The Spark Plug FAQ: or "What spark plugs should I use in my DSM?"
Every few weeks, sometimes even every few days, there comes a thread where a new owner of a DSM asks what the best spark plugs are for his or her car. More rare, but still seen every once in a while is the question posed where the owner is having problems with the car stumbling, hesitating, losing power, and otherwise not running quite right. In some cases, it is due to not running the correct spark plug or plug type. In this FAQ, I'll try to depict a few different types of spark plug and the pro's and con's of each. There's a fairly definite answer to the question you may have: "What spark plug should I use in my DSM," but we'll get to that later.
First, a few pictures of some various spark plugs you may be currently using, have used in the past, or have considered using. Note: The following applies mostly to turbo DSM's and may not reflect usage in a non-turbo application.
#1. The NGK BPR6ES. This is what the majority of DSM'ers who don't have too many mods or are running fairly low boost will tend to use.
#2. This is the NGK BPR6EKN. This is what you'll most likely be offered if you walk into an auto parts store or dealership and ask for plugs for your turbo DSM, because this is the plug called for in the Owner's Manual and the shop manual. It was the standard factory plug for turbo DSMs. Notice the dual electrode. It's fairly pointless, since the spark will only jump to one of them, but these are an option for our cars, although not the best option. Unless part of your shop's income is generated by selling spark plugs, of course.
#3. This is a Bosch Super plug for the DSM 4g63t. It's a copper plug, fairly similar to the NGK, more or less. You may be offered this plug when you go to an auto parts store.
#4. This is a Bosch Platinum plug. This is another option you may be given when you go to your local auto parts store. It has been the experience of nearly ever DSM'er that you should avoid platinum plugs at all costs in turbocharged applications. The salesperson will most likely tell you that platinum plugs last a long time, or maybe they're on sale. It doesn't matter. They simply are not the best, nor worth the cost, for our cars.
A note about the pic: Do you notice anything missing that was visible in the previous pictures? That's right. The center electrode is amazingly small, nearly invisible. Below are two internal diagrams of the Bosch plugs (copper and platinum) from the exterior of their respective boxes.
#5. Here is a Bosch Platinum +4. It has four electrodes and a small platinum center electrode.
I don't have any pictures of any iridium plugs because they're special order where I work, and we didn't have any in stock. This isn't suprising because of their cost. For the price of a single iridium plug, you could have an entire set of standard copper plugs with money left over for a gapping tool and a frosty beverage.
One of the most frequently asked questions that crops up often here on DSMtuners is: "What kind of spark plug should I use in my (turbo) DSM?"
Use NGKs. They are the best for our cars. For some unknown reason, our cars just 'prefer' them.
An important feature of spark plugs that often goes unnoticed, or is often misunderstood, is what is known as the "heat range" of a spark plug. The spark plug must dissipate heat. Different heat ranges of spark plugs dissipate heat at different rates, which allows people to use different plugs for different applications. The plugs do not create heat, but instead remove it. The heat is transferred through the metal shell of the plug, to the head, where it is removed by the oil and water passages in the head. The way it does so is best shown by this diagram from NGK's website:
Different companies sometimes use different methods for determining the heat ranges of their plugs. NGK, for example, uses lower numbers for hotter plugs and higher numbers for colder plugs; i.e. BPR6ES plugs are hotter than BPR7ES plugs. Using too cold of a plug in your car will lead to fouling, but using too hot of a plug may lead to a hot-spot developing on the plug surface, which may result in pre-ignition/detonation. The ideal situation is to use the coldest plug possible without fouling.
Here's a comparison of three spark plugs made by NGK. At first glance, you may not notice a difference. Upon closer inspection, you may find that the shape and thickness of the white insulator around the center electrode thickens as the plug's heat range goes colder. In addition, the insulator is in contact with more of the outer shell where the threads of the plug are as the plug's range goes colder. On the left is a BPR5ES, in the middle is a BPR7ES, and on the right is a BPR9ES.
The more contact the insulator has with the outer shell, the more heat can be transferred out of the plug and into the head. Heat doesn't travel through air as well, so in a plug with less contact with the outer shell, the core of the plug stays hotter.
Another frequently asked question seen here (now that you know you need NGKs) is: "What heat range of NGK do I need for my (turbo) DSM?"
