54 replies to this topic

[Wil_h]

£48 for a spark plug that wears out quickly? cool.

I think we will have to agree to differ on whether it is a worthwile expense, and if the gains are to be believed.

It must be fraustrating not being able to convince me, but I know how you feel. I once bought one of these CG lock, mentioned it on here and got shot down in flames. But actually it's a great product IMO and really does improve lap times, hey-ho.

[Czar]

£48 for a spark plug that wears out quickly? cool.

I think we will have to agree to differ on whether it is a worthwile expense, and if the gains are to be believed.

It must be fraustrating not being able to convince me, but I know how you feel. I once bought one of these CG lock, mentioned it on here and got shot down in flames. But actually it's a great product IMO and really does improve lap times, hey-ho.

No it's not frustrating in the slightest, I deal with non believers day in day out, and eventually they sit up and listen to experience!

I am merely offering advice based on actual fact, my experience and knowledge in the field of Motorsport, Performance and technology.

the mentioned £48 was for 4 not 1, it's not about convincing you or anyone else, I am just mentioning to the OP that there are better performing spark plugs other than the standard.

Here is a little bit of basic information written by me, for a guide to new vehicles which use Platinum or Iridium spark plugs, as fit from the factory, however I have slightly adjusted it, so you can at least see the point being raised in this thread.

Lets first look at the thermal and electrical conductivity chart below.

 P1000704.jpg   58.9K   19 downloads

Now that you have seen the thermal and conductivity chart, we can see that Silver is the best of all metals when it comes to thermal and electrical conductivity, so why not fit these instead of the more popular Platinum and Iridium? Well very simply, you would need a more regular maintenance schedule, unlike the Platinum and Iridium spark plugs, which can be fit and forgotten about for 20,000 miles + if you use or consider using Silver or copper spark plugs, remember these will require more frequent service schedule replacements than the Platinum or Iridium, if you are looking for more performance over longevity, or you track your Mini, then you should be aware and looking if not using other alternatives to Platinum or Iridium.

Now I've got you thinking, So what's the best spark plug for my Mini? That all depends on what you do with your Mini, and of course your budget, if your Mini is your daily driver and you rely and trust your knowledgeable mate down the pub, then you may as well stop reading now, if on the other hand your Mini is your daily driver come weekend warrior, or is just your weekend warrior, and you do your maintenance yourself then read on.

So your now thinking about the possibility of a better performing spark plug, with the Mini you must run a Resistor spark plug, if you were to run a non Resistor spark plug you will have issues with the electronic system.

So lets now forget about stock/standard Platinum and Iridium spark plugs, and concentrate on PERFORMANCE, if you want the best performance then you have to look at Silver or Copper, as you can clearly see from the thermal and electrical conductivity chart, these two materials are No 1 Silver and 2nd Copper, so you've upgraded your engine/fuel system/ignition system wires and coil or coil overs and had your Mini tuned, why are you still running Platinum or Iridium spark plugs?

The noticeable difference can be quite significant, when running Silver or Copper spark plugs, Just because these tend to be aimed at and marketed as Performance/Racing spark plugs, does not mean their sole purpose is for track use, however the term, Racing spark plugs, are generally just an indicator of the colder heat ranges available from the standard stock spark plug specified for your particular Mini.

The term spark plug heat range refers to the speed with which the plug can transfer heat from the combustion chamber to the engine cylinder head, it has been found the optimum combustion chamber temperature for petrol engines is between 500 degrees C – 850 degrees C when it is within this range it is cool enough to avoid pre-ignition and plug tip overheating which can cause engine damage, while still being hot enough to burn off combustion deposits which cause fouling.

The spark plug can help maintain the optimum combustion chamber temperature, when a spark plug is referred to as a “cold plug” it is one that transfers heat rapidly from the firing tip into the engine cylinder head, which keeps the firing tip cooler. A “hot plug” has a much slower rate of heat transfer, which keeps the firing tip hotter.

An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, water/meth injection, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70 degrees C to 100 degrees C from the combustion chamber!

The heat range numbers used by spark plug manufacturers are generally the higher the number, the colder the plug.

Do not make spark plug changes at the same time as another engine modification such as different injectors/timing changes different boost loadings from your chosen forced induction, as in the event of poor results, it can lead to misleading and inaccurate conclusions, an exception would be when the alternate plugs came as part of a single precalibrated upgrade kit. When making spark plug heat range changes, it is better to err on the side of too cold a plug. The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage!

