

If thats true then why does the New ZO6's have that butterfly valve in the exhaust that stays closed during take off and opens up when the car is up to speed? Also, just 2 days ago I installed an off-road pipe on my buddies SVT Focus and the low end torque was lower but top end was greater. Does that not have anything to do with backpressure?

There are many states that have "noise pollution" laws, and some require the automobile to be under a certain level at idle, 45 mph, and > 45 mph. It could be for noise regulations. I googled it and found a few states that have pdf charts for vehicles under 6000 lbs.

[ConElite]

There are many states that have "noise pollution" laws, and some require the automobile to be under a certain level at idle, 45 mph, and > 45 mph. It could be for noise regulations. I googled it and found a few states that have pdf charts for vehicles under 6000 lbs.

I never heard about any laws that have to do with backpressure. If your implying that with backpressure a car runs quieter then of course b/c the exhaust is restricted. I thought there were noise pollutions across the US. I think its like 98 dbs or something. But Im talking about Backpressure effecting low end torque.

[Craig 94 TA GT]

Ummm, you wrote this: "If thats true then why does the New ZO6's have that butterfly valve in the exhaust that stays closed during take off and opens up when the car is up to speed?"

I'm trying to say that maybe it's to reduce noise levels at low speeds NOT to increase backpressure for the sake of more horsepower and/or torque.

EDIT: I did some more research and I am 100% convinced (but was 100% convinced after Fred said it) that the Z06's butterflies have absolutely nothing to do with gaining low-end torque. The butterflies are there to keep noise levels down at low RPM, and GM engineers even give some secret tips on how to keep them open all the time, by pulling a fuse.

[ConElite]

Interesting. I dont know but Ill take your word for it.

[Injuneer]

Correct.... the Z06 has to meet Federal noise criteria at low throttle positions. Google "Z06 exhaust noise".

Another way to look at it.... why do drag cars run open headers? Not because it reduces torque/HP.

[ConElite]

Another way to look at it.... why do drag cars run open headers? Not because it reduces torque/HP.

Got a Point. But then again of us have Blowers that take a min. of 1000hp to turn.