[Biginboca]

Originally Posted by cwlo

So it looks like you were able to just press the metal sleeve out of the manifold?

Not sure if it would worth it to fab up new metal sleeves with offset holes. Your approach will probably last long enough, except it might be a pain if the manifold has to be removed and those little nylon pieces fall out. Minor inconvenience though.

I am going to inspect my manifold when I get a chance....I had no indications of any leaking, but will keep an eye on it. Thanks Big

I’m going to make a little tutorial soon of how I’m making these offset sleeves, but you needn’t worry about the plastic part falling out. They are a true press fit and they 100% won’t fall out.

For the outer metal sleeve parts they just slip out of the manifold. Unfortunately they don’t have their own part number the only way I know to get them is with a manifold. It might take a light hammering but they will come out of the manifold pretty easily. Then I’m just grinding a slot down the sleeve with an angle grinder. The width of the grinder wheel is the perfect width for the slot you need to make, so it’s really not challenging just time consuming. It’s taking me like 10-15 mins to make one sleeve. Maybe if there’s enough interested we can get someone to make a jig and mill slots in a bunch of them.

On the good side, the n52 and n54 manifolds use the same sleeves. There’s 6 identical larger ID sleeves and the 7th center sleeve is slightly smaller diameter. I’m planning on drilling that center hole in the manifold to the size of the 6 other holes and then using one of the larger sleeves in that spot. (Because I have 2 manifolds I have some extra sleeves.)

Check around where your runners meet the head by spraying carb cleaner in that area especially the bottom of where they meet the head. If your idle stumbles then you have the leak. I don’t see how you couldn’t have it when you look at the heads and the manifolds it’s just very likely.

[Biginboca]

Progress made today. Finished up making the inserts I needed for this new N54 manifold I’m getting ready to mount. (I still have to drill the PCV heated angle port out then this manifold is ready to go on the car.). Here is the simplest tutorial I can make for the offset mounting solution...



I only did plastic inserts for 5 of the seven holes. I think that will be enough to locate the manifold properly. And FYI here is the tool you will need. It’s $13.99 at harbor freight lol

[Biginboca]

Bob@BPC So an update...

Just installed the modded mount N54 manifold. Car is running great! I don’t think I’ll be getting any more lean codes. (I hadn’t gotten a lean code in over a month anyway but the weather has been a lot warmer also.)

What I’m really pleased about is the fuel trims have dropped quite a bit they are now about 1/3 what they were when I first started watching them and was getting codes every week with the original N54 Manifold.

These are my fuel trim logs:

Left is 3 months ago when I was getting lean codes every week.

Middle is last week after I did some cleaning up of my intake tract and addressed every other possible vacuum leak source like valve cover, valvetronic motor gasket, intake tubing, and installed another N54 Manifold but didn’t change the mounts.

Right is 10 mins ago on a test drive after installing the third N54 Manifold with the offset mounts...



Short and long Trims for a bank that sum over 30 seem to set the lean codes. Trims that sum under 10 for a bank are considered pretty much normal at idle.

[Noir]

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[Biginboca]

Ok so it’s been about 5 days since I put the modified manifold on the car. Fuel trims still continuing to drop and have pretty much settled into the perfect range. So this fitment fix is definitely good to go and I would recommend it for anyone who wants to go the N54 Manifold route....

[cwlo]

Thanks for posting all the detailed info! I am going to take a look at mine once I get the exhaust back together. Will do the leak test and see what I find.

[Zajac1]

I'm curious. In what BMW models and years is N54 manifold ??

[Biginboca]

So I made a pass this morning with the new manifold to see. Looks like I picked up some power it’s running more than 1mph faster at the end of the 1/4 mile. The pass on left was before manifold revisions and the pass on right is after. These runs are ideal to compare because temps within 3 degrees, similar D/A’s, and same exact 60’ times:




FYI I don’t feel these represent the best the car can do looking at the 60’ times (2.18’) there is plenty of room for improvement (driver mod). Both runs same launch style-clutch dump at 2500rpms and spinning tires all the way through 1st gear. I think with a 2.00 60’ time the car can pull a 13.5-13.6 1/4 time.