Forged Pistons for Subaru, EJ257 WRX STI (stroker), 99.75mm, 10:1 (CP Pistons SC7442)
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|
Make |
Subaru |
|
Model |
EJ257 WRX STI (stroker) |
|
Part Number |
SC7442 |
|
Cylinders |
4 |
|
Bore (in) |
3.927 |
|
Bore (mm) |
99.75 |
|
Size |
+0.25mm |
|
Stroke |
83 |
|
Conrod |
130.5 |
|
Comp Height (in) |
1.123 |
|
Comp Height (mm) |
28.5 |
|
Dom/Dish CC |
|
|
Compression Ratio |
10 |
|
Weight (Grams) |
395 |
|
Pin (mm) |
23 |
|
Rings |
RS1658-3927-0 |
|
Ring Thickness |
1.2 x 1.2 x 2.0mm |
|
Pin included (Standard) |
905-2500-18CP1S |
|
Upgraded Pin |
905-2500-20CP3S |
|
Ultra Duty Pin |
905-2500-26CP3S |
|
Locks |
905x055 SUB |
CP pistons are compatible with oversized valves and high lift camshafts. CP Pistons represent the highest quality and is engineered for maximum power. Standard features include: Deep valve reliefs accommodate high lift camshafts; Larger valve reliefs for +1mm valve sizes; Custom skirt cam and barrel design; Accumulator grooves; High strength aluminum forgings; High performance rings; Fully CNC machined and balanced to +/- 1 gram; Wrist pins included at no additional cost; Double pin oilers force fed from oil ring groove; Pin lock grooves for easy lock removal; Pin fitting included.
| Product Name | Forged Pistons for Subaru, EJ257 WRX STI (stroker), 99.75mm, 10:1 (CP Pistons SC7442) |
|---|---|
| Brands | CP Carrillo |
| Engine | EJ257 WRX STI |
| Make | Subaru |
Delivery & Freight
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Product images are for description purposes only. Actual product may vary.
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If you are unsure, get in touch by emailing [email protected], messaging us on Facebook, or phoning us at +61 7 5645 1333 (8am to 2pm AET).
What information do I need to match these pistons to my engine?
You need the engine code, bore size, stroke, rod length, pin diameter and target compression ratio. These determine the correct piston compression height and crown design.
How should ring gaps be set for these pistons?
Ring gaps must be set by your engine builder based on fuel type, boost level and the intended rpm range. Forced-induction engines usually require larger gaps.
Are forged pistons suitable for street engines?
Yes. Forged pistons handle detonation and high cylinder pressure better than cast units. Your builder should set the piston-to-bore clearance to suit your application.
What is the recommended bore clearance for the SC7442 pistons?
For the SC7442 pistons, a typical bore clearance of 0.0015" to 0.0020" is recommended. This ensures proper thermal expansion and prevents piston scuffing. Always verify with your engine builder based on specific application and tolerances.
Can I use these pistons with stock EJ257 rods?
Yes, the SC7442 pistons are designed to work with stock EJ257 rods, but ensure that the conrod length and pin height are compatible. It's crucial to check for proper clearances and fitment during assembly.
What type of rings are included with the SC7442 pistons?
The SC7442 pistons come with high-performance rings, specifically the RS1658-3927-0 set. These rings are designed to provide optimal sealing and durability under high boost conditions.
What compression ratio do the SC7442 pistons provide?
The SC7442 pistons have a compression ratio of 10:1. This ratio is suitable for a balance of performance and reliability, particularly in a stroker application.
What is the weight of each SC7442 piston?
Each SC7442 piston weighs 395 grams. This lightweight design helps reduce reciprocating mass, which can improve engine response and performance.
