exhaust manifolds

[donm]

Now that I've got the intake side of my car updated, the next project is to replace the current 4-1 manifold and downpipe.
Can someone tell me what year manifold and downpipes will fit? The car is an '80 with a new DFEV. I'd like to know in advance if a particular4-2 manifold and a particular 2-1 downpipe I mght run accross on the used circuit will fit before I buy them. What should I be looking for? If it matters, I have a new cat installed which I'd like to keep.

[Kent124]

FI manifold with 6 studs and a FI downpipe works perfectly. The down pipe routes under the passenger's side like the stock 80 single pipe so it is an easy tie in.

What FI manifold looks like.
What FI down pipe looks like
What FI heat shield looks like

[donm]

Thanks for the info. I've seen some for sale that have a 4 bolt pattern. Would that work too?

[Kent124]

The 4-bolt pattern manifolds will fit. The possible issue is with the downpipes. There may or may not be an issue. The 2L engine is the tallest and whether there are clearance issues using a downpipe from an 1800 or 1608 engine I am not sure

However some non-California 1979 spiders came stock with a 4-bolt manifold and 2-1 downpipe. That would definitely work.

Also, FI manifolds can be purchased for under $50 if you ask around.

[donerehart]

Does anyone know if there is a gasket that works for the 6 bolt model? Also, can some of you who have made the modification talk about whether it is really worth it. I have the parts, but haven't taken the step to swap them...
Thanks,
Dob

[So Cal Mark]

the 6 bolt manifolds never used a gasket on the lower flange

[Kent124]

the 6 bolt manifolds never used a gasket on the lower flange

I just cleaned it up good and used RTV to give a good seal.

[Exit98]

Does anyone know if there is a gasket that works for the 6 bolt model? Also, can some of you who have made the modification talk about whether it is really worth it.

On my 76 California Spider the engine was completely de-smogged and the cat removed (before I bought it) but the stock 4 to 1 restrictive header was still in place.

I recently replaced it and the downpipe with a 4-2-1 set up. The difference is amazing. It revs freely to 6000+ (before it labored to get there). It's like free horsepower.

Do it.

[donerehart]

Thanks Mark, 124, and Doug,
I appreciate your help. I will get this done soon!
Don

[manoa matt]

If you have a 2L block, use the FI 6 bolt manifold and downpipe. If you have an 1.8L you can use the early 4 bolt manifold or the FI 6 bolt manifold. However if you use the FI manifold on a 1.8L block the downpipes may contact the crossmember or be very close. I have a FI manifold and downpipe on my 1.8L and the downpipes do not constantly touch the crossemember, but sometimes when going up hills in high rpms the downpipe will vibrate against the crossmember for a few seconds.

I've never had the parts to try it, but I don't think you could install an early 4 bolt manfiold on a 2L block as the pipes would be very close if not touching the underbody, could be wrong though.

[fiat218]

why can't the muffler shop
make a down pipe

[BEEK]

i have extended the down pipes, its very easy. look at a set of ansa headers if you can, then just mimick the slide fit for the down pipe. i have shortened and lengthened depending on the application.

[manoa matt]

If you had tubular aftermarket headers then yes, making a downpipe is easier and can be adjusted. But if you are talking about the stock cast iron exhaust manifolds, then making the downpipes is much harder. A typical exhaust shop would have a heck of a time fabing together straight and bent sections. It takes some pretty sophisticated equipment to re-produce a fiat downpipe with all the bends from a single piece of pipe.

I remembered that an early 4-2-1, 4 bolt exhaust can be installed on a 2L block, however a 10mm thick spacer and longer studs needs to be fabricated to bolt between the manifold and downpipes. Someone has done it before and posted pictures of the spacer, but considering of the cost of having that spacer made might be more than its worth. I think that fiat owner either already had the early system and did not want to source the later FI system, or wanted it for the cleaner look of the early system over the later FI manifold. It also creates another possible source for an exhaust leak.

[BEEK]

sorry for the confusion, i was assuming that the headpipe was obtainable or already possesed, i was trying to tell how to adapt an already obtained part. not fabricate a new one

[dantye]

Does anyone know if there is a gasket that works for the 6 bolt model? Also, can some of you who have made the modification talk about whether it is really worth it. I have the parts, but haven't taken the step to swap them...
Thanks,
Dob

I just ordered this: http://www.autoricambi.us/cgi/commerce. ... ey=GA4-473 They claim it can be easily modified for my 6 bolt downpipe flange. When I repaired exhaust manifold stud leaks last winter, I made the mistake of fabricating this flange gasket from a so called "exhaust gasket" composite material and it has already blown out at one of the very narrow sections, so I think the type of gasket with the metal rings similar to the ones on the manifold gasket is the only way to go. Vick has a similar one, but they do not mention modifying it for the 6 bolt flange. Hope this helps.