Spark plug guide:All about spark plugs @ FI!

The 1UZFE EGR Delete Kit is available for sale here.

Toysrme

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Since we all run Toyota engines & *most* people are running Denso ignition systems... That pretty well limits us to two brands of plugs that will give consistently good performance over their life. NGK & Denso, so that's what we're concentrating on! (Besides. JDM owns anyways, we all know that!)
*note* All plugs listed will be currently available now. That means old plugs with new names, replaced plugs. Who cares. This is 2/2006.
Stock 1uz-fe plugs: NGK Denso
Normal/OEM Iridium: NA IFR6T-11
Premium Iridium: BKR6EIX-11 IK20
Original OEM (Platinum): BKR6EP-11 PK20R11
Premium Platinum: BKR6EGP NA
Standard: BKR6ES-11 NA
Standard, Grooved Strap: BKR6E-11 K20R-U11
Blah blah blah .

Iridiums last 60,000-80,000+ miles on "unmodified" engines.
Plats, Toyota specifies for 60,000 miles.
Copper, 30,000-60,000 miles. (A year under boost) Then again. Most standard plugs cost $1.50-$2usd per plug... You do the math.
Blah, blah blah .
Quick, random good stuff to know:
* You can not use platinum plugs with n2o. NGK.com (Not NGK affiliated) - "There have been instances where the platinum tip has lost its bond to either the center or ground electrode when they were used in a motor with nitrous."
* Do not use platinum plugs under boost - never, never, never!
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* Only use copper, or Iridium plugs under boost!
* Single electrodes guys. Single electrodes!
* It is advisable to run 2 heat ranges colder when going from NA to boost, plus 1 range colder per bar of boost. (Or one range per 70-100bhp)
* Advancing ignition timing by 10° causes tip temperature to increase by approximately. 70°-100° C.
la-la-la
 
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Now, to understand the most critical part of buying a spark plug; It's heat range!

The insulator nose length is the distance from the firing tip of the insulator to the point where insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. Whether the spark plugs are fitted in a lawnmower, boat, or a race car, the spark plug tip temperature must remain between 500°C-850°C. If the tip temperature is lower than 500°C, the insulator area surrounding the center electrode will not be hot enough to burn off carbon and combustion chamber deposits. These accumulated deposits can result in spark plug fouling leading to misfire. If the tip temperature is higher than 850°C the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition/detonation and expensive engine damage. In identical spark plug types, the difference from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing tip temperature is increased by 10°C to 20°C.
charttempfiringend.gif
The term spark plug heat range refers to the speed with which the plug can transfer heat from the combustion chamber to the engine head. Whether the plug is to be installed in a boat, lawnmower or racecar, it has been found the optimum combustion chamber temperature for gasoline engines is between 500°C–850°C. When it is within that range it is cool enough to avoid pre-ignition and plug tip overheating (which can cause engine damage), while still hot enough to burn off combustion deposits which cause fouling.
The spark plug can help maintain the optimum combustion chamber temperature. The primary method used to do this is by altering the internal length of the core nose, in addition, the alloy compositions in the electrodes can be changed. This means you may not be able to visually tell a difference between heat ranges. When a spark plug is referred to as a “cold plug”, it is one that transfers heat rapidly from the firing tip into the engine head, which keeps the firing tip cooler. A “hot plug” has a much slower rate of heat transfer, which keeps the firing tip hotter.
An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.
The heat range numbers used by spark plug manufacturers are not universal, by that we mean, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. Some manufacturers numbering systems are opposite the other, for domestic manufacturers (Champion, Autolite, Splitfire), the higher the number, the hotter the plug. For Japanese manufacturers (NGK, Denso), the higher the number, the colder the plug.
Do not make spark plug changes at the same time as another engine modification such as injection, carburetion or timing changes as in the event of poor results, it can lead to misleading and inaccurate conclusions (an exception would be when the alternate plugs came as part of a single precalibrated upgrade kit). When making spark plug heat range changes, it is better to err on the side of too cold a plug. The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage.
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Stock plugs for various FI'ed import vehicles:
Toyota
Supra - 2jz-gte Same as 1uz-fe. NGK heat range 6, .044 gap
Supra - 7m-gte (BKR), NGK heat range 6, .032 gap
MR2 - 4a-gze (BCR) NGK heat range 6, .044 gap
MR2 - 3s-gte (BKR) NGK heat range 6, .032 gap
Mazda
MX6 GT - 2.2L Turbo NGK heat range 6, .044 gap
Nissan
300ZX - VG30DETT NGK heat range 5, .044 gap
Audi/VW
Virtually everything FI'ed uses the same plug as a 1uz-fe.
etc. on down the line.
The moral, If it's boosted from the factory & not a rotary, it most likely runs an NGK 6 heat range!

Now for anyone doing some mild-medium FI, or n2o. The obvious choice would be the BKR8E / BKR8ES. The problem, is that while NGK still makes BKR8xx's. They don't make/distribute them anymore! The coldest they go in the BKR seires is the 7. On the other side... The BCR's WILL fit, and DO go to 8.
There in lies the question... Swap to a colder plug with a different end, or stick with the BKR's that don't go as cold.
Here's your answer!
Use the BKR7E! NGK Part no. 6097.
It's the plug of choice for:
The modified 3s-gte crowd, nearly all the boosted/modified Supra owners (Even all NA-T's), 300zx's Audi/VW people.

NGK's heat range is 70-100*C (152-212*F), while most other plug makers are 70-120*F. So, using a 7 instead of a 6 would be like roughly jumping the two heat ranges suggested for going FI on an NA vehicle!
That explains why people with stock FI'ed engines are running NGK's 6, while NA to FI & heavily modified stock turbo engines are getting away with only dropping one heat range on NGK/Denso plugs. Nobody has to feel bad about not being able to drop two heat ranges on NGK plugs!

