Non-restricted exhaust

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brackie1
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Your car is a: 1978 124 spider
Location: Winston-Salem, NC

Non-restricted exhaust

Postby brackie1 » Sat Mar 11, 2017 5:29 pm

One of our club members mentioned today that I should look at a non-restricted exhaust. We were all kind of in a hurry so I didn't have time for him to explain what it is. Does anyone have any experience with this and explain what it is and how it works. I have a 77 spider.
Gene
North Carolina

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aevansgatech
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Your car is a: 1982 Spider 2000

Re: Non-restricted exhaust

Postby aevansgatech » Sun Mar 12, 2017 10:11 am

He probably meant removing the catalytic converter and replacing it with a "test-pipe" or straight through exhaust. Removing the catalytic converter results in a less restricted exhaust flow, but will also make the car louder, possibly smell worse/different, and won't give you much hp benefit in my opinion.

If you think your exhaust or converter are shot, then consider it, but if your exhaust is in good shape I wouldn't modify it.
1979 Spider 2000 (gone)
1984 Pininfarina Azzurra (for sale)
1982 Spider 2000 (here to stay)

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focodave
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Re: Non-restricted exhaust

Postby focodave » Sun Mar 12, 2017 11:44 am

If you want to hear what it may sound like without the cat in place, I made a video of mine with no cat, no rear muffler, and just the center resonator in place: https://youtu.be/zxc9TEcS1Eg
1980 Spider 2000 F.I. (my hobby)
1970 MGB GT (my other hobby)
2008 Ford Expedition (daily driver)
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So Cal Mark
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Re: Non-restricted exhaust

Postby So Cal Mark » Sun Mar 12, 2017 11:46 am

free-flow exhausts are important for power increases, I can't imagine why in your opinion they aren't worthwhile? Exhaust systems with back pressure cause reversion to enter the cylinder during overlap, sapping hp.
Would you care to offer some proof to back up your opinion?
Mark Allison
allisonsautomotive.com Fiat and Alfa Romeo parts and service. Performance parts our specialty!
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RRoller123
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Re: Non-restricted exhaust

Postby RRoller123 » Sun Mar 12, 2017 12:59 pm

aevansgatech wrote:He probably meant removing the catalytic converter and replacing it with a "test-pipe" or straight through exhaust. Removing the catalytic converter results in a less restricted exhaust flow, but will also make the car louder, possibly smell worse/different, and won't give you much hp benefit in my opinion.

If you think your exhaust or converter are shot, then consider it, but if your exhaust is in good shape I wouldn't modify it.


I put a Test Pipe in my 80FI, and noticed a great improvement in Mid-Range Torque, whereas before I would climb a long moderate hill at speed but would have to shift down to 4th or 3rd, I could absolutely now stay in 4th, and often stay in 5th. Big difference with just the pipe.

Pete
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brackie1
Posts: 523
Joined: Sat Dec 14, 2013 1:24 pm
Your car is a: 1978 124 spider
Location: Winston-Salem, NC

Re: Non-restricted exhaust

Postby brackie1 » Sun Mar 12, 2017 5:53 pm

My '77 spider does not have a cat and badged as such
Gene
North Carolina

brackie1
Posts: 523
Joined: Sat Dec 14, 2013 1:24 pm
Your car is a: 1978 124 spider
Location: Winston-Salem, NC

Re: Non-restricted exhaust

Postby brackie1 » Sun Mar 12, 2017 6:12 pm

Sorry didn't get to finish my post. Since I don't have a cat does that mean I have a free flow exhaust? My exhaust is somewhat loud a lot like the video.
Gene
North Carolina

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Nanonevol
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Your car is a: 1977 Fiat 124 Spider
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Re: Non-restricted exhaust

Postby Nanonevol » Sun Mar 12, 2017 7:16 pm

If it's loud maybe you have a leak. Otherwise, if yours is a stock '77 it has a 4 into 1 exhaust manifold and you would see improvement with a 4 into 2 manifold from an earlier or later Spider.
1977 Fiat Spider
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1967 Triumph Bonneville (hard-tail chopper)
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vandor
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Location: Texas, USA

Re: Non-restricted exhaust

Postby vandor » Sun Mar 12, 2017 7:54 pm

+1 on upgrading to the earlier moanifold and downpipe to make the system a 4-2-1.

