Please educate me on cats

I need a bit of education! My 1977 308 GTB was originally fitted with air pumps and cats etc. The air pumps are long gone, but the cats are still there, and the exhaust system is looking a little bit tired.

Assuming that I put a new exhaust on it, would it also make sense to replace the cats? Emissions requirements are grandfathered out for my vehicle where I live, so am I correct in assuming that I can replace the cats with straight through sections of pipe? I assume this makes more sense than going for new cats (assuming the old ones are shot)?

Thanks.

 

As far as I know, 1977 308s were pre-cat. Maybe it's different in Canada.
Mine came with no cats, but had a heavy thermal reactor in place of a muffler. It's long gone now, along with the air pumps. I would dump the cats totally and go Ansa.


Greg

 

if you want to keep the air clean, replace the cats. now on carbed cars there is no 'feedback' for fuel trim to keep from toasting the cats and setting the car on fire. but with a proper tune and i'd really add a AFR gauge so you can run the cats and keep the air clean.

it's your call, most remove them and run straight pipes, the air will be dirtier but your risk of a car-b-q just went down.

 

I don't know what the emission laws are like up north, but down here it is illegal to tamper (or remove) emission equipment even if you are not required to test anymore. That said, if you were to remove the cats, I don't know how anyone would find out since you don't have to test it anymore. On the other hand there are hi-performance cats out there now that will clean up the emissions and have minimal restrictions (back pressure). And I know I like to breathe clean air (as does the rest of my family).

When I was younger, I'd do anything for more power, but having a family changes your priorities (OK, off my soapbox now).

First, check to see if your old cats are good or bad.

On a side note, I just had my '78 "smogged" and it passed (AGAIN) with flying colors. Generally, I was emitting about 10% of the allowable. I'll post my results in another thread soon. Also, I will soon dyno my car, both with the cats on and off to see what type of differences there is.

Henry

 

I'm curious about how to gain perspective in this matter. I do indeed have a carb car so I have been planning on eliminating the cats to lessen the fire hazard. I had a case of points closing up on one bank and know now that the slow down light really mean STOP . Lucky no fire and by sheer luck was on my way at the time to Lolaman's shop and was only a mile or two away when it happened.

In general I like to think I am responsible in these matters. But what seems to me as a joke of emissions apparatus on these cars is a lot to keep going forever. The posts about valve damage due to a freezing smog pump pulley are one example. You CA boys have to deal with a whole different set of rules so not much choice there for you.

Most of these cars are not daily drivers. There are a *lot* of tractors and Harleys running straight pipes and worse out there every day. If it's not all or nothing then it seems to me these old collectibles are fine being in the gray as it were.

Seamus

 

My car was built in November 1977 (chassis # 22891). All of the documents (i.e., owner's manual etc.) call it a 1977, but I wonder if it's really a 1978 model year. Anybody care to shed some light on this?

Regardless, I guess I will dump the cats at the same time as I replace the exhaust system.

 

There are a lot of posts about the benefits of the hyper-flow cats vs. test pipes. Are you positive the car originally had cats, could it be a euro model with cats added after importation? I think if it were my car that originally came with cats, I'd go with hyper-flows, if not I'd probably go with test pipes. I have heard complaints of the smell with test pipes so might be best with the hyperflows anyway. Mines an '89 328 and I'm in Calif. so my options are pretty much one anyway.

Jeff

 

Oh year, here is a link to Ricambi. Give Daniel a call to see what he'd recommend. He's probably got both options in stock.

http://www.ricambiamerica.com/index.php?cPath=175&osCsid=acf82b3126884634117fd18407799f44

 

The spec plate in the engine compartment should tell you what model year it is. But I was under the impression that July was the begining of the new model year, so I would opinion that a november 77 car is a 78. Does it have the zippered cover over the spare, or is it a fiberglass tub?

 

No, it does not have a zipped cover over the spare.

Although the original owner's manual is a 1977, the warranty and service manual is for a 1976, but with a Ferrari insert stuck on the inside saying that it's for the 1977 model. It was originally sold by Grand Touring Cars of Scottsdale, AZ, who were an official Ferrari dealer at that time. I therefore believe it is full US spec rather than a Euro. This is supported by the hideous marker lights and bumpers etc.!!

 

PS - and the spec plate in the engine bay definitely says it's a 1977.

 

It kind of funny to read this this. The break-down seems to be CA residence say replace the cat, everyone one else says scrap it. I don't live in CA, so I'll join the scrap it crowd.

I melted the core in mine a few years back. Here in PA I can regester as a classic and am exempt from the tail-pipe check, but they are still supposed to look to see that everything is there. Honestly, the local shop has only ever seen my ferrari, so he doesn't know what to look for anyway, but I figured he mine notice the missing cat. I hollowed it out and inserted a straight pipe inside the housing. Now everybody (except the CA residence) are happy.

 

There are lots of things to consider. My 348 originally had test pipes, and I loved the throttle response, sound, etc. However, I hated the stinky smell in the garage and the pain-in-the-arse emissions testing.

I put Hyper Flow's on my personal car, and never looked back. Throttle response (according to my butt-dyno) is exactly the same, sound is just as good, and no stinky smell whatsoever.

For me, it was also a question of 'resale'. That is, selling a car with test pipes will have a much smaller pool of likely buyers (certain states, or those buyers willing to immediately put cats on the car).

Either way, give me a call (or email) and we can discuss pros and cons. Without question, the cats are more expensive than pipes... but in my personal case, it was WELL worth it.


-Daniel

 

My 77 is a Feb. born car and specificly states it is a "catless" car on the driver door post. It would be interesting to see when they changed over to cats and cams for the 78 cars. Do you still have the twin air pumps or does it only have 1.

 

CA has some draconian emmision requirements, yes i understand the need for clean air. however i'm not going to put my life in danger to make some beurocrat happy. for newer cars with lambda feedback it makes all the sense in the world to use cats, the EFI was designed to use them. for cars with early CIS and carbs it's not safe and causes far more problems then it's worth. if you have it properly tuned the 'stink' will be at a minimum, and for the few to little miles driven i would not worry about it.

CA even has some odd loopholes, apply for historic plates on a car at least 25yrs old and the emission testing is no more.

suffice it to say this can cross over into a political debate FAST! in regards to 'clean air'.

if the smell reallly bothers some, just drop in the dragsters fuel additive that makes it smell like anything from oranges to cherry

 

From what I can tell, it HAD twin air pumps.

 

Interesting. My September '77 (22393) 308 is a non-cat car, so it must be right at the very end of the 1977 model year. Somewhere between Sept and Nov they transitioned to the 1978 model year.

I'm not sure what advice to give on cats. For sure, if I replaced they, I would use hyperflow and Daniel is the man. You will get all the sounds and HP of catless, without the stink. I am not crazy about the stink of non-catted cars. (My 308 stinks, the Mondial has cats and doesn't stink).

However, I also appreciate and agree with the sentiment that carb cars and cats are a bad combination for fires.

So there you go, I have contributed nothing meaningful here!

Birdman

 

I recently had HYPER-FLOW cats installed on my 308 GTBi.

No exaggeration, I feel almost like I'm driving a stock 355.

It sounds great, and the emissions hardly even registered when I went to get the car "Smogged."

If you want to run super clean with better than stock performance, this is one fantastic product. Plus, Troy is a great guy.