SpeedFactory Bottom Mount Turbo Manifold for H/H2B Series

SpeedFactory Bottom Mount Turbo Manifold - H-Series & H2B

If you've been around turbo Hondas long enough, you know the sound: that faint ticking at idle that turns into a raspy leak under boost, the telltale sign your manifold's cracked again. Cheap turbo manifolds do that. They cook, they crack, they warp, and you're back under the car with a welder every season. This SpeedFactory bottom mount manifold is the fix for that headache. It hangs your turbo down low, spools it quick, pulls hard to redline, and it's fabbed to actually survive the heat and abuse of a real H-series or H2B turbo build.

This Is Where Cheap Manifolds Fall Apart

Let's talk about why manifolds fail, because it's the whole ballgame. A turbo manifold lives in violent, nonstop heat and vibration, it glows orange and shakes every time you're on it, and the budget stuff just can't take it. Thin tubing fatigues and splits, sloppy welds crack, and warped flanges start leaking exhaust and boost until your spool goes to garbage. SpeedFactory built this thing to shrug all that off. It's made from 1.5" schedule 40 stainless, so you've got thick, tough material instead of flimsy tubing waiting to crack. The welds are TIG-welded and back purged, and that back purge matters more than it sounds, they flood the inside of the pipe with argon while welding so the welds come out clean and strong instead of scaled and brittle. That's the difference between welds that hold and welds you'll be chasing cracks in later. And every flange, the cylinder head, wastegate, and turbine inlet, is CNC machined from 1/2" 1018 steel plate and cut dead flat, so everything seals up tight and stays leak-free. This is the fab work that decides whether a manifold lasts one season or ten.

Spools Quick, Pulls Hard

Here's where the equal-length design earns its keep. When the runners are all the same length, your exhaust pulses reach the turbo evenly and clean, and that's what lights medium to large turbos up fast and builds a fat, broad powerband that just keeps pulling all the way to the top of the tach. That's the holy grail on a big build, real torque and quick spool down low so the car's actually drivable, plus the top-end horsepower to back it up when you lay into it. It's dialed in for high-power setups and right at home under a drag car, where you want a turbo that's awake the second you ask for it.

Pick Your Turbine Flange and Wastegate

You've got a few configs to choose from, so grab the one that matches your turbo and the gate you're running. Don't overthink it, just line it up with your parts:

• T3, 44/46mm V-Band Wastegate Flange. A T3 turbine flange with a V-band gate flange for a 44 or 46mm wastegate. This is your setup if you're on a T3-frame turbo running a 44 or 46mm gate.
• T4 Open, 60mm Turbosmart Wastegate. A T4 Open turbine flange with a 60mm wastegate flange cut for a Turbosmart gate. This is the big-boy route for a T4-frame build that needs serious boost control.
• T4 Open, 60mm TiAL Wastegate. Same big T4 Open setup, just with the wastegate flange cut for a 60mm TiAL gate instead.

Match the turbine flange to your turbo and the wastegate flange to your actual gate, and you're good. Going for big numbers? The T4 Open with a 60mm gate is the way to get the boost control a serious build wants.

You Keep Your Alternator And Power Steering

This one's a bigger deal than it sounds. A ton of turbo manifolds force you to yank your alternator or gut your power steering just to make room, and now you've traded a streetable car for a stripped-out pain in the neck. Not this one. The bottom mount layout keeps your factory alternator right where it belongs and clears all your factory power steering, so your accessories stay put. If the car still hits the street, that's huge, and even on a dedicated build it just makes for a cleaner setup with fewer compromises.

Who It's For

Straight up, this is a high-power, race-leaning manifold for a real H-series or H2B turbo build, the kind chasing big torque, quick spool, and a nasty top end. If that's what you're putting together, this is the manifold to hang your turbo on and not think about again.

What You Get

• SpeedFactory bottom mount turbo manifold for H-series and H2B setups
• 1.5" schedule 40 stainless steel construction, TIG-welded and back purged
• Cylinder head, wastegate, and turbine inlet flanges CNC machined from 1/2" 1018 steel plate
• All mating surfaces machined flat for a leak-free seal
• Equal-length design for fast spool and a broad powerband
• Available in three flange/wastegate options: T3 with a 44/46mm V-band gate, T4 Open with a 60mm Turbosmart gate, or T4 Open with a 60mm TiAL gate
• Retains the factory alternator location
• Clears all factory power steering components

Fits These Setups

• Honda H-series engines (H22/H23)
• H2B swap setups (H-series engine with B-series transmission)

Note: SpeedFactory bottom mount turbo manifold for H-series engines and H2B swap setups. Constructed from 1.5" schedule 40 stainless steel, TIG-welded and back purged for strong, clean welds, with cylinder head, wastegate, and turbine inlet flanges CNC machined from 1/2" 1018 steel plate and all mating surfaces machined flat to seal without leaks. The equal-length design spools medium to large turbochargers quickly and produces a broad powerband that carries to the top of the RPM range, making it suited to high-power and drag applications. This bottom mount design retains the factory alternator location and clears all factory power steering components. Available in three turbine flange and wastegate configurations: T3 with a 44/46mm V-band wastegate flange, T4 Open with a 60mm Turbosmart wastegate flange, or T4 Open with a 60mm TiAL wastegate flange; select the option that matches your turbo and wastegate. One manifold per order.