Waht are you guys running for spark plugs
 

Need to replace the plugs on my '81SC. What's everyone running? Don't have MSD, just stock coil.

Todd

Stick with the OEM's. Bosch W5DC.
Im having all sorts of problems now that Ive changed to NGK. But it might be related to other issues.

I've always used Bosch but went to NGK on the last change and they work fine. Two things to know:
1) Stick with a plain copper plug, it works better in our cars.
2) This question has been discussed many times already. Become friends with the search button and you will find a wealth of information at your fingertips.

I switched to NGK; note the difference of the heat ratings for NGK vs. Bosch plugs,
If you run an NGK you should use 6's or 7's.

I have an MSD system and wires and run 6's.

http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml

I used to have bosch platinum. After reading about the NGK coper plug on this board, I switched to these coper plugs. I can't feel the different at all.

+1 on W5's

i had the bosch platinums in my truck. i DID notice a difference when i put autolites. my gas mileage went up 3-4 MPG and it runs better. bosch plat's are crap!

As you can see (and your further research will show) there is quite a diversity of opinion.

I tend to separate sparkplugs into two groups: cheap and expensive. I have had engines that I want to use new sparkplugs more often than oil changes. That can be for a variety of reasons; diagnostics (chasing MFI gremlins), selecting heat range, etc. for that day’s activity (mountain tour, PCA DE event) or to simply save my ‘expensive’ plugs. There is too much Scot in me to waste money.

‘Expensive’ sparkplugs have a definite use. There are clearly technical advantages in many circumstances. Features such as platinum (a catalyst), fine-wire (high potential field density) and others are clear benefit. Many times these features allow a given sparkplug to operate successfully over a wider set of operating conditions (typical for normal street use) and give an extended service life.

Anecdotal testimony may be useful for sorting out the ‘charlatan’ junk. Personal testing is very difficult because of the cost and small sample. Manufacturer’s choices may be influenced by factors that aren’t important to you (how much does Exxon pay Porsche for Mobile 1 to be OE?)

I suspect Bosch goes to considerable technical effort in conjunction with Porsche’s research fo find the best ‘recommended compromise’ for sparkplugs for our old engines. I think there is little in common with the current technology engines.

Probably the best we can do is to understand the published technology and settle on a high-end group of sparkplug types. I suspect only an exhaustive (and expensive) research study could do better.

You will find many cases where there are reports of “I installed XYZ and my 911 ran best ever.” Seldom do I see someone putting his ‘old style’ plugs (but new examples) back in and having the 911 revert to previous ‘poor running’.

There are also a myriad of other conditions that affect the seeming sparkplug performance. High on the list is the type and condition of the ignition system as a whole. Others include the age and condition of the engine, injection (carb) settings and condition, exhaust, fuel, environmental conditions, driving conditions and sometimes just the ‘phase of the moon’.

You should note that sparkplugs (along with tires, oil and filters) probably have the largest marketing costs associated with the price you pay.

Best,
Grady

I ran Bosch Copper 7 range plugs for years in my engine. I recently changed to 8s on the advice of my mech. The engine seems to be running cooler since then. We'll have to see over time.

A couple of years ago,I bought a s--tload of NGK BP8ES at auction--short notice-- I believed the Chart showing them to be suitable for my 2.7.
Anybody want any?