[Jros]

Originally Posted by Jros

Update: for now i feel like I lost power, particularly mid-hi around 5k rpm.

Engine MAF reading curve peaks now around 7100 rpm, keep in mind mine is a 2.5 liter and i don't know if a 3 liter would peak higher or lower in the rpm range than mine with this mod.

Mine peaked at 6500 before with 3SIM, but the air flow at peak was about the same, that reinforces my hypothesis that i lost power.

Gonna ask Bob at StageFP if it could be the tune. Considering i had done MILVS too i was expecting gains only over 4k rpm versus 3SIM and no MILVS.

Gonna update again when i have got an answer.

Gave Bob some logs and it's been a week and no answer, guess he is a very busy guy. By my gut feeling i will get back to the 3SIM, maybe the 2.5 liter N52 doesn't have enough spare torque to run with this mod. Car still feels a bit dead and dragy times confirm my feelings.

If someone wants to know, my AFR at WOT is around 14.7 in lower rpms to 13 on upper rpms, which is good, and timing advance is around 27 degrees more or less at any rpm.

Quarter mile a pitiful 15.35 (best, average 15.5) with 146 kmh trap speed. I was hitting 14.9x with 3SIM and no MILVS.

To be continued...

[mtnbikeman123]

I am working on doing this swap as well. Big thanks to Biginboca for documenting it all.

First photo is a comparison of the two sets of ports, notice the N54 is visibly larger. I am not sure why my 3IM ports look so much smaller than what Biginboca shows on the first page of this post. The previous owner did the 3IM swap on this car. I didn't realize that there are potentially more than one version of the 3IM, small and large ports?

Then the second photo is how the N54 manifold sits on the N52 head without slotting the sleeves. You can see the grease outline of the gasket and the gasket is trying to seal right on the edge of the port in this configuration.

Third photo shows the the fit between the N54 manifold and N52 head without sleeves(how it will sit once the sleeves are slotted).

I just thought this was interesting and others might want to see it as well. I am looking at machining some new eccentric sleeves but haven't committed to anything yet. Not sure it is really worth the hassle.

[neilvan]

The 2.5L N52 cars will have smaller runners than the 3.0L cars (both manifolds shown are the 3 stage but the 1 or 2 stage versions will have the same dia's)

[Biginboca]

Good info there guys! I didn’t realize there were 2 versions of the 3IM. Luckily there is only one version of the N54 so we can’t screw that part up

[shimstack]

Originally Posted by mtnbikeman123

Then the second photo is how the N54 manifold sits on the N52 head without slotting the sleeves. You can see the grease outline of the gasket and the gasket is trying to seal right on the edge of the port in this configuration.

Thanks for the photos.

It sure looks like the difference in port shape and size creates a serious step between the inner surface of the runner and the passage into the head. That can't be good for flow. How much room is there for an "adapter" that port matches the two parts for shape and offset? Would the manifold interfere with anything if it were pushed off the head like 15mm?

My N54 manifold is waiting its turn on my workbench- kitchen remodel setbacks!

[mtnbikeman123]

Keep in mind my photos are showing the gasket on the head, not the ID of the manifold runners. There are probably some gains to be had in port matching the head but that is outside of the scope of what I want to achieve. If I end up having new sleeves made, I will try to carefully center the ports, but I am just not sure it's really worth the extra effort.

I can't really speak to the space for an adapter but it seems like it could work.

Originally Posted by shimstack

Thanks for the photos.

It sure looks like the difference in port shape and size creates a serious step between the inner surface of the runner and the passage into the head. That can't be good for flow. How much room is there for an "adapter" that port matches the two parts for shape and offset? Would the manifold interfere with anything if it were pushed off the head like 15mm?

My N54 manifold is waiting its turn on my workbench- kitchen remodel setbacks!

[Noir]

Originally Posted by Jros

Gave Bob some logs and it's been a week and no answer, guess he is a very busy guy. By my gut feeling i will get back to the 3SIM, maybe the 2.5 liter N52 doesn't have enough spare torque to run with this mod. Car still feels a bit dead and dragy times confirm my feelings.

If someone wants to know, my AFR at WOT is around 14.7 in lower rpms to 13 on upper rpms, which is good, and timing advance is around 27 degrees more or less at any rpm.

Quarter mile a pitiful 15.35 (best, average 15.5) with 146 kmh trap speed. I was hitting 14.9x with 3SIM and no MILVS.

To be continued...

Don't feel too bad — I was waiting on him a while, too. And likely to continue waiting as we data log my current setup and forward the findings to him to tweak. Just give it another week and try emailing him.

[MOD.Works]

The N54 intake manifold can slightly porting.

I'm a bit of a porting n54 runners. Now the shape and size is almost the same as the N52 heads intake port. Only small step.
In some situations, a step is a good thing. The step prevents back flow. But the flow can be a little worse.
Please note. The N52 Intake port top end is a slightly larger dimension because it has a bevel.
I guess BMW has been thinking of the purpose of the bevel that is a small step. Also for the installation of the manifold is slightly space and tolerance. In this case, the other edge may remain a slightly larger step and the other edge is smoother.
The N52 port size for the greatest point of the bevel is 52mm x 32mm.
The dimensions of the B30 manifold runner are slightly smaller. (50mm x 30mm)


I don't think I'll go n54 for long. I will only try it for comparison.

[AdrianE36]

Not a technical post but for anyone interested in "beautifying" their N54 manifold a little, I used the stock beauty cover and mounted it onto the N54 airbox studs using super glue, screws, and a black hose clamp I had lying around. It's not perfect but I like it and can remove it if I ever need to.
And I'll be able to install the manifold this weekend with the combination of nice weather and not having any errands to run..

