Atomic Barra Wiseco Pistons
Engineering Overview
SPEC-DOC
Atomic Wiseco Forged Pistons
A New Era of Strength
We’ve been quietly working behind the scenes to replace our legendary Icon pistons with a completely new forging from Wiseco. We shared our full 20+ years of Barra design IP directly with Wiseco to bring this custom piston to market. This is a proprietary Atomic design and carries our own custom part numbers—these are not the standard off-the-shelf Wiseco Barra pistons. There are now off the shelf Wiseco options that include some but not all of our features.
The "No-Bore" Advantage. If your block's cylinder walls are in good, clean condition, you can use our 92.25mm Atomic Standard size. This requires honing only—no expensive boring machine time. This simple choice can save you over $500 in machining costs as well as time.
Strutted For Supremacy
It was critical that these pistons remained exceptionally light (ranging from 370g to 378g) to reduce reciprocating mass, but we demanded a significant increase in horsepower capacity per cylinder as an upgrade over the legacy Atomic ICON pistons. Wiseco delivered with a deep skirt, strutted forging architecture that directly resembles our top-tier Cosworth F1 series pistons.
Engineering Highlights
Quiet Operation
- Atomic proprietary quiet crown geometry
- Extended skirt design
- Significantly reduces cold-start "piston slap"
Premium Components
- Advanced skirt friction coating
- Low-drag, Japanese-made competition ring set
- High quality 2618 forging, precision CNC'd in USA
Power Ratings
- Standard Pin (0.200"): Rated for 250hp per cylinder (1500hp total)
- Upgraded Pin (0.250"): Rated for 350hp per cylinder (2100hp total)
Size & Machining Options
All sizes feature a 9.0:1 Compression Ratio with a 10cc Dish.
| Part Number | Bore Size | Machining Requirement | Weight |
|---|---|---|---|
| TBC | 92.25mm (Atomic STD) | Hone Only (No Boring) | 370g |
| TBC | 92.50mm (+0.010") | Bore & Hone Required | 374g |
| TBC | 92.75mm (+0.020") | Bore & Hone Required | 378g |
⚠️ Machining & Clearance Notes
- Recommended Clearance: 4.5 thou (0.0045"). Always verify with the included specification sheet before final honing. We recommend 5.5 thou (0.0055") for grouted engines.
- Pin Upgrade: If you are planning to run sustained high RPM, or push beyond 1500hp, you must select the heavy-duty 0.250" wall wrist pin upgrade to prevent pin flex and piston boss failure.
- Ring Gaps: The included Japanese competition rings must be filed to suit your specific boost application. Refer to the supplied guide for gap recommendations.
