Diamond Special Order Subaru WRX VA FA20DIT Forged Pistons — 86 mm Stroke / 5.090 in Rod
Diamond Special Order Subaru WRX VA FA20DIT Forged Pistons — 86 mm Stroke / 5.090 in Rod
DIAMOND PISTONS · SPECIAL ORDER
Subaru WRX VA FA20DIT forged piston kit
Specify a Diamond four-piston kit for a Subaru WRX VA FA20DIT build. Choose the finished bore, crown volume and included gudgeon pins for the engine you are machining.
Made to order. Allow approximately 5–6 weeks for delivery, pending Australian customs processing time.
Precision in the details
- 2618 forged aluminium with a full-round forging profile.
- Oil-ring-fed pin lubrication and fitted gudgeon pins.
- Moly-coated skirts.
- 3D-machined crown and valve-pocket profiles.
- The specified ring set, pins and retainers are included in the kit price.
Choose your specification
Choose 86.00, 86.25 or 86.50 mm finished bore, then the -9.00 cc or -12.00 cc crown and its published nominal ratio. The ratio varies slightly at the largest bore: -9.00 cc is 10.50:1 at 86.00/86.25 mm and 10.60:1 at 86.50 mm; -12.00 cc is 10.00:1 and 10.10:1 respectively. Finish by selecting standard G-series or H13 pins.
Build dimensions
| Dimension | Published specification |
|---|---|
| Piston quantity | 4 |
| Crank stroke | 86.00 MM |
| Connecting-rod length | 5.090 IN |
| Compression height | 1.285 IN |
| Forging profile | Full Round |
Engineering reference: rings, pins and valve pockets
Ring sizes are listed as top / second / oil ring. Verify pin dimensions against the connecting-rod small end. Valve-pocket depths are catalogue dimensions; check piston-to-valve clearance with the actual cylinder heads, camshafts and cam timing.
| Kit SKU | Ring package | Pin diameter | Pin length | Valve-pocket depth: intake / exhaust |
|---|---|---|---|---|
| 36046-4 | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36046-4-H | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36047-4 | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36047-4-H | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36048-4 | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36048-4-H | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36049-4 | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36049-4-H | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36050-4 | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36050-4-H | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36051-4 | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
| 36051-4-H | 1.20 mm / 1.20 mm / 2.00 mm | 0.866 in | 2.250 in | 0.190 in / 0.170 in |
Fitment and engine preparation
For the 2015–2021 Subaru WRX VA with the FA20DIT 2.0L turbo engine, using the stated 86.00 mm crank stroke and 5.090 in connecting-rod length. Confirm the actual engine and rotating assembly before ordering. These FA20DIT kits have different crown and valve-pocket specifications from FA20/4U-GSE BRZ and Toyota 86 kits; they are not FA24 WRX VB pistons.
Catalogue bores are finished cylinder-bore sizes. Nominal compression ratios depend on the measured chamber volume, deck clearance and compressed head-gasket thickness. Use the instructions supplied with your exact kit for piston-to-wall clearance, ring end gaps and pin fit; confirm all machining and assembly dimensions with your engine builder.
View kit part numbers and supplied components
| Kit SKU | Bore | Crown volume | Nominal ratio | Included pin | Ring set | Retainer | Oil-rail supports |
|---|---|---|---|---|---|---|---|
| 36046-4 | 86.00 MM | -9.00 CC | 10.50:1 nominal | G8662250180C | 09573385 | 015113-8 | No |
| 36046-4-H | 86.00 MM | -9.00 CC | 10.50:1 nominal | H8662250225C | 09573385 | 015113-8 | No |
| 36047-4 | 86.25 MM | -9.00 CC | 10.50:1 nominal | G8662250180C | 09573395 | 015113-8 | No |
| 36047-4-H | 86.25 MM | -9.00 CC | 10.50:1 nominal | H8662250225C | 09573395 | 015113-8 | No |
| 36048-4 | 86.50 MM | -9.00 CC | 10.60:1 nominal | G8662250180C | 09573405 | 015113-8 | No |
| 36048-4-H | 86.50 MM | -9.00 CC | 10.60:1 nominal | H8662250225C | 09573405 | 015113-8 | No |
| 36049-4 | 86.00 MM | -12.00 CC | 10.00:1 nominal | G8662250180C | 09573385 | 015113-8 | No |
| 36049-4-H | 86.00 MM | -12.00 CC | 10.00:1 nominal | H8662250225C | 09573385 | 015113-8 | No |
| 36050-4 | 86.25 MM | -12.00 CC | 10.00:1 nominal | G8662250180C | 09573395 | 015113-8 | No |
| 36050-4-H | 86.25 MM | -12.00 CC | 10.00:1 nominal | H8662250225C | 09573395 | 015113-8 | No |
| 36051-4 | 86.50 MM | -12.00 CC | 10.10:1 nominal | G8662250180C | 09573405 | 015113-8 | No |
| 36051-4-H | 86.50 MM | -12.00 CC | 10.10:1 nominal | H8662250225C | 09573405 | 015113-8 | No |
Made to order · delivery
Allow approximately 5–6 weeks for delivery, pending Australian customs processing time. Manufacturing schedules, international freight and customs clearance may extend this estimate. Contact BBT before ordering for a build with a fixed deadline.
Plan your build with BBT
Built by Boost & Tune can help select the kit for your measured engine, fuel and intended use. Connecting rods, crankshafts, machining, engine assembly and tuning are purchased separately.
Browse Subaru WRX VA FA20DIT engine parts.
Manufacturer photography shows a representative Diamond piston from this catalogue series. Crown shape, valve pockets, skirt finish and supplied components vary with the selected part number. The exact kit tables define the supplied specification.