Catalytic Converter Question

[Mobtown]

1988 2.9L 4x4 SuperCab

I am beginning the complete replacement of my exhaust system. Most of the flanges are rusted away and there are several leaks up and down the pipe.

Anyway, the stock CC is the two chamber unit seen bellow:

http://www2.partstrain.com/images/pt_products/images/eastern/30291.jpg


Does anyone know why Ford used a two CC system on this motor?

[F150hybred]

Plain and simple. Emissions. Now, I know there's a more elaborate and technical explanation, but if one word can sum it up, why bother?

[85_Ranger4x4]

The cars with single cats have both chambers in one can.

[Mobtown]

The cars with single cats have both chambers in one can.

Excellent, I thought that might be the case.

Next question, Does anyone know of a high-flow, single can replacement for this part?

I have seen some generic CCs that might work, but I wanted to see if anyone has had success with a specific replacement part...

[Hahnsb2]

I used a universal CMX Hi flow cat on mine and had better emissions than my dads rig which is still running 2 stock cats (the rear one was new).

[ZMan]

summit racing has em..

http://store.summitracing.com/egnsearch.asp?Ntt=Ford+Ranger&N=700+4294923429+115+4294838974&NeXID=5&Ntk=KeywordSearch

[Natedog]

I used a universal CMX Hi flow cat on mine and had better emissions than my dads rig which is still running 2 stock cats (the rear one was new).

This one and where did you get it?

http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2009548/p-2009548/N-111+10201+600012669/c-10101

Higher flow than most aftermarket converters
Polished heat shield
Stainless-steel construction

Meets these EPA displacement requirements: Up to 5.9L engine with vehicle test weight of 6,000 lbs. Not legal for sale or use in California-Check local emission laws.

I don't see why it has that last catch phrase... :annoyed:

[MAKG]

Because if it isn't legal in California, it isn't legal in about 20 other states as well, and at more local levels elsewhere. It MAY not be legal anywhere (the displacement requirement is very far from the only one), or for some applications. It's especially interesting that it hasn't been EPA approved. That by itself probably makes it illegal.

FYI, all cats have at least two beds in them. The front one is a reducer and the rear one is an oxidizer. You have to put them in that order or the oxidizer doesn't work and you get high HC and NOx. At least, not without a smog pump. You also need the engine in correct closed-loop operation for the cats to work properly. If it's open loop or just wrong, one of the two beds will not be fed with the reactants it needs.

"Universal" cats are a hugh PITA to install on V6 applications. The inlet is not round, and quite a lot of welding jobs, well, suck as a result.

[Hahnsb2]

Yep thats the one Nate. I picked it up at a local auto parts store, was about $50. I would ignore "not legal in CA" part, as long as your truck is in good working order it will pass emissions with no problem, no one will look under your truck and try and find out if the cat you have on it is "legal" or not. And MAKG is right about using a universal cat on RBVs, the previous owner of my rig had cut the flange off the stock cat and then ovaled a piece of 2 1/2" pipe and welded it to the flange and then bolted it up, he used a catco universal cat, which BTW with that setup it was near failing levels at emissions. I ended up accidentaly destroying that cat while in the process of modifying my exhaust, and thats why I got the CMX unit, the emission numbers were many times better with the CMX cat over the catco cat.

[Seabiscuit]

I think my truck 2001 is a California version which has three cats.......

[Seabiscuit]

Also sucks because I live in Arizona

[AllanD]

Anyone who tells you that the stock two chamber cat doesn't
flow is.... well.... either a liar (advertising people?) or an
idiot (anyone who believes the advertizers claims)

I've even compared the two chambered cat to straight pipe and
the engine (2.9) simply runs better with the cat installed

FWIW the ONLY difference between the '88-92 2.9 catalyst
and the 4.0 cat is that the later 4.0 cat uses a different
style rear flange, though SOME 'later '91's and some '92 2.9's
came wiht the donut/flare/spring-bolt flange used on the 4.0.

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[Neelybd]

I am glad I live in Oregon, I sent a metal rod through my cat.

[krugford]

^ sigh... why do people insist on announcing that they've broken the law on a public forum....

[85_Ranger4x4]

I am glad I live in Oregon, I sent a metal rod through my cat.

FWI cats take very little power, far less than the giant expansion chamber you created.

[Seabiscuit]

How do you improve performance with a truck that has california emissions?

[rickcdewitt]

took the words out of my mouth allen.hes got pretty much the same cat as a 4.0l,plenty of flow.i took the one of my 91 exploder and put it on my 91 ranger 2.9l.much larger than the early 80's cat.

[rickcdewitt]

How do you improve performance with a truck that has california emissions?buy only c.a.r.b. certified headers,chips, etc. and make sure your mixture stays somewhat lean.

[MAKG]

buy only c.a.r.b. certified headers,chips, etc. and make sure your mixture stays somewhat lean.

Mostly. The mixture must stay controlled, which does generally mean slightly lean -- but switching back and forth to slightly rich. If you make a lean mixture all the time, your engine might detonate and you'll have high NOx emissions.

A far easier answer to deal with is to leave the engine alone and improve total vehicle performance by screwing with gears, tires, and the transmission. The first part of this is defining what you mean by "performance." If it's something you can feel in the seat of your pants, it's probably not the usual power modifications. Power may or may not improve acceleration, and can make things significantly worse at low RPM. Note that increasing low and medium RPM acceleration by 30% or more is doable with gearing (in the rear end or transmission), but making the engine produce 30% more torque is VERY difficult.

[AllanD]

ALL the engine mods that anyone has ever done (excepting forced induction or Nitrous Oxide) doesn't ammount to diddly compared to a gear swap.

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