SpeedFactory Top Mount Turbo Manifold for B/D/H-Series

SpeedFactory Top Mount Turbo Manifold for B/D/H-Series

You've picked the turbo, you know what you want the car to run, and now the manifold decides whether it spools when you want it to. SpeedFactory's Top Mount Turbo Manifold puts the turbine up top and short-routes the runners to it, which is why it lights big frame turbos quickly on a B18, B20, D-series, or H22. SpeedFactory positions this one for high power builds and drag cars, and that positioning is worth taking seriously before you order.

What It Is and Why It Works

The tubing is 1.5 inch schedule 40 stainless, TIG welded and back purged so the inside of the weld doesn't sugar and start shedding into your turbine wheel. The cylinder head flange, wastegate flange, and turbine inlet flange are CNC machined from half inch 1018 steel plate, and every mating surface is machined flat so the gaskets have something square to seal against.

Half inch flange plate matters more than it sounds. Thin head flanges warp as they heat cycle, and once a manifold flange is warped you're chasing exhaust leaks at the head for the rest of the car's life. Thick plate resists that.

Top mount geometry is the other half of the story. Short runners feeding a turbine sitting above the head means less volume between the exhaust valve and the turbine wheel, so the turbo sees energy sooner and spools earlier than it would on a long-runner setup. The trade is packaging, because the turbo is now up high in the bay instead of tucked low. Check your clearance before you commit.

Top Mount, Bottom Mount, or Ram Horn

SpeedFactory builds this manifold family in several layouts and they aren't interchangeable in intent.

If your car sees road course time or you want the turbo tucked low, the bottom mount is the one to look at. If you're building a drag car and want the biggest turbo you can light, that's what the top mount is for.

Available Configurations

Pick your engine family first, then the turbine inlet flange your turbo uses, then the wastegate flange your gate uses.

The 60mm wastegate options and the divided T4 with twin gates are the configurations for the highest power setups, and they lean further toward race use than the single 44/46mm versions. If you're not sure which turbine flange your turbo has, check the turbo before you order rather than after, because these are built to your selection and can't be swapped later.

Specs

Fitment

This fits by engine family rather than by chassis, so a B18 in a DC2, an EG, or an EK all take the same manifold. What varies by chassis is whether the turbo clears once it's up there. Top mount puts the turbine above the head, so measure your hood clearance and your firewall side before you order.

What to Know Before You Buy

These are made to order, not pulled off a shelf. SpeedFactory builds each one to your flange selection and the lead time runs weeks, not days. It has moved around a lot depending on their backlog, and at the moment they're quoting toward the long end of that range. Ask us for the current estimate before you plan a build around a delivery date, because we'd rather tell you eight weeks up front than have you sitting on a car with no manifold.

Read the warranty terms before you touch it, because they are narrower than most people expect on a part at this price. SpeedFactory covers welding defects only, to the original purchaser, and they require your invoice plus photos or video of the setup installed. The two things that void it outright: heat wrapping the manifold, and running an improper downpipe or dumptube. Heat wrap is common enough in this community that plenty of people will wrap this without thinking about it and give up their coverage doing it. If you want heat management, use a turbo blanket and shielding instead of wrapping the manifold itself.

Support the weight properly. A big frame turbo hanging off a top mount manifold puts real leverage on the head flange, and manifolds crack where they're stressed, not where they're hot. Get your downpipe supported so it isn't hanging on the turbine housing, and don't let the exhaust pull on the manifold.

SpeedFactory sells their performance parts for off road use only, and this manifold is positioned for drag cars. That's not boilerplate on a part like this. If the car is registered and inspected where you live, know what that means before you buy.

You'll need the matching V-band clamps, wastegate, downpipe, and gaskets. None of that is in the box. If you haven't bought the wastegate yet, buy it before you pick the manifold flange so the two actually match.