For the rest of the system an inexpensive alternative is the Euro-1800 exhaust, which is ~2" in diamter, vs. ~1-5/8" for the US 1800. These will work for any non-catalyst 1800 (ie it will fit all 49-state models, but not California models). The center muffler slips right onto the stock downpipe.

https://autoricambi.us/collections/exha ... erformance

https://autoricambi.us/collections/exha ... erformance
Csaba
'71 124 Spider, much modified
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grrrdot
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Your car is a: 1967 124

Re: Non-restricted exhaust

Postby grrrdot » Mon Mar 13, 2017 9:56 pm

Free flow exhausts are great.
I put a 1608 in my car and was really happy. Then I went from the stock 1197cc OHV exhaust to a 2.25" with both a MagnaFlow and Borla muffler, you can see straight through both of them, I thought it was going to be really loud but its about the same volume and the power change is amazing. It used to only pull between 3-3800 RPMs now its a blast all the way up to 6K.

-G

PhillySpider
Posts: 325
Joined: Tue Apr 26, 2016 6:51 pm
Your car is a: 1980 Spider 2000
Location: New Hope, PA

Re: Non-restricted exhaust

Postby PhillySpider » Mon Mar 13, 2017 10:17 pm

I want to play!

I have a 1980 FI spider. Stock.
1. Do I have a CAT, where is it, what's involved in removing it, what to replace it with.
2. Would I have a 4-1 exhaust or a 4-2-1 exhuast?
3. What does #2 even mean and which do I want.
4. If I'd want what I don't have, how to go about remedying that one?

:)

vandor
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Re: Non-restricted exhaust

Postby vandor » Tue Mar 14, 2017 12:15 am

If it's an FI Spider then you have a 4-2-1 system, which works well for the stock engine. To get a 2-3 HP gain you can replace the cat with a test pipe if your area allows it:

https://autoricambi.us/products/test-pipe-1980on-4-bolt
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town

PhillySpider
Posts: 325
Joined: Tue Apr 26, 2016 6:51 pm
Your car is a: 1980 Spider 2000
Location: New Hope, PA

Re: Non-restricted exhaust

Postby PhillySpider » Tue Mar 14, 2017 12:55 am

vandor wrote:If it's an FI Spider then you have a 4-2-1 system, which works well for the stock engine. To get a 2-3 HP gain you can replace the cat with a test pipe if your area allows it:

https://autoricambi.us/products/test-pipe-1980on-4-bolt


Here in PA i get to sport antique tags. Hence no emissions or inspections required :) . Looks like this is in my futrue, no welding required I'm down. Should I save the old cat for originality when these hit 6 figures LOL!

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So Cal Mark
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Your car is a: Fiat
Location: upland, ca.

Re: Non-restricted exhaust

Postby So Cal Mark » Tue Mar 14, 2017 2:14 am

you'll also need a straight-through muffler to reduce backpressure
Mark Allison
allisonsautomotive.com Fiat and Alfa Romeo parts and service. Performance parts our specialty!
Headers, ignitions, wheels, cams, flywheels
starsmark@hotmail.com 909-981-3566

brackie1
Posts: 523
Joined: Sat Dec 14, 2013 1:24 pm
Your car is a: 1978 124 spider
Location: Winston-Salem, NC

Re: Non-restricted exhaust

Postby brackie1 » Tue Mar 14, 2017 8:11 pm

Mark, since I can't find a 4-2-1 manifold right now I have decided to change mufflers. I have a '77 carb non-cat. What you recommend?
Gene
North Carolina


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