I ran my e28 535i on W8DC plugs (one step in temp range below W9LRS), without the resistor (R). I have run my last two 745i cars with the W7DC plugs.

Why? When our aging cars were made, gasoline was different. Today's oxygenated gasoline blends make our old engines run hotter and fail high NOx in smog testing.

Don found out that one step removes 300 degrees of heat from combustion.

It makes for a cooler running engine and the fatter electrode will not wear as quickly. On one visit to the wet Bay Area, I switched out a set of W8 plugs for W7's. After one month of use, my plugs had worn from .028" to .040"...partly due to the corrosiveness of ethanol in Cali gasoline.

The reason Bosch Platins do not work well is the diminished size of the electrode and the fact that the electrode burns away far too quickly. In my first 745i, my only installation of platinums lasted one week. The spark was originating from inside the insulator.

SoCalVern
12/85 Sonderlakierung 745i
'88 Jag VDP (Neglected stepchild)

Own 'em, drive 'em,
learn about 'em,
fix 'em, love 'em!


Video walk around of Ellie Mae

Get a Pro sig pic by Evan Wollenberg

• Spark Plugs - elbiera 2008-01-31 08:49:50 (152 views)
  • Open mouth, insert sparkplug foot... - Vern 2008-02-03 02:27:13 (147 views)
    • Re: Open mouth, insert sparkplug foot... - elbiera 2008-02-04 13:54:20 (90 views)
      • I think any of the online distributors can get you a set of - Vern 2008-02-04 16:43:16 (81 views)
        • Re: I think any of the online distributors can get you a set of - Area52 2008-02-04 19:22:38 (74 views)
    • Good to see you back here Vern. Hope all is well with Josh's car and you are on - Draleu 2008-02-03 13:24:33 (75 views)
  • NGK ZGR5A - ///ARINUTS... 2008-02-02 14:00:52 (187 views)
  • What is this 'spark plug' that you speak of? (nt) - vance 2008-02-02 07:26:06 (87 views)
  • Bosch spark plugs - WR9LS vs. W8LCR - 2ck 2008-02-01 16:05:56 (178 views)
    • Re: Bosch spark plugs - WR9LS vs. W8LCR (url) - elbiera 2008-02-04 12:46:52 (149 views)
      • Do you there's there was any long-term damage to your car? (nt) - 2ck 2008-02-04 13:37:32 (61 views)
        • Re: Do you there's there was any long-term damage to your car? - elbiera 2008-02-04 13:47:52 (74 views)
  • Stay with stock, nothing more nothing less, otherwise you are wasting your time. (nt) - ejonesie22 2008-01-31 17:05:27 (82 views)
  • We as a group do not use other plugs except the - kff 2008-01-31 11:29:56 (146 views)
    • Every Forum Ive been on..LOVES to Debate this topic.... - wabiker 2008-01-31 20:59:27 (99 views)
      • Re: Every Forum Ive been on..LOVES to Debate this topic.... - elbiera 2008-02-04 13:49:50 (73 views)
      • So we are a different forum. no debate, just three saying go stock. (nt) - kff 2008-01-31 22:46:03 (82 views)
        • I guess it sounds like I was implying *this* Forum too... I wasnt . (nt) - wabiker 2008-01-31 23:32:34 (74 views)