High flow downpipe = gas smell?

[awd.nv]

The younger me would be so disappointed in this message, but I picked up a used SPD downpipe and have LOVED the performance, I was shocked how much of a difference it made without a tune but the downside is the truck now has a pretty solid gas smell unless the Cat is super warm. That part surprised me, I didn't expect it to be so bad.

Edit: Smell is like cold starting a stock truck in the morning. Even after the truck is at normal temp, smell is still there. Only time I think I notice it less is if I run it hard, but have to double check that. A/F ratio is reported in the 14.5 range so I dont think it is running rich or anything.

Since it was a take off part, I am wondering if there is any chance the previous owner gutted part of the Cat or if this is just normal?

I am tempted to buy a new one from maybe CVF but they basically advertise the same spec of 400 cell.

Would having another cat put in the exhaust further down help? I know they need heat and I am thinking too far away from the engine and it may not help at all. The factory exhaust has 2 pin holes so I was thinking of a new setup but one that kept things quiet, they have been there with the OEM Cat and this was not an issue so I doubt that is it.

Just curious about feedback. Sometimes I don't put my windows down because at stops the gas smell is annoying. Especially in my kids school drive line for pickup.

Thanks!

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[Racket]

I don't think any unburnt fuel - at least not detectable - should make it past the turbo. Sounds like incomplete combustion or over-rich unless you need the ignition/timing checked?

 

[awd.nv]

I don't think any unburnt fuel - at least not detectable - should make it past the turbo. Sounds like incomplete combustion or over-rich unless you need the ignition/timing checked?

Well, it kinda smells like a cold start even after driving around town. The A/F is usually in the 14.5 range so it is not running rich (Per Scan Gauge 2). Depending on how the wind is blowing I smell it at lights if the windows are down or AC vent is open and windows up.

So Ford did replace my engine at 50k miles (67k now) and when I got it back it almost felt like timing was retarded but they also had me in a Hybrid F150 and that thing has tons of torque off the line, so I attributed it to that comparison since I had it like 2 months. This engine does seem to use a little more fuel but they also added a few more red lights and stop signs in my area so I was never sure about environment or engine efficiency. A/F ratio seems about right though.

I just don't think there is a way I can get Ford to check the timing without me paying for it. It would be cam timing and I assume their factory uses the right tools to do it right.

 

[Racket]

There were concerns about fuel in the oil when this forum started and while I didn't experience this (Blackstone oil analysis didn't turn up anything) my next guess would be the new engine breaking in.

 

[Frenchy]

I have to ask if you have a tune to compensate for such. Some things like a catback you can get away with. A Catalytic Converter on the other hand is different.

 

[MistaBiz]

Not sure if this will be helpful to you, but I had a completely catless setup on another vehicle of mine, a 2008 Toyota N/A V6, and the smell was very strong. Everything was operating fine, it wasn't running rich or anything like that. I didn't mind at first but after 10 years I really started to hate it. Did it in my early 20s after getting a new job and didn't know any better I guess. That experience is why I think I'm going to leave the downpipe alone on the Ranger.

 

[Superspirit]

CVF Catted downpipe for 25k mi and no gas smell. Unleashed tuned also maybe that's why there are no offensive odors either.

 

[Deleted User 38384]

10k miles on my CVF Downpipe and Revolution Automotive tune with no issues at all. Love the sound.

 

[awd.nv]

Thanks for the feedback with the CVF downpipe, I love the performance from the downpipe that I may try a CVF one in the future. Would go stainless if I do since this one isn't.

With this cat/downpipe the smell is similar to cold starting a stock truck in the morning, before the OEM cat warms up. With this downpipe I have, it is like that all the time.

My younger self wouldn't care since my 66 mustang has horrible exhaust smell and I didnt care but now in my 40s and kids, rather my daily driver be dummy proof should my wife take the truck for some reason.

I won't go back to stock though, the turbo spooling faster makes it fun to drive lol I also have a mishi intercooler and pipes so they probably are working well together.

 

[Colo_Ranger]

@AndyMedic has had issues. I know he's working with Livernois to address it. He will have more insight but... there is something to do with tuning and, since you're not tuned, this may be your problem.

 

[DukeCanBuildit]

@AndyMedic has had issues. I know he's working with Livernois to address it. He will have more insight but... there is something to do with tuning and, since you're not tuned, this may be your problem.

“Honey, when I picked up the kids from school today, I noticed your truck smelled really funny, like gas or something - kinda made name nervous“

”Oh really? I think I know what’s causing that. You know, we can never be too careful when it comes to the safety of the kids. I can fix that - just have to order a new part.”

Smiles, grabs phone and calls Livernois.

 

[Onemig]

Not on my Ranger, but I had 2017 VW GTI that I had installed 2 different brands of high flow downpipe. One had a high quality catalytic converter and the other had a lesser kind.

the high quality DP acted like an OEM unit, smells rich when cold start and odorless at operating temperature. The other one smelled rich even at operating temperature.

 

[awd.nv]

Not on my Ranger, but I had 2017 VW GTI that I had installed 2 different brands of high flow downpipe. One had a high quality catalytic converter and the other had a lesser kind.

the high quality DP acted like an OEM unit, smells rich when cold start and odorless at operating temperature. The other one smelled rich even at operating temperature.

That is helpful, yeah I remember years ago installing one on my buddies Audi and never recalled any smell once it warmed up, which is what kinda threw me off with this one.

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