Spark plug codes help
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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
My question is, what's the difference between a B plug and an H plug? Is it the centre electrode type?
Cheer's
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.
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; Feb 22, 2012 at 01:52 PM.
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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.
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.
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
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.
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.
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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.
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.
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.
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.
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.
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Thread Starter
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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.
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. Is your engine a 2.0L or 2.5L ?
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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?
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.
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.
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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.
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.
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.
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Glad I could help.
ILFR7H seem quite expensive compared to LFR7AIX , I got mine from the offer that JP4mance have HERE
ILFR7H seem quite expensive compared to LFR7AIX , I got mine from the offer that JP4mance have HERE
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