Printable Version of Topic

Click here to view this topic in its original format

914World.com _ 914World Garage _ Spark Plug Question..

Posted by: Lawrence Mar 30 2005, 05:36 PM

I have several sets of plugs here... some Bosch W5DC plugs and some W7DC plugs?

I know that the numeral in the part number is the heat range - but what does it mean to me and my little /6 cylinder monster?

-Rusty

Posted by: Root_Werks Mar 30 2005, 05:41 PM

For Bosch, the higher the #, the slower it transfers heat (hotter plug). If you do nothing but race, then the 5's are good. I usually stick with 7's for street use. Sometimes even 8's.

My favorite plug bosch makes is a W7DTC, grab some, you will see why I like them.

Posted by: ArtechnikA Mar 30 2005, 05:42 PM

QUOTE (Lawrence @ Mar 30 2005, 06:36 PM)
I have several sets of plugs here... some Bosch W5DC plugs and some W7DC plugs?

I know that the numeral in the part number is the heat range - but what does it mean to me and my little /6 cylinder monster?

5's kinda cold for a stock 2,0 although you might keep 'em in case you do a track event weekend.
might you have bought those for the E ?

7's a good range for a stock, street, 914.6

Posted by: Lawrence Mar 30 2005, 06:08 PM

I've got three sets of W5DCs here.

I called my FLAPS and they told me that W7DCs weren't available anymore. Does anyone know if the part number was superceded? The kid on the other end of the phone got confused when I asked him.

-Rusty

Posted by: Cap'n Krusty Mar 30 2005, 06:25 PM

QUOTE (Lawrence @ Mar 30 2005, 04:08 PM)
I've got three sets of W5DCs here.

I called my FLAPS and they told me that W7DCs weren't available anymore. Does anyone know if the part number was superceded? The kid on the other end of the phone got confused when I asked him.

-Rusty

They're hardly gonna drop a plug that fits literally millions of cars still on the road. The trouble with FLAPS is they hire Mac Donald's trained people, and give 'em an electronic parts catalog. There's NO incentive to think outside the screen. In fact, they may not even know there's an "outside the screen" out there. Try "7500", see if that works. I prefer NGK BP6ES, myself. New number is "7333". The Cap'n

Posted by: Lawrence Mar 30 2005, 06:27 PM

QUOTE (Root_Werks @ Mar 30 2005, 06:41 PM)
For Bosch, the higher the #, the slower it transfers heat (hotter plug). If you do nothing but race, then the 5's are good. I usually stick with 7's for street use. Sometimes even 8's.

My favorite plug bosch makes is a W7DTC, grab some, you will see why I like them.

Thanks for the info.

Okay... I'll bite. Why?

Posted by: Gint Mar 30 2005, 09:33 PM

I'm with Krusty. I prefer the NGK's. Been using them for years.

Posted by: trekkor Mar 30 2005, 09:41 PM

I followed Gint's advice and run the NGK's as well. They fire nicely.

KT

Posted by: mihai914 Mar 30 2005, 09:50 PM

Here's a handy chart, personally I liked NGK very much untill one of them had part of the insulator surrounding the electrode break and went who knows where. Bosch spark plugs, although may run less smooth, if you look closely have a thicker construction than NGKs.

Attached image(s)

Posted by: campbellcj Mar 30 2005, 10:51 PM

I've been using the NGK's as well, but BP7ES in my case -- 2.2S-spec track car in desert climate; I even keep 8's on hand but have not seen a need to go that extreme as of yet. IIRC the BP6ES is recommended for the milder and/or mainly street driven early engines; and maybe even 5's if you have a tired old oil-burner.

The tricky thing to remember is NGK's get colder as the number goes up; Bosch (and others I think) get hotter as the number goes up.

Posted by: Root_Werks Mar 31 2005, 09:40 AM

QUOTE (Lawrence @ Mar 30 2005, 04:27 PM)

QUOTE (Root_Werks @ Mar 30 2005, 06:41 PM)
For Bosch, the higher the #, the slower it transfers heat (hotter plug). If you do nothing but race, then the 5's are good. I usually stick with 7's for street use. Sometimes even 8's.

My favorite plug bosch makes is a W7DTC, grab some, you will see why I like them. ;)

Thanks for the info.

Okay... I'll bite. Why?

NGK's are great plugs, you can tell by the number of people referencing them here. Buuuuut, I still like the W7/8DTC's over any of the NGK's listed. That said, I have dropped in NGK's into air cooled Porsches and VW's for years. No complaints. But for many years, 90% of what I work on get these: (well, not these, but the W7DTC's).

Your spark is not covered, better exposure. Don't use the platnum plugs with 3-4 tips that look like these. Carb'd air cooled engines don't seem to do well with the little platnum tips.

Attached image(s)