Looking to buy header - question about exhaust fume smell
 

Hello folks,

I'm seriously considering buying a set of headers for my car and so far I've only been looking at catted headers. Reason for this is that I really hate the smell of exhaust fumes (perhaps more so than regular people), so I thought a catted header would be the way to go with this.

However, catted headers tend to run above $1100 CAD while uncatted can be had for a little over half that. My question is, how bad is the exhaust fume smell when running a catless header with the stock catted frontpipe? I'm fine with a faint whiff of it when driving hard, but I really don't want to be able to smell it when I'm just puttering around with regular traffic, or when stopped at a traffic light.

I'd rather not spend an extra $500-600 just to get rid of a smell if its only minor.

Thanks in advance :)

For reference, I was looking at the Gruppe-S uncatted UEL header vs the JDL catted UEL header.

I have a JDL catless header. I commute in Southern California traffic. The only time I smell it is at startup when letting in warm up in my driveway. Other than that, it is not an issue.

It’s pretty bad catless...but my setup also had a high flow secondary cat.

I wouldn’t smell it when I was moving, but coming to a stop with the windows down the smell would totally get in the car.

I was catless for nearly 3 years but decided to go back to oem cats/ stage 1 to get a more pleasant driving experience. I may have lost 10hp...but no smell = no regrets.

When going Catless Header with a Stock Front Pipe, I didn't really notice a smell difference.
After going Catless Front Pipe, I can smell it now, but I don't normally smell it while driving, just every now and then. You really notice if you're standing behind it, loading your trunk or something.

I have been considering going HFC Front Pipe.

You'll still have a cat in the system so the smell shouldn't be bad. Or go E85, you'll get rid of the petrol smell completely and probably welcome the smell of ethanol on the morning!

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This I would do if my city had more than literally just a single E85 pump. 1.3 million people, and only a single E85 pump :mad0260:

This would be perfect for me I think, but now I have conflicting answers from other people. I'm still just as confused as I was when I started haha

It's down to a lot of things like there tune and how sensitive their noses are to smells. I wouldn't buy a header without an OFT or a similar offering from ecutek, more bang for the buck and it makes the mod worth it power wise, and no more CEL or torque dip.

As for me with the Stage 2 93 octane tune and CNT uel, with stock front pipe, I couldn't notice any smell. Only on cold starts when the secondary cat is warming up, but editing in a quiet cold start meant it took longer for that cat to warm up as well, but didn't have the ridiculous loud overlap or cold start smell as bad. Running E85 the smell disappeared completely and was replaced with a sweet ethanol smell only in certain situations .


I wouldn't worry about the smell honestly, the power increase and the removal of torque dip makes it worth it. Keeping the stock front pipe will definitely help, plus you don't really lose a noticeable amount of power keeping it in a NA setup.

Yeah that makes sense. I already bought an OFT a month or so ago with the intention of buying a header eventually. I'm fine with the smell while the second cat is warming up - as long as it doesn't get into the cabin after that I'm fine with it.

I think I'll get the Gruppe-S uncatted UEL header in that case then. $650 CAD for it vs $1200 for the JDL catted one I think is a no-brainer.

I am completely catless(Gruppe-S, Fujitsubo FP), the smell is not noticeable unless the wind is blowing the exhaust back up to the front of the car when you're stopped, and or at a drive-through. If you can smell it while you're driving you have an exhaust leak into the cabin.

Best bang for your buck Gruppe-S UEL header and keep stock OP and FP. Smell is only on cold start. After that you don't smell anything. Also if you work with your OFT tune, you can disable the cold start which should help with smell at start. IMO Gruppe-S UEL + used OFT and stock FP,OP over a catted UEL Header any day.

Same here. This is 100% the right answer. You'll never smell it when driving.

But what about at rest? A smell on a cold start makes sense (and is fine), but I'm more curious if there will be a smell when I'm idling at traffic lights or similar.

If you have the stock FP you will be fine.

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When you go catless, everyone behind you suffers. Don't be a selfish asshole. At least keep the secondary, please.

I have an Ace header with the stock front pipe. I get a little bit of fuel smell on cold starts and after running the car hard but otherwise it's not noticeable. Just keep the stock front pipe. You sacrifice 10hp but you don't have to worry about a cheaper high-flow cat pipe breaking.

You don't need an aftermarket frontpipe/cat for it to breakhttps://uploads.tapatalk-cdn.com/201...87ddf9a31e.jpg

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You're over thinking this, keep stock front pipe and you'll be fine.

He definitely messed with the tune in romraider and did the pops and bangs edit and messed something up, I've run e85 with a snap crackle pop tune for exhaust backfiring on overrun and have yet to see any damage to the cat after 40k miles.....

That's best, the gruppe-s is basically the tomei.

It won't get into the cabin unless you have an exhaust leak, I recommend buying grimmspeed gaskets and high temp RTV and it'll guarantee no leaks and long and you torque it down properly and to spec.

Do you do much track work? This one does I'm pretty sure. Not saying it is going to happen all the time but I've heard of similar things happening with cats in other non 86/BRZ vehicles. My point was doesn't matter if it's a aftermarket or OEM cat there can still be issues.

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Which cat back? Could you post a video plz?

Stock catback, it's too loud with my aftermarket catback on the car.

Cool, thanks! I think I've made up my mind now - will go with the Gruppe-S with some decent gaskets.

Thanks everyone :thumbup:

Not an issue. Leave the stock FP. You'll be fine

The exhaust gaskets that come with the Gruppe-S header work fine, no need to spend extra money on different gaskets. I am going on over a year with no leaks, just make sure you torque everything down correctly when you install it.

What's the torque spec on those bolts?

I just used my impact gun(18 volt cordless) at a lower speed setting :)

I've done autox STX stuff but thats about it, I drive pretty hard on some secluded back roads as well. Your point makes sense, but there's going to be some latent other issue if your blowing out your cat on our cars at under 80k miles imho....

The 6 bolts on the header manifold should be 23 ft lbs, and the overpipe to header should be 26 ft lbs. I used a torque wrench and re-did them after a week of hard driving, I still highly recommend high temp rtv on those gaskets though even on the gruppe S some times the flanges aren't perfectly decked and it cuts down on any possibility of leaks.