Switched to an H-pipe and the smell is unbearable

I had the same issue with my car. I started getting tired of smelling like the car after driving it and having it stink at stop lights etc. It's a common problem if you have deleted your egr setup. I don't like the egr but It helps decrease the combustion temp and in turn reduces the nasties like NoX gasses etc. I ended up buying 2 of the magnaflow high-flow metallic spun cats. I hacked up my bbk h pipe and welded them in. I have hardly noticed a change in tone and no obvious decrease in power. The smell is not 100% gone but is noticeably better. I think they were about $90 ea. it's important to choose ones that do or do not need the air injection. I removed all my smog assembly so I had to get the 3-way catalyst ones that do not require the additional air to operate. Make sure your A/F ratio is close, cats won't live long in a rich condition for long.

I was never able to find a H pipe with high flows that didn't have the air pump line, hence why I hacked my own together. I deleted my whole smog system so I have to run cats that don't require the extra o2 injection. I like the magnaflows because they still have the 3-way catalyst but no need for the air tube. That being said these cats aren't as tolerant and need the tune to be good. Too rich and you can plug them up in a hurry from what I hear. I've got maybe 3k miles and still working

I think most of us have forgotten how smelly cars were before cats came out in 1975. My son's 94 GT (Explorer heads & intake, no EGR, 195K miles on stock bottom end) has an off-road pipe, and it's smelly but no worse than what we used to call "normal."

Didn't know about the really-high-flow cats. Nice. My own car has a CARB-legal high-flow catted H-Pipe (one of the last ones made, I understand) and it runs fine but does not sound like an off-road pipe. Theres as much difference between my car with catted H-Pipe and Bassani cat back versus my son's 40-series Flomasters as there is between my car and a stock exhaust.

Old5Oh said:

I think most of us have forgotten how smelly cars were before cats came out in 1975. My son's 94 GT (Explorer heads & intake, no EGR, 195K miles on stock bottom end) has an off-road pipe, and it's smelly but no worse than what we used to call "normal."

Didn't know about the really-high-flow cats. Nice. My own car has a CARB-legal high-flow catted H-Pipe (one of the last ones made, I understand) and it runs fine but does not sound like an off-road pipe. Theres as much difference between my car with catted H-Pipe and Bassani cat back versus my son's 40-series Flomasters as there is between my car and a stock exhaust.

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To me, the smell of exhaust from a carb'd engine is one of the best smells in the world!

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PW_Pony said:

To me, the smell of exhaust from a carb'd engine is one of the best smells in the world!

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Thats what I thought too till I tried daily driving my built 66 coupe..

The smell is noticeable, but if its unbearable you have an exhaust leak...I rum a late 5.0 in my 66 with longtubes and dual exhaust, no cats...and typically i smell it very little to not at all

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Thanks for the info guys, I will have to pull the codes to see about the mix. I have been blessed with my moms super sense of smell, and it may not be as bad to others. My brother has a 71 with the 351C in it and it doesn't smell nearly as bad though. I got the car from a friends dad who passed away last year, and I had to do the complete tune up, new gas tank, blow the lines, etc. just to get her running again. She only had about 500 miles put on since 2004, mostly in 2004. Since then I have been slowly chipping away at speeding her up. Very slowly. It is almost time to take her off insurance for the winter so I will have plenty of time to get to the bottom of this.