I came across an interesting article in Honda Tuner Magazine online.

They took a 2009 GE8 and did some minor modifications to it. They changed out the spark plugs because their dyno expert claimed that the OEM plugs can cause a hot spot on the pistons robbing HP from the engine.

I don't remember the specifics, but the article can be found simply by searching "Fit" at the magazine's website.

Anyone notice a difference when changing plugs?

 

when you say smaller, they gapped it more aggressive

so these numbers aren't right but for example if they were Gapped at a 55 stock, they would have it gapped at like a 35, because a smaller gap means it would always fire off.

but the problem is the smaller you gap it, sooner its going to be for when you have to change it... i used to have mine gapped at like 35 when i was boosted and those things can't last more then 10k miles.. you already felt the power decrease after 3k+ miles...

unless your boosted i wouldn't recommend changing them because these iridums are designed for 1 purpose.. less maintaince.. and if you change it out and gap it shorter/smaller then you'll be changing your sparkplugs more often for almost no reason...

so with that being said you see alot of people changing to Denso sparkplugs right? well our cars sometimes come with stock Iridum Denso's as well.. so you might just waste your money if you ended up buying the OEM sparkplugs again.. and if you wanted to change to NGK you might be out of luck too... because honda also uses NGK sparkplugs in their OEMs.... people are like playinga gamble here each time they buy sparkplugs to switch for the name brand they want.. because Honda uses the TWO more popular sparkplug brands anyways.

i wouldn't recommend changing it untill you far away from stock.. and when i mean far away from stock, i mean minimal you have nitrous... at the very least.


also if you did go this route, i would recommend doing just regular copper sparkplugs, maybe a few steps colder, but copper is the cheapest and you will end up changing Iridium (expensive) sparkplugs anyways if they were gapped really aggressive/smaller. so you can buy the cheapest.. to the most expensive.. if you gap it aggressively, they will not last long no matter if they are copper.. or iridium.

Take it from me... i used to put iridium in just because it was supposed to be the LONGEST lasting sparkplug... it still won't last long if they are gapped way below stock.i ended up just wasting so much money, expect to pay TWICE as much

 

you never "gain" more HP, you are simply back to peak efficiency with new plugs, (assuming plugs are old)

 

No, check out the article. Oscar Jackson recommends Denso Iridium IK22's because of the physical shape of the end of the plug, it promotes more efficient combustion because it doesn't protrude as far into the combustion chamber.

He posted about it on fitfreak almost a year ago: https://www.fitfreak.net/forums/fit-...ark-plugs.html

 

He is really speaking specifically to supercharged Fits and even says the stock plugs are just fine if you're stock.

"...The added length and metal ring result in hotter plugs—which is fine for an otherwise stock Fit engine—but for supercharged engines..."

Also if you're getting 3HP from a mod if you're running a supercharger, you can expect what .5HP to 1HP if your na, if any?

 

If you read the thread & the subsequent discussion, you'll see that the same results were found on a naturally aspirated Fit. They took the highest N/A hp result at the dyno day, swapped in the Denso IK22's, and redynoed for 3% better results.

 

I was there when they did it.

 

Hey, I hope u read my DIY spark change. Like I said in the thread, it's not a rocket science. Make sure u have a strong back otherwise it will make the job so much harder. I don't know about HP addition just changing to IK22 but with intake, exhaust, and 93 octain fuel makes huge difference. Just FYI, the stock plugs r NGK irritium plugs which will do fine. I just happen to have very bad lucks with NGK plugs so I decided to change them Let me know if u need any help on it

 

i would not swap your plugs out, running colder or hotter plugs can damage your engine in the long run
your plugs are warrantied to last 100,000 miles, I would not change these unless you're supercharged or turbo,
changing plugs will get you as much power as running 92 octane in your car, waste of money.
I have a lot of experience with cars.
If you want to modd, i would recommend the Mugen exhaust and a k&N filter intake, forcing more air through your cars engine, will increase power but ultimately this will effect your fuel mileage as well.

 

what someone should really do is get a mugen exhaust, take it to an exhaust shop, you can probably get a custom build with the same specs for a lot cheaper.
In the long term, If you live in a climate with various warm and colder temps, you will be taking these plugs out in a 6 months or less

 

I've been running them for 11 months now.

