83 Spider Exhaust Manifold

1222 Views 8 Replies 6 Participants Last post by Geezer, Jan 8, 2008

rictorg

Discussion Starter · Jan 7, 2008

So, we got the young lady to the shop, and started sniffing around. One of the known issues was an exhaust leak, and we traced it to a smallish crack in the exhaust manifold.

Seeing as this is something I'd like to fix, I understand I have several options. I can...

(a) weld the crack, thus repairing the stock manifold
(b) replace the manifold with a used but structurally sound one
(c) replace the manifold with a new one
(d) take this opportunity to replace the manifold with a header, thus falling into the rabbit hole of performance upgrades.

My question to the enthusiasts more knowledgeable to myself (which is, well, nearly everyone on the board

) is which of the choices would you select, why you'd select it, and what effect will it have on reliability, performance, and ability to have it smoged in the future (fortunately, I'm not required to do so currently or in the expected near future).

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Zunige

· #2 · Jan 7, 2008

Specifically in a 1983 Spider, I'd go with headers - hands-down! The manifold of the series 3 is purposely restrictive, and this will have a positive effect on performance and power efficiency. If the car still has the OEM cat, I would also suggest that when the time comes (that could very well be now) you replace it with a modern unit.

I would also encourage you to do a search... There are several threads about perfromance covering this subject, and some are pretty long, so take your time. For starters, and rather than trying to repeat some of what I've written, I'll point you to this post and this thread.

Best regards,

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lasajef

· #3 · Jan 7, 2008

If you decide to go with a stock replacement, I have one off of an '84 that is in very good condition and a reasonable price.

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tmrobinson23

· #4 · Jan 8, 2008

Depending on your budjet, as noted above, the headers are the way to go hands down. We (my wife & I) have an 87 that we put headers on and it gained quite a bit of power with no other mods.

If you really want or need to keep it stock though, I have the stock manifold from the 87 you can have for the cost of shipping. Some parts are just not worth holding on to if someone else could use them. Everyone at alfabb has been very kind, helpfull and enjoyable to talk with, so I'm happy to give back to help an alfista out. If interested e-mail:
[email protected]

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Geezer

· #5 · Jan 8, 2008

As another option you could go to the '71-'74 2 piece manifold and not put up with the aggrivations of a header.

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bianchi2

· #6 · Jan 8, 2008

..i agree, headers..long turm they will cause loss problems..no more cracking...as cast old replacement manifold might do down the road...but if the manifold is cracked..how are the motor mounts, and the mounts onder the transsmission, are the saging,, that helps crack the cast manifolds,,,on the motor mount..go for paul spruel mounts... lots of folks say they are better..soo far i like them...but if you replace the motor mounts..go for the exhaust mounts onder the tranny. if they are soft, or worn out..

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Zunige

· #7 · Jan 8, 2008

Geezer said:
As another option you could go to the '71-'74 2 piece manifold and not put up with the aggrivations of a header.

Going with the '71-'74 two piece set is also possible, but since the cat is being retained, there is some customizing to do. This would require sourcing different downpipes, since the ones from the '83 don't fit the 2 piece design of the earlier series. Furthermore, the '71-'74 downpipes and the rest of the mid section are one piece, so this would require cutting them, and also making a threaded bung for the O2 sensor, which the '71-'74 pipes does not have. All possible, but requiring getting all the pieces and then customizing them... From a performance standpoint, the '71-'74 set-up is very good, and would function very nicely.

When you say "the aggrivations of a header" are you referring to fitment issues, such as the ones mentioned with the IAP set? (I would never suggest using the IAP headers, but can vouch for the consistent good fit of the Centerline unit, which also comes with all the pipes and O2 bung.)

Best regards,

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rictorg

Discussion Starter · #8 · Jan 8, 2008

My buddy suggested removing the O2 sensor and cat converter completely if I upgrade to headers... what are the risks and challenges involved? I assume there would be no chance in hell that the car would smog if I had to do so in the future.

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Geezer

· #9 · Jan 8, 2008

I don't have a problem with you removing the converter if smog is not an issue in your area. If smog is an issue leave it in place. What ever you do retain the O2 sensor. Without it the car will run like [email protected]

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