Catless Vs Cats

[theinfamousdrew]

Lets discuss the environmental affects of going catless....

Go!

[_BSMM5]

Originally Posted by theinfamousdrew

Hey guys!

So I recently picked up a well-cared for BEAST!
This car was built correctly with all the right parts, however not 100% what I need in my life at the moment. lol


The car has RK Autowerks carbon intakes, downpipes, stage 2 tune, and a Turner exhaust.
Five years ago this would have been perfect for me, but at this stage in my life I need to tone it down a little.

Two things that I would change about the car....
1. Exhaust volume
2. Exhaust smell.

I've always had catless cars but the wife isn't too fond of it these days.
With all that being said, I reached out to RK with questions and advice.
Raza was great, but couldn't offer much advice.

If I go back to stock cats, I would also need to buy a new tune.
I like tunes that I have some control over. For instance, if I need to take it to the dealer, I can flash it back to stock and then back to tuned afterwards.

I’m thinking there are three possible routes for this and each has pros and cons and cost differences.

1. Stock cats + new tune (solves both issues)
2. Quieter exhaust (solves one issue)
3. High flow catted downpipes (solves both?)


I'm hoping you all with your infinite knowledge can help me reroute this build to suit my current needs.


Photo just because…

I'm a fan of bootmod3 because its so quick and easy to flash plus support for custom tunes from a number of tuners. You can also sell the license if you want.

I just put in downpipes and I also hate the smell (and the thought of how much pollution i'm releasing, a study said 1 car without cats = 600 cars with cats, making my morning trip to work nearly two years worth of trips to work... everyday). I love the sound, so I'm going to try to install some high quality high flow cats in the mid pipe, since catted DP are crazy expensive. I've heard this kills the smell albeit not as effective as stock cats - its a good trade off. I'll make a post once I do this week.

[mister2d]

Originally Posted by _BSMM5

...
a study said 1 car without cats = 600 cars with cats, making my morning trip to work nearly two years worth of trips to work... everyday)
...

Interesting statement. What kind of car, diesel or petrol? Turbo or non-turbo? And what time period does that 600 cover? Ten minutes? Ten years? 10,000 years? More context is needed.

[_BSMM5]

Originally Posted by mister2d

Interesting statement. What kind of car, diesel or petrol? Turbo or non-turbo? And what time period does that 600 cover? Ten minutes? Ten years? 10,000 years? More context is needed.

It isn't a time period, just the overall magnitude of Hydrocarbons released at any given moment.

Took me a minute to find the study but it looks like I was way off on the 600x more, and it looks like it's actually 6-12x more which makes me feel less guilty. The information about "600x more" was me repeating another forums thread.. another reason why its always good to do your own research.

Graph at WOT (Unsure of engine size/coverter, but our cats are wire mesh)

[Dwaynos]

Originally Posted by _BSMM5

It isn't a time period, just the overall magnitude of Hydrocarbons released at any given moment.

Took me a minute to find the study but it looks like I was way off on the 600x more, and it looks like it's actually 6-12x more which makes me feel less guilty. The information about "600x more" was me repeating another forums thread.. another reason why its always good to do your own research.

Graph at WOT (Unsure of engine size/coverter, but our cats are wire mesh)

Probably a load of garbage, they just try to make the motorist feel guilty for driving and even more so for driving a modded car. It all depends on what toxin is being measured at the tailpipe. A dpf filter on a diesel car converts toxic gasses and releases another gas that is supposedly more toxic but its not monitored on an emissions test. A petrol cat is probably a very similar story but I haven't taken to time to look into it.

[_BSMM5]

Originally Posted by Dwaynos

Probably a load of garbage, they just try to make the motorist feel guilty for driving and even more so for driving a modded car. It all depends on what toxin is being measured at the tailpipe. A dpf filter on a diesel car converts toxic gasses and releases another gas that is supposedly more toxic but its not monitored on an emissions test. A petrol cat is probably a very similar story but I haven't taken to time to look into it.

btw, I installed those downpipes (it was a PITA) and i'm going to do a write up once i put my secondary cats in the midpipes.

