Do Spark Plugs Matter? CHEAP vs EXPENSIVE | Engine Masters | MotorTrend

Did any of these test results surprise you?

The phone number on your hoodie is missing a few numbers

I don't think it would have made more but you definitely should have waited till you had the e3 to test

I think what might be important to talk about is spark plug gap under boost. When I turbocharged my mr2 spyder certain spark plugs would misfire as soon as boost hit at 2 psi yet ran perfectly fine naturally aspirated. I learned it was because the fuel would blow out the spark meaning i had to have a smaller spark plug gap.

I put Autolite iridium plugs in my Tundra because they were on sale, 1/3 the price of the NGKs. 30K miles later they are running fine.

The Bosch commercial
Said it was for longevity they went with two straps and because when they fouled At idle, it had a chance of cleaning it out at more the half throttle.

The same with Imodium, they started with being 3times as expensive, and lasting 2-3 times as long, results may very.

But over time we went from a 500km of a plug life on carb engines, til 15k km-beyond on EFI.

Just curious, if you get less power, at more gap, then less gap, your coil is too weak.
I know, it tops at a point, but more gap, more spark.

I would have liked to se a test of HALO ones, they was the crace 10year ago, but haven’t seen them in about 5 years.

And my own “tests” have shown that NGK are good, but over fueling kills them.

But testing what wrong heat range does to power. I know what it does over time, but not what it does right of the bat.

Who here fell for the split fires back in the day?🤔 I bought them when they were having a promotional sticker with a set. Well I guess I got a sticker😅

Maybe multiple ground straps make for easier plug indexing.

Come from
NA Rotary race world
I am believer of wider gap will make slightly higher hp
But recently learn u need to reduce the gap when u are at E85 flex fuel tune with boost 😅

So how much gap should I be running on a 638 with 400 worth of NOS broke into two stages? I have been at .028 to .030,

Does it matter how much you spend on plugs?

I really wanted to see the results on the e3 plugs

I think I might be regapping my plugs now after seeing this.

Considering many of the things you do explain on the show it would make sense to also inform the audience that if you actually showed the entire range from 0-10,000 rpm on the monitor, it would be impossible to see any difference on almost all of your tests no matter what the things you're testing for.

I love the show guys. Keep on truckin'!

Guys, cut your hair and give it a wash… look like old dirty greasy women

In my 20 years of turning wrenches on my own cars, NGK have always been the least reliable.

I used to have a Toyota Mr2 and I was able to watch over the span of 2500 miles as the fuel economy would drop. Additionally, as the miles poured on, acceleration (butt dyno) was also diminished. I've tried from their $2 per plug to the $12 per plug, and the results were always the same. I tried basic Autolite plugs and those were decent and reliable.

After having grown very weary of this, I switched over to Denso plugs. Not only did the fuel economy stay consistent (better than NGK), but the butt dyno told me that acceleration did not diminish - and that was over 15,000 miles without touching the spark plugs.

In my daily driver, NGK is what the manufacturer (Subaru) calls for. And the results were identical to those experience in my Mr2. I switched over to Denso and not only has fuel economy and acceleration remained, but starting is easier, idle is smoother, it has improved (vs NGK) throttle response as well.

As per the gap increasing and power increasing, it doesn't surprise me all that much. From my very limited understanding (please correct me if I am mistaken), increasing the gap in a forced induction application is a big 'no no' as you run the risk of the not igniting the air/fuel mixture properly or 'squishing' it. I do NOT know the validity of that.

A more useful test would be testing different heat ranges, ignition advance and gap. I believe you will find some surprises there.

There is an outfit in New Mexico that makes spark plugs with a capacitor in it. I'm curious about those.

no they don't matter and never touch them unless you want misfire problems

I run autolites in everything I own.. never had a problem

getting a phd in spark plugs

Smokey Yunick could tell you all about spark plugs, Smokey Yunick forgot more about spark plugs this these guys will ever know. Rest In Peace Smokey Yunick.

