Gain extra benefits by becoming a Supporting Member Click here find out how!

Classic Performance Products Nu-Relics Power Windows
American Auto Wire Hellwig Products IncPerformance Rod & Custom
Danchuk Catalog



Username Post: Adding a catalytic converter ?        (Topic#368685)
doubleE 
Valued Contributor
Posts: 3914

Loc: Eagan MN
Reg: 06-02-03
06-13-22 10:49 AM - Post#2842844    

Getting a little sick of smelling the fumes on my stock 72 C10 with the original 2 barrel 307 using E87 gas. I have notice most other old cars seem to smell the same. My previous 62SS was the same. Wondering if adding catalytic converters (dual exhaust) would help. Anyone try this?

There are a few gas stations selling leaded gas but not close and more expensive. Do you think using leaded gas would change the smell? I'm thinking E87 is the cause? I sure don't remember these cars and trucks smelling like that back in the day.

Eric

Proud owner of My Blue 62 Impala SS


Edited by doubleE on 06-13-22 10:53 AM. Reason for edit: No reason given.

 


Tony1963 
Frequent Contributor
Posts: 1406

Loc: Orlando Florida
Reg: 07-09-18
06-13-22 01:14 PM - Post#2842863    
    In response to doubleE

There are other forums where people with older vehicles have the very same complaint. They have added catalytic converters and cleaned up their exhaust.

Keep in mind that you cannot use leaded fuel in a converter as it will render it useless. The lead contaminates the converter.

Also keep in mind the location of the converters and necessary heat shielding that may be necessary.

Switching to electronic ignition to eliminate most misfire conditions is required as well as a proper engine tune. If you run too rich of an exhaust, you'll overheat the converter.

Good question.

People fear change because it threatens what they know, or what they claim to know.


 
doubleE 
Valued Contributor
Posts: 3914

Loc: Eagan MN
Reg: 06-02-03
06-14-22 03:19 PM - Post#2842919    
    In response to Tony1963

Thank you for the input, will give it some more thought.
Eric

Proud owner of My Blue 62 Impala SS


 
Mel Foye 
*VIP* Original Founding Member Group
Posts: 5423
Mel Foye
Reg: 09-29-00
06-14-22 05:29 PM - Post#2842924    
    In response to doubleE

Well Eagan old time Shakopee guy here. Millions did not need converters from the factory and didn't smell so go that way.
Had a 69 suburban. Sb 400 with a small cam upgrade replaced stock 350. Always flew past smog standards that were 15 years tighter.
Bad stink could be old gas, poor timing layout, carb not properly adjusted etc. Remember that stink is unburned gas.
What is your timing layout first?



It Was On Fire When I Laid Down.


 
someotherguy 
Senior Moderator
Posts: 29587
someotherguy
Loc: Texas
Reg: 08-01-03
06-16-22 10:37 AM - Post#2842982    
    In response to doubleE

  • doubleE Said:
Getting a little sick of smelling the fumes on my stock 72 C10 with the original 2 barrel 307 using E87 gas. I have notice most other old cars seem to smell the same. My previous 62SS was the same. Wondering if adding catalytic converters (dual exhaust) would help. Anyone try this?

There are a few gas stations selling leaded gas but not close and more expensive. Do you think using leaded gas would change the smell? I'm thinking E87 is the cause? I sure don't remember these cars and trucks smelling like that back in the day.

Eric


Hey Eric,

Are you sure you have leaded fuel still available nearby? Maybe confusing it with non-ethanol fuel (aka pure gas) - there's no lead in that, either.

Mel's reply is spot on, you may have a mixture or timing issue that needs to be addressed. Do beware that if your situation is extreme enough and you do add cats to it, you can melt them down in a hurry and cause yourself a lot of issues. Excess fuel in the cats will light off in there and they'll glow red hot and eventually fail.

All non-cat engines will have *some* detectable "fuel" smell to the exhaust, how much is too much will be a bit subjective. Most of us are just so used to smelling "cleaned-up" exhaust from modern vehicles that a non-cat exhaust seems especially odorous.. personally, they don't bother me, unless they are in fact in poor tune.

What bugs me more are the modern cat-equipped vehicles that smell like ammonia when they floor it in front of you. Always reminds me of the beauty salon my grandmother would go to for a perm. Bleh!

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
1983G20Van 
Super Senior Member
Posts: 3928

Loc: Hurst, Texas, USA
Reg: 11-13-02
06-19-22 12:20 AM - Post#2843100    
    In response to someotherguy

I would definately switch to a closed loop EFI system with a target air/fuel ratio of stoichiometric or leaner before adding cats. I do run my 383 Express van and my 8.1L Tahoe in lean cruise at 16-16.5:1 AFR at cruising speeds without hurting the cats. So long as the engine is leaner than stoich and not misfiring the cats will not overheat as there is no fuel leftover fuel for them to combust. Then again GMs method on my 80 C10 for cleaner emissions was a cat but they pumped air via the smog pump into the manifolds to combust the extra fuel prior to feeding the exhaust into the cat.

I also hate the smell of a cat when the engine is in PE. It has an odor of Ammonia or Hydrogen Sulfide aka rotten eggs. I will hammer down to stay in front of the pack leaving a traffic light so I don't have to smell the cats on these small 4 banger crossover SUVs that are flooring it from the light. Even my 4.0L V6 Pathfinder will stay well ahead of the crossovers.

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 06-19-22 12:23 AM. Reason for edit: No reason given.

 
Tony1963 
Frequent Contributor
Posts: 1406

Loc: Orlando Florida
Reg: 07-09-18
06-19-22 11:29 AM - Post#2843118    
    In response to 1983G20Van

The catalytic converter is fully functional at 14.7 to 1 ratio. Leaner and its functionality drops off.

I will advise caution when doing a home brew emissions system.

People fear change because it threatens what they know, or what they claim to know.


 
Stinky 
Senior Member
Posts: 1827

Loc: Whitewater, CO
Reg: 05-25-01
06-24-22 01:33 PM - Post#2843304    
    In response to Tony1963

It makes no sense to me...a cat when you don't need it. HUH?



 
Tony1963 
Frequent Contributor
Posts: 1406

Loc: Orlando Florida
Reg: 07-09-18
06-25-22 02:36 AM - Post#2843329    
    In response to Stinky

As the original poster explained, the goal was to clean up the smell of the exhaust.

People fear change because it threatens what they know, or what they claim to know.


 


Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

278 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.16 seconds.   Total Queries: 17   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 09:35 AM
Top