Spark Plugs

[Corolla121]

Hi People, I just grabbed this portion from NGK web site, Thought it would be helpful.

Q: How much of a performance improvement can I expect from changing plugs?

A: A common misconception is that changing spark plugs will result in a large power increase. In most cases, removing even seriously worn out spark plugs will only result in very modest power gains, typically about 1-2% of total engine output. This could be even less for computer-controlled vehicles, primarily because most newer vehicles have more powerful ignition systems and the vehicle's computer can make adjustments so that vehicle operation seems smoother and more seamless.

Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they don't understand is that most newer cars' engines are so efficient that they are already burning all of the available fuel. Simply adding more spark voltage can't burn more fuel because there is no more fuel to burn.

When a stock or near-stock engine is given a fresh set of spark plugs, peak efficiency is restored. The power gains that come from this restored state of tune are usually minimal. Any company that tells you that their spark plug will provide significant gains in power in a stock or near-stock engine is making blanket statements that may not be supportable.

To add to the story, my cars' plugs (Denso) are 40,000Km's old and still performing well. What Im so surpriced is, my service manual says to change sprak plugs every 120,000Km's.

Edited September 6, 2009 by Corolla121

[JadeyBlitzen]

I can partially agree with what you said. i just replaced my densos in my 1nz with ngk iridiums and performance wise i'd say there was little if not any gains at all. but the engine does seem to run quite smoothly after the switch and i'm expecting a slight improvement in fuel economy cos so far its returned 9km/l after a bit of thrashing.

the bit part i don't agree with is that with 70k on the clock (39k when i bought it) the tips of the plugs have seized to exist. so even if they weren't changed before i bought the car and it was still running the original densos the plugs have reached the end of their service life.

it could be a real pain getting to the plugs on a 1nz. but at 40k you might wanna see if they are ok

[charitha19]

macho where did u get the iradiuims from... and the cost please..

[SpEeD FrEak]

Iridiums are expensive than Normal plugs Dude.Its about rs1300 or 1400.U can get it from Douglas and Sons.Anyway Ive heard that they dont provide any performance increase and its no use spending so much on plugs(correct me if im wrong).Had Iridiums on ma Brothers car and it didn't have any performance increase.How about NGK Platinums

[NPP]

Iridiums are expensive than Normal plugs Dude.Its about rs1300 or 1400.U can get it from Douglas and Sons.Anyway Ive heard that they dont provide any performance increase and its no use spending so much on plugs(correct me if im wrong).Had Iridiums on ma Brothers car and it didn't have any performance increase.How about NGK Platinums

Denso iridiums cost me 7k for the set of 4

[JadeyBlitzen]

I bought them on ebay. cost me £25 and i had them shipped to my uni. not sure if they'll get detained by the customs if you have them shipped straight to sl. but when i checked out the price of the same plug in sl it was qouted 2000 rupees. so its well worth the trouble i'd say.

performance wise its quite mystery. sometimes i feel like its pulling much strongly. but with such little gains qouted i've dismissed that as a placebo effect.

[shanX]

Iridiums are expensive than Normal plugs Dude.Its about rs1300 or 1400.U can get it from Douglas and Sons.Anyway Ive heard that they dont provide any performance increase and its no use spending so much on plugs(correct me if im wrong).Had Iridiums on ma Brothers car and it didn't have any performance increase.How about NGK Platinums

For me, some people have recomended NGK Platinums over Iridiums, but there were some dynoed tests on some forums, which proved like just a small gain could be achieved with them over normal copper plugs, like they were not worth the investment

[Devinda_Z]

your signature "ant" is funky!

i scratched for a good 30 seconds

[JadeyBlitzen]

your signature "ant" is funky!

i scratched for a good 30 seconds

Finally! someone admits it

[virensti]

Finally! someone admits it

I agree! bloody annoying bugger, everytime i see it i'm like wtf! lol. and on the topic, I bought NGK Iri's last week for the vios (Also running 1nz-fe) no difference in power (but I expected none) I bought them hoping to get better fuel economy cause since petrol went up, thrashing around hurts me wallet and pay cheque that much more so during "sane" driving, i need to get as much fuel economy as possible. I actually started using 5th gear at 40 km/h now. but its not bad. no knocking or anything

[SpEeD FrEak]

Does iridiums save fuel???

Is it jadyes signature or My 1??

[nira74]

I bought them on ebay. cost me £25 and i had them shipped to my uni. not sure if they'll get detained by the customs if you have them shipped straight to sl. but when i checked out the price of the same plug in sl it was qouted 2000 rupees. so its well worth the trouble i'd say.

performance wise its quite mystery. sometimes i feel like its pulling much strongly. but with such little gains qouted i've dismissed that as a placebo effect.