There are no set rules, but there are guidelines:
-For stock to near-stock cars, BPR6ES.
-For mildly modified to - heavily modified or high-boost, use BPR7ES.
-For heavily modified, high boost applications, use BPR8ES.
If plug fouling occurs, go one step hotter and monitor performance and results.
Stock car, T25/14b, 12-15 psi, upgraded intake/exhaust: 6ES
16g, 20 psi, water/meth injection : 7ES-8ES
GT35R, nitrous, the works: 8ES-9ES-10ES
Copper, Platinum, Iridium. (What's next, Adamantium?) What's the right one for you? As mentioned earlier, the vast majority of DSM'ers will swear by standard NGK copper plugs. Platinum is not as good a conductor as copper, but it's harder so it lasts longer. Iridium is also very hard, but it's also very rare, which makes it expensive. The consensus regarding iridium plugs is that while they work, they're not worth the price when standard $2/each copper plugs work more or less the same. Even though platinum plugs are closer in price to copper plugs, it's been my experience along with many other members, that running platinum plugs caused fouling, stumbling, hesitation, a loss of power, a decrease in gas mileage, and poor idle. Switching to standard NGK copper plugs solved the problems immediately.
Here's the answer to one of those common questions: "My car stumbles/hesitates/has no power/idles oddly/has lost gas mileage/does not perform well..."
If you are running platinum spark plugs and notice that your car isn't running right.... take them out and put in NGK BPR6ES spark plugs and see if your situation improves.
Another common question is in regards to the proper gap of a spark plug. This refers to the space between the center electrode and the side electrode. The average auto-parts store computer will usually suggest a gap for each spark plug that they have in their computers. However, in most cases, the best gap to use is the one specified by the manufacturer of your car. In the case of turbo DSM's, many people choose to gap their plugs to .028". DSM'ers have had good experiences with slightly larger gaps (.030-.032") as well as with smaller gaps (.026"). The computer where I work suggests a gap of .032" for the spark plugs for our cars.
Spark plugs do not come from the factory pre-gapped. You may open a spark plug up and find that it meets your gap needs, but this does not mean that the next identical spark plug will have the exact same gap. To be sure, manually gap each spark plug you install. There are several tools to help you measure a spark plug's gap. Here are three of the most common: a gapping disc ($.99), a blade measurer ($3) and a wire-gapper ($3). What you use is your preference. Many people say that the ramp-style gappers are not as accurate. They'll work in a pinch, but the wire and blade gapping tools are preferred.
Here's an answer to another commonly asked question: "What should I gap my spark plugs to?"
Gap your plugs to .028"
My good friend Anthony (DSMunknown) has brought to my attention that there has been some discussion in past years regarding the gap of spark plugs opening up over time, possibly due to long projected tip or high exhaust gas temperatures. If you race or dyno your car regularly, checking your spark plug gaps on a regular basis (once ever 5 dyno pulls or once every 3-5 1/4 mile runs, or so) and monitoring whether they are opening up or not. If they are, you'll need to replace or re-gap more often than drivers who daily-drive their cars. More info on this will be forthcoming as research is conducted and reported.
To sum up: In general the BEST spark plug for our cars is the NGK BPR6ES gapped to .028", varying heat range depending on modifications.
For more information:
NGK Spark Plug Information
Decoding NGK Spark Plug part numbers.
Reading spark plugs
An in-depth look at spark plugs.
A VERY in-depth look at plug, brought to you by our cousins, the Stealth/3kGT.
A conglomeration of threads discussing different experiences with spark plugs.
Best Posts in Forum: Frequently Answered DSM Questions
- Thread: Spark Plug FAQ
Many of the new people coming into the DSM arena come from other car enthusiast backgrounds (Honda, Toyota, and even domestic cars). The first thoughts are to apply the same techniques as they've done with other cars. The problem is, all cars are different and react differently to modifications. The first thing a newbie should do is to read up on how their car works and gain a better knowledge of the mechanics of automobiles in general.