[Noir]

Looks good!

[Biginboca]

Originally Posted by Noir

Looks good!

I agree it really looks great!

[AdrianE36]

Manifold swapped in and runs great and I'm sure she'll run even better once I get the StageFP tune!

Also: I recommend using the opportunity to spray some lithium grease on the upper & lower steering joints if needed. Mine were making a faint creaking sound while turning and it went away after spraying them down.

[Noir]

Originally Posted by AdrianE36

Manifold swapped in and runs great and I'm sure she'll run even better once I get the StageFP tune!

I love the valve cover! Nice bay.

[Biginboca]

Looks great AdrianE36 let us know how you like it after the tune!

[AdrianE36]

Originally Posted by Noir

I love the valve cover! Nice bay.

Thanks, I try to keep it clean! And the VC is a no-name aluminum unit off of eBay.
https://www.ebay.com/itm/ALUMINUM-Va...-127632-2357-0

I'm not one to throw eBay parts on my car but a few guys on the N51/N52 Facebook group are running them (initially as guinea pigs) with no issues. I've put 1200 miles on mine so far!

Originally Posted by Biginboca

Looks great AdrianE36 let us know how you like it after the tune!

Will do! I did a few pulls to red line and felt like it had a bit more to go so I definitely need the 7500RPM limiter!

[Jros]

Love the aluminum cover, really. You made me think about doing the valve cover the third time just to switch to aluminum...damn

[Jros]

I thought this would be useful.

I graphed maf readings of my N52B25 with N54 manifold and then with 3SIM (the smaller stock one for EU 325I, not the larger 330I one).

Both were pulls in third gear with 20 degree Celsius intake temp, both manis where run with the respective tune and throttle body.

rev limiter was at 7k5 for the N54 manifold and 7k for 3SIM, so the N54 mani has one more data point on the graph.

By the look of it, the N54 manifold isn't really suited to my N52B25 engine, the loss in torque / power is very large until the very top end.

Readings are in g/sec, and taken every 500 rpm interpolating my data.

[mtnbikeman123]

I also got my car buttoned up this weekend. I ended up shipping my DME to StageFP so they could return it to stock and then flash the correct calibration. Overall I am really happy with the result, the power delivery feels a lot more linear than with my 3IM, no more humps. It does feel like I lost a bit of low end but honestly I don't really care, I love revving the car out. Note that I was coming from the 2.5L 3IM so maybe I lost less torque than I would have coming from the 3.0L 3IM? Probably...

A couple notes that may or may not be helpful to others attempting this work.

I ended up buying 3.25" ID silicone couplers (rather than any 3.5" parts) and they fit well on the throttle body and on the OEM air filter housing. I did use the same configuration though, with one 90 deg and one 45 deg and one aluminum coupler. I got these from Amazon.

I used a dremel and thin cutting discs to slot the sleeves, I feel like I got nice clean cuts and I could cut them to the exact slot size I wanted.

After slotting the steel sleeves, I found that the small center sleeve still was restricting the total motion of the manifold to align with the head in the vertical direction. So I drilled this location in the plastic manifold to accept one of my spare larger slotted sleeves. I dont remember which drill size I used but it was a slightly tighter press fit but it seemed to work ok. This allowed the whole manifold to come down and better align with the ports on the head. It was pretty quick and easy and I would recommend it. I attached another image of a grease transfer that shows the nice alignment of the gasket on the head(in the vertical direction at least). You can actually see the manifold does sit a bit lower than my previous photo, drilling and using a larger center sleeve does make a tangible difference.

And then I ended up using high temperature epoxy to create the offset in the slotted sleeves. And then I also only added this feature to 4 of the 7 sleeves. I really should have stopped at 2 since you only should need two sleeves to fully constrain the manifold in place but I didn't think of that until I had filled 4 with epoxy.

I also lengthened my MAF harness by a couple inches by splicing in some extra wire length. I ended up using the N54 mounting bracket for the wires under the manifold so I didn't have enough length to reach the MAF. I forgot about Biginboca's suggestion to reuse the N52 bracket and I had already put the car together so I opted to lengthen wires rather than take everything back apart.

Of course your mileage may vary, I am only sharing my experiences.

Again, I am super happy with the result and I feel that my 128 is more fun to drive with this powerband! Thanks to Biginboca and Bob at StageFP for your hard work!!!

[Biginboca]

mtnbikeman123 Thanks for sharing all that. Your slotted sleeves look great, and the alignment in your grease transfer looks spot on. Nice work man! The dremel with cut off wheels to slot the sleeves is definitely a good route to take also, probably takes half the time of the angle grinder that I’ve been doing.

[dmytro98]

I am in the process of doing the n54 swap from a single stage but I was trying to keep the n52 throttle body. One issue that I have from doing that is there is a vacuum hose that on the n52 connects directly to the manifold but on the n54 intake manifold that port gets moved to the throttle body. First question is do I need this vacuum hose at all? Could I merge that line with the other pcv line or would I have to create another port or just go with the n54 throttle body.

[Jros]

Go with N54 throttle body, they are cheap. And have somewhat larger ID so somewhat better flow for what it's worth.

[MOD.Works]

Originally Posted by Jros

Go with N54 throttle body, they are cheap. And have somewhat larger ID so somewhat better flow for what it's worth.

The diameter of the N54 throttle body and the n52 throttle body butterfly are the same. 76mm on both. N54 slightly larger ID which tapers about 76mm for the butterfly. However, the N54 throttle is better and flows a little more. Butterfly thinner, etc.