Simon Blythe
Zorg Guru (I)
I recently took a gamble on a very cheap 2.8 which, touch wood, has turned out to be much better than expected and will make a nice car as its a long term project.
I had purchased a complete kit for my regular 2.8 but as its a tu engine the kit didn't fit. It was in process of being returned when my curious side kicked in.
Anyway as per the title, the manifolds were swapped so I wanted to give an overview of what's involved and help those thinking about it to decide one way or another.
This is the original manifold:
This is the 2.5 - note the lack of pipe work attached to the manifold.
Once the original is off it looks like this:
Quite busy and somewhat scary to the less mechanically inclined. I'm an ex RAF fast jet mechanic and even I thought twice! However, I just can't help myself so I continued.
Removal is actually relatively straight forward the only advice i have is to take your time and be methodical it looks worse than it is. Secondly when you are removing the manifold bolts put a bit of tape in the socket head so it "grabs" the nut stopping it falling away into the engine bay or worse - once the head is off put tissue in the ports...just in case!!
You will hear talk of the last bolt next to the bulkhead being a pain to access, it's not.
What you will need to do is remove the loom from the brackets, bend the brackets up and remove the passenger side bracket completely - don't worry it won't break! You can now access that last bolt. Removing the rest of the plumbing is self explanatory. The earlier pictures show what you'll be left with.
Now there are only ONLY two modifications you will need to do.
Firstly is to modify the IAT, file it down and put an M12 thread on it. Once that is done, screw it in with some gasket sealant. The upper one is the original.
You will then need to plumb everything in - just follow the flow on the original manifold and replicate it with the fitting kit on the m50 one. The scary part comes due to the lack of ports in the M50 manifold however, once done it should look something like this:
Basically there is one port and 2 vacuum connections. The one on the manifold is for the fuel vacuum, the second one will be on the connector into the manifold itself and is for the charcoal canister.
Note this will need to be stepped down from 8mm to 4mm, use an inline connector as one hose fits in the other - the connector acts as a strengthener and you can put a small clip, along with gasket sealant, to make it air tight.
When you fit the new manifold you won't be able to reuse the original brackets the help secure it to the engine block - you won't need them. When connected with the T piece and silicon hoses it will all be held in place and you can secure it after fitting. You will need to fit a bracket to the manifold to hold the dip stick in place. You and also use this bracket to tie wrap the ICV in place too. The oil breather sits on the block and is fine. Brackets can be fabricated and fitted afterwards - once you've done the install you'll be amazed at how quickly you can remove and refit it.
Once it's all back together, air box, throttle cables etc you need to turn your attention to the fuel rail. You will need to remove one bracket and cut part of the other. Remove this holder/bracket.
And remove the right hand edge as you look at it on this one.
The fuel rail will sit lower than the fittings on the manifold so use some bent sheet metal or spacers to hold it securely.
You will also hear talk of "bending" the fuel pipes. You will need to to allow them to clear the manifold but not too much - be careful!!
Unless you purchased an ECU also (apparently it adapts) you can drive the car and check for leaks. I purchased the ECU too so felt the benefit straight away.
First drive was to prove the install check for leaks etc. To be honest I wasn't sure what all the fuss was about however, I only tickled the throttle plus for some reason I was expecting the performance of my 330d - probably because I've been thinking of this engine in a Z3. Today was a slightly different story, she got ragged and then I got what all the fuss is about and why people do this upgrade.
Firstly the exhaust note is very different, much more gravelly and throaty but hollow sounding at the same time. The car is definately more purposeful in its power delivery and it encourages and almost grades youintto driving it hard! The talk of the power above 4000rpm is justified because there is more and the delivery doesn't stop. For me the car is now a proper roadster in both the way it sounds and drives. Would I recommend it? Most definately. Will I keep it on the car? Absolutely!! Will I sell my first Zed? Quite possibly!!!
In reality you can get away with just the manifold, adaptor plate and some brass piping and silicone hose and let the ECU adapt - remember to have the adaptations reset. This will keep the costs down that's for sure. It may be worth checking your local breaker for a 2.5 E46 - they may sell the manifold for just a few pounds if you are lucky.
In the days to come I'll add more detail about the install but if anyone wants to discuss or ask questions then pm me and we can exchange numbers. Hope this write up helps.
