Cats or no Cats

[TexasMetallic5.0]

UTI is Universal Technical Institute. Decent school, a couple buddies went there. If you have to pass emissions, leave them on or have a set to throw on for inspection. Otherwise, ditch them.

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[Semp1]

If adding a cat would increase torque every race car in the world would have one.

I've been building engines for 30 years

Post up those sheets, with video showing if there was a cat or not on the pull. Also show the correction factor.

It doesn't "increase" torque having high flow cats. No one ever said that. The back pressure is different requiring the tune to be different causing a loss of torque due to free flowing exhaust. You understand I am speaking solely of a longtube header set up.

 

[Semp1]

Here is how confident I am.

If you pay for the dyno time at Turn in concepts in Cincinnati I will do before and after same day pulls with cats and no cats. If I lose torque I will pay you back double.

If you don't like them we could do Pauls automotive.

I honestly don't need to prove anything. This honestly for the most part is known and understood by anyone in this field or familiar with modifying cars in general. Considering you build engines you should understand the statement I stated in the above post, maybe if you tuned cars you would understand the concept more. The statement is not meant to be combative but it seems there's a certain disconnect with understanding what I am saying.

 

[K4fxd]

I also tune cars.

Freeing up the exhaust will not kill torque. Unless you go overboard.

Just removing the cats will not cause a reduction in torque.

Quit spreading falsehoods.

And who said anything about "high flow" cats? Although having high flows installed will kill some power over not having any at all.

 

[Semp1]

I also tune cars.

Freeing up the exhaust will not kill torque. Unless you go overboard.

Just removing the cats will not cause a reduction in torque.

Quit spreading falsehoods.

And who said anything about "high flow" cats? Although having high flows installed will kill some power over not having any at all.

Honestly It seems like you’re one of the only people that seem to have the idea that going catless doesn’t dip slightly in the low end torque dept in regards specifically to longtubes. Like I said it’s nothing major but it absolutely occurs. In regards to “high flow cats”. My statement is specifically about after market Longtube headers with high flows and catless. Not stock that are catless. When it comes to going catless on stock headers to me again unless boosted., completely pointless. But I’m not going to argue. I said it in my original post. Agree to disagree.

 

[K4fxd]

The whole point of long tubes is the torque boost. So you can agree to disagree with proven facts all you want.

You keep changing the parameters.

IF adding cats gave a torque boost all race cars would have them.

The above statement is saying the same thing as removing cats will lower torque. I'm willing to say "if the tune is off" adding cats MIGHT improve torque.

Don't take my word for it. Give these guys a call and ask them.

https://rehermorrison.com/

https://www.shafiroff.com/

https://www.sonnysracingengines.com/

 

[Jordan @ Lethal]

I also tune cars.

Freeing up the exhaust will not kill torque. Unless you go overboard.

Just removing the cats will not cause a reduction in torque.

Quit spreading falsehoods.

And who said anything about "high flow" cats? Although having high flows installed will kill some power over not having any at all.

^^^^^^^^
Remove your cats if you can, it's most ideal. If you're boosted it's essentially necessary unless you like replacing cats when they inevitably go.

 

[Zelek]

Cats or not cats, your O2 sensors are still going to fail you on inspection because one of the O2 sensors is not positioned where the stock one was on long tube headers. Pick whichever one floats your boat and if you can stand the smell of regular gas without cats. E85 is much more pleasant catless.

 

[Semp1]

Cats or not cats, your O2 sensors are still going to fail you on inspection because one of the O2 sensors is not positioned where the stock one was on long tube headers. Pick whichever one floats your boat and if you can stand the smell of regular gas without cats. E85 is much more pleasant catless.

My long tubes were refabricated to relocate the O2 sensor. Combined with the defouler I pass no issues and now have 2 extra ports for bank 1 and 2 gauges to boot. Bonus. Lol.

 

[WildHorse]

I mean honestly, I think we need to agree to disagree on this topic but at least from what I’ve seen and many others I 100% will say you are losing at least a little low end torque going catless with longtubes

Maybe off idle. At any other RPM range your are losing nothing, unless YOU put on mismatched components cause the interwebs told you too.

 

[Jordan @ Lethal]

My long tubes were refabricated to relocate the O2 sensor. Combined with the defouler I pass no issues and now have 2 extra ports for bank 1 and 2 gauges to boot. Bonus. Lol.

What kind of angle did they end up putting the sensors at? Did they recess them at all? Just curious.

 

[Zelek]

My long tubes were refabricated to relocate the O2 sensor. Combined with the defouler I pass no issues and now have 2 extra ports for bank 1 and 2 gauges to boot. Bonus. Lol.

Curious here too. I switch intakes and to a tune where I have the O2's turned off (gray status) on monitors and that's how I pass inspection. Big name tuners are no longer doing that because the EPA will come after them with fines. I'd like to not have to do that every year and if it's a simple O2 fab to get the front to read correctly and have the O2 heater readiness go green, I'm all ears.

Option 2 is getting a dyno tune where the tuner simply doesn't care and will turn it all off, lol.

I still have my O2 sensors horizontally placed from the ARH headers and still haven't had a single O2 go out on me or have a problem running E85 with any kind of evaporation and whatnot.

 

[Semp1]

Curious here too. I switch intakes and to a tune where I have the O2's turned off (gray status) on monitors and that's how I pass inspection. Big name tuners are no longer doing that because the EPA will come after them with fines. I'd like to not have to do that every year and if it's a simple O2 fab to get the front to read correctly and have the O2 heater readiness go green, I'm all ears.

Option 2 is getting a dyno tune where the tuner simply doesn't care and will turn it all off, lol.

I still have my O2 sensors horizontally placed from the ARH headers and still haven't had a single O2 go out on me or have a problem running E85 with any kind of evaporation and whatnot.

I have ARH long tubes 1-7/8x3 with high flows and to run defoulers the refabrication was mandatory or the sensors would have had to be turned off since the defoulers did not fit properly with the trans cross member getting in the way other wise preventing a perfect fit with the defoulers. Without the defoulers I was getting a bank code. ARH high flows seem to not be quite as good as Kooks from what I’ve heard at least. The 02 sensors were moved back just a little. A very, very small amount. If the exact angle is something you guys need I can find out but I’m pretty sure the same Angie was kept and just moved slightly back to prevent a code and to allow the defoulers to be properly installed.

 

[Zelek]

I have ARH long tubes 1-7/8x3 with high flows and to run defoulers the refabrication was mandatory or the sensors would have had to be turned off since the defoulers did not fit properly with the trans cross member getting in the way other wise preventing a perfect fit with the defoulers. Without the defoulers I was getting a bank code. ARH high flows seem to not be quite as goood as Kooks from what I’ve heard at least. The 02 senators were moved back just a little. A very very small amount.

I think my P0420 code is just turned off completely in my tunes. I can't throw any codes regardless of defoulers or like I have it right now, both sensors just plugged in the rear with no spacers. Flip side is I can't ever get the O2 heater readiness to pass due to the O2 location.

I hear you on the location on the rears. It's a real tight fit with some of the defoulers I've used and the extensions really stretch too.

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