Carbon vs. Platinum Spark plugs

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70
Location
Egypt
I have a chery A5 with chery SQR484F 2.0 L engine installed. it replaced the original chery SQR481FF 1.6 engine. car's manual stated that suitable spark plugs for the original engine is FR7DTC which is Bosch made (Carbon). this spark plug's Gap is 0.8mm and its heat range is 7 (Bosch standard) with resistor 6K Ohm. i want to try platinum ones, as life span is much longer (60.000 km vs. 20.000 km) and as far as i know spark is more accurate. so i made a research and finally found Bosch 6724 FR7DPP30X Gap: 1.1mm Heat Range: 7 with resistor 6K Ohm. https://www.boschsparkplugs.net/product.aspx?zpid=27961 and its equivalent NGK 7092 BKR6EGP (BKUR6EGP) Gap: 1.0mm Heat Range: 6 with resistor 5K Ohm. https://www.ngk.com/product.aspx?zpid=9329 Gap can be modified easily to match 0.8mm and heat range 6 in NGK is the same 7 for Bosch. both are same measurements of the Carbon one. my question is: am i going to face any problems replacing Carbon with Platinum?? also what's the difference between 6K & 5K Ohm resistors?? is it safe to use the 5K Ohm NGK?
 
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16,002
Location
Silicon Valley
First off, you should try to keep the same heat range so you don't get into problem, that's unless you know what you are doing and run a different heat range to address a problem (in racing or in an engine with issues). If you want to try a different plug, try to get the same or smaller diameter and gap size. You may pick a larger gap size with a smaller diameter plug tip electrode (dielectric strength equation, surface area is inversely proportional to distance), but I personally prefer not to adjust fine wire precious metal plug gap because I don't want to break them. The resistance is there to suppress noise, 5k vs 6k should be reasonably close as it is only 20%. If you have noise in the radio right after changing plugs, you know why. Keep your old plugs until you know the new plugs are working fine.
 
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Omar_Eltahan

Thread starter
Messages
70
Location
Egypt
Originally Posted by DrDanger
Denso and NGK are reputable internationally available brands of good quality and reasonable price. Get an Iridium or Ruthenium tipped plugs, you wont regret it. In case you want to read up as to why: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5322738/spark-plug-tips#Post5322738 Denso and NGK have part catalogues on their websites, which will give you the right part number for your car.
I'll read carefully, but why you don't recommend Bosch? just curious to know.
 

Omar_Eltahan

Thread starter
Messages
70
Location
Egypt
Originally Posted by PandaBear
First off, you should try to keep the same heat range so you don't get into problem, that's unless you know what you are doing and run a different heat range to address a problem (in racing or in an engine with issues). If you want to try a different plug, try to get the same or smaller diameter and gap size. You may pick a larger gap size with a smaller diameter plug tip electrode (dielectric strength equation, surface area is inversely proportional to distance), but I personally prefer not to adjust fine wire precious metal plug gap because I don't want to break them. The resistance is there to suppress noise, 5k vs 6k should be reasonably close as it is only 20%. If you have noise in the radio right after changing plugs, you know why. Keep your old plugs until you know the new plugs are working fine.
Thank you for the Ohm information. as for the plugs, both NGK & Bosch models i listed are identical to the manual's recommended copper plugs in everything, except for the gap which can be adjusted easily with below tool: [Linked Image from cdn.gsparkplug.com] so as for heat range the copper from Bosch is 7, same for Bosch's platinum ones, 7 for Bosch equals 6 in NGK which is the one in the model i listed.
 
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16,002
Location
Silicon Valley
Don't use that tool to adjust platinum, iridium, rhodium plugs, they can crack the fine wire tip. When you are going from copper to these rare earth / precious metal plugs, you will notice that the tips are now a lot smaller, and therefore don't worry about the plug gap anymore. 0.8mm vs 1.1mm is not a big deal if you go from the wider copper plug to fine wire platinum / iridium / rhodium. Don't go the opposite way though, the ignition will not like it.
 
