Alfa Romeo Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter #1
Greetings all!

I am in the process of reworking the exhaust on my '78 Spider. I have removed the A.I.R. pump and all associated hardware, and I am installing a set of headers, and want to eliminate everything between the headers and the rear ANSA muffler, such as the cat and monolith muffler. In other words, the new pipe will go between the header and the ANSA muffler. Does anyone know if there is such a pipe made to accomplish this, or if I will have to have one custom made? Many thanks to in advance.

Dan
 

·
Registered
Joined
·
293 Posts
Why not use a set of pre-'75 manifolds and a '72-'74 exhaust? Best bang for your $ and best performance for a street car. It's a 100% bolt-on swap.
 

·
Registered
what part?
Joined
·
10,108 Posts
i really would keep the ' cat ' on,, newer cats are not restrictive at all. and remember,,if you have kids or grandkids.. you inherit the would from you childern and grandchildern..it is not yours..and if you go to headers, a cat will help in just enough backpressure to make your car run better...headers and a straight pipe to the rear, you will loose tq at lower pm's, and we need that on our 2 liter cars..my car is a 1974 ( really a re-vin'ed 1984 spider, a co-worker backed into my driverside front wheel fender, bent it, insurance co. ' salvaged my car, so she now is a 1974 spider )spider, an i am running bosch fuel injection,/ headers and a cat.. with out the cat, i noticed a lack of low end power..anyhow.. keep the cat.. with the flat tails of our spiders, it will keep the bad stuff away from you lungs..
 

·
Registered
what part?
Joined
·
10,108 Posts
and yes. i am in CALIFORNIA, but don't confuse me with a tree huger..i just do the right thing..
 

·
Premium Member
Joined
·
2,628 Posts
I as well converted my exhaust on my 82. I put a IAP Header w/ a 2 to 1 pipe. I bought a FLOWMONSTER 410200 cat smallest I could find 11' and it's placed perfectly under the Heat Shield. I fabricated a small 2ft pipe with a bend to use the stock resinator and my ansa muffler. I even have the O2 sensor, can't wait to see how it works. A question for you Cali Alfistis Why are most cats not legal in your state? What makes it a Legal Cat for California?
 

·
Registered
Joined
·
627 Posts
I...A question for you Cali Alfistis Why are most cats not legal in your state? What makes it a Legal Cat for California...
$$$, testing to make sure it passes Ca. requirements, $$$, & $$$ to etch some $$$ stupid numbers on the side of the cat that indicates it passes Ca. requirements, & more $$$.

Oh yeah, about another $100.00 on top of every other $$.
 

·
Registered
Joined
·
373 Posts
i really would keep the ' cat ' on,, newer cats are not restrictive at all. and remember,,if you have kids or grandkids.. you inherit the would from you childern and grandchildern..it is not yours..and if you go to headers, a cat will help in just enough backpressure to make your car run better...headers and a straight pipe to the rear, you will loose tq at lower pm's, and we need that on our 2 liter cars..my car is a 1974 ( really a re-vin'ed 1984 spider, a co-worker backed into my driverside front wheel fender, bent it, insurance co. ' salvaged my car, so she now is a 1974 spider )spider, an i am running bosch fuel injection,/ headers and a cat.. with out the cat, i noticed a lack of low end power..anyhow.. keep the cat.. with the flat tails of our spiders, it will keep the bad stuff away from you lungs..
I agree with this sentiment. However, the cat on my 78 has been removed for a Magnaflow system. As the system is too loud for my tastes I was thinking of putting on a resonator again in the same spot as a cat. The only reason I'm reluctant to do a cat instead is because the car no longer has its smog pump, and my understanding is that the cat would likely wear out rapidly as a result because of O2 mix. Am I right about that?

I would be happy to put on a free-flow cat instead if I didn't have to replace it every year or so because it burns out on me. Anyone know if the answer to this?
 

·
Premium Member
Joined
·
1,479 Posts
It's not a burning out issue. The cat will plug up due to it's inability to convert the unburnt hydrocarbons without the air pump injecting added oxygen. I doubt it would catalyze much at all.
 

·
Registered
Joined
·
2,080 Posts
exhaust

my 86 has the manifolds and front pipes from a 74 with a universal cat replacing the front resonator. A little custom pipe work places the cat properly and connects to the standard center muffler. Added a bracket and O2 sensor bung to match original 86 converter pipe assembly.

This universal cat is suitable for air injection or no air injection. The air injection port is sealed and would have to be opened for connection to air injection line. (directly into cat vs into exhaust manifold) Passes emissions inspection year after year, so it is still working.

It may have made a difference with the old pellet style vs the modern ceramic honeycomb.

I don't know if anyone (auto shop, muffler shop, etc.) can legally make you what used to be available as a converter test pipe, if they know what it is for. Available in the old days to replace the converter to test for plugging. Made to check converter plugging by installing the pipe and see if the car runs better. You were then supposed to remove the pipe and install a new cat.
 

