My cat died.

[Bassyaks]

Look at the good point, "You now have a rattle"

[r39o]

[boof1306]

The problem is people compare the performance of their half blocked twenty year old cat to the evacuated case and say there is a huge power increase. I have compared a good cat back to back with an empty case and there is minimal power increase.
Cessnajon, its not so much about the quantity of exhaust fumes its about reducing the harmful ones - oxides of nitrogen, carbon monoxide and hydrocarbons.

[Terry Kay]

<<The problem is people compare the performance of their half blocked twenty year old cat to the evacuated case and say there is a huge power increase.>>>

Really?
Try this and report back how well your Van runs , both ways.

Stuff a potato in your tail pipe--with the empty cat attached.
Go for a ride.
See how much power you have.

Then yank it out, go for the same ride & report back on the minimal power difference.

The problem really is --how that stone stuff's itself into the outlet of the converter, or gets hung up in the muffler.

If it's sideways and totally blocking the outlet , your test was not including this scenario.
_________________
T.K.

[boof1306]

Terry you are saying exactly the same thing I am. If the monolith is broken down and blocking the hole you will not have a well running engine and this is no basis for comparison.

[Terry Kay]

It didn't seem to read that way--
You tested the van with a loaded & an unloaded converter & didn't see much of a power increase.

This in itself can only mean one of 27 different things, excluding the Black Monolith.

If you didn't see / feel much of anything, I would have to say your engine didn't have much compression in the first place for a plugged cat or muffler to be limiting performance.
This is what it sounds like to me anyway--
_________________
T.K.

[boof1306]

The engine is a low mile Mv in great condition. I have seen cats removed from other makes and models of cars and substituted with a straight pipe, all drivers have said the same thing post doing this - no point. It might be a couple of hp at most. If you have made no additional mods to the engine that require increased flow there is little benifit to gutting over a new cat. If you want to save cash, don't give a s@#t about the enviroment or just want the easy way out take to it with a crow bar, but don't expect a fire breathing vanagon.

[Terry Kay]

And to develop a little more on this theory--

If every engine management system in the vehicle is cattie wompus--forget it.
There will be no power gains to be felt in the seat of your britches with a opened up converter.
However, if everything is up to snuff, and dialed in, you will feel big difference removing that hot potato outa the tail pipe.

Look, your only talking about a 95 horse, push rod engine here,
nothing exotic at all.
If you reaped a couple of more horses by unplugging the converter, it would be like being on the Obama entitlement plan--free HP.

What I am saying to you in essence is, every electrical engine management system component was changed on my 2.1, excluding the ECU.
( what I knew about anyway )
The engine ran good, but was a slob on gas, and had no Umph--

I asked, & asked some more, the allegid guru's on the vanagon.com list.
Replace, replace , replace.
Nada, Nada, Nada.

I was at wits end.

I replaced everything---
Except the TPS (not one of them in months even brought this up)---
It was so far outa wack I didn't know how the Van was running.
I found it totally by accident & replaced it & the operating cam, & adjusted it properly.

Bingo--no burnt, wet eye's when I walked past the tail pipe.

Then--a week or so later I see my tail pipe waving at me as I walked outa the post office--shit.
I yanked the whole converter to tail pipe assembly.
The gasket was weeping a little at the union pipe to the converter.

I split everything apart---all new gaskest & fastener's from the front of the converter to the tail pipe.
And I sure don't know why I did this--but just for the hell of it I stuck my drop cord to the outlet of the converter.
Guess what?
No Light passing through it.
What?
The other end was jammed so tight with busted pieces of
converter stone I was amazed the engine ran at all.
It was in the muffler too.

The van--all 95 HP of it is now actually pushing it down the road too.
It's not being 3/4's held up in the exhaust system--especially with an empty converter.
I'm getting everything that the engine was designed to put to the wheels--nothing lost in fighting to get the exhaust outa the tail pipe.

PTL,Amen and Haleluija !!

So, what your saying is there is no benifit of a free flowing exhaust?

I think so---
No--I know so.

And in no way shape or form am I talking about 6.0 Holden performance---
I know much better than that.
_________________
T.K.

[vanagonjr]

Please people, gutting it to get home, or buy some time - fine, but replace it! A new cat is $120 - less than a few tanks of gas - do me, and the environment a favor - please And a new cat is not restricting your 95 HP WBX'er - no how, no way.

Even the high-flow cats for the V8 boys that are are more a marketing success than a HP success in most cases. While certain application might see a slight gain, I have seen at least one automag build with dyno results that showed little to no gain with the cat removed.