 

read the article, he did this on a fit that was slightly boosted, not on a stock fit, did he do this on a 07-08 fit or an 09?

KraftWerks: OSCAR JACKSON ON SPARK PLUGS

 

Not sure how much more clearly I can put it.

 

not sure how much more clearer i can get either...

Dyno testing on a low-boost-equipped Fit with an automatic transmission yielded a peak power gain of 3.3 whp (104.8-108.1 whp) after swapping a brand-new set of OEM plugs for the colder heat range Denso IK22 Iridium plugs. Torque gains were even more impressive, measuring in at 118.1 lb-ft versus the stock plugs’ 109.3 lb-ft. Equally impressive was that average wheel horsepower and torque between 3,000-6,400 rpm improved by 4.8 whp (88.3-93.1 whp) and 4.9 lb-ft (101.4-106.3 lb-ft), respectively—all from a simple spark plug swap. There aren’t many places you’ll find these types of power and torque gains at such a reasonable pric

 

3.3 hp isn't even noticeable. Although running a colder heat range plug will help with pre-detonation when you're boosted or significantly modified. FWIW, I've run 1 colder heat range plug on my Buick for a few years now (it has some ported/polished engine parts and a remapped PCM) with no discernible difference in power.

 

Seriously doubt any significant change from smaller spark plug gap. The larger spark has a bigger 'flame front' so the 'explosion' occurs faster and a smaller gapdoesn't likely increase the spark occurring. A bad electrode yes, or carbon coated one or cone yes, but not fresh plugs with clean surfaces.
The shorter stem is the result of shortening the heat conduction path so the plug is not overheated, which is why colder plugs are used in competition but that isn't likely to help much unless you run the engine at very high rpm for a long time. That naturally is verifiable on dyno runs; its how you find the optimum spark plug for the service. Plugs like to operate in an optimum temperature range, neither too cold or too hot. Thats why plugs come in a range of 'heats' by manufacturers.
Oscars improvement is more likely due to construction of the Denso plugs that decease the voltage loss in transmission. Not having taken one of the Denso plugs apart can't offer any commentary but I do know Denso has a relatively strong research progrm in improving spark plug ignition of lean air / fuel mixtures. That should include a desire to reduce voltage loss thru the plug. Lesser loss means more power to jump the gap with a larger spark, thus better ignition.

 

If you're modded a lot (Boosted) I recommend the Denso's BUT if you're stock or slightly modded, it's a complete waste of money.

 

Do you know the sensitivity of a dyno test? You could run the same car 5 times each day for 5 days and get different results, even under the same atmospheric conditions. Do you know the accuracy and repeatability of the test?

These articles are designed for the non-critical thinking consumer. The spark plug change may indeed produce more power for the particular car being tested but you cannot fully believe unless someone does an independent study (and I mean independent like a university study with no bias to a company or industry) to show different spark plugs will change your power levels. To date I have not seen any data like that.

Do you think it's coincidental that the kraftwerk web site sells Denso plugs and even has a link in the article?

 

Many have verified with our own data pulled from the ECU via AEM FIC in my case, and various scan tools (UG, SGII, etc.) from several users that in fact timing is advanced under load and the mixture can lean out.

For the uninitiated: Spark angle advance/retard is directly tied to torque production. Horsepower is derived from torque. This sort of spark-hook adjustment is how OE Calibrators program ECUs.

The colder plugs have less ceramic surface area exposed to the combustion chamber, and the tips themselves do not project as far into the combustion chamber.

I am all too familiar with dynos, corrections and the effects that dynamic ambient conditions have on performance. There is no conspiracy here, no matter how much you'd like to believe.

And for the price of some plugs, you can bet Oscar Jackson/Kraftwerks is not shilling for Denso.

You Sir, figure yourself too clever by half.

Way to resurrect a two year old thread with suppositions on the credibility of a well established member of the motorsports community.

 

We've tested and changed thousands of spark plugs; comparing new plugs with one another is only of interest to racers where 1-2% can matter.,
As far as comparing runs on the same dyno, there's little difference unless you change something like intake pressure, jets, etc. Now if you change dynos that can be quite different. Thats why all testing for performance must be done on the same dyno under the same intake pressure and temperature. Only the attribute under study can change.
The problem witgh testing plugs is that it takes a while to find how much they fall ofgf with miles.