Notices

Spark plug codes help

Thread Tools
 
Search this Thread
 
Old 22 February 2012, 12:07 PM
  #1  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default Spark plug codes help

I think the standard spark plug in my RB320 is ILFR6B. I want to go for a colder plug so was looking at ILFR7B but i've been advised to use ILFR7H.
My question is, what's the difference between a B plug and an H plug? Is it the centre electrode type?

Cheer's
Old 22 February 2012, 01:50 PM
  #2  
PeeVee
Scooby Regular
iTrader: (1)
 
PeeVee's Avatar
 
Join Date: Dec 2000
Location: Canterbury. Kent
Posts: 1,496
Likes: 0
Received 0 Likes on 0 Posts
Default

Well I know that the difference between the other type of Subaru plugs PFR6B & PFR7G is that the 7 means that it is 1 cooler than the 6 and the difference between the B & G is that the material used for the center electrode is different.

It follows that the difference between a B & H would be along the same lines, but will check it for you this afternoon when back at work.

Last edited by PeeVee; 22 February 2012 at 01:52 PM.
Old 22 February 2012, 01:56 PM
  #3  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by PeeVee
Well I know that the difference between the other type of Subaru plugs PFR6B & PFR7G is that the 7 means that it is 1 cooler than the 6 and the difference between the B & G is that the material used for the center electrode is different.

It follows that the difference between a B & H would be along the same lines, but will check it for you this afternoon when back at work.
Cheers mate.
I checked on this chart but it doesn't seem to have the numbers for the plug type im interested in.
http://www.sparkplugs.co.uk/pages/te...-plug-code.htm
Old 23 February 2012, 10:59 AM
  #4  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default

bump
Old 23 February 2012, 11:44 AM
  #5  
DT-SPD
Scooby Regular
iTrader: (7)
 
DT-SPD's Avatar
 
Join Date: Jun 2010
Location: Rugby
Posts: 798
Likes: 0
Received 0 Likes on 0 Posts
Default

Hi Chopperman,

The NGK chart does list the plugs, I recommend using the real NHK chart from their catalogue HERE as it is a more detailed chart.

H instead of the B just means a different design which could be a manufacturing process or material used somewhere in the plug to get the lower heat rating, the physical size of the plug is the same.
Old 24 February 2012, 10:33 AM
  #6  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by DT-SPD
Hi Chopperman,

The NGK chart does list the plugs, I recommend using the real NHK chart from their catalogue HERE as it is a more detailed chart.

H instead of the B just means a different design which could be a manufacturing process or material used somewhere in the plug to get the lower heat rating, the physical size of the plug is the same.
Cheers mate.

Looking at the NGK chart it still seems a bit vague. It shows if the last letter is a B its to do with the electrode construction but the only H i can see in the chart refers to the thread reach. Very confusing.
Old 24 February 2012, 12:46 PM
  #7  
DT-SPD
Scooby Regular
iTrader: (7)
 
DT-SPD's Avatar
 
Join Date: Jun 2010
Location: Rugby
Posts: 798
Likes: 0
Received 0 Likes on 0 Posts
Default

Are you looking at the bottom part of the NGK chart ?? as below ?



In the box titled "Design Feature" there is A, B, C ..... the H is just further along in that series.

An alternative plug ( and ones that I am going to fit as soon as I can walk again ) are LFR7AIX these are NGK's premium Iridium plugs.
Old 24 February 2012, 01:30 PM
  #8  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by DT-SPD
Are you looking at the bottom part of the NGK chart ?? as below ?



In the box titled "Design Feature" there is A, B, C ..... the H is just further along in that series.

An alternative plug ( and ones that I am going to fit as soon as I can walk again ) are LFR7AIX these are NGK's premium Iridium plugs.
Ah i see what you mean now mate Is your engine a 2.0L or 2.5L ?
Old 24 February 2012, 01:57 PM
  #9  
DT-SPD
Scooby Regular
iTrader: (7)
 
DT-SPD's Avatar
 
Join Date: Jun 2010
Location: Rugby
Posts: 798
Likes: 0
Received 0 Likes on 0 Posts
Default

mines a 2.5 Spec D so same as in your RB320 ( excluding mods etc )
Old 24 February 2012, 02:04 PM
  #10  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by DT-SPD
mines a 2.5 Spec D so same as in your RB320 ( excluding mods etc )
Cool, i may look into these plugs your thinking of buying. Whats the difference between LFR7AIX and ILFR7H. am i right in thinking these are a longer reach with the L instead of I and will these fit? Not sure what the standard reach is on our cars?
Old 24 February 2012, 02:26 PM
  #11  
DT-SPD
Scooby Regular
iTrader: (7)
 
DT-SPD's Avatar
 
Join Date: Jun 2010
Location: Rugby
Posts: 798
Likes: 0
Received 0 Likes on 0 Posts
Default

Reach is the same, this is where the chart is a little confusing.

