Tech Forum : Iridium spark plugs???

MayanArch

Posted Friday, Feb 22nd 2:43pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1510

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

These things can be twice as expensive....why? Worth the money?

Autolite, Champion, and Denso makes them.......who is the best?

Will "racing" spark plugs muddle up the daily driving experience?

ArnZ

Posted Monday, Feb 25th 6:32am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 132

Qld, Australia
BMW 323i

normal spark plugs are what my m20 uses. i dont think any other typre spark plugs get hot enough to clean themselves, so after a week of using iridiums your plugs might foul up.

MayanArch

Posted Tuesday, Feb 26th 3:22am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1512

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

arent iridium spark plugs supposed to be hotter?

ArnZ

Posted Tuesday, Feb 26th 4:50am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 133

Qld, Australia
BMW 323i

im not too sure, but i remember seeing an e21 owner who used iridium spark plugs which fouled up.

jdench

Posted Saturday, Mar 1st 12:48pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 191

Sussex, UK
1979 E21 323i, 1998 E36 323i touring

All spark plugs have a heat rating, the fact that the electrodes are made from Iridium shouldn't make any difference as long as the heat range is correct. I have Silverstone silver electrodes in my m20 and they run fine. The Bosch triple electrodes are supposed to be good as well. The only difference should be that the Iridium plugs should last longer. My friend has a Mk2 Supra that uses titianium tips, they are very expensive (about £30 each, and he needs 6!) but they last for about 70,000 miles.

Phasma

Posted Wednesday, Mar 5th 10:26pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 115

Latvia, EU
E21 323i "Phantom"

Iridium plugs are total crap for N/A engines. They are way too cold and are made like this to avoid detonation on boosted engines. We tried Iridium plugs on M20B25, 3SGE celica, N/A Eclipse and it ended up with lumpy idle and "acceleration lag". So we tried them also on Subaru STi, 3SGTE Turbo Celica and results were great - engines allowed to be slightly overboosted till ignition electronicaly retards because of knock sensor readings.

MayanArch

Posted Thursday, Mar 6th 2:09pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1514

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

Phasma wrote:

Well, thats exactly what I am experiencing with normal spark plugs. They may have fouled, because I am experiencing throttle lag and lumpy idle.

What spark plugs work with our M20s?

aussie323i

Posted Friday, Mar 7th 1:04am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 611

australia
1979 323i

well... I have tried a few, and I always come back to normal old NGK BP5ES plugs. They are much more reliable than the Bosch plugs, and they don't break the bank

MayanArch

Posted Sunday, Mar 9th 7:56pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1516

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

aussie323i wrote:

well... I have tried a few, and I always come back to normal old NGK BP5ES plugs. They are much more reliable than the Bosch plugs, and they don't break the bank

My car has BP6ES in them. Are you sure of the number. What is the difference? Did someone put the wrong plugs in there?

Also, admitedly this may be a stupid question, but why does the new plugs I got have a different nib. (sorry for the bad pic)

The nib on the new one doesnt fit into the spark plug change tool or the plug wires.

jdench

Posted Monday, Mar 10th 3:59pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 192

Sussex, UK
1979 E21 323i, 1998 E36 323i touring

They look nice and sooty! It's either running far too rich and sooting up or they are too 'cold' a rating, try the BP5ES as that is what is says in my Haynes manual.
The nib should unscrew to leave you with the threaded part and you can swap them over if you need to.

jdench

Posted Monday, Mar 10th 4:01pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 193

Sussex, UK
1979 E21 323i, 1998 E36 323i touring

Have a look at this as well,
http://www.spark-plugs.co.uk/pages/technical/iridium_spark_plugs.htm
http://www.spark-plugs.co.uk/pages/technical/ngk_symbol_code.htm

g323

Posted Monday, Mar 10th 7:09pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 239

California
323i 1982

A while back we had a discussion (http://e21.tricord.be/forum/view.php?view=24857&highlight=WR8DC )

on this and here were the results:
The following people or places recommend the following plugs for the 323i

BMW_M_320i - W9DC - Bosch
Arnz - BP5ES - NGK
ImaRadiostar - ZGR5A - NGK
Haynes for e21 six cil, N10Y - Champion
Bav Auto - WR8DC - Bosch

Myself - I use WR8DC+ and they work great

g323

Posted Monday, Mar 10th 7:13pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 240

California
323i 1982

how´s your distributor? i found changing the rotor and cap made a HUGE difference, and replacing the whole thing made the car seem new.

luck

MayanArch

Posted Tuesday, Mar 11th 1:52am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1517

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

jdench wrote:

Which one is "colder"? The BP5ES or the BP6ES?

They both fit the threaded end, and I suspect both will fit the plug wires if I remove the nib. The car had 6ES on it....and cold starting and cold running have always been a problem.

My mechanic suggested using "hotter" plugs....but how do you know which is hotter?

Are the cap and rotor auto parts store items still?

g323

Posted Tuesday, Mar 11th 6:46am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 241

California
323i 1982

jdench wrote:

Have a look at this as well,
http://www.spark-plugs.co.uk/pages/technical/iridium_spark_plugs.htm
http://www.spark-plugs.co.uk/pages/technical/ngk_symbol_code.htm

5 is hotter, check the link jdench put up for more info.

im thinking of running hotter too, had no idea about the self cleaning thing

g323

Posted Tuesday, Mar 11th 6:47am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 242

California
323i 1982

mmm cap and rotor, i always get on bav auto.(you can get some part numbers off their website and what you cant get there you can get from realoem, i think it might be the same as a 5 series m20 but im not sure)

definatly recomend them!

MayanArch

Posted Tuesday, Mar 11th 7:08pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1518

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

put in the 5EM today, and it fixed the lumpy idle and sluggish acceleration.

They were really bad and got progressively worse from back cylinder to the front cylinder.

we will see how it starts tommorow morning.

MayanArch

Posted Thursday, Mar 13th 12:12am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1519

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

This completely took away my cold start problem. It started on the first try.

What I am wondering is why neither of the two mechanics that I took my cold start problem to figured this out.

melloh

Posted Thursday, Mar 13th 8:26am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 653

California, USA (San Jose)
1980 320is, 1991 318is

well, I guess the 'obvious' can elude even the best of us.
Let's all cross our fingers and legs and hope that this permanently fixes your problem at hand so you can continue spending more time and money restoring that amazingly beautiful bauer!

jdench

Posted Thursday, Mar 13th 11:27am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 194

Sussex, UK
1979 E21 323i, 1998 E36 323i touring

I'm glad to hear it! I am surprised it started at all with those black plugs

The spark plug should be light brown on the metal and the white ceramic around the core should be a nice tan colour. If you take the plugs out after about 2000 miles and just have a look at them to see what they are like, it is the best way to tell how sweet your engine is running.

MayanArch

Posted Wednesday, Mar 19th 2:41pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1521

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

jdench wrote:

I'm glad to hear it! I am surprised it started at all with those black plugs

lets see how long it runs like this. I will check them again at 1k and then again at 2k.