The topic of spark plugs, like most everything car related, seems very controversal. Why, aside from higher cost, does most everyone HATE Bosch 4's? I've used them before, and thought they ran/fired great. In a car like our 3rd gens, a plug like this makes sense, since a plug change can be a little tight at times. Does anyone have any hard, cold facts/eveidence that these are, in fact, a bad plug choice, and they REDUCE performance? I'm aware that Delcos seem to be the plug of choice on this board, but does it stand to reason that a company like Bosch, that makes quality injectors, oxygen sensors, etc, the very brands that come in our 3rd gens stock, would use inferior spark plug technology/engineering, just for the heck of it? Comments, please

 

There is still only one spark that meets the fuel anyways, right?

Maybe not so much that they reduce performance, but let's see you can get a decent set of plugs for cheap, or spend $64 on a set of those +4s, I don't see the point.

For one, if you want all out performance get copper, it conducts better than platinum, platinum just lasts longer.

 

no hard fact or dyno sheets, but i think they're over priced and offer no preformance gains. if changing plugs in a thirdgen is that big a chore you might want to consider finding another hobby or farming the work out.

 

One point that has been brought up in the past is that you cannot get these plugs indexed properly in a motor that the plugs come in from the sides of the combustion chambers. With standard plugs you have a pretty good chance of geting them so that the fuel air mixture is pushed directly into the spark(good enough for hi performance street use) If you use the plus 4s then you have something sticking up on 4 sides. This blocks the fuel/air mixture from directly hitting the spark in most cases. Another thing is that electricity will always follow the path of least resistance. This means that only one spark will occur at a time. As far as platinum plugs they are designed to last longer not perform better. I also agree that it is not really that hard to change plugs compared to most things we do to our cars. Some can be a little tight to get to but so is most stuff on these cars.

Ben

 

Since were already talking about plugs, what do you guys think about NGK plugs? I've worked at a couple parts stores and some people would buy the iridium plugs for foreign and domestic alike.

 

I think the iridium plugs are in the same boat. Probably good quality, but not worth the price if you are looking for a performance increase.

I don't have much experience with the NGK iridiums, but I've heard a lot of people say that there was no noticable SOTP difference when they purchased DENSO iridium plugs ($44 US for 4 plugs).

 

.....quote..."if changing plugs in a thirdgen is that big a chore you might want to consider finding another hobby or farming the work out"

Frequency of plug change interval was NOT the point of my question. Just trying to ask a question about what I would think is a relevant ignition issue.

 

Hooooo, ede, I think he's got a point here.

But, he doesn't need to be a snot about it.

 

Hey, no flamin intended. I just felt that "ede" tried to make it look as though the POINT of my plug question was because I was unable / unwilling to change them as often as needed. Not true. But if your going to change them anyway, why not use a plug that, after doing a bit of research , seems to be both a good performance , AND longevity choice .

 

None of those plugs are going to hurt you but then again they're not going to help you either. Those Bosch +4's rank up there with Zmax and the rest of those shams. Platinum is supposed to last longer, but in older cars or in performance applications, any benefit of using those kind of plugs is probably nullified. Any generic plug is more than adequate. I always used AC Delco plugs on both of my rides and they never gave me a problem. Even with my GTA running super rich, i pulled the plugs and they never showed a hint of fouling. I have headers now and i use these accel shorty plugs. I used to work at a Kragen parts house when I was in high school and i used to tell all my customers the same thing. Didn't make me good friends with my DM or the bean-counters. I miss the old days when the only "gimmicks" were Marvels Mystery Oil and STP, and even those were semi-useful.

 

I use an Jacobs Ultra-Team and cannot use Splitfires or Bosche +4 or any of that ilk. They have a detrimental effect on the Jacobs system. Probably the same story for MSD, ACCEL and Crane.

So I use AC Delco plugs.

Might want to keep it in mind in case you ever get the notion to upgrade your ignition system.

RP.

 

I don't like platinum plugs. The idea behind platinum is that it is stronger and does not erode away. What I don't like is the electrode is so small and can foul out very easily if your motor is not highly tuned or burns any oil. I have fixed many cars by changing the platinum plugs a customer just put in a few days ago. Save your money for good wires and an upgraded distributor, cap, rotor, module, and coil. IMO platinum plugs are junk.

 

simple answer to this one.

the idea of the spark plug is to provide a CONSISTENT reliable spark that allows the flame front to travel away from the spark in as many directions as possible for quickest total burn time.

if you want to see this in fact, formula one engines use spak plugs with no ground electrode. they just have a center and the spark grounds to the case of the plug.

the plus 4s are similar in design to the no electrode plugs in that the spark could go any number of directions out from the center to ground (bad - will problably end up going to the same one after awhile anyway) but the plus 4s actually block lots of flame front with those 4 prongs in the way.

when I had them I had idle problems and I cut half the electrodes off and they worked much better but still not as smooth as regular single electrode plugs.

 

Actually changing plugs IS a pain in the butt in my opinion. I run the Bosch 4's in all my cars with fine results. This topic is kind of like what oil to use. Fact is that with electronic ignition just about any decent plug will perform fine. I have tried a lot of different plugs in my sportbikes and never really noticed any difference at all. With platinum there is a definite advantage, my wifes Blazer had 50k with the AC-Delco platinum and they were at gap spec with that mileage. It's really a matter of personal pref. than anything else. You know the story, my dad ran pennzoil for a hundred years-yada,yada,yada.

 

the 400 would have cool start woes with ACs. Its much easier to get lit off with NGKs. I think they perform over a wider temp range.. (they seem to have less plugs that span the same heat ranges as AC).