Time to replace the damn things - might as well grate my knuckles on concrete...

Anyways, the question everyone asks when standing in front of the wall of plugs...which ones? I'm not going for the Bosch Platinum +4 anytime soon...I just need your slightly above average plugs - I'm not sure I remember what I've got in there now - car is still in storage...any advice?

Thanks.

NGK part number - UR4 gap at .040" . If you are using any type of power adder .035" these are good baselines you can fine tune for the best tune from there

I am a big fan of the platinum +4's, i use them in all of my cars. :-)

I wouldn't use bosch platinums as anything other than a catfish weight.

btw what headers are you using? full length? shorties?

Whether or not the Bosch's are good - my engine isn't running smooth enough nor do I have the cash to fork out on sparkplugs that cost twice as much as everything else

I have short - tube headers - I'm looking forward to working around them...I might have to remove them anyways to "fix" an exhaust leak, so that may make things a little easier.

i had bosch platinums and I had to clean them about every 300 miles. They'd foul up quicker than anything I've ever seen. Those headers pretty good though?

that means you have the incorrect heat range. a plugs job is to simply live in the chamber and provide spark and remove heat. if your plug does not live in its enviornment then it is the wrong plug for the motor. you cannot tune with a spark plug, spark plugs do not affect the way the motor runs, they only live in the enviornment. if they are the right plug for your motor, then you can tune by looking at the plug, but changing to a different heat range will not make the motor have a hotter spark or any other type of mythical pfm.

veja- I suggest you get your information correct before you try to help anyone else with incorrect statements. You CAN tune with your spark plugs ie. if you have a detonation problem they may be too hot of a heat range, standard tip plugs may provide less preignition than extended tip designs, and plug gap makes a HUGE diffrence in the kind if mixture you can send into an engine without losing spark. By the way last I checked spark plugs were inanimate objects they have never "lived" and unless there is some kind of dramatic improvement in technology they probably never will.

i used the spark plugs bosch recommended for my car and they fouled. Wasn't a matter of having the wrong plug. It was the plug they said I needed. I have plain bosches in my volvo and couldn't be happier with them, but their platinum plugs where the electrode sits flush with the insulator is trash

that is not tuning. having the incorrect heat range plug would means it is the wrong plug. why dont you go read up on it and then make assumtions? if you were to have a ridge on one of the pistons that caused a heat spot and preignition, then removing it would not be tuning the engine. the same with extended reach plugs. you know what i mean by "living" in the motor, to exist without failure. what does plug gap have to do with spark plug design? you can change the gap on a plug. but you would not be changing the plug. all of your info is irrellavent to what i said. look at it again and this time try to understand instead of making incorrect assumtions.

who are you saying had the incorrect heat range? Mine was correct and they still fouled. I switched to another platinum tipped plug with the same heat range and I didn't have any problems

I use champion spark plugs and haven't had a fouling problem. They are #RV17YC. Ever since I've been using them I haven't had any detonation problems, hesitation, or anything for that matter. Its what I recommend but I also heard the NGK plugs are good too.

I originally had NGK's in the volvo. They did ok. I usually use AC Delco

could be many other things going on though. and from the sounds of it you DID get the wrong plug if they are fouling out

plugs that foul out are doing so because they aren't getting hot enough to burn the stuff away.

just because they said that is what your car uses doesn't mean it's the end all of that. old cars run different and sometimes use different things

if I got the wrong temp then they were in the wrong box. I don't even have the car anymore. It was a Daytona with a 2.5. I've known other people who used the Bosch Platinums and had the same problems. I switched plug brands to cheap autolite platinum junk and never had a single problem after that.

veja that is how is changing plug styles to better suit your needs not tuning? If a person were to use a car as a not so daily driver and hardly (if ever) go to full throttle then you might want to use a hotter plug in their car. In the same aspect if you are beating the snot out of a car and it spends little time without the blades wide open then you may not need to go with such a plug because cyl pressure/temp will be high enough to keep them clean.. In my opinion that is the very esscense of tuning, changing a car to perform best in the environment it "lives" in.

the spark plug does not change the way your motor runs. diff driving styles and enviornments might need a different plug so that it will not foul or burn, but changing the plug does not change the way the motor runs, except if it fouls or burns. just go to ngk's website and read.

