944 sparking plugs

[Martin Sage]

Any advice on plugs to use on my 944S please and what gap to set them at?
Thinking of going for Bosch WR7 DC unless anyone has a better idea [8|]

 

[Veerzigzag]

I use NGK Iridium plugs - good spark and they keep their gap for a lot longer than plain copper ones.
Here's a pic after 10k miles in my 160k miles 2.7 engine - good as new!

 

[Copperman05]

+1 for iridium plugs, more expensive but worth every penny.


Edd

 

[zcacogp]

Bosch is good (and what I use), NGK is good, Denso is good.

Changing them frequently is important. A huge number of ignition faults arise from failed spark plugs. And at a pound a pop, you're daft if you don't change them nice and often.


Oli.

 

[Veerzigzag]

A huge number of ignition faults arise from failed spark plugs. And at a pound a pop, you're daft if you don't change them nice and often

At the risk of winding you up Oli - do you think there is a connection between the cheapest ones at £1 and a high failure rate??

 

[zcacogp]

No, although it's a good question. Bosch tend to do quality stuff and I'd happily rely on them; the problem is more people using plugs for much longer than they should have done and neglecting to maintain them. Back when I was doing a lot of automotive fault diagnostics then a large number of faults were caused by plugs which were yonks old, cracked, yellowed or contaminated with sparks freely tracking across the ceramic insulators (and also often of the wrong heat rating, but that's another discussion). The link between cost of plug and longevity is only fairly vague, so the general rule of changing them often is well applied.


Oli.

 

[Veerzigzag]

so the general rule of changing them often is well applied

Point well made - also a good early indicator of problems if they come out looking less than perfect..

 

[andy watson]

Hi Martin,

Bosch for 12 years..no problems ( not the same ones you understand [] )

 

[zcacogp]

ORIGINAL: Veerzigzag
Point well made - also a good early indicator of problems if they come out looking less than perfect..

'Zactly. That's another good point.


Oli.

 

[Martin Sage]

Thanks guys for all your suggestions and such a great response []
Any ideas on plug gaps?
+ Just to confuse the issue has anyone tried the Bosch Super 4s?

 

[zcacogp]

I have to say I always run the plug gaps that they come with. I probably should measure them as they are always supplied a bit large, but an electronic ignition system in good order should be able to jump several mm so I don't bother.

Super 4's are much the same as the regular Bosch items but last twice as long and cost four times as much. They were designed to allow longer service intervals, if that's your sort of thing. I'll refer back to my previous comments and say the regular plugs changed every 5k miles are a better bet.


Oli.

 

[Martin Sage]

Thanks Oli. The super 4s have 4 'prongs' instead of 1 it seems and are not adjustable.
I am torn between these and the iridiums at the moment

 

[zcacogp]

CarParts4Less (loatheful name but good place to buy parts) currently have Beru plugs (part number 408771805) for £1.32p, or Bosch single electrode ones (408771840) for £1.92p each.

Or you could buy 10 of the Bosch WR5DC for £10 from here:

http://www.ebay.co.uk/itm/10-X-BOSCH-SUPER-WR5DC-SPARK-PLUGS-/290905867348?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43bb574454

Any of those options will do you just fine. Spending more won't get you a better plug, and putting the money towards something else would be my choice.


Oli.

 

[andy watson]

I'll refer back to my previous comments and say the regular plugs changed every 5k miles are a better bet.

I'll refer back to my previous comments and say the regular plugs changed every 5k miles are a better bet.

+1

Common "ole bog standard" Bosch OPC style will be just fine []

 

[zcacogp]

ORIGINAL: andy watson
Common "ole bog standard" Bosch OPC style will be just fine []

OPC's fit Bosch, eh? I had a feeling they were standard-fit from new, but wasn't 100% sure so didn't want to mention it.

What more can I say?


Oli.

 

[eddieedmo]

Bosch ,tried mine on NGK and didn't run as smoothly .

Nick []

 

[Copperman05]

FWIW there is more to iridium plugs than service intervals, in my experience they produce a better spark which can be felt via increased performance and improved mpg, etc. Not bad for a spark plug and why most who have used them are willing to use them again.

Our engines particularly benefit due to the oversized cylinder capacity where an improved ignition spark can really help. In fact I am so convinced that they make a difference over standard plugs that it was my intention to have runs done back to back to see if it could be measured on our dyno day.

Not scientific or conclusive, but you get the idea...
http://www.youtube.com/watch?v=wbuGpJWNX1M

http://www.youtube.com/watch?v=0A9_7RtFoZ4

Having used both, yes the Bosch plugs work fine, but the iridium plugs work better.

PS I used Denso IW22 for the S2


Edd

 

[944 man]

Im just wondering what to buy for my 220 Turbo as we speak. I should be working, of course...

 

[david924s]

I have tried Iridium and Bosch super 4 in my S2 and can honestly say I did not notice any difference to the standard Bosch single electrode, think it is now running on NGK but nothing special just the cheapest ones I could get that would fit. Maybe I am not driving it hard enough or too insensitive to the improvements.

 

[Copperman05]

I too tried the Bosch super 4 but noticed no difference, the iridiums however were different, subtle but noticeable, like when you renew a worn dizzy cap or similar. Only a dyno run can measure any real world difference hence my idea.


Edd