This next little bit of information may not be of much use to many of you reading this, however for those that have the time and patience, then you may want to try degree orientation, (indexing) this is lining up the ground electrode with the inlet valve/s, this usually has a window of 45 degree, working from the direct central position alignment of the ground electrode with the inlet valve/s, getting this correct can be quite difficult, firstly you will need to mark the ground electrode position onto the spark plug hex head or porcelain body with a suitable marker, then unscrew the sealing gasket from the spark plug, you then need to place a flat Copper washer of a specific thickness of your choice directly onto the spark plug shoulder, then screw the sealing gasket back onto the spark plug, once you then install and correctly torque down your spark plug you will get an indication as to the general direction of the ground electrode in relation to your inlet valve/s, you may need to do this many times using + or - to your first installed washer thickness to get the ground electrode in the correct orientation to the inlet valve/s, this operation can give a small benefit in terms of performance, but generally this gain can only normally be read on the dyno or felt at the track, and such is the small gain it may not be worth your inconvenience, time or effort to do, however that said if you are looking for every possible FREE amount of performance gain, then it may well be worth your while!

Now all of the above information is just a very quick guide to spark plugs, there is a lot more I could and can add, however I hope it will help all who read this, understand a little more about spark plug selection and fitment for the Mini. (or any internal combustion engine.)

[Gulfclubby]

A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase.

So basically, some 80% of all A-Series Engines will actually be within the same group for plugs and only if you have a seriously tuned engine, an overhead camshaft modification or a complete engine swap to a Honda or Vauxhall or whatever, you will need non-standard plugs? Wasn't that everyone else's point so far?
I'm running BP7es and was running 6es before and didn't notice any difference and that's on a seriously modified A+ with ~105 bhp.
I'm not trying to discredit your knowledge on all this, but it sure sounds like the debate is moot for the vast majority of all minis.

[Czar]

A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase.

So basically, some 80% of all A-Series Engines will actually be within the same group for plugs and only if you have a seriously tuned engine, an overhead camshaft modification or a complete engine swap to a Honda or Vauxhall or whatever, you will need non-standard plugs? Wasn't that everyone else's point so far?
I'm running BP7es and was running 6es before and didn't notice any difference and that's on a seriously modified A+ with ~105 bhp.
I'm not trying to discredit your knowledge on all this, but it sure sounds like the debate is moot for the vast majority of all minis.

Your missing the point, the OP asked if there was a better spark plug than standard, and so here we are, many posts away from when I originally said, there was, and that design and material choice would offer this.

In your case changing from heat range 6 to a 7 will not offer any butt dyno difference in feel, what it will do is prevent your original 6's from failure, due to the inability of the 6 to dissipate the extra heat into the cylinder head.

[Wil_h]

All very interesting, but I've not learned anything new, I've already indexed my plugs. In fact thinkong about it the lack of requirement to index the the Brisk plugs may just account for the apparent increase.

I also don't understand the argument about the conductivity; electrically we already know that there is a 5k Ohm resistor in the plug, so not much gain to be made. Thermally, well the exotic material (silver, copper etc) is only used for the tip and core (and surely the core of Brisk plugs is not silver otherwise at £15 each they'd be a bargain), not the whole spark plug, in the main they are constructed from steel. The heat conductivity is all to do with keeping the nose at the right temperature. This is achieved by exposing or shrouding the nose, which is ceramic, not metalic.

So all the above has done is convince me further that it'd be fifty quid down the drain.

[Czar]

All very interesting, but I've not learned anything new, I've already indexed my plugs. In fact thinkong about it the lack of requirement to index the the Brisk plugs may just account for the apparent increase.

I also don't understand the argument about the conductivity; electrically we already know that there is a 5k Ohm resistor in the plug, so not much gain to be made. Thermally, well the exotic material (silver, copper etc) is only used for the tip and core (and surely the core of Brisk plugs is not silver otherwise at £15 each they'd be a bargain), not the whole spark plug, in the main they are constructed from steel. The heat conductivity is all to do with keeping the nose at the right temperature. This is achieved by exposing or shrouding the nose, which is ceramic, not metalic.

So all the above has done is convince me further that it'd be fifty quid down the drain.

The 5K ohm ceramic resistor in a spark plug, is there to suppress RFI/EMI and does very little to the voltage passing along the core of the spark plug, now when we introduce precious metals such as Silver for the core and tip (yes BRISK silver spark plugs have a Silver core and tip!) then the electrical conductivity of Silver is better than any precious metal currently used in spark plug technology, and requires less energy from the ignition system, therefore provides a far stronger spark.

Silver is the best at firing tip heat dissipation, and therefore offers faster thermal conductivity, keeping the tip at it's designated working temperature, and allowing the spark plug to transmit heat away into the body and so into the cylinder head.

[Wil_h]

V=IR. Of course at such high voltages, the drop across the resistor is small, but even if the rest of the core is zero Ohms, the whole plug is still 5k. The ignition system doesn't know the spark plug has a silver core, it is just connected to a load, and most of that load is the spark gap. Lets say that a copper core is 10 ohms (it'll be way less than this) and silver is 10% better, so 9 ohms. the resistor is 5k ohms, so if 5k makes no differance, 1 ohm will make almost fun all differance.

All spark plugs need to operate at the correct temeperature whatever material is used, as you know, if they didn't they'd melt or carbon up. So using Silver just means that you can potentially expose less of the nose of the plug as you can dissapate heat quicker. Your argument suggests that the tip could run colder, which it can't because it wouldn't work.

