Wow, I gotta get my nose checked, I guess. When we cold start the catless GT4 and let it sit for 15-30 secs, I don't smell anything.

 

def anosmia

 

Yeah but I can smell my track cars when they start up. Oh well...

 

I have three catless bikes as well and they all smell the same way. All of them '15 or newer and all turned. But even before the tune you get the smell.

As for fines or being towed, it isn't an issue in Georgia. Some counties still don't do emmission testing. I'll see what happens later this year and might have to reinstall the factory headers, but feel it's still worth it.

 

If you have a stock tune and no cats you will get a strong fuel smell on startup due to fuel enrichment and cam overlap to light off the cats and quickly warm them up (but they are not there). A tune helps decrease this.

 

 

Ditto on the smell with my DMS headers and tune.. In the interest of my fellow drivers, I am adding high flow cats to my pipes in the coming weeks. BTW, gas additives like Stabil makes the smell even worse...

 

it's extremely noticeable with dundon headers

 

Nice thread bump. I think my wife is fed up with the smell - she threatened to sell the car this weekend. I might need to move it to the storage unit (or at least not warm it up in the garage) until the heat dies down...

 

Having just got out of a big cammed C6Z with no cats, these problems for catless header cars should be obvious to me.

However, I had hoped the smell might be slightly less considering the amount of valve overlap I had at idle on my previous car.

From the sound of these posts (likely due to the exhaust run length being half, if not a third, of the distance my C6Z's was) that is not the case... Darn.

 

I don't even notice it anymore ...

 

I'm no expert, but I thought the smell from removing cats was caused by sulfur left in unburnt fuel what would otherwise be burned/oxidized within the catalytic convert. What affect would length of exhaust tract have on the amount of unburnt fuel? I'm just genuinely curious. Cooling of exhaust gasses to the point the vaporized fuel turns liquid?

 

my girlfriend hasn't complained yet and they've been on for three months. She's noticed it's louder though haha

 

As a young child my Father would tell me to go play in the street.
And I would, even though I knew better, just to smell the wonderful diesel fumes as I dodged the trucks passing through.
Gasoline fumes aren’t as good as diesel, but there's little smell if any with my GT4 and DMS tune.
It’s using an East Coast blend of Mr. Gas 93 octane and Redline SI-1.
When I first put on the DMS race headers and started it in the garage, my eyes were burning though, best to not do that.

 

Just curious, but when you guys smell the gas fumes, can you identify the different octane levels? Hear about a guy one time who had huffed so much gas he could tell the difference between regular and “high-test.”