standard exhaust manifold

[reggid]

There is the two different standard log manifolds.

1 piece
2 piece

which is better for performance?

I understnad that the earlier higher compression cars and some Alpina's used the two piece?

[gooner1]

There is the two different standard log manifolds.

1 piece
2 piece

which is better for performance?

I understnad that the earlier higher compression cars and some Alpina's used the two piece?

How early are we talking? Mine is an 86 H/C block and came with a one piece manifold. Having said that i think most after market
6 branch systems are two piece.

[HairyScreech]

all depends if you are lhd or rhd, as i think nearly all rhd cars had the single piece one.

[eta]

Also isn't the one piece system essentially two 2 pieces manifolds oined together. i.e 3 cylinder feed into one port and the other three feed into the other. I could be wrong.

[HairyScreech]

yes, a full log manifold on a 6 causes problems, so they need to be split.

[daimlerman]

Seem to remember that only M20'd E34 came to the UK with a two piece cast manifold.

The one piece cast manifold tends to warp banana shaped,this pulls it's fixing studs out...
I had this issue years back with an E28 520i,surface grinding the manifold back to flat was the cheap option.

Stangely,these days,this issue only rarely crops up in Tech Help,wonder why?

[eta]

All the ones that where going to warp have done so already?

[reggid]

I have a one piece (yes not all pipes are linked) the inside looks terrible for flow was hoping that maybe the 2 piece was nicer inside.

[eta]

So if the the one piece manifold is split in that not all pipes are linked as I thought, would the two piece be that much better inside. Why not save up and fit a 6 branch manifold. It not like the E34 525i (M20) has any more power than the 325i from the same year.

[reggid]

So if the the one piece manifold is split in that not all pipes are linked as I thought, would the two piece be that much better inside. Why not save up and fit a 6 branch manifold. It not like the E34 525i (M20) has any more power than the 325i from the same year.

Will eventually be selling the car and the BTB2 aint going with it.

The 2 piece may not be better hence the question really.

If the LHD vs RHD required a change then maybe the single piece one was compromised in order to clear the rack or watever else neccesitated the change.

I might see if i can get a pair cheap on US EBAY.