Those who are new to turbocharged cars have an even steeper learning curve to adjust to. They have to learn how a turbo system works, as well as the intricacies of the Mitsubishi powertrain and turbo system. Here are some common mistakes and misconceptions by these people we call "newbies":
1. Big turbos - not a good first mod
Most newbies come in and immediately want to know what the biggest turbo is that will fit on their car. They think that it's the biggest single power adder they can install. That is false. You can not add a larger turbo to your system without adding several other parts first. If you do so without adding the appropriate modifications, the turbo will not give you any more power than you already have. In fact, your car will run even worse until you add all of the necessary supporting mods. On the flipside, if you add the proper supporting mods first, the car will have significantly more power without even touching the turbo.
2. Loud BOVs (the pssshhhhh sound between shifts)
The second most common question is, "how do I make my BOV louder?". Most of us DSMers will cringe when we hear this question. The fact is, a louder BOV on these cars will conflict with vehicle performance. In order to make a BOV loud, you have to vent to the atmosphere (as opposed to back into the intake, like our cars do from the factory), releasing the excess air instead of routing it back into your turbo system. The problem with this, is that your ECU has already accounted for this "excess air" and adjusts fuel curves accordingly. If it's not in the system anymore, the ECU is compensating incorrectly. This means that the car will not run the way it's supposed to. It may idle poorly, or it may not be noticable - but it will have a negative effect, even if you can't feel it (the logger will prove it). In any event, it is not the best thing to do if you are serious about making maximum performance. And if you are more interested in making your car sound "furious" and not making it "fast", expect a good deal of heckling, as this is a performance community.
3. Running 10's - not cheap, and not easy
An unachievable goal for 95% of the DSM community. I love seeing people come in here and think they're going to run 10's and 11's. Sure, it's possible, but it is only done by those who have a lot of money to spend. If you have your car parked in the driveway and have $10k in your wallet and know what you're doing, you may have a chance. The truth is, it will require just as much technical knowledge of your car as it does money. Spending the money is the easy part. It's not the parts that make your car run 10's. It's the testing, tuning adjustments, repairs, new trannies, and driving practice that will get you there. DSMs are very capable of running fast times, but like any other car, they require money and know-how to go fast.
4. Raising boost too much, too soon
It is well known that raising the boost levels is the quickest and easiest way to raise your horsepower. It's also a quick way to mess things up and hit "fuel cut" (when the ECU cuts fuel at WOT when your boost is too high). If you raise your boost levels with a boost controller, be sure you've first installed an aftermarket boost gauge. It is critical, as the stock gauge is not a true boost gauge. Also, if you have not made any changes to your fuel system (fuel pump or injectors), do not raise your boost any higher than 16psi. That is all the stock fuel system is able to handle.
4a. Maintenance - some newbies try raising boost levels and installing parts without doing the proper maintenance on their 15-25 year old DSM. Rubber hoses dry out, timing belts need religious replacement, oil, gear lube, coolant, and brake fluid have limited lifespans, and most parts end up needing replacement to work correctly. If you don't know when they were changed last, change them. If you don't take good care of your car, you deserve the problems that will arise from such neglect.
5. Intakes and Headers
Many people coming from the Honda world quickly start asking about which intakes and headers are available. This is because those mods have always been common in other import non-turbo applications. The intakes on turbocharged DSMs can be replaced, but aren't significant power-adders. Changing filters is very important though, and is recommended early on. The factory exhaust manifold is more than adequate though, with some porting work (except the 1G crack-prone manifolds, which should be replaced with a ported 2G manifold). Trust me, it's the rest of the exhaust that needs attention, not the manifold.
6. Tuning makes the most power - not modding
Tuning is something that, many of those entering the DSM community, may not be familiar with. Yet, it's the single most important aspect of building up a DSM to meet its potential. Most other cars have many chips or ECU replacements available for them. DSM owners aren't so lucky, as there aren't as many user-friendly options available to us. This means, you'll probably need to learn more than you anticipated about how your car's ECU works. Otherwise, you may destroy your motor. Tuning requires adjusting the fuel curves used by the ECU in order to maximize power output. Of course, you could just take your car to a DSM specialty shop and have them make the adjustments for you, but then again, being your own backyard mechanic is what owning a DSM is all about.
7. Lowering Springs
Rarely do these really help aid handling, mostly because the rates are too low for the amount of lowering. Also, lower cars need shorter shocks (but people don't shell out for Konis, which are the shortest OTS shocks), while high-rate springs need more rebound damping and not more compression damping (which is why Tokikos and AGXs don't work well). Finally, lower does not automatically mean better handling, because you might now be hitting the bumpstops and you also might now have lateral control arms that angle upwards.
