theshow72

Hi,
I was talking to a mechanic I have done lots of business with in the past about my 928 (he has not worked on the 928, but I wanted him to do a few things for me). I told him that I was thinking of putting a Y pipe on it, and removing the cat (it is an 82, and in my state nothing older than 83 needs to pass emissions). He told me he thought it was a bad idea because the car was made a certain way, that engineers at Porsche had sat down and planned how to get the most power out of everything, and changing anything would throw all of that engineering off. Granted, he is not specifically a Porsche mechanic, but I trust this guy a lot. What he is saying makes sense, but I really don't know. I read about you guys tweaking and changing everything. What do yo guys think? I want more power!!!!
If I put a Y pipe specifically made for my car on, and remove the cat, am I going to get warning lights coming on and things like that? Anybody done this to an 82? I've been told it is the quickest/cheapest way to get a good performance boost, and I can understand why (less restriction = more power). I just don't want to mess her up!!! If the engine is expecting a certain amount of back pressure, and it is not there, then what happens?

Thanks,
Joe

whitefox

First off you won't get any warning lights, and second, if Porsche had it their way, there wouldn't be catalytic converts on the car because they just rob power, but in order for Porsche to be able to sell their cars in the US the federal law required them to fit the cars with cats. You will be more than happy with a Y pipe, and you will be very happy if you do not let your mechanic work on your 928. Thats just my .2 cents though. Good Luck.

AO

Find a new mechanic.


Actually on second thought, he may have been trying to avoid saying no because I believe it is a federal offense for a mech to permanently remove a catalytic converter (or as the homies say here in Detroit - Cadillac Converter!)

cold_beer839

It's a Porsche 928, not the space shuttle.

Get the Y-pipe w/o cats. It will produce a noticable power increase and a nice aggressive tone in the exhaust note.

Any muffler shop can do the install if you don't want to do it yourself.

And tell your mechanic to grow a set of *****.

mark kibort

your mechanic = Moron

Ive done more to an 82 than probably anyone on this list, and taken more steps along the way too

It responds beautifully, powerwise, all along the way.

Yes, less back pressure, more power, less restriction on the intake , more power. Think of the 82 US as a car that cant have the gas pedal go all the way down to the floor.

One thing the list has provided is the limit and the downside of performance altering changes. If anderson ran 420rwhp for 5 years of racing, this should show that running your 82 or my 87 at 200 to 300hp is like anderson running his car around at half throttle. These motors are well designed yes, but the 82s got the short end of the stick, and could use all the help they can get to get up to their euro brothers of the same time period. (ie 300hp vs 220hp US). bigger valves, no cat, wider intake ports, bigger throttle body, higher compression, etc.

mk

aggravation

He's probably more familiar with kids strapping giant chrome noise cans on little rice burners and doesn't really know that in your case it really will help

Nightfly

He probably recommends staying 'stock' because once you travel off the known path, you're above 'mechanic' level thinking and into 'engineering' level thinking, and many mechanics either can't, or won't, venture into that area. Some people don't like to stray away from what's in the manuals; once you have, you don't have anyone to rely on except yourself if you need to, oh, lets say, pass an emissions test. If a problem arises, and you can't do the work yourself, most mechanics were trained to simply return everything to 'stock' as the most likely way to pass, rather than start fiddling with all kinds of things he isn't familiar with. The more changes you have made, the less likely you will be to find someone willing to work on your car, and the more expensive it will be for you. On the other hand, if the place you live in doesn't have strict inspections, or no inspections, then feel free to make any changes you want. Then, all you have to do is worry about keeping the car running.

FRporscheman

Taking out your cat is bad for the environment. Just because the law's ok with it doesn't make it ok. Can't you just get a nice free-flowing cat?

Nicole

That is entirely incorrect.

The late Ferry Porsche himself said (many years before he passed away) that the only way for sports cars to survive is if they are environmentallyl friendly.

When the cat frenzy started in Europe around 86/87 new Porsches were the only cars on the market rated the same horse power with or without cat.

Porsche consistenly pushed the envelope when it came to pollution controls. The 993 turbo, for example, had the most advanced emissions control system of its time.

If you dig through history, you'll probably find a few more such examples.

Also, the company has done many other things to be easier on the environment - the first galvanized body shells for longre life, and the early adoption of water based paint come to mind.

Having said that, we all know that the early 928s were fitted with rather restrictive cats (or maybe they have just become restrictive over the years). While I have yet to see clear evidence that removing the cat from an S4 increases power (not just noise) in any significant way, the older cars seem to benefit more from cat removal or replacement with a modern, free-flowing metal cat.

The main difference between removal and replacement is that the no-cat version will emit about as many toxic fumes as 20 928s with cat. Or like driving 5k miles and producing the same amount of toxic fumes as someone who drives 100k.

So, my vote would be for the Y with a metal cat.

cold_beer839

DUDE OMG?

Tell you what, take the old cat down to the metal recyclers and plant a tree on the way home, then you'll be even-steven with the enviroment.

Oh and buy a pair of hemp underwear too.

Daniel Dudley

I believe you will find that almost any Porsche from about 74 to 90 will respond to exhaust upgrades. Modern cats are way better, but the actual exhaust itself is also restrictive on many models. I believe the 86.5 928 was the first to have an effective exhaust system, but all 928s will pick up top end power from cat upgrades or removal. You will absolutely notice the difference in power. The general concensus is thet headers are nice, but not cost effective for what you get, so a Y and a good exhaust is the way most people go.

Well worth doing, you will not regret it.

SeanR

That made me giggle.

Mrmerlin

Check out Roger on the list he sells a Y pipe for your car and you have the option of adding a cat to it or not, you should notice a power gain cat or no cat. You can install it yourself if your mechanically inclined or the mechanic could

OJ GTS

Actually, the Cat simply catalyses the gases that are nasty to Humans... you might not want to run it in your garage with the doors shut for too long but the Pandas will live another day.

Plus every person has their own Carbon Footprint, so if someone dies from the fumes you're significantly reducing Carbon Dioxide output!

whitefox

I do remember reading this in Ferry's autobiography.