So then based on your theory if you run a delco r45ts then a ngk ur4 is the exact same plug and the design difference has no bearing on performance. What about ground strap design? What about a grooved or non-grooved electrode? What about extended or standard tip design? What about the way a platnum electrode will actually glow in a high compression or forced induction engine? Does this mean you have some delco r45ts' a couple ngk ur4's and maybe some bosh platnums of the same heat range all together in your own engine? I would hope not. In other words, you read too much..

how about you assume too much. you assume an r45ts and a ur4 are the same heat range when the manufacturer says they are not, they are only close. using different materials is going to change conductivity. but would you use a ngk ur4, ur45,ur5, or a ur55 in your motor? what plug is used and works best is the plug to use, and putting a different heat range than what the motor needs will not help power.

you dont "tune" a motor by changing the plug, you simply would be putting the more acceptable plug in. you would be putting the correct plug in, and thats what there is, the right plug, and the wrong plug and a whole lotta grey area.

do you believe that all your cylinders run the same a/f? its compramise. now go find something else to talk about that you something know about and leave the theroy to politics.

Alright this is getting old I give up. You'd better do the same i think your spark plugs are hungry they need to eat if you want them to continue to live in your engine...

Last time I changed my plugs, I threw in a set of Autolites AP26. got them cheap at Wally's world. They work just fine.

I also have a set of Rapidfires that I'm going to use next time.
If you're going to change your plugs, change the cap and rotor as well. And inspect your wires.

Tip design, gap, heat range all change the way the motor runs, all effect fueling and timing tables, etc.

Perhaps on a stock GTA, the 'mfg recommended range' is fine, but for those of us running 500-600hp, we need to 'tune' with our plugs.

Thats why aftermarket heads recommend a "starting point", not a specific plug to use.

-- Joe

tell me exactly how tip design, heat range and gap affect how the motor runs.

if you dont know exactly how they affect "fueling and timing tables" then you are just regurgitating **** you have heard from some other idiot who heard it from another. dont fight ideas that go against your previously logical assumptions, you do not have all the information to create such informed theroys.

What exactly would you like to know? Would you like to discuss how the delco 45's responded with timing on my motor last season, or when I switched to the 43s and was then able to ramp out timing sooner? Or maybe just change plugs around and see how the different heat ranges affect closed loop corrections.

Oh and if you switch to a colder plug, you need less AE too.

You do prom tuning right? Ever tune a 500 hp motor? 600 hp? Spend hours at the track trying various maps and plugs until you got it 'just right" ?? Didn't think so.

-- Joe

I agree with anesthes and formula355tpi, you can tune with your plugs. I have experiemented with this on my 70 Firebird and also on my 72 454 chevelle. I have played with heat ranges, gaps, extended tips, and I have also experimented with grinding the ground strap back to expose some of the electrode. I have found some things that worked for me. My Firebird is very sensitive to detonation,,,by switching to a colder plug and going to a standard tip instead of the extended tip, I was able to remove alot of the detonation. I have found the biggest improvements on plugs by grinding the ground strap back to expose some of the electrode, this made a slight improvement on my chevelle. Also indexing the plugs when installing them is a known practice that has been around for many years.
If you don't believe any of this, spend some time at some of the Nascar tracks, those guys are scraping for every last hp they can get, and they do alot of experimenting with plugs to do it. Those guys know what they are doing, pulling 800 hp from 358 cubes is a tall order. Ever see a plug from a Nextel Cup engine? I have seen some where they have removed so much of the ground strap it would be impossible to even gap the sucker any more, this is what gave me the idea to experiment with this. Can't argue with the Nascar engineers, they know there is some horsepower to be found in the spark plugs. As far as plugs for a stock engine? Well I am partial to AC Delco, I would just run a stock heat range for the application and go with it. Just my experiences, hope this helps, Larry.

Don't know anyone who likes the platinums, sorry!! AC Delco for me.

Why doesn't this topic ever go away. The horse's corpse is already decaying and yet the poor thing is still getting beat.

Tuning means, generally, doing anything to improve the resultant output (what you are tuning for). If you think that increased goals such horsepower or fuel efficiency is not an improvement... As for the micro-definition in our world contextually, it typically means getting your chosen combination to run optimally. Much like jet selection, plug selection, and modification, is tuning. No buts about it.

As for plugs...