Ok here is the deal I have a 86 420SEL and I am planning to remove the cat. Please spare me the legal and enviro warning. Has anyone done this and have you noticed a big difference and how. I am also replacing the O2 sensor and I cut the belt on the smog pump already. Has anyone experimented on a better air filter on the 4.2 V8 or other engine mods?

Jake
Ottawa

You can run the dual intake from a 560. You might also replace the O2 w/ a 4 wire (run the extra ground wire to your negative batt terminal) for faster response times.

My better half can't help but say that running a set of high flow cats will result in a loss of less then 2 HP. It's Really time for people to think globally on items such as this... I do as much not because of regulations/legality but because it's the reputable/responsible thing to do.

Jonathan

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x2. the gain in performance will be small compared to the cost financially and environmentally.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Illegal both Federal and State. Why bother.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

Yes I know it's illegal. as I said above that was not the point of the inquiry. LOL This car will use less fuel without the cat and it's one less dollar in the hands of the Saudi Gov. Plus my cat is starting to get worn out and it's big $$$$ to replace.

thanks jhodg5ck for the advice. I am sure proper tire inflation will effect gas consumption more. I think the dual intake is a great idea, I will add those new K&N style air filters to the end of each intake tube... Just an idea. If this makes enough of a difference with the new 02 sensor then I will keep the old Cat. New wheels are on the list too.

Jake, do you not have to get emissions inspections where you live? We have to get them in Virginia every other year. Can you bolt them back on if you have to?

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OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

Did you knock out the precat or the main cat?

Random Tech and Magnaflow both now carry HIGH flow spun cats, they flow tons better than the older higher flows from 10 years back.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

I'd like to know the same thing... I have custom exhaust from the main cat back.
(removed the resonators and tossed in a magnaflow muffler, spent $120) But if you got this kind of a difference by custom precat back... well i just may consider it, I can always have it welded back in later.

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"I don't regret the things I've done, but those I did not do"



1990 420sel with a 560sec motor and transmission and magnaflow exhaust.
(grand total for engine, transmission, parts, and install $1,893.oo)

*champagne taste and a beer budget*

Well precats are known to be, from my experience, more restrictive than the main cat is why I asked.

I could have sworn all the factory stuff on the Gassers was also basically straight through?

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

hmm... well i'm not sure, I don't know much when it comes to exhaust. I'll educate myself a bit more and get back to you.

until then... details people, details.

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"I don't regret the things I've done, but those I did not do"



1990 420sel with a 560sec motor and transmission and magnaflow exhaust.
(grand total for engine, transmission, parts, and install $1,893.oo)

*champagne taste and a beer budget*

The Magnaflow spun metal cats really are high flow low restriction.
They use a metal catalyst and are a small tubular straight thru construction.

I'm running twin #59954 in a true 2" dual exhaust on my twin turbo M103-12V.

Originally tried a SL500 style OEM cat, but the Magnaflow showed a 11HP increase on the Dyno over the single large OEM V8 cat !!!

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1971 280SL ROADSTER
1988 300CE TWIN TURBO WIDEBODY
1994 E320 CABRIOLET
1999 C43 AMG
2005 G55K AMG
2008 CLK63 AMG BLACK SERIES

I knocked out the main cat right in the middle of the car, it's the only one that I have, I am pretty sure the other cat like thing where both sides meet is a collector. Let me tell you there is a difference, but the new O2 sensor helped with the smoothness of the performance. They just need 2 36 inch tubes to replace the cat... 30min with a Saws-All and welder. not. But less oil will be bought from our Saudi friends.

I like that reasoning a lot.

But our "friends" in the DOT/EPA probably don't. They are not so enlightened, you know.

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1991 560 SEC AMG, 199k <---- 300 hp 10:1 ECE euro HV ...

1995 E 420, 170k "The Red Plum" (sold)

2015 BMW 535i xdrive awd Stage 1 DINAN, 6k, <----364 hp

1967 Mercury Cougar, 49k

2013 Jaguar XF, 20k <----340 hp Supercharged, All Wheel Drive (sold)

I am not pointing fingers when I say this... and anyone on the page with a W126 should agree to what I am about to propose as a thought (my way of not trying to insult a great country) but my Yank brothers who reside in the US as I have noticed on my receent 20,000 km journey around N.America are obcessed with buying a new car every 5 years and it's usually a truck or SUV for 1 person. So with that in mind the Government does its best to counter these polution monsters. On my trip I saw NO W126s or anything close to those years except for a Mexican Gent in a old 60s GMC. I rarely saw Mazdas, Hyundais, or a Smart Car. Its was all trucks and SUVs. Here in Canada it's $4.30+ / gallon of gas, compact cars are the majority of vehicles sold. No one under 50 buys a Crown Vic and people hands down keep their Vehicles longer then they do in the US. There is a great supply chain of auto-parts stores called Canadian Tire that has perpetuated a culture of do it yourself auto repair for decades here, plus we Canadians have not been in the same financial bracket at the US was until 1995 or so.
Thus why smaller Jap cars easily out-sell US cars here.
The point is that your Gov is smart and knows how it's National wide fleet of cars, trucks and SUVs compares to the rest of the world and it knows that if "we are all going to pollute we have to give a hoot"
We old Benz owners are not the norm here, the life of this 1 car over 20 years has been matched by 3 cheaper pieces of junk that now rot and leak poisons in a dump, not to mention how much coal and electricity was used to make the raw materials to make those cars.
We need to think bigger... errr Smaller and start driving smaller more reasonable cars and focus less on the rare old ride that MIGHT fail emissions tests. Keeping old cars inshape and NOT living a life of "Newer is Better" but of "recycle and Renew" that's many of us here at the forum, and is the only way to go.

Jake in Canada
With E testing until 1987