The ILFR7H are a Iridium, Long reach, 14mm, Resistor, heat 7, design H

The LFR7AIX are Long reach, 14mm, Resistor, heat 7, design A, Iridium

The IX at the end indicates they are the aftermarket Iridium plugs whereas the ILFR7H are branded as Laser Iridium and are OEM spec.

In my experience ( based on 15yrs developing and mapping engines ) there is a difference between the plugs, the IX has a finer centre electrode which gives a better base for a spark. These plugs may wear out before reaching ~60k miles that a OEM plug needs to get too, hence they are sold in the aftermarket where enthusiasts tend to change plugs more often then OEM recommendation ( I change mine every 20k but yet to do that mileage in my Subaru ).

Some of it is marketing, especially as the aftermarket is so huge. But I have measured spark profile from different types of plugs on a special dyno engine and they do a make a difference.
Old 24 February 2012, 02:47 PM
  #12  
scooby red
Scooby Regular
iTrader: (2)
 
scooby red's Avatar
 
Join Date: Apr 2010
Location: Melton Mowbray, Leics
Posts: 614
Likes: 0
Received 0 Likes on 0 Posts
Default

Suscribed (as i'm gonna use the chart in future)
Old 24 February 2012, 02:53 PM
  #13  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by DT-SPD
Reach is the same, this is where the chart is a little confusing.

The ILFR7H are a Iridium, Long reach, 14mm, Resistor, heat 7, design H

The LFR7AIX are Long reach, 14mm, Resistor, heat 7, design A, Iridium

The IX at the end indicates they are the aftermarket Iridium plugs whereas the ILFR7H are branded as Laser Iridium and are OEM spec.

In my experience ( based on 15yrs developing and mapping engines ) there is a difference between the plugs, the IX has a finer centre electrode which gives a better base for a spark. These plugs may wear out before reaching ~60k miles that a OEM plug needs to get too, hence they are sold in the aftermarket where enthusiasts tend to change plugs more often then OEM recommendation ( I change mine every 20k but yet to do that mileage in my Subaru ).

Some of it is marketing, especially as the aftermarket is so huge. But I have measured spark profile from different types of plugs on a special dyno engine and they do a make a difference.
Thanks for the info mate
My car has done under 22k but im changing more for placebo effect i think more than anything. Also because its mapped with racerom so running 1.4 bar on race so im leaning towards a colder plug than the ILFR6B that are standard (i think). Bob Rawle advised me to get ILFR7H but while shopping for best price i noticed they were being listed for evo's and one particular sites compatibility tool claim they don't fit subaru . Now with your advice in reading the NGK chart i can see they do indeed fit the subaru.
I always compare the new plug with the old taken out as a matter of habit, so i can check reach and seat design but buying online ,its not something i can send back if their wrong.
Thanks again. Rog.

ps/ i trust Bobs advice ,its just i felt compelled to research after conflicting website part numbers.
Old 24 February 2012, 03:01 PM
  #14  
DT-SPD
Scooby Regular
iTrader: (7)
 
DT-SPD's Avatar
 
Join Date: Jun 2010
Location: Rugby
Posts: 798
Likes: 0
Received 0 Likes on 0 Posts
Default

Glad I could help.

ILFR7H seem quite expensive compared to LFR7AIX , I got mine from the offer that JP4mance have HERE
Old 24 February 2012, 03:09 PM
  #15  
chopperman
Scooby Regular
Thread Starter
 
chopperman's Avatar
 
Join Date: Dec 2010
Posts: 3,241
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by DT-SPD
Glad I could help.

ILFR7H seem quite expensive compared to LFR7AIX , I got mine from the offer that JP4mance have HERE
Yeah, there quite a bit cheaper. Must admit it looks a swine of a job, especially as i still have the air pump
Old 24 February 2012, 04:01 PM
  #16  
DT-SPD
Scooby Regular
iTrader: (7)
 
DT-SPD's Avatar
 
Join Date: Jun 2010
Location: Rugby
Posts: 798
Likes: 0
Received 0 Likes on 0 Posts
Default

yeah is a bit fiddly, taking battery out gives a bit more room.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Darrell@Scoobyworx
Trader Announcements
26
30 January 2024 01:27 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
12
18 November 2015 07:03 AM
Sam Witwicky
Engine Management and ECU Remapping
17
13 November 2015 10:49 AM
thunder8
General Technical
0
01 October 2015 09:13 PM
shorty87
Other Marques
0
25 September 2015 08:52 PM



Quick Reply: Spark plug codes help



All times are GMT +1. The time now is 07:01 PM.