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Messages
129
Location
North Carolina, USA
It's perfectly ok to up grade to a newer technology when replacing plugs as long as they are the correct part for the application. copper/nickel -> platinum -> double platinum -> iridium -> ruthenium Downgrading is probably not a good thing. (if you're doing nitrous injection, skip platinum)
 
Messages
264
Location
Canada, Russia
You may try platinum spark plugs but I think you need to do deeper research if other people had problems. If your car has a waste spark ignition system than you may have troubles. It looks like your OEM spark plugs are not usual ones. There could be a good reason for that. [Linked Image]
 
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16,002
Location
Silicon Valley
Originally Posted by Ded Mazai
You may try platinum spark plugs but I think you need to do deeper research if other people had problems. If your car has a waste spark ignition system than you may have troubles. It looks like your OEM spark plugs are not usual ones. There could be a good reason for that. [Linked Image]
These fancy side electrode plugs are now obsoleted. The same can be done with double platinum for a better flame for the same mileage, they were invented back when platinum was too expensive to use.
 
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15,226
Location
N.H, U.S.A.
I would go with a K20PRU-11 Denso copper in place of that bosch, but the bosch copper is a quality plug The bosch heat range is a bit cold for a 7 unless you work the engine real hard. NGKBKR6ES-11 tend to overheat their GND electrode. I Know as it is the STD plug in most Toyota and Subaru and Suzuki from 15 - 20 years ago. Tried 'em all in many of my cars and customers cars. [Linked Image]
 
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2,401
Location
pa
exotic metals used in todays spark plugs are for long life NOT performance so unless plugs are to hard to DIY use standard plugs as i do in my 2001 1.8T audi TT 225Q
 
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7,665
Location
MI
Originally Posted by benjy
exotic metals used in todays spark plugs are for long life NOT performance so unless plugs are to hard to DIY use standard plugs as i do in my 2001 1.8T audi TT 225Q
Not according to DrDanger and Molakule's link in the post above.
 
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2,896
Location
Chicagoland
Originally Posted by benjy
exotic metals used in todays spark plugs are for long life NOT performance so unless plugs are to hard to DIY use standard plugs as i do in my 2001 1.8T audi TT 225Q
Iridium has lower resistance than nickel, which is what the electrode of a "copper" spark plug is made of. It also has better thermal conductivity. Nickel Thermal conductivity: 90.9 W/(m·K) Electrical resistivity: 69.3 nΩ·m (at 20 °C) Iridium Thermal conductivity: 147 W/(m·K) Electrical resistivity: 47.1 nΩ·m (at 20 °C)
 
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16,002
Location
Silicon Valley
Originally Posted by Skippy722
Originally Posted by benjy
exotic metals used in todays spark plugs are for long life NOT performance so unless plugs are to hard to DIY use standard plugs as i do in my 2001 1.8T audi TT 225Q
Iridium has lower resistance than nickel, which is what the electrode of a "copper" spark plug is made of. It also has better thermal conductivity. Nickel Thermal conductivity: 90.9 W/(m·K) Electrical resistivity: 69.3 nΩ·m (at 20 °C) Iridium Thermal conductivity: 147 W/(m·K) Electrical resistivity: 47.1 nΩ·m (at 20 °C)
Resistance of that tiny amount is nothing when you already have 5k or 6k inside the plug for noise suppression. The main advantage of exotic metal is higher melting point, so they can make it fine wire, so the firing voltage for the same plug gap is a lot lower, so they have a lot less misfire ratio.
 
Messages
1,466
Location
Maryland USA
Originally Posted by Omar_Eltahan
Originally Posted by CT8
Use which ever type of spark plug was oem.
I'm afraid i don't understand.
What he is saying is OEM= abbreviation for Original Equipment Manufacturer, i..e the factory original part. However I feel it is fine to use a major brand plug that is not OEM. Since you are in a very hot climate , I think you may find an advantage in a cooler heat range plug. If your plug specifications have been adjusted for hot weather in Egypt then stay with an identical heat range as the factory specifications. If the specifications are not adjusted for your region, then consider going with a cooler heat range.
 
Messages
15,226
Location
N.H, U.S.A.
Originally Posted by Skippy722
Originally Posted by benjy
exotic metals used in todays spark plugs are for long life NOT performance so unless plugs are to hard to DIY use standard plugs as i do in my 2001 1.8T audi TT 225Q
Iridium has lower resistance than nickel, which is what the electrode of a "copper" spark plug is made of. It also has better thermal conductivity. Nickel Thermal conductivity: 90.9 W/(m·K) Electrical resistivity: 69.3 nΩ·m (at 20 °C) Iridium Thermal conductivity: 147 W/(m·K) Electrical resistivity: 47.1 nΩ·m (at 20 °C)
Not even a consideration with high tension: 20k volts and a 1.3mm air gap that must be ionised for the spark to jump. A High melting point and resistance to sputtering of the electrode metals is the factor here. Thank you for the material research, though, Skippy772. -Ken .
 
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