Which exhaust manifolds are the best?

[FastGT31]

i have a 91 Beretta and am looking to put some higher flowing exhaust manifolds on it. i thought about doing some custom headers but that is out of the question for now. what i was wondering is what exhaust manifolds would bolt up to my 3.1L, fit the car, and give me more power than the stock log type manifolds. would any 3100 or 3400 exhaust manifolds bolt up?

[geoffinbc]

Well they will bolt to the engine. But you will need a new down pipe. They are much better than the "logs"

[FastGT31]

any particular year that is the best?

[geoffinbc]

1999+ That when all engines changed to the bigger valves so that should be the latest edition of exhaust manifold.

[Jon89LE]

Does anyone have a picture of these manifolds? Are there actual short runners to each exhaust port?

[bszopi]

Courtesy Colin

[Jon89LE]

Ahh, my rear one looks like that already on my GrandPrix. Do the front manifolds have a similar design?

[FastGT31]

bszopi, what car (and year) is that rear exhaust manifold from? and do u have pics of the front?

[v6h.o.]

the "header" style have been used since 96, the one pictured came off a 96 model 3100.

they are on the Uvans, and other model cars. in resent years thats all GM is using now is the "header" style rear.
there are no other updated Front manifolds other than the Log. unless you get into the 3500 Parts which each manifold is separate from the other no Xover.

[Berettaspeed]

Im not sure the newer 3X00 manifolds will work for the 3.1MPFI. because the ports are different. the ones for the 3.1 are circular or oval and the 3X00 are D shaped. I don't know if this will affect anything but it might. I would make sure this won't affect anything before buying anything. If they work then more power for you to use. But why not just do a 3X00 top end swap.?? or maybe something to loo at in the future.

[v6h.o.]

Im not sure the newer 3X00 manifolds will work for the 3.1MPFI. because the ports are different. the ones for the 3.1 are circular or oval and the 3X00 are D shaped. I don't know if this will affect anything but it might. I would make sure this won't affect anything before buying anything. If they work then more power for you to use. But why not just do a 3X00 top end swap.?? or maybe something to loo at in the future.

No, they do work. you can go with the newer manifolds. the "D" shape can be used on the older "O" ports due to they are larger than the stock gen2 ports and the corners of the "D" just sit against the head surface with no issues. You cannot however do the Reverse "O" port manifolds on a "D" shaped head.

You do however Need the X-over pipe from the GEN3 manifolds. it is completely different and needs to stay with the corresponding generation of manifolds.

[TurboSedan]

can GEN-2 exhaust manifolds be modified to work on GEN-3 heads? i would like to use my TGP manifolds and crossover pipe on a 3400 if possible.

[bszopi]

You cannot however do the Reverse "O" port manifolds on a "D" shaped head.

You do however Need the X-over pipe from the GEN3 manifolds. it is completely different and needs to stay with the corresponding generation of manifolds.

I think he already answered your question...

[TurboSedan]

sorry, i was just wondering if they could work after some modification ie grinding...i take it that's not an option.

[TurboGTU]

Actually..if you grind the bolt holes taller on the drivers side exhaust manafold of a RWD S10 2.8..they will bolt up to the 2nd gen heads. They have a semi header look desighn. Might want to look into that. Which brings another thing..people looking into turbocharging their 2nd gen can use S10 manafolds...no need to Cork the rear stock manafolds anymore. Just an idea.