Spark Plug Comparison Test

[diamondlarry]

Author:diamondlarry
Publication:www.gassavers.org

When Fran reported on his experiment with spark plugs, I decided to round up my plug collection and do some tests of my own. I have acquired quite a collection of plugs in an attempt for mileage increases. I have a set of Splitfire Triple Platinum, Bosch Platinum +4, E3, Torque Master, and for control purposes a set of NGK standard plugs. It wasn't until Fran's report that I knew how to find out how effective each plug was at improving mileage and power.

The route I chose was a one mile stretch of a county road near my house. I also chose 50 mph as my testing speed. I crossed the starting point already at my test speed. At the end of the mile, I turned around at a small township firestation to go back to my starting point. To keep the conditions as constant as possible, when I turned around, I accelerated to 15-20 mph in 1 st gear then shifted into 3 rd gear and accelerated to 40 mph then shifted into 5 th gear to accelerate to my testing speed of 50 mph. At each acceleration, I pressed the gas pedal to 2/3-3/4 throttle. I did 5 runs for each of the 5 plugs. After the 5 th run for each plug, I did 5 acceleration runs to test for possible power increases. I did the acceleration run by cruising at 30 mph in 4 th gear and flooring the gas pedal. When the speed reached 35 mph, I started my stop watch and continued accelerating to 55 mph at which time I stopped the stopwatch. Below are my test results.

(click to zoom)

I took the highest and the lowest mpg and times and discarded them to come up with an average for each plug in each category. My tests indicate that the only significant increase was with the Splitfire Triple Platinum plugs. It also shows that mpg actually decreased with the E3, Torque Master, and Bosch Platinum +4 plugs. According to the Splitfire website, their plugs sell for $5.99/plug. My conclusion: While Splitfire Triple Platinum plugs do give slightly increased mileage, it may not be worth the added cost.

[chasgood]

I was just wondering if spark plug gap has any effect on mpg. Try your collection of plugs with a more narrow then wider gap and see what happens.

[diamondlarry]

I had thought of that but three of the 5 plugs I tested can't have their gaps changed; the gap is a part of the design of the plug. The three are the E3, Torquemaster, and Bosch Platinum +4. Fran Giroux has been after me to do a gap test on the others but I haven't had the time. I did see on http://www.lubedev.com/articles/ that the author in one of the articles suggests that running the gap .010 smaller would give better mileage. His reasoning was that the amperage would be higher which should be a hotter spark. It does sound like it makes sense though.

[wadak1234]

Larry what kind of vehicle did you use for you spark plug tests and how did you measure your gas mileage. Did you use something like a Scan-gauge or does your vehicle have a built in computer? I have been running spark plug tests in my 97 Dakota v6. I also have an after market ignition and I have been using a Scan gauge with my truck to check mileage averages. I found the Scan-gauge was off about 2 mpg on the high side. It does give you the option to compensate for that. I believe that now it gives me pretty accurate reading. I have tested the E3, Bosch Platinum +2, Autolite 3923's in 2 different configurations and I currently am running a set of Torque Masters that are a direct substitute for for the Autolite 3923s.
It seems to me that I have had the best results on mpg using the Autolite 3923's that I had side gapped. I currently running the Torque Masters and had them in for about 1500 miles. The truck runs well on them. I think plugs differences are minimized with the after market ignition.
By the way, I found a way to increase the gap on a set of E3's buy using drill bits to measure gap and using a Jewelers Flat Blade screw driver to gently pry open the gap. I wouldn't recommend this to anyone. I did ruin a brand new plug by doing this. I was able to sucessfully open the gap up a maximum of 15 thousands without messing up the other plugs. My truck started to ping on these. I think it's due the fact that they develop a much faster flame front than other spark plugs. I still waiting for the company that develops the E3 to come with an equivalent to the Autolite 3923-one range colder than stock to prevent pinging. So far the best average mpg for city driving I have achieved is 17.5 using the torque masters and about 18.5 with the side gapped Autolites. So far after my tests, I'm wondering if all the exotic expensive plug types are really woth it. Remember this is only my experience and I do have a complete MSD system. Your experienced may be different. I looking to increase my gas mileage any way I can. I have been doing this long before gas prices took the big jump due to Katrina.

[diamondlarry]

After I looked at the article for awhile I realized it doesn't say what vehicle I used. It is a 1997 Saturn SL 5-speed. I do own a Scanguage and that was how I measured the mileage. I have found that the Scanguage mileage can vary even without changing any of it's settings but overall it's pretty close once you get it calibrated.
I too have been looking for ways to increase mileage for a long time. I'm 42 and my quest for mileage came at around the time when I was 16 and had to start buying my own gas. Smiling

[Matt Timion]

Originally Posted by diamondlarry

After I looked at the article for awhile I realized it doesn't say what vehicle I used. It is a 1997 Saturn SL 5-speed. I do own a Scanguage and that was how I measured the mileage. I have found that the Scanguage mileage can vary even without changing any of it's settings but overall it's pretty close once you get it calibrated.
I too have been looking for ways to increase mileage for a long time. I'm 42 and my quest for mileage came at around the time when I was 16 and had to start buying my own gas. Smiling

A little off topic, but since you guys seem to be talking about the scangauge, let me ask about it. I understand that it's a OBDII toy, correct? Do you know of a OBDI equivilant?

[diamondlarry]

Unfortunately, no.

[TechGuy61]

I'd be interested to see your results with "side Gapped" plugs. You can find more information at this site about how to modify your stock plugs to get more complete combustion:

http://performanceunlimited.com/documents/plugsidegapping.html

I haven't tried this on my car yet but will soon. I'm currently experimenting with Acetone in the fuel. So far so good. I'm seeing better acceleration but haven't burned through my first tank yet so I can't comment on MPG yet.
http://www.lubedev.com/smartgas/additive.htm

[kickflipjr]

this is a good test diamondlarry. I just came accoss it.

[diamondlarry]

I'd be interested to see your results with "side Gapped" plugs. You can find more information at this site about how to modify your stock plugs to get more complete combustion:
http://performanceunlimited.c....html

I thought about that but I don't have a die grinder and I'm not sure I could do it very well with a hacksaw. Later this spring I may try comparing my Halo plugs to my Splitfires. That is if I don't lose my Splitfires by then.