New build 454 and the wife hates the exhaust smell

andybflo · Monday at 10:55 AM

You really want to eliminate the smell? Put cats on it.

I put cats on my '76 GMC Motorhome, which has a Sniper 2. Have cats on my '63 Impala with a Holley Terminator Stealth. In both cases, I got sick of smelling like, and smelling, exhaust. In those cases, the 455 and 409, respectively, lost zero throttle response, fuel economy, or drivability. I'm out about $600 in total, for both cars (pair of Magnaflow, high-flow cats in each), I can take my wife out for a cruise and neither of us smell like unburned hydrocarbons. It will change your exhaust tone a little. I also run them on my LS Swapped, '86 C10. I've gotten various responses from local inspection stations here in NY as to if I need them on that vehicle or not. Being a heavy-half, in NY, you get told yes and no, depending on who you ask.

My old solid cam C1? That stinks, as it should, but anything where I want to *go* somewhere, in a level of comfort, and get out not smelling like a Mobil station, I stuck cats on. They're not a performance loss anymore, don't weigh much, and are the surest way to eliminate those smells, exactly as they were designed to, for the last 50 years.

Then the Sniper can do as it wishes, and as long as it's not terminally rich, it'll have little effect on the cat.

And, no, I'm not mandated to do so by my state, just choose to solve the problem my wife (and I, as I age) brought to my attention years ago...

andybflo · Monday at 11:07 AM

3 Ton said:
Dump the Chinese made Holley crap, some of them work, some do not. Why take the chance.
i had one client that both Mom, Dad, and he installed Holley crap on all 3 trucks. They had to go back to a carb because one would not work right.

BTW I did carburation parts before I retired. Holley went out of business the same time Carter and Rochester were forced out of business. Everything NEW is from China, and its all junk. Any of these names on new carbs are Chinese made. 100%

Where do your tail pipes end up? Blowing exhaust back into he cabin is usually on how far back they go.
You have not stated if its leaking form the pipes OR coming form outside in.

The last Eddys I installed on a car (a 800 CFM AVS and an 600 or 650 CFM AFB) were cast by Weber in Italy and built in the US. That AVS went through my hands six weeks ago. AFB was mid-summer.

The last Holley I bought, for myself was a 4150HP. That was cast, assembled, and flowed in the US. Beginning of this summer.

Might needles/springs/metering rods/jets/etc be made in Asia? Sure. But tell me what isn't. And, sadly, their machine shops are as good or better than ours right now.

I love me some Qjets, but find me one that wasn't cast four plus decades ago... Most, if not all, are tired. I keep a few around here in great shape, but many are whupped and rebuilt/rebushed by questionable shops during those four decades.

I've never had a FI system not work; even down to the lowly, poorly built, Powerjection I once was silly enough to buy. That was terrible to tune, but worked once you dialed it in. I've installed probably fifteen FiTechs, probably fifty Holleys of various flavors over the years. Had one bad mainboard on a Sniper, but that was easy to diagnose, and Holley second-day-air'd me the replacement board. Had one Atomic EFI I struggled with, but even that ran well, eventually...

Almost every time I've had a non-runner brought to me from a peer or friend, it's fuel system not being sorted out properly. Wiring being a close second.

77Dmax · Monday at 11:53 AM

Are the floors/quarters rotted out?

chris3353 · Monday at 12:06 PM

txaggie said:
Howdy all!

I recently rebuilt an 85 suburban 454 and stripped the factory exhaust off for a hooker black heart 2.5” x pipe dual system. Well, my lovely wife hates the exhaust smell and I was curious if some high flow cats might cut down on it?

Let me know if anyone has any recommendations! 454 bored .030 over, Holley sniper, long tubes, etc.

Something is not right.

Can you data log with the sniper?
what is the AFR at idle when you smell it?
What is the engine temp?

SquareRoot · Monday at 12:37 PM

andybflo said:
You really want to eliminate the smell? Put cats on it.

I put cats on my '76 GMC Motorhome, which has a Sniper 2. Have cats on my '63 Impala with a Holley Terminator Stealth. In both cases, I got sick of smelling like, and smelling, exhaust. In those cases, the 455 and 409, respectively, lost zero throttle response, fuel economy, or drivability. I'm out about $600 in total, for both cars (pair of Magnaflow, high-flow cats in each), I can take my wife out for a cruise and neither of us smell like unburned hydrocarbons. It will change your exhaust tone a little. I also run them on my LS Swapped, '86 C10. I've gotten various responses from local inspection stations here in NY as to if I need them on that vehicle or not. Being a heavy-half, in NY, you get told yes and no, depending on who you ask.

My old solid cam C1? That stinks, as it should, but anything where I want to *go* somewhere, in a level of comfort, and get out not smelling like a Mobil station, I stuck cats on. They're not a performance loss anymore, don't weigh much, and are the surest way to eliminate those smells, exactly as they were designed to, for the last 50 years.

Then the Sniper can do as it wishes, and as long as it's not terminally rich, it'll have little effect on the cat.

And, no, I'm not mandated to do so by my state, just choose to solve the problem my wife (and I, as I age) brought to my attention years ago...

Excellent writeup. I put the magnaflo cat on mine and it's 95% improved. Zero loss in power.

SquareRoot · Monday at 12:42 PM

People tend to think that EFI is precise and therefore there is little to no emissions. Wrong. It's much better than a carb by design but any internal combustion engine produces emissions regardless of the AFR. After putting PF4 on my truck my buddy asked me why it still stunk. I could only stare at him like he was stupid. But, you don't know what you don't know.

Brads74 · Monday at 4:01 PM

Have you done a cost analysis of new exhaust system vs new wife???

Just kidding…

Vbb199 · Monday at 7:02 PM

SquareRoot said:
Sniper, cats? I got nothing. @Vbb199 did use a word I've never seen before though. "Enlean"? Lol

******* hilarious. What a comedian.

GTP51 · Tuesday at 7:29 PM

I have the Sniper on mine and have the same extractors as you (small block 355 worked), I fitted cats and it helped a lot over the previous exhaust system but its still has the fuel smell my exhausts exit just before the rear tyres on each side .At present the fuel table at idle is around 14 to 4.2 and I intend to lean it out to around 14.7. One thing I am dealing with it that where the old fuel vapor return line that went to the charcoal canister is no longer used and it is creating exactly the symptoms you have described, stopped at the lights and smell fuel. My canister return line ( canister has been removed)is running through a catch can with an absorbent sand in it but still fumes like crazy despite the exit line being directed under the truck. Anyway hope this helps although its 2 issues not one. I am thing of using vented fuel caps(duel tanks) and blocking off the canister return line.
cheers
Geoff

WP29P4A · 2024-11-13T14:48:53-0500

Are you sure that what you are smelling is exhaust and not the new coatings and gaskets? When I installed the new exhaust system on our 74 Charger, it smelled for almost a year before it normalized. It was the paint, new gaskets and coating on exhaust manifolds that was causing the smell.

Ricko1966 · 2024-11-13T14:54:02-0500

Here ya go.

idahovette · 2024-11-13T15:02:08-0500

^^^^^^How in the he!! do they know what the X girlfriend smelled like????^^^^^^^

New build 454 and the wife hates the exhaust smell

andybflo

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