I was always taught to run whatever plugs the manufacturer uses when they ship it off the factory floor. 🤷🏼‍♂️

Silly video. Don't waste your time.

More like they didn't want to run the E3 spark plug because its one of their sponsors

Why didn't you try Denso u groove plugs? I ran them in my RD350 2 stroke and I NEVER fouled a plug. NEVER. I ran I set of plugs for an entire race season in Colorado in 1982. They were called Nippon Denso Hot U plugs back then.

Use expensive Iridium spark plugs. That way, the next owner of your car can experience the catharsis of cursing you out because you allowed the plugs to become one with the engine by not changing them for 100,000 miles.

the info you share on your vid is priceless

I am 0% surprised by the result. I was taught that you should generally run the widest gap you can that is reasonable for your ignition system.

This does come with some caveats, however. The first to note is cold starting. Or starting when its cold outside. A larger gap means a longer spark, but a weaker spark. Typically this trade off is okay, however the weaker spark may have a tough time igniting the AFC due to lower spark temperature.

The second is charge densisty, which really only applies to forced induction. however, a longer spark may have difficulty overcoming. Low cylinder pressures mean the charge may have difficulty carrying to the next air molecule, reducing spark intensity. High cylinder pressure results in the charged particles colliding too often, and losing energy before they reach the anode.

The solution in both instances is a beefier ignition system. The resistance of air is quite high, which is why most modern ignition systems run in the ballpark of 30000 Volts. A stronger ignition coil creates more voltage, allowing for a larger spark gap, which translates to better combustion of the AFC.

I will finish off by saying that my VW golf calls for 35 thou, and I've ran it up to 45 thou with no trouble starting a -35c on stock coils with 200000km on them.

So go get a shorter E3 ? Lol you can look up spark plug specs to find the applicable ones. And I think you meant perpendicular. The two ground straps are to prevent spark misfire from fouling.

Please Compare Copper Plugs to crappy Long Life Rare Metal plugs.
Yeah they last 100K Miles but they dont spark as well.

Hence why real tuners only use copper plugs

What about indexing the plugs

Setting your gap determines alot

Copper is king.

Electricity doesn't take the path of least resistance, it takes ALL paths in proportion to their resistance of the circuit. It bugs me that people still believethat stupid myth.

Get the automates a bargain

I'm at a minute twenty seven secs, I'm guessing there will be some power difference, 5-10 depending on design... Not one better than the other, just how they fit in that particular chamber compared to the others.

I think the theory on the Bosch 7404 is that if one return strap pits/burns out, the other is there to compensate. But to the point: it's a rare event to get spark across both - it has a favored side, which steps away from simple mechanical configuration and visits self induced electromagnetic steering [matched gaps be damned]. I'll let a physicist sort that one out - it just is, as far as I'm concerned.

Cheap Autolite's for the win.

So a bigger spark made more power? Would love if you tested a MSD coil/box vs stock for HP.

I used the Bosch plugs that had 4 grounds , I dont recall the name, in a 92 chevy truck (5.7) that had 160K, when the plugs were installed, i gave the thing to my dad at 290K and using a quart of oil every 800 mies never fouled a plug...

ON MY 327 FUELIE, A SHORTER GAP IMPROVED THE PONIES ON THE DYNO

GREAT VID; SAW IT ON TV. THANX !!!!!!!!!!!!!!

Of course you left out the coolest most real-improvement plug to date: the NGK Ruthenium HX plugs (PSPE for boosted engines and DFE for n/a engines). These are a genuine game changer

O'reilly's manager here... I NEVER have NGK or ACDelco brought back with problems.
Other, cheap brands, have had issues. Last week a guy brought back a set of autolight APP65 that lasted 5,000 miles and the electrodes were GONE. Ground straps ghosted. All of them.
He replaced ACdelco plugs after 90,000 miles.

The only difference I've ever seen was a 4 ground strap bosch plug would idle better. I'd argue get an MSD and stay with the cheaper plug.

E-3 is junk

Good knowledge to have, thank you for sharing

what I learned here, I'm sticking with my Autolite plugs gap at .065