Bosch HR9LI33U 7421 Spark Plug

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Rating

3.8 / 5 Overall
Bosch	HR9LI33U
Brand	Code
4.0 / 5 Materials
Copper	Iridium
Ground electrode	Center electrode
3.5 / 5 Design
Standard	Fine Wire
Ground type	Center type

Specifications

1mm (.039")	9
Gap	Heat range
⌀14mm	1.25mm
Thread diameter	Thread pitch
17.5mm (.689")	16mm (5/8")
Reach	Hex size
Tapered	Solid
Seat	Terminal
1	Non-Projected
Ground count	Projection

Cross-reference and alternatives

Cross-reference (2)

Alternative spark plugs found in cross-reference docs provided by manufacturers

XP5245

Iridium-Platinum

4.2/ 5

.045"18mm, ⌀14x1.25HR 3

IZTR5B11

Iridium-Platinum

4.2/ 5

.043"18mm, ⌀14x1.25HR 5

Deep reference (3)

A second level of cross-reference: if A=B and B=C, then A=C

HR8LII33U

Iridium

4.5/ 5

.039"17.5mm, ⌀14x1.25HR 8

XP105

Iridium-Platinum

4.2/ 5

.050"17.5mm, ⌀14x1.25HR 3

TR4IX

Copper-Iridium

-

3.8/ 5

.039"18mm, ⌀14x1.25HR 4

Bigger gap (8)

0.1..0.3 mm gap increase for better performance given your ignition system can handle it

RS14PYP

Platinum

-

3.8/ 5

.043"17.5mm, ⌀14x1.25HR 14

7940-2

Platinum

-

3.8/ 5

.049"17.5mm, ⌀14x1.25HR 14

RS14PYPB5

Platinum

-

3.8/ 5

.049"17.5mm, ⌀14x1.25HR 14

HR9DPX

Copper-Platinum

3.3/ 5

.043"17.5mm, ⌀14x1.25HR 9

HR9LCX+

Copper

2.9/ 5

.043"17.5mm, ⌀14x1.25HR 9

408C2

Copper

2.9/ 5

.045"17.5mm, ⌀14x1.25HR 14

408CC

Copper

2.9/ 5

.045"17.5mm, ⌀14x1.25HR 14

RS14YC

Copper

2.9/ 5

.045"17.5mm, ⌀14x1.25HR 14

One step colder (4)

Colder spark plugs with same characteristics for moderately tuned engines (75–100 hp increase)

9204S

Iridium-Platinum

4.2/ 5

.039"17.5mm, ⌀14x1.25HR 12

RS12WYPB4

Iridium-Platinum

4.2/ 5

.039"17.5mm, ⌀14x1.25HR 12

401CC

Copper

2.9/ 5

.039"17.5mm, ⌀14x1.25HR 12

401C2

Copper

2.9/ 5

.039"17.5mm, ⌀14x1.25HR 12

Two steps colder (3)

Two steps colder spark plugs with same characteristics for heavily modified engines (150-200 hp increase)

RS9PYP4

Platinum

3.7/ 5

.039"17.5mm, ⌀14x1.25HR 9

RS10ZPYCB4

Copper-Platinum

3.5/ 5

.039"17.5mm, ⌀14x1.25HR 10

RS10PYC4

Copper-Platinum

3.3/ 5

.039"17.5mm, ⌀14x1.25HR 10