The exhaust is 100% poisonous, I was getting something out of my trunk while the vehicle was running for about 2 minutes and it made my eyes water and I felt nauseous and dizzy afterwards. Friend driving behind me told me he could not be close to me because it was coming through his car even with his windows up. I don't think its completely a load of garbage... What reason do they have to make someone feel guilty for a modded car?

Anyways, I bought a CO monitor that measures in PPM and I will post the results before and after the secondary cats to show the difference.

Here is a news article of a couple that was killed after installing downpipes (albeit improperly). Carbon Monoxide is a completely odourless, and tasteless gas. Catalytic converters are proven to remove this from the exhaust.
https://www.telegraph.co.uk/news/201...ed-up-improve/

I'm not saying all this because I'm completely against modding vehicles or downpipes or anything. I have catless downpipes installed. I'm just trying to share more information on the consequences and potential health effects of doing so.

[theinfamousdrew]

This took an unexpected turn........

[Dwaynos]

Originally Posted by _BSMM5

btw, I installed those downpipes (it was a PITA) and i'm going to do a write up once i put my secondary cats in the midpipes.

The exhaust is 100% poisonous, I was getting something out of my trunk while the vehicle was running for about 2 minutes and it made my eyes water and I felt nauseous and dizzy afterwards. Friend driving behind me told me he could not be close to me because it was coming through his car even with his windows up. I don't think its completely a load of garbage... What reason do they have to make someone feel guilty for a modded car?

Anyways, I bought a CO monitor that measures in PPM and I will post the results before and after the secondary cats to show the difference.

Here is a news article of a couple that was killed after installing downpipes (albeit improperly). Carbon Monoxide is a completely odourless, and tasteless gas. Catalytic converters are proven to remove this from the exhaust.
https://www.telegraph.co.uk/news/201...ed-up-improve/

I'm not saying all this because I'm completely against modding vehicles or downpipes or anything. I have catless downpipes installed. I'm just trying to share more information on the consequences and potential health effects of doing so.

Carbon monoxide was the biggest reason cats were fitted to cars, I understand that it is poisonous but only if breathed in for a prolonged period of time or in an unventilated area. The government want us to believe that cars are the only cause of global warming and it's a drivers fault that this is happening. You will now be judged even more harshly for having catless downpipes although you are not going to speed up global warming with your decat m5.

They want everyone to drive electric so they blame us hoping we will be converted, although we will have no choice in the matter one day.

[_BSMM5]

Originally Posted by Dwaynos

Carbon monoxide was the biggest reason cats were fitted to cars, I understand that it is poisonous but only if breathed in for a prolonged period of time or in an unventilated area. The government want us to believe that cars are the only cause of global warming and it's a drivers fault that this is happening. You will now be judged even more harshly for having catless downpipes although you are not going to speed up global warming with your decat m5.

They want everyone to drive electric so they blame us hoping we will be converted, although we will have no choice in the matter one day.

The overall effects of having a decatted car on the environment is neglible in the grand scheme of things... having an entire country with decatted cars would definitely cause a noticeable affect in air quality (lets be glad 99% of people don't mod their cars )

According to wikipedia automobiles are responsible for 50~% of the worlds carbon monoxide - however pollution in general (Hyrdrocarbons, CFC, things bad for the ozone etc.) automobiles are a small small percentage.

If BMW or Porsche were to release an electric performance or M vehicle I can't say I wouldn't be interested. The Torque in the Teslas is intoxicating lol

[theinfamousdrew]

Originally Posted by _BSMM5

If BMW or Porsche were to release an electric performance or M vehicle I can't say I wouldn't be interested. The Torque in the Teslas is intoxicating lol

Meet the Porsche Mission E (lectric)

https://www.porsche.com/usa/aboutpor...iew/article01/

[_BSMM5]

Originally Posted by theinfamousdrew

Meet the Porsche Mission E (lectric)

https://www.porsche.com/usa/aboutpor...iew/article01/

[SapphireM5]

I'm going to stay stock cats and a DME tune locally. I'm not looking to break any records, weekend car w the family. That will be plenty for me, my days of exhaust fumes are over lol.

GL!

[_BSMM5]

Originally Posted by theinfamousdrew

This took an unexpected turn........

