ahwang

I have just installed a set of 4 bosch platinium +4 spark plug in my C230. The result is that the engine is a bit quieter and smoother. The vibration coming from the engine is significantly reduced when it is rev above 3000rpm. Nevertheless, there is one big issue I just found out. The coolant has increased to around 92C, from 86C before I changed the plugs. Does this additional heat harm the engine in a long term status? Need suggestion!!!

Mike T.

Six degrees C is a large increase in running temperature from just changing plugs. Are you sure they're the right "heat" rating for the car? I would be concerned, especially in slow traffic, that the engine would be hotter and therefore more reliant on cooling fans than it should be. Did you consult with the dealer about this? What do they say?

Also, though this is a longshot, if the +4 plugs are the ones with 4 electrodes, there would be a nominal increase in compression ratio compared to a normal one-electrode plug. Likely not enough to be noticeable on a temp gauge though, or in power

Why did you change the plugs on a new car anyway? You DO know that the spark only travels to one of the four electrodes at a time, don't you? So what's the reason for changing?

My general advice is: leave well enough alone. Do you really think Mercedes puts el-cheapo plugs in the car that make it run rougher than it should? Ask your dealer's service manager for advice.

linh

Yes it does because platinum is a hotter plug then non-platinum plug and that is why they burn fuel better. But i think the temp increased due to because you are driving the car a little bit harder now. Keep driving hard, even with factory Bosch super still will increase the temp. 92C is still consider normal just like when your car wait at a stop light.

linh

I asked Kleemann about Bosch platinum +4 for Slk 230, and he said that it ok to use as long as it does not detonation.

DavidC230k

What tool did you use to remove the ignition wire connectors to the plugs?

KJ-TypeR

Bosch Platinum +4's suck.

They dyno'ed on my Type-R for a loss of 3whp.

Don't bother wasting your time by changint spark plugs, the possibility of losing HP is MUCH higher than any possibility of gaining HP.

Your judgement is clouded by marketing. Bosch +4's suck. No racer/enthusiast uses them.

SoCal240/6

You should write to the idiot engineers at MB for not figuring out which plugs to put in the car. They probably have not seen the commercials for the Platinum +4s, so they may not be aware of them.

linh

KJ-TypeR,

I believed you that +4 plug is suck for your car, but your statement about +4 for other cars is as suck as what you think about +4 !!! Every car is different in many way !!! Just becuase it don't work in your car, it does not mean it won't work it other cars. Why do Honda used NGK and Mercedes used Bosch? If you ask both of the MFG. What do you think they would say? They are both right, because both car are different. Your engine is a very high free rev. engine and Mercedes is not. We all know that platinum plug are better then non-platinum plug because they are hotter plug and it burn fuel better and last longer. But deciding which engine to use it, is the most importance thing. Your type R engine is a very high compression engine, by using platinum plug (hotter plug), your ECU properly retarded your timing and that is why you lost 3 hp at the wheel.

I personally like the +4 on my Slk 230, but becuase it a supercharger engine (just like high compression engine) hotter plug is not good for the engine. Kleemann, said that it ok to use the +4 but just to watch out for "detonation".

I remember when "Plit fire" plug first came out. It suck on my Celica All-Trac Turbo but those Mustang owner are loving it at the track.

gab

If anyone is installing the pulley kit do you think its beneficial to use colder plugs or gapped the tips narrower? What about Iridiums plugs? i heard they as good as copper but last as long as platnium

hrh

I agree. My `94 Jetta had a cold (winter) miss for the first few minutes at idle. Replacing the usual suspects (O2 sensor heater, plugs, wires) did not cure it. Problem actually got worse with a performance chip in the car. Bosch +4s not only cured the problem, the car seemed to drive better generally, particularly in that initial off-idle stage.

+4s also cured the massive pinging in my wife's 4cyl Wrangler w/31" tires, which simply had no ability to climb hills at highway speed. The new plugs (put in at 1K miles) didn't suddenly make the Jeep a Porsche, but did reduce the pinging almost entirely under load.

They also seem to last longer. Many plugs (even stock) offer an intial benefit when new, but for some plugs, the "newness" benefit is gone, in some cases, in just a few hundred miles.

Other friends, with different cars, had no improvement with +4s, which is why most advice comes with YMMV (Your mileage may vary).

Buellwinkle

Exactly, how dare they think that they can design a spark plug for every situation. Idiot fools! They must be they same idiots that put a cassette radio in our cars. Same idiots that made the crankshaft pulley too small and put high dust brake pads. OK, do you have an e-mail address so we can write to these idiots and do they understand english? We need to make the next generation of MBs better for our childrens sake.

linh

Gap,

Kleemann use colder plug with their's pulley upgrade because, the higher the boost the hotter the compression chamber is gonna get and so it can create "detonation". So Kleemann just want to play on the safe side by included the colder plug with the pulley upgrade. Factory plug can not re-gap. If you play with re-gap plug, it also has it benefit and dis-benefit to it. Now let just say that you take a factory plug and make the gap a little bit bigger. The benefit is on the bottom end, you gain a lot of torque because you just created a bigger "spark" but the down side is that on the top end power, you actually loose hp because the gap is too bigger, therefore, at high rpm the "spark" does not have enough voltage to reach the electro. If you use MSD high voltages, then you can gap the plug bigger because the MSD is a high power that can create a bigger "spark" to reach the electro to create that big spark.

KJ-TypeR

Let's get something straight.

A platinum plug is not hotter than a copper plug. The heat range of a plug is not determined by it's material. In other words, you could replace a copper spark plug with a platinum one that is colder.

The stock plugs on the Type-R are platinum plugs. The stock plugs on MOST cars these days are platinum plugs.

