Fitting a M54 Inlet Manifold

[NZ00Z3]

Hi

There are 2 well known manifold changes for the 2.8 L cars:
- If single VANOS fit the M50 manifold
- If duel VANOS fit the M54B30 manifold

Not much has been done for the smaller sized 6 cylinder engines. Having both time and parts, I recently installed a M54B25 inlet manifold on a M52TUB25 powered BMW 323 to see what the improvements are. While the car is not a Z3, the results can be used as a guide for the 2.0 L Z3's as all M52TUB engines (2.0, 2.5, 2.8) use the same inlet manifold. I chose the M54B25 manifold as it was in the shed and getting another one for my Z3 would be cheaper than the popular M54B30 manifold.

It resulted in gaining 3% more torque and 6% more power plus the engine with the M54B25 manifold accelerated 38% faster during the tests.

The data was captured using the app "TestO" and can be seen in the attached graph.

The differences between the two manifolds are:
- The M54 runners are 10 mm shorter
- The M54 runner openings are "D" shaped and match the shape of the opening in the head, where as the M52 openings are Oval (see photo)
- The M54 DISA valve is larger
- The M54 resonant air sections are larger

All this results in letting the engine breath better. The 38% increase is acceleration is likely due to there being a better air supply which reduces the syringe affect as described by @Pingu in post 44 of his testing thread https://zroadster.org/threads/testo-datalogger-what-do-you-think.18350/page-3#post-319060

Now planning on doing the same mod to my 2.0 L Z3 in the near future.

Regards

Murray

 

[t-tony]

@Sean d The 38% increase is acceleration

Tony.

 

[Pingu]

38% increase in anything is epic.

The "post air mass" on your graph is a massive improvement. It shows how strangled the original setup is at high revs.

 

[Lee]

This is amazing. @Murray Wall thanks for taking the time to try this.

 

[Bazza]

Brilliant well done, good info I'm sure there be a few people trying this with the gain you have stated

 

[Devon Z]

Great write up and many thanks, those inlet ports look much bigger. Top of my list of things to do over the winter now.
One question, was the thottle body the different?

 

[Bazza]

Just thinking on? If we were to gas flow the inlet would this give the same results, awaiting your answers with baited breath

 

[Devon Z]

Just thinking on? If we were to gas flow the inlet would this give the same results, awaiting your answers with baited breath

That's a thought? But I'm thinking that overall the manifold maybe slightly bigger? As Murry said the disa's bigger.

 

[Sean d]

I'm not sure I understand the 38% increase in acceleration, are you saying that the 0-60 would be 38% faster, I'm really interested in doing this upgrade, would I need the full inlet manifold including throttle body.

 

[Sean d]

I'm not sure I understand the 38% increase in acceleration, are you saying that the 0-60 would be 38% faster, I'm really interested in doing this upgrade, would I need the full inlet manifold including throttle body.

Just read it again and realised that you are talking engine speed, I'm not sure if I see the benefits as it only results in 6% more power.

 

[NZ00Z3]

Hi

Just thinking on? If we were to gas flow the inlet would this give the same results, awaiting your answers with baited breath

I don't know what is done to gas flow an inlet so can't comment.

I'm not sure I understand the 38% increase in acceleration, are you saying that the 0-60 would be 38% faster, I'm really interested in doing this upgrade, would I need the full inlet manifold including throttle body.

I compared the time for the car to accelerate from 1,500 rpm to red line from both runs and the difference was the post run was 38% quicker, so yes it would improve the 0-60 time. I noticed the difference when doing the post run. The calc's were double checked as it looked to good to be true.

Yes its only 6% more horse power at the top of the rev range, which people will rarely use, but the real benefit is the 38% acceleration change due to the removal of air way restrictions that allow the air to get to the engine quicker. This benefit you'll use every time you pass a car.