Another on Civic with a high flow cat test "Apparently, the metallic core unit does indeed flow slightly better than the ceramic unit. But when we say slight, we mean slight. The metallic core cat netted us a 1hp gain (to 151hp) and no increase in torque"
_________________
John - 86 Wolfsburg Westfalia "Weekender"
Flint reversed 1.8T W/Passat 5-Speed
LiMBO (late model bus club) www.limbobus.org
LiMBO is on Facebook too! https://www.facebook.com/groups/
FAQ thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=525798

[boof1306]

Terry, again you are saying what I am saying. You had a stuffed cat, you unblocked it and this difference was night and day. I get it and I agree. But some people seem to be debating the merit of new cat vs gutted cat. This is where I am saying the difference is minimal on a stock factory efi engine. Just to confuse matters, if you want to talk about restrictions, take a look at the syncro dust bowl filter and the genuine mufflers.

[DLJ]

If you want more then the EJ-22 go bigger ! Go frankensuby, or better yet go H-6 .

[Terry Kay]

Go LS-7 and be all done with the lack of power forever.
_________________
T.K.

[plummerdesign]

Question...
How did you get the cat material out of the chamber? Seems pretty solid and not a substance one would want to breathe in.
Cheers,
Jeffery

(Westfalia travel/camping videos at YouTube link below)
_________________
It is old and green and it makes me grin.
1984 Westfalia 1.9

[chojinchef]

[r39o]

[Terry Kay]

I must opine on several of the above mentioned posts.

I know of not one guy around here who has built any kind of performance hot rod that is running a converter for any kind of reasons mentioned above.
Zero.

They restrict exhaust flow--period.
Why in the heck would anyone build a 5--600 hp car, van, whatever, have an exhaust built that will efficinatly scavange the exhaust at the right time out & away from the combustion chamber's as fast as it can--impede this process with a converter?

Maybe on the left coast this may apply--
Not here, or anywhere I can think of other than the land of strange & odd.

This all does not apply where normal happens.
_________________
T.K.

[chojinchef]

I guess that was part of my point but I inaptly made it after a couple glasses of port last night. Building a 5-600 hp car and having 'an exhaust built' - which would infer considerations to optimize the pressures for filling and purging of the cylinders.

Not just swapping the cat for a straight pipe. The stock system of the modern automobile is made for noise suppression as well as for emissions reduction, so a simple swap of a good cat for a straight pipe is not going to make much difference other than the sound profile.

Building a system for a V8 that is not stock in order to optimize for performance would likely include, but not limited to proper sized header tubes into a correct length collector, most likely a dual exhaust profile probably containing a crossover pipe, high flow muffler (if on road use) and correctly sized pipes. There is no generic setup that can be made for all cars, they are too different. The exhaust guys who live and breath (pun intended) this stuff daily don't agree across the board.

Even the BMW M3 has a dual exhaust with its inline 6, high velocity - high flow exhaust with cats. Other considerations just need to be made in the modeling of the exhaust profile for a cat, but most opt not to do it because common practice is not to. Those things will change at some point, whether by preference due to increased knowledge on the subject, or government mandate. Taboo technology now.

Fuel injection was the taboo technology at one point .

A long and drawn out over caffeinated babbling to get to the point; pulling a cat from a 90 hp 25 year old van will probably seem like a boost as the cat was most likely half clogged anyway, but the design of the system with all its bends and technology limits probably wont make any appreciable gains.

Just my opinion
_________________
Its a mistress; an expensive, whiney, needy bitch of a mistress. She is a chunky, dirty girl with bad skin, little motivation and yet she always makes me smile. She sure has been around before shacking up with me. She has a direct line to my wallet, plays with my emotions, is consistantly jovial yet with a sarcastic and sardonic side, is consistant in her inconsistancy, and every once in a while gives me a great ride and a fantastic memory.

[vanagonjr]

Chef - you got it on the customized V8 exhaust. On the old 70-80's v8 cars, pulling cats surely helped, now so much now, they have some impressive high power cars (even Cadillacs!) - messing with the exhaust on those can actually cause loss of power.

Back to the WBX'er - I'm going to guess I'm the only one here that went from a gutted cat to a good one - just this summer - guess what? No difference. I wish I had run 0-60 times before and after, but I did not even know the old cat was essentially empty. And even if you got a gain, what are we talking .1 or .2 seconds off a 25 second 0-60 time? Do our kids a favor - run a good cat!

You want to see restriction in your exhaust - got the Danish replacement pipes every vendor sells ? see this thread http://www.thesamba.com/vw/forum/viewtopic.php?t=362495&highlight=exhaust
excerpt -

[j_dirge]

[Brianfromutah]