Recent content by Todd

I'm running 20" wheels using a 325/25 tire in the back.

I'm pretty sure that tire will be too tall and will rub on the fender. I'm running a wheel/tire combo that is just 0.8% larger diameter than stock, 0.2", and it's damned close to the fender, but does not rub. You're talking about putting a tire on there that is a whopping 4.6% larger diameter...

Right? Not sure why someone would be so angry about learning something, strange. Anyway, the more we understand how mods work, the more we’re educated consumers. Considering how many people get CELs and flagged for emissions violations when modding, I didn’t see how I was “crapping on a...

Bizarre response.

And CARB and EPA are two different things. CARB is state level. EPA is federal level, which supersedes state level. EPA governs 50 states. CARB extends to 14 states based on California emissions standards. The more you know…

Not sure what’s up with your extreme hostility here. My credentials? I’ve been in the performance exhaust design and manufacturing industry for 35 years. Not a joke.

Hey, you’re not doing your fellow enthusiasts a favor here. This a learning opportunity. There are four cats, total. Two per side. One on each side is a primary cat, usually 800 cell. There is an O2 sensor before and after this cat to monitor its function. The second O2 sensor sits between...

Here’s the break down: Purple arrow is the inlet, coming from the turbo outlet. Green dot is the primary O2 sensor. Light blue is the primary cat. Yellow is air gap between the cats. Red dot is secondary O2 sensor. Dark blue is the secondary cat.

Secondary cats have less precious metal loading, they’re used mainly in conjunction with the primary cats during the warm up phase. Once the primary cats are up to temp, there is little demand on the secondary cats, that’s why they are unmonitored. Further, because the primary cats take the...

Technically that description is correct. The secondary cats are positioned further down the exhaust stream (by 2”). Typical cat assembly design.

Ok, looking into this further, I can see that there may be confusion here. I can even tell from the thumbnail of this video that there are secondary cats. Common misconception, as the OE “cat assembly” looks like one big cat, but there is an air gap between the primary and secondary stage...

Granted I am not 100% familiar with the CT4, but unless there are main cats untouched in front of these downpipes, then these pipes have the secondary cats removed. That’s a performance opportunity, but an emissions violation in the eyes of the EPA.

fyi, it doesn’t matter if individual cats are EPA approved if the total number of cats is reduced. All aftermarket downpipes eliminate the secondary cats, and that is most definitely not EPA approved. Just an FYI. It’s a common marketing “pseudo truth” that downpipe and header companies like...

huh, I stand corrected, but that break in process seems to refer to "lower quality aftermarket cats", not to OE-grade (which come with a much longer federally mandated warranty)...

I've never, ever heard of a "break-in" for a cat. The way they work is basic chemistry. The bricks are "padded" in their cans with a wrap of furnace-lining type material to account for differentials in expansion/contraction, as well as vibration (which isn't limited to break-in). For what it's...