As I said above, maybe indexing is the key here, NGKs are required to be indexed to operate optimally, Brisk don't, this could account for the 1 or 2% varience seeen in the tests.

[Czar]

V=IR. Of course at such high voltages, the drop across the resistor is small, but even if the rest of the core is zero Ohms, the whole plug is still 5k. The ignition system doesn't know the spark plug has a silver core, it is just connected to a load, and most of that load is the spark gap. Lets say that a copper core is 10 ohms (it'll be way less than this) and silver is 10% better, so 9 ohms. the resistor is 5k ohms, so if 5k makes no differance, 1 ohm will make almost fun all differance.

All spark plugs need to operate at the correct temeperature whatever material is used, as you know, if they didn't they'd melt or carbon up. So using Silver just means that you can potentially expose less of the nose of the plug as you can dissapate heat quicker. Your argument suggests that the tip could run colder, which it can't because it wouldn't work.

As I said above, maybe indexing is the key here, NGKs are required to be indexed to operate optimally, Brisk don't, this could account for the 1 or 2% varience seeen in the tests.

There is no argument from me, the compatibility between the ceramic and the Silver core is much more stable than any of the precious metals used for the central core electrode, even under extreme load conditions.

The benefit of using Silver for the central electrode core and tip, are quite clear, Silver can dissipate the heat faster, it maintains firing tip temperature more constant across a wider temperature range VS any other precious metal used in current spark plug technology, there is also less resistance due to Silver's heat dissipation qualities, the electrical resistance increases with temperature a fractional change in resistance which is proportional to the temperature change.

No amount of discussion is going to change the fact that Silver cored/tipped spark plugs are and do offer the best performance over any other type of spark plug, no matter what exotic precious metals are introduced.

[Wil_h]

This really will be my last post on the subject.

The problem I have with the argument about thermal conductivity is that even with the worst metal you list above still has to maintain a defined temperature range in the engine. Now with the best metal you need to do less to keep it at the right temperature than the worst metal.

But if the worst metal had a thermal conductivity that was so bad, the the plug would just get hotter and hotter and hotter, but they don't.

Some quick calculations of increase in electrical resistance owing to temperature shows that silver would have 2.5% lower resistance than copper if you compared the increase in resistance from 20 deg to 800 deg. Now the resistance of the copper in a spark plug is pretty low (lets say 1 ohm). This will increase to around 4 ohms at 800 deg, silver will be 2.5% better, 0.1 Ohms. Remember there is 5k Ohm resistor in the plug, 0.1 is prety insignificant however you look at it.

I think snake oil describes the benefits of these plugs IMO.

[Czar]

This really will be my last post on the subject.

The problem I have with the argument about thermal conductivity is that even with the worst metal you list above still has to maintain a defined temperature range in the engine. Now with the best metal you need to do less to keep it at the right temperature than the worst metal.

But if the worst metal had a thermal conductivity that was so bad, the the plug would just get hotter and hotter and hotter, but they don't.

Some quick calculations of increase in electrical resistance owing to temperature shows that silver would have 2.5% lower resistance than copper if you compared the increase in resistance from 20 deg to 800 deg. Now the resistance of the copper in a spark plug is pretty low (lets say 1 ohm). This will increase to around 4 ohms at 800 deg, silver will be 2.5% better, 0.1 Ohms. Remember there is 5k Ohm resistor in the plug, 0.1 is prety insignificant however you look at it.

I think snake oil describes the benefits of these plugs IMO.

The reason the inferior metals of heat conductivity don't continue to rise in temperature is, that the poorer the heat and electrical conductor of the precious metal used for the central electrical conductor and tip, the finer the wire gauge!

As you think it's snake oil (your opinion), then perhaps the manufacturers of Silver core/tipped spark plugs, should discontinue production, and stop supplying championship winning teams with Silver racing spark plugs!

Just me.............

[samsfern]

yep, just you.... I think ill stick my ngk bp7es's for mine.

[tangerinebean]

I think to clear matters up,

Q: is there a better spark plug?
A: Yes, using (better/expensive materials)

Q: Will it improve the performance of your mini? (noticeably)
A: No, i don't think these kind of spark plugs are suited to the application,

IMO if you were running a highly tuned Twin Turbo Supra/Skyline etc then you'd pay out the money to see what return you might get.

In the mini, i dont think it is worthwhile. Money down the pan.

[Cooperman]

I can't believe that we've taken 3 pages to tell the OP that a BP6ES will be fine for most road use!

[Gulfclubby]

I can't believe that we've taken 3 pages to tell the OP that a BP6ES will be fine for most road use!

Remember the famous quote "Arguing over the internet is like winning the special olympics: even if you win you're still a retard"

[tangerinebean]

I can't believe that we've taken 3 pages to tell the OP that a BP6ES will be fine for most road use!

Remember the famous quote "Arguing over the internet is like winning the special olympics: even if you win you're still a retard"

PMSL !!!