2 vs 3-piece & cab vs saloon exhausts

[Ziggy]

My ('87) 325i cab's currently got a 3-piece system on it, & I want to fit a 2-piece system... mainly because my system's dead & I've got a supersprint rear half here to go on!

The problem is that the front half of the 2-piece system won't mate up to my manifold The fitting is the same shape, but the one on my car is a bit smaller...

So can I get the front half of a 2-piece system from a later convertible? Or am I going to have to get creative with a hacksaw & a welder (or get an exhaust place to)?!

Basically I guess I need to know if anyone's fitted a 2-piece system to a car that came with a 3-piece. Ie is the smaller manifold mounting because it's a convertible, or are all pre-facelifts smaller?

Cheers

[Ziggy]

I'm confusing myself now... I've got the gasket to go between the manifold & downpipe on my car; it's part number 18.11.1.728.364
I know there's a bigger one (part no 18.30.1.711.969), as I ordered it by accident when I did my short shift & had to change it.

I've just looked on realoem.com to see which cars had which gasket, & all the ones I tried (early & late, tin-top & cab) listed my gasket not the bigger one!

[Simon13]

theres 2 types of manifold the all on one and the other 2,3 piece manifold. But i thought the latter ones were rare Jon.

To my knowlege the systems are pretty much the same apart from howmany pieces they came in!

my sport had an original 2 piece
my se has a original 3 piece

both cars are facelift and a few months apart on build dates!

[JOSEMI]

Mine is a 3 piece system if that helps, 1987 320i saloon

Jose

[Simon]

Most cars will be wearing 3 piece systems if they have fallen outside the dealer network, they are cheaper to replace than 2 piece systems.

[billgatese30]

Sion, can you remember what was on mine...have always wondered but never actually checked when i've been under the car

[Ziggy]

theres 2 types of manifold the all on one and the other 2,3 piece manifold.

I thought that too! But it appears it's not as simple as that... Both systems I'm talking about have single peice manifolds, just slightly different size flanges on the end where they bolt onto the downpipe
Part number 18.11.1.728.364 (manifolt to downpipe gasket) is a slightly smaller version of 18.30.1.711.969 - I've seen both of them together at the dealer when I had to swap the bigger one for the correct size on my car!

The 2-piece exhaust I've got (from a 4 door SE - facelift) has the bigger flange & my existing 3-piece exhaust has the smaller one... both had single piece manifolds though.

[Ziggy]

Most cars will be wearing 3 piece systems if they have fallen outside the dealer network, they are cheaper to replace than 2 piece systems.

Have you actually seen a car that's been swapped from one to the other though? Not trying to doubt you here, honest! Just rather confused!

Cheers

[Simon]

Sion, can you remember what was on mine...have always wondered but never actually checked when i've been under the car

It's a 2 piece system, you should know me and originality!
The centre section should last at least another 5-6 years too, as it was replaced about a year before I sold it to you with a proper boysen centre system.
The back box is also a boysen box, but it was starting to rust a little when I bought it off Roger, but the rust was only on the outer jacket so should be OK for another few years!

[billgatese30]

yeah, the outer jacket is slightly worse for wear with a few holes, but the inner jacket looks fine and hasn't started to rusr yet so it should be ok for a few years at least

[Simon]

Most cars will be wearing 3 piece systems if they have fallen outside the dealer network, they are cheaper to replace than 2 piece systems.

Have you actually seen a car that's been swapped from one to the other though? Not trying to doubt you here, honest! Just rather confused!

Cheers

The J plate sport I recently sold 'should' have had a 2 piece system on it, but it had a 3 piece system.
As long as the whole system is swopped it should be ok?

[Ziggy]

Was that without swapping the manifold? The 2-peice system I've got, simply will not mate up with my manifold

[Simon]

Was that without swapping the manifold? The 2-peice system I've got, simply will not mate up with my manifold

I have no idea! I've had nightmares (has as a few other on the zone) with these gaskets, I've always ended up with the wrong size ones.
What actually decides what cars these different size manifolds should be on I have no idea!

[DemonDaz]

I ended up having mine done at the dealers, and even then they needed to see the manifold before ordering parts to make sure they got the right one. Most independant garages couldn't find the exact fitting of my exhaust.

[Ziggy]

B***er!

From what I seem to be able to work out from realoem, the smaller type was for e30 & e28, & the larger for e30 e36, e34 & z3... so I guess they changed over at some point during e30 production. I'm assuming that this point was before they went to 2-piece systems, hence the availability of 3-piece systems that can fit a later car.

GSF don't even list a 3-piece downpipe so they're no use for finding out if there's 2 types.

According to realoem again, a 1992 cab has the same gasket (& so the same manifold) as mine, but I can't work out their exhaust diagrams so I've no idea if it would have had a 2 or 3 piece system.

Does anyone out there have a cab with a 2-piece??

[Ziggy]

I ended up having mine done at the dealers, and even then they needed to see the manifold before ordering parts to make sure they got the right one. Most independant garages couldn't find the exact fitting of my exhaust.

So what system have you got on there now?

[stevetigger]

I ended up having mine done at the dealers, and even then they needed to see the manifold before ordering parts to make sure they got the right one. Most independant garages couldn't find the exact fitting of my exhaust.

