Identification of DENSO spark plugs

W	16	E	X	R	-U11

The sales designation code consists of heat rating, prefix and suffix for identification of the principal features of the spark plug design. Each character has a specific significance.

Thread and hexagon size W16EXR-U11
Character	Thread size	Hexagon size	Designation
I	8 mm	13.0 mm	0.4 mm centre electrode with iridium tip
L	18 mm	22.0 mm
M	18 mm	25.4 mm
MA	18 mm	20.6 mm	Cone seat
*J	14 mm	20.6 mm	Extended electrode
*P	14 mm	20.6 mm	Electrodes with platinum tip
*PQ	14 mm	16.0 mm	Electrodes with platinum tip
*Q	14 mm	16.0 mm
*QJ	14 mm	16.0 mm	Extended electrode
*K	14 mm	16.0 mm	ISO
*KJ	14 mm	16.0 mm	ISO extended electrode
*PK	14 mm	16.0 mm	Electrodes with platinum tip
*PT	14 mm	16.0 mm	Electrodes with platinum tip
S	14 mm	20.6 mm	Special surface discharge electrode gap for Mazda R.E. screw-in depth 21.5 mm
SF	14 mm	20.6 mm	Surface discharge electrode gap
SK	14 mm	16.0 mm	Centre electrode with iridium tip earth electrode with platinum tip
T	14 mm	16.0 mm	Cone seat
W	14 mm	20.6 mm
TR	14 mm	20.6 mm	Thread screw-in depth 12.7 mm
X	12 mm	18.0 mm
XU	12 mm	16.0 mm
U	10 mm	16.0 mm
Y	8 mm	13.0 mm
* These characters signify thread screw-in depth of 19.0 mm

Heat rating W16EXR-U11
Hot						Cold
9	14	16	20		22		24		27		31		34		37
				21*				25*		29*		32*		35*
*Specific heat rating

Thread screw-in depth W16EXR-U11
Character	Screw-in depth	Designation
D	19.0 mm +1.5	KJ20DR-M11
E (flat)	19.0 mm (3/4") or 20.0 mm	W16EXR-U W2SEBR
E (cone seat)	0.708"	T16EPR-U
F	12.7 mm (1/2")	W20FP-U
FE / UH	19.0 mm (3/4") half thread	U24FER9
G	21.8 mm	X27GPR-U
H	26.5 mm	K16HPR-U11
L	11.2 mm (7/16")	W14L
N	17.5 mm half thread	T16NR-U11
V (cone seat)	25.0 mm	PT16VR13
None
18 mm thread (flat)	12.0 mm	M24S, L14-U
14 mm thread (flat)	9.5 mm (3/8")	W20S-U, W9PR-U
18 mm thread (flat)	0.480"	MA16PR-U
14 mm thread (flat)	0.460" or 0.325"	T16PR-U T20M-U/WA20M-U

Electrode design W16EXR-U11
Character	Description	Example:
A	Double earth electrodes for Mazda R.E.	W22EA
*A	Electrode projection (7.0 mm)	QJ16AR-U
B	Triple earth electrodes	W20EPB
*B	Electrode projection (9.5 mm)	J16BR-U
*C	Electrode projection (5.0 mm)	QJ20CR11
D	4-earth electrodes for Mazda R.E.	W27EDR14
*H	Electrode projection (8.5 mm)	QJ16AR-U
K	Special type for Honda CVCC	W16EKR-S11
LM	Special type for lawnmowers	W14LM-U
M	Compact type	W20M-U
MP	Compact type + protruding insulator nose	W22MPR-U
PT	Racing type (platinum earth electrode)	W27Ept
P	Protruding insulator nose	W16EP-U
S	Normal type	W24ES-U
T	Double earth electrodes for Toyota T.G.P	W20ET-S
V	Semi-surface discharge electrode gap	W20EVR-ZU
X	Particularly protruding insulator nose	W16EX-U
A-Z	Slim platinum centre electrode short earth electrode	K27A-Z
* If the first letter is J, KJ or QJ

Internal design W16EXR-U11
Character	Description
None	No resistor
R	Resistance

Special electrode gap configuration W16EXR-U11
Character	Description	Example:
C	Shortened earth electrode	W27EMR-C
L	Special type for Honda and particularly protruding type for mopeds	KJ20CR-L11 W14FP-UL
M	Earth electrode	KJ20DR-M11
N	Special internal design	U27ESR-N
P	Platinum tip for DIS double terminal	PQ20R-P8
S	Semi-surface discharge electrode gap	W20EPR-S11
U	U-groove earth electrode	W16EX-U
US	Star centre electrode	W14-US
V	Slim centre electrode	W24ES-V
Z	Cone earth electrode	VK20PR-Z11
CLOSED	Slim platinum centre electrode with cone earth electrode	W24ES-ZU

Electrode distance W16EXR-U11
Character	Electrode distance
Character	mm	inch
9	0.9 mm	0.035"
10	1.0 mm	0.040"
11	1.1 mm	0.044"
13	1.3 mm	0.050"
14	1.4 mm	0.055"
15	1.5 mm	0.060"
20	2.0 mm	0.080"

Iridium Power IU27A
A	Short earth electrode
B	Protruding insulator nose
C	Cone earth electrode
D	Cone earth electrode
T	LPG (Gas) Version
J	Electrode projection (5 mm)