·
Registered
what part?
Joined
·
10,108 Posts
i had a 1978 spider.. 10 years ago...i now wonder is it possible to tune the spica injection system useing a o2 sensor...
 

·
Registered
Joined
·
293 Posts
i had a 1978 spider.. 10 years ago...i now wonder is it possible to tune the spica injection system useing a o2 sensor...
I've got the OEM exhaust on my '74, with an 02 sensor bung welded into the front pipe just past the 'Y', and a wide-band 02 sensor installed. That feeds into a little circuit board with a series of LED's and shows mixture as I drive. Works OK, but the "old" method of tuning still works best. I bought the circuit board from an Australian company maybe 8 years ago (can't recall the name) as a kit. Wes Ingram mat still sell something similar (he used to).
 

·
Registered
Joined
·
837 Posts
Commercial exhaust/muffler shops legally can't remove a catalytic convertor. Last month I asked the owner of the local Meineke if they would remove my cat and replace it with a straight pipe on my '83, and although the owners are drag racers and general car enthusiasts after thinking about it a bit, he declined.

Speaking of headers, will a car with aftermarket headers, O2 sensor and a California legal catalytic convertor pass the CARB smog test, or will it fail on visual since it doesn't have the stock exhaust manifolds? That is assuming everything else emissions related is operating correctly.
 

·
Registered
Joined
·
293 Posts
Commercial exhaust/muffler shops legally can't remove a catalytic convertor. Last month I asked the owner of the local Meineke if they would remove my cat and replace it with a straight pipe on my '83, and although the owners are drag racers and general car enthusiasts after thinking about it a bit, he declined.

Speaking of headers, will a car with aftermarket headers, O2 sensor and a California legal catalytic convertor pass the CARB smog test, or will it fail on visual since it doesn't have the stock exhaust manifolds? That is assuming everything else emissions related is operating correctly.
CARB = Calif. Air Resources Board, so it only applies to cars in that state, right?

When we had inspections here in Florida, my '87 Spider passed the visual inspection because I've got the pre-'75 manifolds and a '72-'74 exhaust, complete with an O2 sensor installed just past the 'Y' section of the downpipes. I guess they thought that front resonator was a cat, and I didn't volunteer anything different. The emissions standards for cars of that vintage were also so loose that the car passed that test, too.

FWIW, this was the single biggest performance upgrade I've ever made to any of my Spider's ('74, '87, '92), and if you ever cut open a pair of Series-3 downpipes, not to mention the cat, you'll see why.
 

·
Registered
Joined
·
837 Posts
Spider Aftermarket Headers/Passing California Smog Test

CARB = Calif. Air Resources Board, so it only applies to cars in that state, right?

When we had inspections here in Florida, my '87 Spider passed the visual inspection because I've got the pre-'75 manifolds and a '72-'74 exhaust, complete with an O2 sensor installed just past the 'Y' section of the downpipes. I guess they thought that front resonator was a cat, and I didn't volunteer anything different. The emissions standards for cars of that vintage were also so loose that the car passed that test, too.

FWIW, this was the single biggest performance upgrade I've ever made to any of my Spider's ('74, '87, '92), and if you ever cut open a pair of Series-3 downpipes, not to mention the cat, you'll see why.
Yes, California Air Resources Board; I'm planning on moving to California, but would like either install the pre-'75 cast iron headers, or tubular headers, with an O2 sensor on my '83 Bosch injected Spider.

I was under the car yesterday attempting to change the engine mounts, so while under there I did take a look at the down pipe/catalytic convertor pipes. I was planning on cutting out the convertor and temporarily inserting a section of exhaust pipe (till I buy a small muffler), but I see that Alfa flatted the down pipe to an oval where it meets the convertor; arg, not as simple as I thought, although I suppose I can for now, flatten a piece of pipe!

I might have to go to Plan B and just go ahead and buy a pre-'75 header and down pipe!
 

·
Registered
Joined
·
293 Posts
Ouch. Maybe the earlier set of manifolds, earlier exhaust, with an O2 bung added, and replace that front resonator with a universal cat. The pipe on the earlier exhaust is round, so that should be pretty simple. The appearance would likely fool an inspector, but no promises on the emissions part of the test.

Even if I had the choice to use headers, I'd pick the early manifolds. I don't know of a set of headers which will actually improve the performance of a street-driven Alfa, and then you've got all the other associated issues - poor fit, lots of extra engine bay heat and noise, lack of longevity, etc. Alfa did it right with their pre-emission control exhausts, and they went back to a very similar system with the S4 cars (except for the added O2 sensor and cat).
 

·
Registered
Joined
·
46 Posts
Discussion Starter #17
We do not require a smog test on any car over 25 years old down here in Texas. I am not going to reinstall a Cat. as it will plug up due to not having the AIR pump any longer. I realize that most exhaust shops will not remove a Cat., but I will not be asking them to due so, only to bend a pipe for me to fit between the header and ANSA muffler. My only real question is to remove the monolith or not, as I do not feel the sound is enough with both installed.
 
1 - 17 of 17 Posts
Top