8. Camber vs Toe
99% of tire-wear problems come from the toe-out that you get when you lower the car. The problem is not the extra negative camber. Yes, lots of negative camber hurts traction on a straight-ahead launch, but it helps in cornering. After lowering a car, you might need to remove some rear camber (or the understeer will be awful), but you don't need to take out any front camber unless it's a dedicated drag-racer or slammed to the ground (but see above).
We'll probably keep adding to this list....
For all those thinking of venting your BOV to the atmosphere - read up:
Enter "BOV venting" in the keywords field and hit Search. Also try separate searches using "BOV atmosphere", "BOV vent rich", and "venting atmosphere". You'll find plenty of info on this subject that has already been beaten to death. Select the Thread Titles option for better results.
Quick summary: don't vent your BOV to the atmosphere unless you're running a MAFT or standalone engine managament system, or you simply just don't care about your car's performance. A chip and/or S-AFC won't make it work right. If you vent your BOV with the stock MAF and you have stalling or stumbling problems, we don't want to hear about it. You've been warned. The only forum you may ask about venting your BOV (if you don't have an MAFT or standalone) is the Newbie forum.Last edited: Jun 11, 2014
I've seen an increasing number of threads where people will post a picture of a wing, bodykit or gauges and ask others whether they think it's ricey or if it looks good. While it's all well and good to ask the opinions of others, I feel that too many of our members live and die by the opinions of their fellow DSM Tuners members.
The fact of the matter is that your car is representative of your personal expression. While this is a performance based site, we have members who have managed to blur the lines of distinction by adding body kits and wings to some beautifully prepared and very fast cars. The point is that if you like something, that's all that matters. This is your car, your money and your freedom of personal expression.
Asking others whether they like something is like asking someone else to tell you who you are. Make a decision, enjoy it and we'll respect you for being an individualist and standing on your own two feet as opposed to constantly having your choices validated.
- Thread: Download a 2G Service Manual
- Thread: Maintenance Schedule
There are a lot of threads on mods and upgrades, but it is very important to make sure that all the maintenance is done on your car. Check your repair manual for the complete list, here is the minimum list that I recommend:
Every week or every 250 miles or when you get gas/fuel:
1) Check engine oil level
2) Check brake fuild level
3) Check tires and tire pressures
Every 3000 miles or 3 months
1) Change engine oil and oil filter
- The most commonly used oil is synthetic 10W30, 10W40 and 15W50.
Every 6000 miles or 6 months
1) Rotate tires
Every 15000 miles or 12 months
1) Change PCV valve. (When you buy it, blow on one end and then blow on another, you should only be able to blow one side. If you can blow on both sides, it is bad, get another one)
2) Change spark plugs
- If you have no or mild mods get - NGK BPR6ES or Autolite 63 Copper
- If you have moderate mods get - NGK BPR7ES or Autolite 62 Copper
- If you have a LOT of mods get - NGK BPR8ES
Gap plugs to 0.028 to 0.031". Use no other plugs. No platinum or dual electrode stuff.
Every 30000 miles or 24 months
1) Replace air filter
2) Spark plug wires - (I use NGK premium wires: part# ME77, stock# 8100)
3) Coolant flush - 50/50 (with one or 2 bottles of water wetter if you want to use it)
4) Change the tranny fluid - most commonly used on manual transmissions is Pennzoil Synchromesh, which is a cheaper alternative to BG Synchroshift. After having issues with Synchomesh for a while (it is too thin), I switched to a combo of Redline heavy and light.
5) Change the transfer case and rear diff fluid (if you have AWD) - most commonly used gear oil is Redline Heavy Shockproof gear oil.
Every 60000 or 48 months
1) Replace fuel filter
2) Timing belt change: A complete list of 60k timing belt service would include all these:
- Timing belt
- Balance shaft belt
- Timing Tensioner
- Water pump
- Timing belt tensioner pulley
- Balance shaft tensioner pulley
- Idler pulley
- Crank seal
- Oil pump seal
- Balance shaft seal
- 2 Cam seals
- Harmonic balancer
- All other belts
Get only MITSUBISHI parts for the list above. OEM part does not always mean that the part is made by MITSUBISHI. If you don't know where to but parts from, this is a good start - Where Can I Buy OEM Parts Besides Junkyards and Ebay? - DSM Forums.