Copper plugs are BETTER for performance than Platinum plugs. The benefit of using Platinum plugs is that they last longer and perform more consistently over their lifetime.

At first, copper plugs perform better than platinum plugs but the performance of copper plugs falls off much more quickly than platinum plugs (which means they will require more constant changing).

PoloJCP

I am happy that this site finally have more people that knows about cars. I mean no offense to anyone else out there, but I think a lot of people on this site should go out and do more reading instead of talking among each other and bounce false information off each other.

SoCal240/6

Sorry, but that is the biggest joke so far.

Linh unfortunately has no idea of what he is talking about. He has a total misunderstanding of what a "hotter" and "colder" spark plug means, and why some are specified for certain cars (he seems to think hotter is always better, not true, he also thinks a "hotter" plug means a bigger and hotter spark, LOL! Totally not true, the HEAT RANGE OF A PLUG HAS NOTHING TO DO WITH SPARK SIZE OR TEMPERATURE! He simply has no idea what "hot" and "cold" means when applied to a spark plug).

I am not going to argue, though, b/c I don't care. People can apply whatever misinformation and junk science they want to their cars. (there are lots of reliable sites for spark plug information, etc.)

I will say, though, that anyone who relies on the technical information passed on this board is playing with fire.

SoCal240/6

Marketing, not engineering, puts the radio in the car.

How do you know the crankshaft pulley is too small?? They tested the engine for millions of miles before deciding on the crankshaft pulley. How many aftermarket sellers have done that? I would not be so certain that they have the "right" size, weight, material, etc. Maybe, maybe not. Who are you going to believe?

I never could figure out why they use such high dust brake pads, though. Seems to be a German car thing, though, since every German car suffers from it. I've heard that high carbon pads are required by German law, but that may not be true. It does seem to be regulatory, though, since every German car uses dusty pads.

But changing brake pads is very different than changing spark plugs. The OEM pads have a known and observable undesirable issue. You use aftermarket pads to get rid of that issue. There is no known problem with the OEM spark plugs, and absolutely no reason to believe that they are not the optimium plug for the car. No reason at all. (other than the totally unsupported guess that MB puts cheap spark plugs in to save money. LOL. What is the basis or evidence for THAT statement?)

Buellwinkle

OK SoCal240, they are not all the same idiots, they are different idiots working in marketing, german government and engineering.

I do think they left some performance on the shop floor. They are only spinning the supercharger at about 12,000 rpm and Eaton specifies 14,000 rpm for it. It was probably more marketing related than engineering. They can't have their low end 4 cylinder eating into V6 sales. Who would by an SLK320 if the SLK230 was more powerful? That just makes them clever marketing idiots.

From what I've heard, Kleemann is no longer providing spark plugs in their pulley kit. If anyone that bought the kit knows otherwise let me know.

KJ-TypeR

I'm glad other people are agreeing with me on the spark plug issue. All the guys in the early part of the thread had it all wrong, and I was almost positive that they'd jump on my back and say "Platinum is HOTTER you fool!".

For the record, this is the difference between a hotter and colder plug.

Grab a spark plug and take a look at the white part that holds the electrode.

Now, the more the white part sticks out, the HOTTER the plug is. This means that the plug sits further into the combustion chamber. Therefore the heat range of a spark plug is determined by the insulator nose length (white part), not by the electrodes construction material.

I know Linh loves his Bosch +4's, but unless he does a before and after dyno, he has no REAL proof that they are better. There definitely is a placebo effect going on here. Let's be real, you should not be able to feel a difference in power just from changing spark plugs, that's just SILLY.

Ignition systems on today's cars are VERY VERY GOOD. Unless your plugs are really old and beat up, you shouldn't get any power from changing them. On the other hand, you can very well lose power, or cause engine damage by using the wrong plugs.

SoCal240/6

Yup, what KJ said.

Also, multiprong plugs are for 1 thing and 1 thing only: Longevity. Another myth is that you will get mulitiple or larger sparks with multiprong plugs. Nope. As long as there is only one electrode, there will only be one spark. The spark will seek the path of least resistance. So, the other 3 prongs will just be sitting there uselessly (until the plug wears to that one of them becomes the path of least resistance, at which time the spark will go there).

Performance wise, having all those extra prongs in the combustion chamber can really only hurt, not help.

Its all about marketing, which Bosch does very aggressively and effectively with its Platinum and "+4" plugs.

Buell, just because the Supercharger can spin faster does not mean that you should spin it faster. A turbo car that comes from the factory with 7 lbs of boost can easily be made to put out 18 lbs of boost, but that doesn't mean you want to do it. The turbo could handle it, but it would blow the engine up in short order.

The engine is designed to run with a certain amount of supercharger boost or pressure. Just because the Supercharger itself can turn faster doesn't mean the piston rings are spec'd to handle that, over the long haul. Or that the engine will get the longevity that MB expects, if you raise the boost (raising boost WILL, by definition, shorten engine life, the only question is "how much"?)

That being said, I think most pressurized engines historically have been able to handle small amounts of raised boost, while still living an acceptable life (shorter than it would have otherwise, but still acceptable). With the Hatchback, there is no history or data on engine life at higher boost, though, so the effect is unknown.

SoCal240/6

Actually, I read and was just chuckling about the posts in the early part of the tread, to which you refer.

I wasn't going to post anything, though, because it was just so wrong, and so out in deep space, that it didn't seem worth it. And, I've pretty much given up on tech discussions on this board (Because its pretty much hopeless, and there are other, better places for that), and just use it for entertainment now.

But one the one poster said, after reading Lind's post, that he is glad Lind is here because its good to see "people who know about cars," that just went too far to let go . . .