Went to the $tealer to get some plugs for my 98 M3/4 and they only had 4. So now i have to wait till next week before they get more in. They raped me 10.34 after my CCA discount for each plug...ouch!!! Anyways i decided to call around at the local autozone, pepboys, etc., to see if they had the same plugs. Most places told me that the platinum + 4 Bosch plugs were the same plug as the dealer sold me. The BMW part number i got is FGR8KQC. The plug is a Bosch and has 4 prongs. So is the platinum + 4 the same plug? If so i can get them for 6.00 each. I thought the Plat. + 4 was a crappy plug for the M3.

Sucks if i have to wait till next weekend to change my plugs.

Im so confused.:confused:

I wouldn't mix 'em. I put in Bosch +4s, but then changed them because of all the negative stuff I read about them. I used NGK BKR6EQUP. Also very spendy. I paid $8 each. Retail is $12+

Jay

Originally posted by LUNI2NZ
I wouldn't mix 'em. I put in Bosch +4s, but then changed them because of all the negative stuff I read about them. I used NGK BKR6EQUP. Also very spendy. I paid $8 each. Retail is $12+

Jay

What are the bad things?

I don't remember all the specifics. I just remember reading several posts regarding problems with the Plat 4+ plugs. I decided not to risk any problems.

Jay

I have heard of plug failures on the track with the platinum 4's. The plugs for the M3, i.e. factory ones you mentioned, are copper core, which is a better conductor, platinum is for long life, as others have said, I would go with the stock Bosch or the NGK. The best are silver plugs, but I don't know if one is made for the M3. Bosch and Beru make silver plugs, the Bosch are called "Silber" German of course for silver, but again, don't think they are made for the M. Hope this helps.

From what I read before, some guy used the Super Bosch +4 and later on had misfire faults. Turned out one of the ground electrodes broke off. This happened on a track event.

I still have the Super Bosch +4 on my M3 with over 20k miles and no problems.

I've been using Bosch +4's on my 93 325i for years. With no problems.

When I had to change the plugs for my 95 ///M3 recently, I thought I'd go NGK instead of the +4's 'cause I had heard the same that there may be some probs w/ the +4's. Soon after, I got a mis-fire from the NGK's. I talked to a BMW tech and he said to try the +4's or OEM. His reasoning on why he likes the +4's were 1) Bosch is an OEM supplier of plugs for BMW 2) BMW doesn't tell every company that makes plugs, BMW's specifications and requirements, so Bosch may have some knowledge about specific issues related to the spark. 3) It's platinum and rated for 100K miles.

So I changed to +4's on my ///M and now no misfires. So go figure?

I am currently using the stock plugs (albeit 2 steps colder) on my 95 M3. I change em every year and will never try anything different. I am sure that BOSCHE specked the system with these
plugs and dont want to deviate from the specs.

The best plugs in the market here in Europe, are the Iridium plugs but are way too expensive (around $75 bucks each). I have seen dyno graphs that show a 2-3hp diff from the OEM or Bosch platinum 4 electrode plugs only by using Iridium technology.

The important thing to remember when installing your OEM or other plugs is that the spark between the gap faces the intake valves. The air-fuel mix is always a bit richer close to the intake valves and a bit leaner close to the exhaust valves.

By making sure that the spark ignites the richest part in the chamber (next to the intake valves) you ensure a that the spark will initially ignite a much bigger flameball that will engulf the whole chamber and ensure a complete combustion.

In slow-mo the ignition inside the chamber is not instatenous. The spark creates a "travelling flame" that follows a certain path in the chamber.

The bigger the initial flame the sooner the complete chamber will be ignited. This also translates into more power.

The pro QM swear by this stuff. I usually mark with a marker the position of the gap(s) on the tip of the plug.

When I then torque the plugs, I stop when the market indicates that the gap is facing both my intake valves.

BTW always go at least on size colder that the OEM.

Regards,

Vlasis

In regard to the last reply, positioning the gap on the spark plug to face the intake valve(s) is called indexing, and racers I am told, always do this and in fact I did this on one of my cars once, marking the socket and extension as suggested and using shims to get the plug to the right position, a tedious and time consuming process, unless you have the head off the engine. However, this is only a factor with single electrode plugs, and with a four electrode plug I don't think it is an issue as there is no one electrode blocking the path to the intake valves. Maybe 95 M3's use a single ground electrode plug, I don't know, but if it is a 4 prong plug, then indexing will not make a difference.

Phil

Originally posted by fstbmwm3
I am currently using the stock plugs (albeit 2 steps colder) on my 95 M3. I change em every year and will never try anything different. I am sure that BOSCHE specked the system with these
plugs and dont want to deviate from the specs.

The best plugs in the market here in Europe, are the Iridium plugs but are way too expensive (around $75 bucks each). I have seen dyno graphs that show a 2-3hp diff from the OEM or Bosch platinum 4 electrode plugs only by using Iridium technology.

The important thing to remember when installing your OEM or other plugs is that the spark between the gap faces the intake valves. The air-fuel mix is always a bit richer close to the intake valves and a bit leaner close to the exhaust valves.

By making sure that the spark ignites the richest part in the chamber (next to the intake valves) you ensure a that the spark will initially ignite a much bigger flameball that will engulf the whole chamber and ensure a complete combustion.

In slow-mo the ignition inside the chamber is not instatenous. The spark creates a "travelling flame" that follows a certain path in the chamber.

The bigger the initial flame the sooner the complete chamber will be ignited. This also translates into more power.

The pro QM swear by this stuff. I usually mark with a marker the position of the gap(s) on the tip of the plug.

When I then torque the plugs, I stop when the market indicates that the gap is facing both my intake valves.

BTW always go at least on size colder that the OEM.

Regards,
Vlasis
Goofy question:
Is the intake in the direction to the passenger or driver's side?
Or is it in relation to the back of the engine compartment or front?

I.E. Looking at the car from the front with the back of the engine bay being South...is it North, East, South or West?

If you're looking at your engine now.........the intake is on the driver side.

the side where u see your throttle body and intake.

Originally posted by M3Jokster
If you're looking at your engine now.........the intake is on the driver side.

the side where u see your throttle body and intake.
Well...NOT RIGHT NOW;) I'm at work...
But thank you:)

I agree that "indexing" is not too important on the 4 electrode plugs, but I still index the plugs in a way that "they are best aligned" to the intake valves.

Old habbits die hard I guess.

Regards,

Vlasis

I have run Platinium +4 for about 12 months and have had no issues with mis-fire and found them to run better then the year old OEM when I switched....

Tim

What's the benefit of using a colder plug?

less risk of detonation and pre-ignition under sustained heavy use and hot weather, at the risk of fouling and poor combustion during light use and colder weather.

look at www.bimmerparts.com they sell OEM plugs for 5 bucks a piece I think.

I had plat + 4 in my 95 M3 and changed back to OEM because of all the talk. With the OEM, my car was idleing rough (is that misfire?) so I changed back to the +4's and everything is smooth again.