Set of 4 NGK Iridiums off e-bay cost less than 35 Dollars from the US including postage to Sri Lanka. No issues at all, and the postman delivered it home a little over one week after purchase.

Some models specify Platinum plugs only. Some time back I was advised by the Nissan agents not to use normal plugs on my Bluebird SSS as it may mess up the ignition coils. Those cost quite a lot (around 9.5k for the set) but the recommended replacement interval is very much longer than normal plugs.

There is no observable performance gain from changing from normal to iridium or platinum plugs, but the more expensive plugs last longer IMHO.

[Ruslan]

Set of 4 NGK Iridiums off e-bay cost less than 35 Dollars from the US including postage to Sri Lanka. No issues at all, and the postman delivered it home a little over one week after purchase.

Some models specify Platinum plugs only. Some time back I was advised by the Nissan agents not to use normal plugs on my Bluebird SSS as it may mess up the ignition coils. Those cost quite a lot (around 9.5k for the set) but the recommended replacement interval is very much longer than normal plugs.

There is no observable performance gain from changing from normal to iridium or platinum plugs, but the more expensive plugs last longer IMHO.

Yep. it doesn't add more power. just the plugs lasts longer. but mine feels bit smoother, anyway that's the same feeling you get when you put new Standard plugs (Copper) brand new.

[JadeyBlitzen]

Yep. it doesn't add more power. just the plugs lasts longer. but mine feels bit smoother, anyway that's the same feeling you get when you put new Standard plugs (Copper) brand new.

I'll be adding some grounding wires soon to make it even sweeter

[JadeyBlitzen]

Does iridiums save fuel???

Is it jadyes signature or My 1??

no "SpEeD FrEak". not everything on this forum is about you

[Mani]

Most iridium plugs will get you ~100k miles before you have to change them on most fuel injected cars. Iridiums do respond well to forced induction cars running high boost. i.e. >1bar and give you less ignition issues due to high cylinder pressure. If you're running crazy boost and have ignition issues, you can remedy some of it by switching out to an iridium tipped plug. Beyond that, no real gain in performance per se as per above posts.

[virensti]

I'll be adding some grounding wires soon to make it even sweeter

what are grounding wires mate? are they the wires that lead to the coils? and how will/might it help with the performance of the iri's?

[virensti]

Does iridiums save fuel???

Is it jadyes signature or My 1??

Jadey's signature mate. he has an ant that always makes us think we got a bug on the screen. lol. and well.. bout the fuel... here's hoping.. lol. on the whole though, i think not... but, maybe it might will let you know.

[virensti]

Most iridium plugs will get you ~100k miles before you have to change them on most fuel injected cars. Iridiums do respond well to forced induction cars running high boost. i.e. >1bar and give you less ignition issues due to high cylinder pressure. If you're running crazy boost and have ignition issues, you can remedy some of it by switching out to an iridium tipped plug. Beyond that, no real gain in performance per se as per above posts.

true, i felt no difference in power with the iri's.. but i heard some turbo car's like the Legacy have some serious issues with iridium plugs? :S I saw it discussed in another topic..

[JadeyBlitzen]

what are grounding wires mate? are they the wires that lead to the coils? and how will/might it help with the performance of the iri's?

they ground critical areas around the engine bay. people have experienced smoother idle, better throttle response, brighter headlights and crisper stereos. again it could be the placebo effect. but there's not much to lose. so i'm gonna give it a shot anyways

[SpEeD FrEak]

Jadey's signature mate. he has an ant that always makes us think we got a bug on the screen. lol. and well.. bout the fuel... here's hoping.. lol. on the whole though, i think not... but, maybe it might will let you know.

I taught it was about My signature.It was about his ANT ne.Its Bit annoying at Times

Edited September 9, 2009 by SpEeD FrEak

[virensti]

they ground critical areas around the engine bay. people have experienced smoother idle, better throttle response, brighter headlights and crisper stereos. again it could be the placebo effect. but there's not much to lose. so i'm gonna give it a shot anyways

wow ok. hehe do keep moi, i mean us informed about this? specially if you do get an improvement

[virensti]

I taught it was about My signature.It was about his ANT ne.Its Bit annoying at Times

alas. again i thought there was an ant on my screen! lol, i wanna get like some freaky spider or something. scare the living daylights outta the other AL members.

[Chris0628]

Hi guys.... im thinking of changing the spark plugs... Honda Civic EXi 2000 (D15Z4 Automatic). What brand/model of plugs should i go for ?