PS - make sure you get the right manifold
I had purchased a complete kit for my regular 2.8 but as its a tu engine the kit didn't fit. It was in process of being returned when my curious side kicked in.
Anyway as per the title, the manifolds were swapped so I wanted to give an overview of what's involved and help those thinking about it to decide one way or another.
This is the original manifold:
This is the 2.5 - note the lack of pipe work attached to the manifold.
Once the original is off it looks like this:
Quite busy and somewhat scary to the less mechanically inclined. I'm an ex RAF fast jet mechanic and even I thought twice! However, I just can't help myself so I continued.
Removal is actually relatively straight forward the only advice i have is to take your time and be methodical it looks worse than it is. Secondly when you are removing the manifold bolts put a bit of tape in the socket head so it "grabs" the nut stopping it falling away into the engine bay or worse - once the head is off put tissue in the ports...just in case!!
You will hear talk of the last bolt next to the bulkhead being a pain to access, it's not.
What you will need to do is remove the loom from the brackets, bend the brackets up and remove the passenger side bracket completely - don't worry it won't break! You can now access that last bolt. Removing the rest of the plumbing is self explanatory. The earlier pictures show what you'll be left with.
Now there are only ONLY two modifications you will need to do.
Firstly is to modify the IAT, file it down and put an M12 thread on it. Once that is done, screw it in with some gasket sealant. The upper one is the original.
You will then need to plumb everything in - just follow the flow on the original manifold and replicate it with the fitting kit on the m50 one. The scary part comes due to the lack of ports in the M50 manifold however, once done it should look something like this:
Basically there is one port and 2 vacuum connections. The one on the manifold is for the fuel vacuum, the second one will be on the connector into the manifold itself and is for the charcoal canister.
Note this will need to be stepped down from 8mm to 4mm, use an inline connector as one hose fits in the other - the connector acts as a strengthener and you can put a small clip, along with gasket sealant, to make it air tight.
When you fit the new manifold you won't be able to reuse the original brackets the help secure it to the engine block - you won't need them. When connected with the T piece and silicon hoses it will all be held in place and you can secure it after fitting. You will need to fit a bracket to the manifold to hold the dip stick in place. You and also use this bracket to tie wrap the ICV in place too. The oil breather sits on the block and is fine. Brackets can be fabricated and fitted afterwards - once you've done the install you'll be amazed at how quickly you can remove and refit it.
Once it's all back together, air box, throttle cables etc you need to turn your attention to the fuel rail. You will need to remove one bracket and cut part of the other. Remove this holder/bracket.
And remove the right hand edge as you look at it on this one.
The fuel rail will sit lower than the fittings on the manifold so use some bent sheet metal or spacers to hold it securely.
You will also hear talk of "bending" the fuel pipes. You will need to to allow them to clear the manifold but not too much - be careful!!
Unless you purchased an ECU also (apparently it adapts) you can drive the car and check for leaks. I purchased the ECU too so felt the benefit straight away.
First drive was to prove the install check for leaks etc. To be honest I wasn't sure what all the fuss was about however, I only tickled the throttle plus for some reason I was expecting the performance of my 330d - probably because I've been thinking of this engine in a Z3. Today was a slightly different story, she got ragged and then I got what all the fuss is about and why people do this upgrade.
Firstly the exhaust note is very different, much more gravelly and throaty but hollow sounding at the same time. The car is definately more purposeful in its power delivery and it encourages and almost grades youintto driving it hard! The talk of the power above 4000rpm is justified because there is more and the delivery doesn't stop. For me the car is now a proper roadster in both the way it sounds and drives. Would I recommend it? Most definately. Will I keep it on the car? Absolutely!! Will I sell my first Zed? Quite possibly!!!
In reality you can get away with just the manifold, adaptor plate and some brass piping and silicone hose and let the ECU adapt - remember to have the adaptations reset. This will keep the costs down that's for sure. It may be worth checking your local breaker for a 2.5 E46 - they may sell the manifold for just a few pounds if you are lucky.
In the days to come I'll add more detail about the install but if anyone wants to discuss or ask questions then pm me and we can exchange numbers. Hope this write up helps.
PS - make sure you get the right manifold
Last edited:
I'll stick to cleaning, being an ex RAF Fireman, I'm good at that 