Sorry didn't mean to hijack this thread!!

[theinfamousdrew]

Originally Posted by _BSMM5

Sorry didn't mean to hijack this thread!!

Not thread jacked now.

[mister2d]

Originally Posted by _BSMM5

It isn't a time period, just the overall magnitude of Hydrocarbons released at any given moment.

Took me a minute to find the study but it looks like I was way off on the 600x more, and it looks like it's actually 6-12x more which makes me feel less guilty. The information about "600x more" was me repeating another forums thread.. another reason why its always good to do your own research.

Graph at WOT (Unsure of engine size/coverter, but our cats are wire mesh)

This is what I suspected, and I'm barely at WOT. I wonder if it's any worse or better for turbo cars.

One observation I made about my car since going catless is that the smell has noticeably diminished after running through a bottle of fuel system cleaner and continuous fuel treatment at every fill up. The smell is still there but not as much as before.

The auto stop / start feature is a good way to mitigate too.

[OneExtra]

I don't agree with removing Cats.

An M5 with a Stage 1 map is fast enough, if people are looking for 1000 bhp then yes I can see why you would need to but for an extra 25 ish bhp by removing cats and leaving it as that what's the point.

[_BSMM5]

Originally Posted by OneExtra

I don't agree with removing Cats.

An M5 with a Stage 1 map is fast enough, if people are looking for 1000 bhp then yes I can see why you would need to but for an extra 25 ish bhp by removing cats and leaving it as that what's the point.

With Catless downpipes and Stage 2, some tunes will push upwards of +200 hp above stock. Many people don't use their M5 just to drive to the grocery store and back, so the stage 1 may not be fast enough for them when there are Z06's lurking

At the same time, I think race catted downpipes are the happy middle ground, but at $3k a pair they are wildly expensive...

I have high flow cats going in my midpipes next week and will post back with CO readings.

[carlitosgomesm5]

Originally Posted by _BSMM5

With Catless downpipes and Stage 2, some tunes will push upwards of +200 hp above stock. Many people don't use their M5 just to drive to the grocery store and back, so the stage 1 may not be fast enough for them when there are Z06's lurking

At the same time, I think race catted downpipes are the happy middle ground, but at $3k a pair they are wildly expensive...

I have high flow cats going in my midpipes next week and will post back with CO readings.

Personally happy with Stage1 however have considered going catless for the better stock exhaust sound. If you place highflow cats in the midpipes, are you taking the resonators out, putting them before the resonators? Which brand are you looking at for highflows?

[_BSMM5]

Originally Posted by carlitosgomesm5

Personally happy with Stage1 however have considered going catless for the better stock exhaust sound. If you place highflow cats in the midpipes, are you taking the resonators out, putting them before the resonators? Which brand are you looking at for highflows?

I'm putting them as close to the downpipes as possible, Cats need alot of heat in order to work properly (which is why cold start exists on vehicles). So in front of the resonators, but I won't know until I have the cats in hand.

Just going with some magnaflow 200 CEL cats. There are better cats out there, but for the purposes of my "experiment" I went for the budget ones.

[mister2d]

Originally Posted by _BSMM5

I'm putting them as close to the downpipes as possible, Cats need alot of heat in order to work properly (which is why cold start exists on vehicles). So in front of the resonators, but I won't know until I have the cats in hand.

Just going with some magnaflow 200 CEL cats. There are better cats out there, but for the purposes of my "experiment" I went for the budget ones.

I'll be one waiting to see the outcome. I've flirted with the same idea but I'm unsure if they will fit side by side in the mid pipe section. If not, I would have to stagger them.

[carlitosgomesm5]

would be interested to see what the exhaust sounds changes are. I want better exhaust sound from the stock but didnt really want to gut my OEMs i would prefer to get gutted OEM cats but then have this to help with the environment and still have better exhaust sound.

[Pikey Motorsports]

Originally Posted by OneExtra

I don't agree with removing Cats.

An M5 with a Stage 1 map is fast enough, if people are looking for 1000 bhp then yes I can see why you would need to but for an extra 25 ish bhp by removing cats and leaving it as that what's the point.

About 10 car lengths