High flow cats Vs cattless downpipes

[Rh7644]

I’ve usually run cattless downpipes in a majority of my past performance vehicles. That being said, are there any performance numbers for high flow cats vs catted down pipes on these vehicles? Is there a huge HP difference between the two, all other things being equal?

 

[WindyDishes]

I cant speak for the ST on the numbers, but my other vehicle has a cattless downpipe and yes I saw a +15hp running a cattless downpipe. But running a cattless I would recommend also putting on external wastegates so you don't over spool, so on a cost stand point it will cost more to run cattless.
But another big factor is finding a tuner today that will tune you with a cattless downpipes, in my option just isn't worth a little gain.

 

[UNBROKEN]

The flow difference between catless and a 400 cell cat like everyone is using is single digit percentage wise…HP differences are about the same. Absolutely no reason for catless with the emission hassle and bad smell.
Not to mention no reputable tuner will touch them with the EPA crawling down their throats.

 

[twin001]

The flow difference between catless and a 400 cell cat like everyone is using is single digit percentage wise…HP differences are about the same. Absolutely no reason for catless with the emission hassle and bad smell.
Not to mention no reputable tuner will touch them with the EPA crawling down their throats.

THIS +100000000. Not worth it to run catless. The noxious smell and terrible riceburner sound aren't worth the minimal gains, aside from the environmental issues.

 

[Rh7644]

The flow difference between catless and a 400 cell cat like everyone is using is single digit percentage wise…HP differences are about the same. Absolutely no reason for catless with the emission hassle and bad smell.
Not to mention no reputable tuner will touch them with the EPA crawling down their throats.

So I usually ran catless on most of my previous vehicles (850 WHP z06 and 820AWHP e63). I just wasn’t sure what the majority of guys are running.

is it safe to assume the majority of guys here run the catted pipes? And Adam at ZFG only tunes for catted?

Thanks in advance.

 

[twin001]

So I usually ran catless on most of my previous vehicles (850 WHP z06 and 820AWHP e63). I just wasn’t sure what the majority of guys are running.

is it safe to assume the majority of guys here run the catted pipes? And Adam at ZFG only tunes for catted?

Thanks in advance.

The EPA has cracked down HARD on tuners over the past few years, mainly because of emission issues. Adam stopped selling his tunes for months so he could get EPA approval for his tunes, and I don't imagine that was a free process for him.

 

[TMac]

Quit buying into the hype of vendors selling "catless" downpipes. This isn't 1976, and they aren't as restrictive as they were then. Especially if those "hi performance catless pipes" are just tubes with no diffuser section post turbine and no abrupt change in angle to take the vortex discharge of the turbine and straighten it for laminar flow. That's just another throwback to supercharged or N/A vehicles- not turbo vehicles.

 

[UNBROKEN]

The EPA has cracked down HARD on tuners over the past few years, mainly because of emission issues. Adam stopped selling his tunes for months so he could get EPA approval for his tunes, and I don't imagine that was a free process for him.

Roughly $15,000 per tune

 

[Cruising68]

These days a good set of high flow cats flow pretty darn good even compared to straight pipes IMO. Not like the good old days when you could pick up good ponies going catless. The early cats sucked. We had a Mercury Monarch that was for sale after a snow storm. We let it idle in the driveway for a while and the cat got so hot it started the carpet on fire and burn the car to the ground

 

[TMac]

These days a good set of high flow cats flow pretty darn good even compared to straight pipes IMO. Not like the good old days when you could pick up good ponies going catless. The early cats sucked. We had a Mercury Monarch that was for sale after a snow storm. We let it idle in the driveway for a while and the cat got so hot it started the carpet on fire and burn the car to the ground

Although I don't have a carpeted driveway, I'm sure the loss of that Monarch was a relief.

 

[Cruising68]

Although I don't have a carpeted driveway, I'm sure the loss of that Monarch was a relief.

No doubt, that thing was a piece of dung. I was afraid it was going to be my first car Fortunately it ended up being a 68 Mustang Coupe with a 289. Much better!

 

[Rh7644]

Ok great. Thank you guys for the input. Catted downpipes it will be then. What’s the point of selling catless then if people won’t even tune for them?

 

[Busychild]

An article on Cobb and their plight with the EPA. Very sudden changes.
https://www.cobbtuning.com/green-speed-update-april-2022/

The converse:
https://www.sema.org/epa-news

 

[Blown F-150]

An article on Cobb and their plight with the EPA. Very sudden changes.
https://www.cobbtuning.com/green-speed-update-april-2022/

The converse:
https://www.sema.org/epa-news

It’s too bad that is North of the border are going to have to ride the EPA coat tails as well. I get the for the most part, there are no real impacts on performance with these changes, I’ll still keep older versions of FW and SW for my SCT and HPT devices if they follow suit.


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