Can you use Iridium plugs under boost? Yes! Despite my inital thoughts on the matter; research has shown they work very, very well! Like N/A, nothing currently works better. If you can afford them, NGK BKR7EIX no.6988 / Denso IK22.
(I would highly suggest doing all of your tuning on cheap copper plugs. Crappy tuning will show up faster as they get destroyed faster. Most of the time... You can replace every copper plug on an engine for what one good Iridium plug costs. Small mistakes, don't tune into $80-120 mistakes!)


Lastly,
Plug gaps!
Stock gaps are .044... We're running FI, and that's no longer acceptable! For mild boost .031-.035 is the sweet spot! for heavier boost, drop down to .028-.031.
*Be very careful adjusting plug gaps. Most OEM's say not to adjust it more than 0.008. Lame... Make sure they still line up when you gap them!
 
AWESOME! I personally asked Toysrme to write this article. He helped me some much on my setup and its running AWESOME. Currently I am using NGK6097 with .030" gapping and I saved also $80 on FI plugs. I got me a set from Napa for only $1.89 each on the NGK6097. However, I blindly got me a set of Iridium and costed me an arm and a leg. I think I paid over $100 for 8. Ouch.... I just found out Denso IK22 is about $14.00 each. I will copy and paste this thread in our tech section..... Great stuff...

From our research, we found out many FI cars use the same plug as the 1UZFE...... We have hope now....
 
I have been running dual, and quad electrode plugs for years with success.
Probably not the best for a pressurized motor though.
 
what do you recommend for a stock sc400? i noticed bosch platinum's are pretty cheap, any recommendations for an inexpenisive plug for a stock motor. autozone doesn't seem to have ngk's any local common chains carry em and which one is best for stock.
 
wouldn't your plugs be different since you have forced induction, i don't know how to tell the heat range of the plug, like autozone.com does not tell the heatrange, are those ngk coppers available in a normal heatrange, i guess the number you listed is for the cold plugs.
 
For NGK 2 is hot and 12 is cold.
Use the BKR7E! NGK Part no. 6097.
B: Thread Size 14 mm
K: Hex Size Projected Tip
R: Resistor Type
7: Heat Rating 2-12
E: Thread Reach 19 mm
NGKsparkplugNum.gif
 
What type of heat range should the plugs have for basicly stock 1uz?

I got BKR6EP-8 (regapped to 1.1mm) so is a plug with heat range of 6 alright for a stocko 1uz?

Cheers
Chris
 
Plats are OK for FI. I'm running PK20TR-11 (twin tips) at 7psi. These are the stock plug for VVTI turbo soarers. Even if I go to a 7 heat range iridium in the NGK I still get detonation until I pull out timing. The heat range dosn't seem to make any differerence on the v8.
 
If it didn't make a differance in the detonation, then it probably wasn't the cause of it. Or somebody else's plug just may be colder to start with.
 
I remember one hard lesson about which spark plugs to use. It was the case when I first turbocharged my previous car a long time ago. I've melted and spent near $200 on the sparkplugs on many different brands. However, I've found out that the cheapest V-power from NGK is the one that suited best for a turbocharged engine. For N/A engines, I use Bosch Platinum +4 and I've found them to be the best.
 
Great thread guys.... currently waiting for the dang UPS truck all week but totally didnt remember the FI plugs!! Just realzied a big no-no and the platinum plugs under my hood are it.

Steve, as you know 6psi-7max for now and you stated colder heat ranges.... should I just look for rangee 7?? also is the gap kept the same for colder plugs at .44? I was about to spend $200 on pulse plugs but caught myself when I heard how many you guys fried from getting air/fuel right and ranging/gap ETC. I wanted to get cheap copper denso's that get the job done, anyone know a product number off hand?
 
Great thread guys.... currently waiting for the dang UPS truck all week but totally didnt remember the FI plugs!! Just realzied a big no-no and the platinum plugs under my hood are it.

Steve, as you know 6psi-7max for now and you stated colder heat ranges.... should I just look for rangee 7?? also is the gap kept the same for colder plugs at .44? I was about to spend $200 on pulse plugs but caught myself when I heard how many you guys fried from getting air/fuel right and ranging/gap ETC. I wanted to get cheap copper denso's that get the job done, anyone know a product number off hand?
I don't remember the part number of the plugs that I use, but I know it's the V-Power with range of 6. I got lucky that I almost got the range 5 when I asked the autopart guy for the SC400. He gave me 5, which is for SC300 and in the hotter range. If I didn't check it first, I believe I'd have rang 5 and knocking right now bad. I just keep whatever gap on the plugs and there's no problem so far. You can try range 7, but if range 6 works fine, then range 7 would decrease the performance.

I always use the thread seize lubrication for the spark plug threads & the O2 sensor threads. They help big time when being removed.
 
gotcha... hey anyone ever put pulse plugs on a 1uz? Really like the technology and wanted to see what kinda gains on our beloved engine.

Anyone subscribed to Dsport? anyway they had an article on pulse plugs and a dyno to prove and they showed noticible gains... OVER TOP OF THE LINE IRIDIUM... so you could aready spend $100 on the current champs and still gain. A VQ nissan got 7rwhp, evo X got 5rwhp and these are gains OVER top shelf denso iridium. The article never tested a V8 and I was thinking if a DOHC 3.5 could get 7 or so then may 10hp or so for the 4.0 dohc? anyway if you were running stock $1.99 plugs you will gain even more.

Only way to tell is to do it... once I get my setup stable i'll get a sat and report the goods...
 


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