The 2.3L MZR DISI turbo engine is one of the most turbo-hungry platforms of its era, and good replacement units are drying up. Boost Lab, Inc. rebuilds the K04 family that powered every Mazdaspeed 3, Mazdaspeed 6 and CX-7: the K0422-881 and K0422-882 on the Speed cars and the K0422-582 on the CX-7. We also service the Hitachi HT12 on the older 626/MX-6 turbos and RX-7 twins. Nationwide ship-in service.
The DISI-era K04s dominate what we see, but the Mazda turbo story goes back much further.
263 to 270 hp from the 2.3 DISI through a K04 running around 15.6 psi stock. These turbos routinely fail from oil starvation long before the wheels wear out, which means most cores are excellent rebuild candidates. If your Speed 3 is on its original turbo, it is living on borrowed time.
Same K04 family as the Speed 3 in the AWD sedan. Parts availability for the Speed 6 is worse than for the 3, which makes rebuilding the unit you have the practical path. Same oil-feed vulnerabilities, same fix.
The CX-7's K04-2274 variant, OEM numbers in the L33L-13-700 family, failed so often that Mazda issued warranty extension SSP 86 for turbo oil smoke. The 582 is not interchangeable with the Speed cars' 881/882 despite looking similar. We rebuild both and will confirm which unit you actually have from the tag.
The FWD turbo Mazdas of the late 80s used IHI RHB5-family hardware. Simple, compact, and fully rebuildable, though heat-checked turbine housings are common on surviving cores.
The FC Turbo II ran a Hitachi HT18; the FD ran sequential Hitachi HT12 twins. Rotary exhaust heat is savage on turbos and rebuildable FD twin cores are increasingly precious. We rebuild both and cover the RX-7 in more depth on request.
Plenty of Speed cars run upgraded drop-in turbos built on the K04 frame. Most are rebuildable with the correct wheel and bearing combinations. Send photos of the tag and wheels through the repair form and we will confirm before you ship.
The root cause of most 2.3 DISI turbo failures is a tiny filter screen inside the oil feed banjo bolt. Direct-injection carbon and sludge choke the screen, the turbo starves, and the bearings die, sometimes in under 60,000 miles. Installing a fresh turbo on the old feed line is how the second turbo dies the same way as the first. Replace the oil feed line and banjo bolt, or delete the screen per the widely accepted practice, and address the VVT actuator rattle if present. Every Mazda rebuild we ship includes this warning for a reason.
Verified BorgWarner/Hitachi catalog numbers, model designations, and Mazda OEM numbers for the 2.3 DISI K04 family and classic turbo Mazdas. Search by any number.
| Turbo PN | Model | OEM PN | Application | Notes |
|---|---|---|---|---|
| 53047109904 / 53047109907 | K0422-582 (K04-2274) | L33L13700B / 700C / 700E / 700F | 2007-2012 CX-7 2.3 DISI | CHRA family 53047109904/05/07; NOT the Speed-car unit |
| 53047109901 / 53047109905 | K0422-881 / K0422-882 (K04-2280) | L3K913700A / 700D / 700E / 700F | 2007-2013 Mazdaspeed 3, 2006-2007 Mazdaspeed 6 | CHRA family 53047109901/02/06 |
| Tag-specific by revision | K0422-582 | L3Y41370Z / ZA / ZB / ZC, L3YC1370Z | CX-7 2.3 DISI service revisions | L3Y-prefix numbers supersede into the L33L family |
| Tag-specific by revision | K0422-881 / 882 | L3Y11370Z-ZC, L3Y31370Z-ZC, L3M713700B-G | Mazdaspeed 3 / 6 service revisions | Verify tag; L3Y prefixes appear on both platforms |
| 53047110003 | K04 repair kit | n/a | All 2.3 DISI K04 variants | Bearing and seal service kit |
| 53041205009 | K04 turbine wheel | n/a | All 2.3 DISI K04 variants | Replacement turbine wheel |
| 53041515708 | K04 back plate | n/a | K0422-582 / 881 / 882 | Shared across the DISI family |
| Tag-specific | IHI RHB5 | Verify by tag | 1988-1992 626 GT, MX-6 GT | Compact late-80s FWD turbo unit |
| Tag-specific | Hitachi HT18 | Verify by tag | 1987-1991 RX-7 Turbo II (FC) | Single turbo, rebuildable |
| Tag-specific | Hitachi HT12 sequential pair | Verify by tag | 1993-1995 RX-7 (FD) | Rebuilt as a matched pair; send tag photos |
The failure pattern on these engines is unusually consistent. Here is what we find.
The defining failure. The banjo bolt screen clogs with DISI carbon, oil flow drops, and the journal bearings wipe. The shaft scores, play develops, and the seals follow. The turbo is the victim, not the cause: fix the feed line or the replacement dies the same death.
Heavy white or blue smoke after idling is the CX-7 signature, bad enough that Mazda issued SSP 86. Worn bearings let the shaft orbit, the piston-ring seals lose control, and oil pours into the hot exhaust housing. Rebuildable in almost every case we see.
As bearing clearances open up, the compressor wheel loses its running clearance and efficiency drops. The ECU sees underboost and throws P0299. Rule out boost leaks and the wastegate first, then measure shaft play; if it moves, it is bearing time.
The DISI's known VVT actuator failure sheds metal into the oil system, and the turbo bearings are downstream. If your engine had the cold-start VVT rattle before the turbo died, tell us: we will inspect for metal contamination, and you should address the actuator before running the rebuilt unit.
Direct injection plus heat coke the turbo's oil drain passage, backing oil up into the center section and pushing it past the seals even when the bearings are healthy. We clean drains to bare metal on every DISI rebuild.
Disintegrating intake components and oil pooling in the intercooler feed debris into the compressor. Chipped wheel blades unbalance the assembly and finish off the bearings. Wheel replacement plus balancing brings the unit back.
No. The Mazdaspeed 3 and 6 use the K0422-881 or 882; the CX-7 uses the K0422-582. They share the K04 frame but are not interchangeable. Check the tag on your unit or send photos through repair.theboostlab.com and we will identify it.
Almost always the oil feed line. The banjo bolt screen clogs with carbon and starves the new turbo exactly the way it starved the old one. The feed line must be replaced or the screen addressed whenever the turbo is changed.
Usually yes. Most DISI failures are bearing and seal failures from oil starvation, which leaves the housings and often the wheels serviceable. With OEM units over a decade old and quality replacements getting scarce, a properly rebuilt K04 on a fresh feed line is the reliable path.
Yes, most drop-in upgrades built on the K04 frame are rebuildable with the correct wheel and bearing combinations. Send tag and wheel photos through the repair form first so we can confirm parts availability.
Yes. The FD's sequential Hitachi twins are rebuilt as a matched pair, and we also service the FC Turbo II single. Rotary heat is hard on these units, so expect turbine-side wear on most cores.
Start at repair.theboostlab.com, then ship to Boost Lab, Inc., 37833 Pineapple Ave, Unit A, Dade City, FL 33523. We serve Mazda owners nationwide and will assess the core before any work begins.