So sorry guys I know this is a very boring question but I have been doing some reading up. So which spark plugs should we use for a stock 88' 930. Bosch W3DPO, NGK BP8ES, NGK BPR8EIX, NGK 9EV, Bosch W24ES-U, Bosch W24ES-ZU or Denso IW24. Beru ??, Champion??

I don't mind using the conventional plugs but they are not widely available. Seems like dealers mostly carry performance plugs like iridium, platinium, paladium... My concern is these high performance plugs generally are easier to foul due to their small electrode size. Any inputs will be great!

 

I was recommended to use the stock plug, W3DPO, even in my 400bhp 930 by Stephen Kaspar.

 

I think the 3 is too cold for the 930 and recommend going to a 4. I have had great luck with the W4CS plug which is a silver plug.

 

What about with twin plug ignition? 3.4L and 7.3CR. What works best for a street driver? I was running an NGK plug...can't remember the number.

 

I'm running Siverstone BERU S9's, gave up on the W3DP0's some time ago. Great plug for the money!

 

I'm having a hard time sourcing S9s...Where are you guys getting them?

 

Geoffrey,

Are you saying a W4DPO?

 

I have some extra new Bosch W4CS plugs if anybody is interested.
6 - for $40 shipped USPS.

 

email sent..

 

I've had good luck with the Denso IW24. With stock ignitions the small center electode is actually less likely to foul, keeps the spark kernel at one point, thus keeping that point cleaner.

 

What difference does the platinum plugs have when comparing to stock plugs? Exept for the higher pricing (for us in Finland approx. 30$ each)...
I´m running CIS with 400 hp.

 

I think the stock W3DPO is platinum.

http://www.924board.org/viewtopic.ph...e4a6e5840b51e5

 

Giving this thread a BUMP. Can I use the NGK BP8ES in my twin plug application? I happen to have 12 new ones. I'm running:
SC cams
3.4L
IA Fuel Head
Electromotive Ignition
K27

 

Sand_Man,

The BP8ES is a standard plug with the large center electrode. The Electromotive ignition is inductive and requires, if I remember correctly, a 0.024" (maybe even less under high boost) gap due to it's lower output voltage. Usually a low-voltage inductive ignition needs a small center electrode to get decent plug life and help prevent fouling.

When I finally clear a few projects out of the way and finish my XDI installation, I'll be using Denso Iridium plugs.

One thing to also consider, is you are still using CIS which goes fairly rich during the onset of boost, then leans as RPM's increase. This fairly rich area will foul a standard plug pretty quickly. Use your BP8ES plugs for break-in of your new engine, then change to a quality Platinum or Iridium plug.

Win

 

.024 is the recommended gap from Electromotive on typical 930 applications. Although the power of the wasted spark XDi system is less than a CDI, it is on for a longer period of time per event. So, if you choose the right plugs (resistor, heat range and length), it should work well.