[Megahurtz]

Regardless of what anyone's opinion is, the truth is if you go catless you will smell fuel odors. It will be at its worse at cold starts. You will smell it with the windows down while idling at a stop light. When I went catless in the past I would always have to leave my windows up and run the A/C in re-circulation mode to avoid the odor.

Some people have a higher tolerance for the odor so view are subjective. But having had multiple cars with catless setups and now my most recent cars have had catted setups, I much rather prefer cats. Plus it helps the environment. With technology today, power loss is pretty much negligible.

[Atomic Ed]

There is no performance loss on going with cats. One of the FI guys is making 730 rwhp on the stock exhaust system.

If you insist with going with headers, then look at Dyntech headers that bolt up to the secondary cats and either eliminate the primary cats or have high flow primary cats that replace the stock primary cats.

[TRich2SS]

Originally Posted by Atomic Ed

There is no performance loss on going with cats. One of the FI guys is making 730 rwhp on the stock exhaust system.

If you insist with going with headers, then look at Dyntech headers that bolt up to the secondary cats and either eliminate the primary cats or have high flow primary cats that replace the stock primary cats.

Going catless does net more HP and trq either when simply using test pipes and especially when using headers. I don't think this is even a arguable point. If your point is that the relatively small gains don't justify the smell\impact on environment then that is up for discussion.

[Dubchitts]

I don't notice the smell when I come up to lights from my car or my buddies mustang. If your getting stuff out of the trunk you can smell it a little.

As for the rant....that makes it all sound much worse than it is. And I didn't buy a v8 to be friendly to the enviornment.....thats what my focus is for lol.

[SSDanny]

Originally Posted by marknagy13

Answer the question and keep your opinions to yourself.

The smell is not nearly as bad as he described it here unless you're at a standstill for like 20 minutes lol.

If you want more noise then go catless. If you want it a bit quieter then go high flo

Is the noise difference from catless and hi flows really that evident or is it just a slight noise difference?

[Megahurtz]

Originally Posted by Dubchitts

I don't notice the smell when I come up to lights from my car or my buddies mustang. If your getting stuff out of the trunk you can smell it a little.

As for the rant....that makes it all sound much worse than it is. And I didn't buy a v8 to be friendly to the enviornment.....thats what my focus is for lol.

As I said, some have a higher tolerance for what they consider smell. A majority of people are used to zero smell and have never owned a big cam catless muscle car. Stock cam cars are much more tolerable, but my advice is for those who never had a catless car before. Those people will most likely not like the smell.

[Atomic Ed]

Originally Posted by TRich2SS

Going catless does net more HP and trq either when simply using test pipes and especially when using headers. I don't think this is even a arguable point. If your point is that the relatively small gains don't justify the smell\impact on environment then that is up for discussion.

While it's true that there is some minor gain from using a test pipe (~10 hp with re-tuning) in place of the primary cat on the stock LT1 system, that gain all but disappears when you use high flow cats designed for headers.

https://ls1tech.com/forums/generatio...un-catted.html

It's pretty hard to beat the performance of the stock exhaust system on these cars. Particularly when considering the cost of headers and the install costs. But if your are going for the sound, headers do sound nice.

[TRich2SS]

Originally Posted by Atomic Ed

While it's true that there is some minor gain from using a test pipe (~10 hp with re-tuning) in place of the primary cat on the stock LT1 system, that gain all but disappears when you use high flow cats designed for headers.

https://ls1tech.com/forums/generatio...un-catted.html

It's pretty hard to beat the performance of the stock exhaust system on these cars. Particularly when considering the cost of headers and the install costs. But if your are going for the sound, headers do sound nice.

That thread is hardly scientific and at best it contains anecdotal evidence which basically amounts to random people throwing our random numbers.... Also, we don't have Ls1 engines so I am not sure that thread is relevant to this conversation about our 6th gens. In any case, I think it is really up to whoever is purchasing the system whether or not its worth it. I personally love my catless system. Sound is louder and on E85 there is almost no smell to speak of.

[somewhatdamaged]

Originally Posted by Megahurtz

As I said, some have a higher tolerance for what they consider smell. A majority of people are used to zero smell and have never owned a big cam catless muscle car. Stock cam cars are much more tolerable, but my advice is for those who never had a catless car before. Those people will most likely not like the smell.

Great advice! I only ran a catless setup once on my old C5 Z06 Vette. I had bought some used long tubes, had the catless setup installed and drove home. The smell was not pleasant, I was not used to it. On that setup, I felt a loss of low end torque as well. As far as sound, I found the high flows to be less raspy as well.

[Atomic Ed]

Originally Posted by TRich2SS

That thread is hardly scientific and at best it contains anecdotal evidence which basically amounts to random people throwing our random numbers.... Also, we don't have Ls1 engines so I am not sure that thread is relevant to this conversation about our 6th gens. In any case, I think it is really up to whoever is purchasing the system whether or not its worth it. I personally love my catless system. Sound is louder and on E85 there is almost no smell to speak of.

There were two posts of before and after dyno pulls, one stated zero gains and the other posted a 4hp gain on a 500 hp engine. Yes, these were LS1 engines verses our LT1 engines; does that really make any difference regarding headers and cat deletes? We'll let the OP decide.

Let's not muddle this point. That is, do not expect real performance gains by leaving off the high flow cats. You'll barely be able to measure it, if at all, on a dyno with back to back pulls.

if you want to leave off the cats for whatever reason, that's your choice, but don't expect noticeable gains in performance.

[Megahurtz]

Originally Posted by somewhatdamaged

Great advice! I only ran a catless setup once on my old C5 Z06 Vette. I had bought some used long tubes, had the catless setup installed and drove home. The smell was not pleasant, I was not used to it. On that setup, I felt a loss of low end torque as well. As far as sound, I found the high flows to be less raspy as well.

The loss of torque was more likely due to timing not being optimal for catless headers. I had a catless longtube w/ x pipe setup on my C5 Z06 and I made more power everywhere on the dyno. Tuning is key.

[1badrwd]

I have 1-7/8 long tubes without cats and its not bad. You do get a little smell sitting still for a few minutes but not bad at all. I've also followed my wife driving the camaro for 20-30mins a couple of times so i can vouch its not that bad when behind one on the road.

[brantley847]

Originally Posted by cooden

I always remote start it--love hearing that sound when I'm walking towards the car. I don't really notice any terrible smell.

Because you are a man

For those of us who have gone or will go FI, cats present a real concern for the increased heat. Red lights generally don't last more 1-3 minutes and it won't be a problem short term and it certainly isn't bad enough to melt all the snowflakes

[MarylandSpeed]

Originally Posted by cooden

If you run a supercharger on your Camaro and you want peak performance without melting the cats, guess what you have to do? Go catless. Don't get behind my car is what I would tell you.

I will say I have been shocked how many 6th gen customers buy offroad (i.e. catless) headers. On most newer cars, it is 75% catted. 6th Gen is more like 40%.

In terms of off road, only reason to do it is save money. Catted systems flow almost the same, and there is a very small difference in sound.

On a supercharged car, the regular cats will last if tuned just right. A crappy tune will kill them fast. If you want something more forgiving, the green cats Kooks offers flow even better and are rated to 900 HP.

http://marylandspeed.com/headers-c-2457_2458.html