boonie

i am in the process of tuning my 91 and i need a recommendation regarding a spark plug.
1. Autolite double plantium
2. AcDelco rapid fire
3. NGK copper Vgrove
which one you would recommend and why?
thanks boonie

Aardwolf

None of those, they are a needless expense. Just a normal plug will be fine and save money. I use Delco, FR5LS for my year. I think I paid $1.80 a piece.

91sTeal

Do not use Bosch Platinums ! In my 91 they were cooked after only 100miles. I think stock Delcos are the way to go.

Pete K

Resist the urge to spend more than needed for a spark plug. I have tried every plug known to man, both at the strip and on the dyno. I have never, ever, seen a difference in power, fuel milage etc.
One may last longer than the other, that I cannot tell. I change my plugs once a year. Every 2 years at the most.

Bob CTS

Use the standard Delco plug.

ToniH

Another vote for the stockers. I think its FR5LS for '91 too.

skybolt31

Stockers for me too. As was said already, you will never know the difference with a more expensive plug, other than perhaps longevity. In the old days with points and carburetors, plugs had a very short life and I could see spending a little more for one that would last longer or fire even through the lean/rich times that a carburator may subject them to. Nowadays though, I change plugs once a year or maybe two years only because I don't want them to get fused to the head and they always look great when I take them out. Save the money and buy a tank of gas, that is more gas than the platinum plugs will save you.

shop14

use what the car calls for,DELCO. thats what i use and she runs fine

Tim_Ko

My experience is a little different. I have had an 85 for the last 10 years ... it just keeps on keeping on. It breaks - I fix it and so it goes. While I was sorting it out early on, I switched to SPLITFIRES with an ACCEL coil - opened the gap up to (as I recall) .040 and my mileage increased 3mpg. (I commute with the car - 100 miles a day, so I go through a lot of gas - same route - so I can compare). The best mileage I got consistantly over the same 50 mile route was 30. I've had those same plugs in there about 5 years. A couple of plugs were fouling out and after replacing everything else, I eventually pulled the injectors to take a look (looked bad) and replaced them with ACCEL. Then it started running pretty good for what it is.

xflagz51

I have to throw in my .o2 because there are just too many people singing AC spark plugs praise, so I'll be the spoiler. I have not had good luck with them, AC Delco is decent quality equipment, but I do not include their spark plugs in that sentiment. I agree with all of you about platinum/irridium/multi-side electrode spark plugs, they're a waste of money in terms of performance. Platinum and irridium will get you a longer life, but that doesn't mean much around here because just about everyone on this forum is changing their spark plugs every year or two and so never realizing the extended life that those materials provide. The multi and split side electrodes are basically getting you "out of the box" indexxing, you can accomplish the same or better results by indexxing your conventional spark plugs. The problem with indexxing is that it takes a lot of time and the supposed 1% gain in power may not be worth it to you. That's my opinon on that, FWIW. My best luck with spark plugs has been with NGK, have been using V-Power's now for three years and they have been the best that I have ever had! BTW, other than the V-groove on the center electrode, the V-Power is just about as conventional as you can get and they cost $2.25 apiece. My best friend has an '84 Mustang with a pretty warm '93 Cobra engine in it and his old stand-by Autolite plugs were always fouling. I recommended the NGK V-Power's to him and he installed them, the car has never run better and no fouling. BTW, this is one of those subjects that no three forum members will agree on, purely subjective.

CFI-EFI

Some of the plugs made with exotic metals, namely platinum, will last longer. If you don't like fiddling with your car (why are you in this section of the forum?) and opening the hood, these exotics can be a good value, especially if you are paying for someone else's labor. If you are like a lot of us, and just can't leave well enough alone, the cheapest plug is the best bargain. The spark has to jump the gap, that's it. The plug goes ZAP, and the air/fuel mixture goes BANG, and that is all there is to it. There isn't a nickles worth more power in any one of them over another.

RACE ON!!!

Corvette Kid

There are many good plugs with which you can't really go wrong. I've used most at one time or another. I've never been impressed with Champions except for their race plugs. Over the years I've used Autolites in many types of engines though and have always been quite pleased with everything about them. I just use their standard ones in my Vette because I like to keep them pretty fresh in it. I had a set of their double platinums in my Nissan that still looked like new after 70K miles.

onedef92

I like the NGK TR-55 Double Platinum. I have also used the Autolite Platinums with great satisfaction.

NEVRL8T

H P Bushrod

I'm running the regular NGK TR-55 with the v-groove in my '93. No problems at all.

rws.1

I have 4 8 cylinder cars and do not want to be changing plugs on all of them every year...
I use Bosch Platinums +4 on my C4. They are now on their 4th season and the car runs as smooth as the day I bought it...
When it is time to replace them I will put in the same plugs

JD'S WHITE 93

My best friend has an '84 Mustang with a pretty warm '93 Cobra engine in it and his old stand-by Autolite plugs were always fouling. I recommended the NGK V-Power's to him and he installed them, the car has never run better and no fouling. BTW, this is one of those subjects that no three forum members will agree on, purely subjective.


There is something wrong with your friends car other than the plugs providing he was running the correct Autolite plug in it to begin with.

CFI-EFI

However, remember the post above...ZAP...BANG! It isn't as convoluted as some would like to make it. If different plugs cleared up a fouling problem, the plugs being replaced were probably the wrong plugs, either in configuration or at least the heat range. Think about it. What can cause fouling and what is it about a plug that could prevent or cure it? Contrary to impressions left by some, it isn't voodoo or black magic.

RACE ON!!!

Strick

I'm the guy everybody says is crazy for installing the NGK 55IX, yes that exotic Iridium plug. I put them in about 4 years ago or about 20K and they are still running well. I put the Vette through some hard driving including mountain runs and auto crossing. She never missed a beat. I've always been into over kill.

Red Tornado

you're right strick, because standard copper plugs on the order of $1.49 each will perform just as well over the same length of time.