If your car is old, go ahead and replace all the vacuum hoses. RRE makes a good kit here - RRE's Larson Silicone Hose Kit
If anyone wants to add to this list, feel free. I hope this helps someone.
Many of you have been asking alot of questions concerning the MAF-T which is why a FAQ has been added. The MAF-T is a piggi-back fuel controller which replaces your stock MAF sensor by changing a Hotwire signal to the stock Karmen signal which is used by DSMs. It allows the use of a GM MAF sensor. Either the 3" or 3.5" sensors can be used. These sensors can be sourced either new or used. The 3" sensor is used by dozens of GM vehicles including 96+ Blazers/Jimmys, S-10 pickups, Any vehicle with an LT-1 engine(Camaro/Firebird), and Impalla SS. The 3.5" sensors can be found on vehicles using the potent LS-1 engine, including Camaros, Firbirds, Corvettes. Aftermarket MAF sensors, such as those sold by Granettelli Motorsports are not compatable with the MAF-T.
The MAF-T's installation is very straightforward with only one wire to splice. There are 2 harnesses from the unit which simply plug into your stock MAF harness connector and the GM MAF itself. The GM MAF can be configured in 2 ways. Blow Through , the most popular, is when the MAF itself is in the upper IC pipe. This is beneficial for 2 reasons. First, it eliminates a restriction before the turbo; and second, you can VENT YOUR BOV , which everyone loves , by putting the sensor after the BOV and allowing backed up charge air to be vented before it is measured. *on a side note, NO, you cannot configure your stock MAF sensor to be used as a Blow through sensor. The operation of a Karmen Vortece MAF sensor cannot operate in this manner, and the sensor itself is not built to withstand any positive pressure.* Blow Through sensor placement has been discussed and still, no deffinative answere has been reached. As a rule of thumb, the sensor should be somewhere on the straight portion of your UICP, at least several inches before the bend into the throttle body. Mine is about 8" from the bend.
The second method of sensor installation is Draw Through, which is far less popular, but still affords less of a restriction for the turbo, over the stock MAF. In this installation the GM sensor is simply installed in the stock MAF location. You cannot vent your BOV this way, since the sensor will be before the BOV and the air has already been metered.
Tuning is usually a PITA. I dont recommend using the MAF-T on it's own. Used In conjunction with some other form of fuel controller will offord the best results. An SAFC or "Jeff O chip" work quite well. The use of a DSM Link has netted the fastest MAF-T cars. Setting the unit up is straightforward. There are 4 small dip switches and 4 turn dials. The dip switches are (1)-sensor type, (2)vehicle, (3)fuel cut defensor on/off, (4) AUX fuel control flat/contoured. The 4 turn dials are(from left to right) Base: This is a global setting to match injector size to the vehicle. Idle: For your idle corection. Mid: This is mostly for setting your cruise map. WOT: Wide Open Throttle setting. You may find that by setting some of the switches/dials contrary to your vehicle/sensor type, will offer the best tunability. For instance, I use a 3" sensor, yet I have the #1 dip switch set to 3.5" sensor. My car runs better this way. *In other words, dont trust the adjustmenst given to you. Get a logger, and or wideband.*
Ramchargers is the designer/builder of the MAF-T and the source to get them. *Be carefull when trying to purchase a MAF-T from Ebay, or non-DSM private sale. I have seen a few MAF-T's designed for the Buick Grand National passed off to unsuspecting DSMers. This unit has a different Harness connector with only 3 wires. The unit also has only 2 turn dials. IT WILL NOT WORK ON A DSM!!
Other things to consider in the cost is placement of the MAF sensor. When opting for Blow through configuration, reducer couplers and a new or modded UICP will be needed. For referance, I spent a total of $500 to install my MAF-T. This included the unit itself, a brand new 3" GM sensor, a custom UICP(which I had my buddy Wes Hess weld up for $90), all the couplers and clamps. Depending on what you do, your bill might be a more or less.
I hope everyone finds this thread informative and helpfull to those planning on a MAF-T. Feel free to contact me for any other questions regarding install/tuning.