I used the original throttle body (without modification) and used an adapter plate from http://www.ebay.co.uk/itm/BMW-e46-3...330272?hash=item1a233cb320:g:cIoAAOSwEK9T5bY- It all just bolted up.

Hope that helps

Regards

Murray

 

[Bazza]

Hi, Murray gas flowing is machining or polishing any miss matches between the manifold and the head to allow gases to flow without any obstructions, you can also enlarge the ports at the same time to allow greater flow, keep up the good work mate and keep us all informed.

 

[Pingu]

I don't know what is done to gas flow an inlet so can't comment.

O/T, but...

Gas-flowing is a very worthwhile mod and is a real benefit to run-of-the-mill mass-produced engines. M engines are already ported and polished, but I suspect that everything else would benefit.

I did my Escort van. Before the mod, my speed would drop from 70 to 50 on the motorway hill to M1 Jct 22 (southbound). After the mod, I could accelerate up the hill.

The combustion chambers only leaked a little when tested, so valve grinding and lapping would have made some of the difference, but I think porting and polishing made the biggest difference.

 

[t-tony]

Last time I suggested this as beneficial it met with negative response along the lines of how do you polish plastic?

Tony.

 

[Sean d]

Hi @Murray Wall what exactly would I need for the upgrade,

 

[NZ00Z3]

Parts needed (minimum):
- 11617525752 inlet manifold off of a M54 engine with either the 2.2 or 2.5 L engine. Aquire one from the guys on the forum parting out Z3's.
- Throttle body adapter http://www.ebay.co.uk/itm/BMW-e46-3...330272?hash=item1a233cb320:g:cIoAAOSwEK9T5bY-
- 13641437487 x 6 top injector O Rings (I completely removed the injectors to avoid damage during disassembly)
- 13641437486 x 6 bottom injector O rings
- 11611436631 inlet manifold gasket
- 11157532649 CCV hose from separator to dip stick tube. Easier to just cut the old one on disassembly and fit a new one later.

Other part:
- 3 mm ID vacuum hose about 500 mm
- Any parts of the CVV system that you want to change while you are in there
- Any water/cooling system parts that you want to change while you are in there

Hope this helps

Regards

Murray

 

[Devon Z]

Well I've just picked up a manifold off eBay, looks like I'm going to need the matching DISA? Then the other bits listed.

Steve

 

[Sean d]

Well I've just picked up a manifold off eBay, looks like I'm going to need the matching DISA? Then the other bits listed.

Steve

Did you just get the blank manifold, I have seen one or 2 for £30-40,

 

[Sean d]

Parts needed (minimum):
- 11617525752 inlet manifold off of a M54 engine with either the 2.2 or 2.5 L engine. Aquire one from the guys on the forum parting out Z3's.
- Throttle body adapter http://www.ebay.co.uk/itm/BMW-e46-3...330272?hash=item1a233cb320:g:cIoAAOSwEK9T5bY-
- 13641437487 x 6 top injector O Rings (I completely removed the injectors to avoid damage during disassembly)
- 13641437486 x 6 bottom injector O rings
- 11611436631 inlet manifold gasket
- 11157532649 CCV hose from separator to dip stick tube. Easier to just cut the old one on disassembly and fit a new one later.

Other part:
- 3 mm ID vacuum hose about 500 mm
- Any parts of the CVV system that you want to change while you are in there
- Any water/cooling system parts that you want to change while you are in there

Hope this helps

Regards

Murray

Hi Murray, what DISA would I need thanks

 

[NZ00Z3]

Assuming that you have purchased the M54B25 manifold, you will need the associated DISA part number 11617544806. The one on your 2.0 L manifold will not be big enough. Be aware that there is also a even larger DISA that is used in the M54B30 manifold. The 3.0 L DISA will not fit the M54B25 manifold.

Both my manifolds came with DISA valves.

The M54B25 Manifold goes onto my car today, so will be able to update with 2.0L Z3 specific results in the next couple of days.