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JE Pistons / SRP · 378136

Part #: 378136
UPC: 193564440792

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Description: Ultra Series - Subaru EJ257 Piston Kit - 100.00/28.70/-21.50; 100.00 mm Bore - 28.70 mm CD - (-21.50 cc) - 4 Cyl. Piston Kit

Description:

Description

Accumulator Groove, Smooth Crown Finish, Pin Fit, Thermal Crown, Lateral Gas Ports, and Skirt Coat. Ultra Series pistons are made 100% in the USA.

Features & benefits

  • JE’s proprietary Aligned Grain Flow forging technology providing next-level tensile strength ideal for the extreme cylinder pressures of power adder engine builds.
  • Lateral Gas Ports: This process mills slots into the top of the top ring groove and provides a pathway for combustion pressure to get behind the top ring. Resulting in increased ring seal and is most common in circle track applications.
  • Skirt Coat: Skirt Coat reduces friction and wear on piston skirts and cylinder walls while simultaneously reducing operating noise
  • Designed specifically for Subaru STI EJ257 Engines. To provide optimized performance durability
  • Includes high-quality wrist pins, locks, and JE Pro Seal premium piston rings
  • Made 100% in the USA
  • Accumulator Groove: A specialty groove between the top and second ring provides added volume for blow-by gases. This helps reduce pressure between the rings, improving top ring seal and minimizing ring flutter at high cylinder pressures.
  • Smooth Crown Finish: Deburs all areas around the valve pocket and dome area, to reduces stress risers and prevent hot spots.
  • Pin Fit: The pin bore is precision honed to attain an exact pin clearance. Clearances typically range from .0003 to .0010 between the wrist pin and pin bore.
  • Thermal Crown: Applied to the piston crown, this thermal barrier coating reflects heat back into the combustion chamber to improve exhaust gas velocity and scavenging while reducing heat transfer to help extend piston life.

Information

These pistons utilize our dedicated Forged Side Relief (FSR) forging that was specifically designed to increase strength.

Specifications

GTIN
00193564440792
Weight
5.1 lb
Height
5 in
Length
5 in
Width
9 in
EO
Offroad
Life cycle
Available to Order
Warehouse brand code
JEP
AAIA brand code
BHXG

Attributes

2nd Groove Width
0.04800
3D Undercrown Milling
No
Accumulator Groove
Yes
Anodize Top Ring Groove
No
Bore Diameter
100.00
Bore Diameter - Web
100.00
California Proposition 65
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
Category Hierarchy
Auto>JE Ultra Series>Piston Kits
Combo 2
No
Compression Height
28.70
Compression Ratio
8.50:1
Connecting Rod Length
130.50
Contact Reduction
No
Cylinder Head
EJ257 STI
DVGP
No
Double Pin Oilers
No
EBAY Category ID
33623
EN Plating
No
Econo Undercrown Milling
No
Engine
EJ257
Engine - Web
EJ257
Engine Detail
2004-2017 Impreza STI, 2005-2006 Outback XT/Legacy GT
Engine Displacement
2457
Engine Family
EJ Series
Engine Stroke
83.00
Engine Type
ICE
Exhaust Angle
13
Exhaust Depth
.195
Exhaust Diameter
1.290
Forging Type
FSR
Gas Distribution
No
Industry
Automotive
Intake Angle
13
Intake Depth
.190
Intake Diameter
1.540
Lateral Gas Ports
Yes
Make
Subaru
Make - Web
Subaru
Mill Undercrown
No
OEM Bore Diameter
99.50
Oil Groove Width
0.09950
Out of Stock Message
Call for Availability
Oversized
Yes
Oversized Amount
0.50
Pin Fit
Yes
Piston Average Weight
404
Piston Head Type
Inv Dome/Dish
Piston Material
2618
Piston Quantity
4
Piston Series
JE Ultra Series
Piston To Wall Clearance
-0.004
Piston Volume
-21.50
Product Market
Sport Compact
Product Type
Engine Piston Kit
Ring Quantity
4
Ring Set Included
Yes
Ring Set Part Number
JG4904-3937
Ring Set Thickness
1.20 MM x 1.20 MM x 2.50 MM
Skirt Coat
Yes
Smooth Crown Finish
Yes
Stroke
3.268
Thermal Crown
Yes
Title
JE Pistons Ultra Series Subaru EJ257 Stroker Piston Kit
Title - Web
JE Pistons Ultra Series Subaru EJ257 Stroker Piston Kit
Top Groove Width
0.04750
Tuff Skirt
No
Ultra Dome
No
Ultra Groove
No
Ultra Groove Plus Gas Port
No
Vertical Gas Ports
No
Wrist Pin Included
Yes
Wrist Pin Length
2.250
Wrist Pin Outer Diameter
0.905
Wrist Pin Part Number
905-2250-21-93S
Wrist Pin Quantity
4
Wrist Pin Retainer Included
Yes
Wrist Pin Retainer Part Number
905-042-CT
Wrist Pin Retainer Quantity
8

Fitment status

This product is universal and will fit your application.

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