So what system have you got on there now?

Get the dealer to do it, cost me Ԛ£57

[Ziggy]

Get the dealer to do it, cost me Ԛ£57

Get the dealer to do what?!

[Ziggy]

So does anyone have a cab with a 2-piece system?

& has anyone fitted a 3-piece to a car that came with a 2-piece?

[DemonDaz]

The dealer replaced my 2 piece with a new 2 piece!
Pain really cos if it goes again I'll have the same trouble.

[Ziggy]

The dealer replaced my 2 piece with a new 2 piece!
Pain really cos if it goes again I'll have the same trouble.

So what was the problem then? Or did it originally have a 3-piece? If so, dya happen to have a receipt for your current exhaust with a part number on it?!

Or if you're working on it sometime, could you measure the flange on the end of the manifold (assuming it's a 1-piece mani?)?

I'm just trying to work out if there's a stock 2-piece exhaust out there that'll fit my car, before I get something custom knocked up!

[jesmond]

Ziggy
I had exactly the same problem when I was trying to source a replacement manifold, namely, on my '87 sport with one piece man, 3 piece system. All manifolds I looked at in scappies - about a dozen or more manifolds (luckily they were all off the shelf!), were slightly larger bore than mine- approx 1 to 1.5 ml, at both the downpipe flanges and all head ports. I assumed these were from either facelifts or perhaps e28's. The only thing wrong with mine was a crack which was leaking. I just got a guy to weld the cast manifold with rods incorporting nickel in the end. Worked well, and hasn't leaked since. Having said that, after having had a lovely stainless steel back box made up, an reasonable price, if I decide or need to re-address the manifold situation, I think I might just go the custom stainless route. What about just getting a downpipe made up to required spec?
Paul

[Ziggy]

Cheers Paul - at least I know I'm not the only one now!

I'll get something custom made if I have to, it'd just obviously be easier not to if possible...

I've got the whole 2-piece system here (standard front, supersprint rear ), so I could potentially get it modified using the flange from my old downpipe if I can find someone willing... Failing that, I've been meaning to learn to weld for a long time!

Jon

[jesmond]

Jon
Sounds like a pretty good compromise mate. And any local welder would do something like that for you no probs. I just looked on the web, found a local geezer, who turned out to be a right diamond, full of advice etc, and only charged me 20 quid for the nickel weld - "the nickel rods are a bit more expensive that the normal ones", which may or may not be true, but hey, I was happy, and back on the road, with no more unwelcome exhaust blow noise or raspy feel - smooth
I am also, one of these days going to learn to weld properly. I see this as opening up a whole new world of possibilities!!
All the best
Paul

[Ziggy]

Good plan! I'll have to look into it... It'll probably be cheaper than getting another front section, the only problem being that I won't have a car while it's being sorted. Shouldn't exactly take long though!

I reckon I could cut the flange off the new one & slightly shape the old one to fit between the maifold & pipes... Or perhaps I could just modify the new system to fit! The mounting holes are slightly too far apart IIRC, so should be able to be modified to mate up. I'll have a closer look & see how different the gasket i've got is, compared to the new exhaust.

[jesmond]

Jon
Sounds like you could be on to a couple of winners there, good luck. Also, you can always make gaskets up with anything you want. And thanks for the advice on me door mirror.
Cheers
Paul

[Ziggy]

Just been having a look at it, & a bit of filing / dremelling should do the job... It doesn't quite match up, but if I flatten down a bit of the welding on the inside of the downpipe, it'll be ok Won't be a particularly fun job, but it'll be worth it

Cheers all ( & NP Paul )

[BrAdZ]

I have just fitted a 325i 3 peice to my cab, was a 2 peice on a 320i

Fitted perfectley!!

[Ziggy]

Cheers; I'm going with the theory of 2 sizes of 3-piece system still at the moment!

Dya happen to know the part number for the manifold / downpipe gasket that you used?

[BrAdZ]

...............tbh i didn't use one, just a bit of paste, worked a treat and it doesnt leak!

It was fitted on a sunday at the guys house i bought it from on his 4 poster..... dint even think about the gasket lol

[stevetigger]

Get the dealer to do it, cost me Ԛ£57

Get the dealer to do what?!

To fit the exhaust!!

[Ziggy]

Get the dealer to do what?!

To fit the exhaust!!

Yeah, I'm sure they'd just do it! The point is that it's the wrong exhaust

It *will* be fitted, but I'm not sure the dealer'd be happy to get files/grinders out to fit an exhaust!

dint even think about the gasket lol

Genius! Let me know which one you fit when it starts leaking ;)

[BrAdZ]

dint even think about the gasket lol

Genius! Let me know which one you fit when it starts leaking ;)[/quote]

Well its been on there for about 5k and stil not leaking

[jacko]

I have a 2 piece system on my cab 1990, fitted it couple of months ago, dont think it ever was a three piece, i had to order pre 87 saloon fitment.

[DaveD]

all the later production models had 2 piece ...something to do with matching up to the cats that went on in the states,,,fritzs' bitz do a very nice manifold but it wont mate to a 2 piece