The same question arrives most weeks. The manifold has six injector ports cast into it, so does that mean you need a port-injection system before you can run it? No. They ship plugged. Here is what the part actually does, why the tanks are cast and everything else is billet, and what we changed after the first version went out.
The short answer: they ship plugged
Every one of the six port-injection positions leaves here with a plug in it. Nothing about the manifold depends on them. Fit it to an otherwise standard car, run it on a tune, and it behaves like a bigger, better-cooled version of the part you took off.
The ports are there so that the day you do want port injection — bigger turbo, more boost, ethanol, a dyno session that keeps pulling timing — you take the plugs out and fit injectors. You don't buy the manifold a second time.
That is the whole design intent, and it is worth saying plainly because the alternative framing — "you'll need port injection to make this work" — is both wrong and the reason some people put off buying it.
Why the manifold is the part you change
On the Gen 2 B58 the charge cooler is not a separate item bolted somewhere in the front of the car. It lives inside the intake manifold: a water-to-air core sitting between the throttle body and the runners, cooling the charge on its way to the six intake ports.
That has one consequence that drives everything else. You cannot upgrade the charge cooling on this engine without changing the manifold, because they are the same casting. Whatever the core can shed is what the engine gets — and on a stock car, on a hot day, on the third pull, that is where the power goes.
What we did about it
Our core is the same height as the factory one and more than twice as wide.
| Factory core | Ours | |
|---|---|---|
| Height | 19.25" (489 mm) | 19.25" (489 mm) |
| Width | 2" (51 mm) | 4.5" (114 mm) |
| Depth | — | 100 mm |
| Water rows | 6 | 14 |
Same height, 2.25 times the width, and 14 rows of water against the factory's six. The plenum above it holds 6.2 litres. It is a bar-and-plate core, not a tube-and-fin one.
We are showing you the photograph with the dimensions on it rather than a percentage, because percentages in this corner of the market are not worth much. Go and read the claims on four different manifolds and you will find figures that cannot all be true at once — including, on at least one product, two different numbers on the maker's own site and on the shops that sell it.
Why we went dual-pass
This is the decision we would defend hardest, and it has nothing to do with size.
In a single-pass core, coolant enters at one end and leaves at the other. The water arriving at the first cylinder is the coldest water in the system. By the time it reaches the last cylinder it has already absorbed heat from everything it passed. The charge going into cylinder one and the charge going into cylinder six are not being cooled by the same thing.
On a standard road car that difference is academic. On a tuned car running real boost, it isn't: your tune has to be safe for the hottest cylinder, so the whole engine gets calibrated around the worst one.
The same core area plumbed two ways. Dual-pass doesn't make the core bigger — it makes the six cylinders agree with each other.
So the water in our core runs the length of it and comes back. Each cylinder sits over both the outbound leg and the return leg, and the spread between the first and last cylinder closes up.
Cast tanks, billet everywhere else
Here is the criticism we get, stated fairly: it's a casting, so they built it down to a price.
Half of that is true, and we would rather explain it than dance around it.
The tanks are cast. They are large, hollow, pressure-carrying volumes with curved internal walls, and casting is how that shape gets made repeatably — it is also how every factory intake manifold on every one of these cars was made. Casting costs a great deal up front, in tooling, and very little per part after that. Machining the same volume out of a solid block costs nothing up front and a lot every single time.
Everything else is billet, and the assembly is welded. The flanges, the port bungs, the mounting faces — the surfaces where tolerance actually matters — are machined, not cast.
We paid for the tooling once so that the finished part lands at $2,295 rather than where a machined-from-solid version of the same thing would have to sit. That is a price decision, made deliberately, and it is not the same thing as a quality decision.
Here is the number that puts it in scale. A replacement factory manifold — the standard part, with the standard two-inch core — is itself around $1,900 at the time of writing. Ours is roughly four hundred dollars more than the part it replaces, and it arrives with a core two and a quarter times as wide, fourteen rows of water instead of six, a dual-pass circuit, six port-injection positions, three auxiliary ports, and the fuel rail and lines in the box.
That comparison is the one we would rather you made, because it is the one you can check for yourself in five minutes.
What we have actually tested it to
We have pressure-tested the manifold to 65 psi. That is where we stopped, not where it failed.
The port-injection half
Six positions, one per cylinder, plugged from the factory. Alongside them, by the throttle body, are three auxiliary ports for a properly configured methanol system or whatever else a build needs.
The kit includes the fuel rail and the fuel lines. The line is plug-and-play: it tees into the factory fuel line, so nothing has to be cut.
Injectors are not included, and that is on purpose. Which injector is right depends on the fuel you are running and the power you are after, and we would rather you buy the ones that suit your build than pay us for a set you have to replace.
What we changed after the first version
The first version shipped with a coolant line long enough to touch the firewall. We shortened it. That is the whole story, and it is fixed on everything going out now.
We mention it for the same reason we published the core dimensions instead of a percentage: the useful thing to know about a part is not that nothing ever went wrong with it, but what went wrong and what was done about it. On the core itself, across everything we have shipped, we have not had one come back for a leak.
Which cars it fits
Every Gen 2 B58 — the B58TU — takes it as a direct fit, including the mild-hybrid cars:
- M240i / M240i xDrive — G42
- M340i / M340i xDrive — G20, and the Touring, G21
- M440i / M440i xDrive — G22 Coupe, G23 Convertible, G26 Gran Coupe
- Z4 M40i — G29
- X3 M40i — G01, and X4 M40i — G02
- GR Supra 3.0 — A90 / A91
The manifold is built around the engine rather than around any one chassis, so the same part suits other cars in the B58 family too — the larger SAVs, and the 5 and 7 Series among them. What changes from one car to the next is not the engine, it is the room around it.
Gen 1 is the clearest example. The manifold physically fits, but it is long enough that the wiper motor housing needs trimming to clear it. That is why Gen 1 isn't listed on the product page: the part works, the installation isn't a drop-in, and we would rather tell you that first.
So if your car isn't in the list above, it is worth asking rather than assuming either way. Send us the VIN before you order and we will tell you whether it is a direct fit, what clearance work it needs, or whether it isn't one we would put on your car.
Technical questions are welcome — write to info@shopprojectgamma.com or call +1 (832) 303-2795.
