Bosch super 4 plugs

Oooops!

30csl said:
Last time i removed them they were more white in colour.
They are Bosch W78 - what is that like for heat range etc?
Click to expand...

A big OOOPs.

I dare say that some of us, including this poster, may have misread your post and incorrectly presumed you were asking about a different spark plug: Bosch's 4 electrode platinum series (as pictured by Sr. Jacobs). Aside from the platinum center electrode, you may note the plug is a different design akin to an air gap. It is self cleaning and will fire under the most adverse conditions - according to the sales literature. It is also several times more expensive than the stock plugs.

I do not know anyone running the exact same plug you have pictured although I suspect that many do. As it appears to be the same heat range as the W7DC/W8DC it looks like your plugs are suited to your engine. I do not think there is much difference between your plug and the standard single side electrode. I believe I have used a similar plug with three electrodes BP6ET W7TC? but never found much advantage other than gapping becomes tedious. (I think the makers discourage regapping these plugs!)

The one benefit to these plugs is that they displace more volume so they improve compression (very slightly). The extra electrodes are more typically seen in aviation applications. I do not know why but can postulate that the extra electrodes offer more area for the spark to jump if there is unforeseen fouling. (Not that important in a terrestrial based vehicle without wings.)

It seems that your plugs might be a tad too cold, but reading the plugs can be misleading since you could have been idling too long before you shut the engine down. Ideally, you would make a full power run - cut the engine, coast to a stop, and pull the plugs. That is hardly feasible for most of us and besides, it doesn't account for the major use of the plug: idle and part throttle. Your plugs have to function under all of those conditions.
 
Oooops!

30csl said:
Last time i removed them they were more white in colour.
They are Bosch W78 - what is that like for heat range etc?
Click to expand...

A big OOOPs.

I dare say that some of us, including this poster, may have misread your post and incorrectly presumed you were asking about a different spark plug: Bosch's 4 electrode platinum series (as pictured by Sr. Jacobs). Aside from the platinum center electrode, you may note the plug is a different design akin to an air gap. It is self cleaning and will fire under the most adverse conditions - according to the sales literature. It is also several times more expensive than the stock plugs.

I do not know anyone running the exact same plug you have pictured although I suspect that many do. As it appears to be the same heat range as the W7DC/W8DC it looks like your plugs are suited to your engine. I do not think there is much difference between your plug and the standard single side electrode. I believe I have used a similar plug with three electrodes BP6ET W7TC? but never found much advantage other than gapping becomes tedious. (I think the makers discourage regapping these plugs!)

The one benefit to these plugs is that they displace more volume so they improve compression (very slightly). The extra electrodes are more typically seen in aviation applications. I do not know why but can postulate that the extra electrodes offer more area for the spark to jump if there is unforeseen fouling. (Not that important in a terrestrial based vehicle without wings.)

It seems that your plugs might be a tad too cold, but reading the plugs can be misleading since you could have been idling too long before you shut the engine down. Ideally, you would make a full power run - cut the engine, coast to a stop, and pull the plugs. That is hardly feasible for most of us and besides, it doesn't account for the major use of the plug: idle and part throttle. Your plugs have to function under all of those conditions.
 
Hi guys,

yes Nash - the aero plugs have two electrodes and are uber expensive so get cleaned and gapped a lot! They are mainly made by champion.

I remember reading somewhere that the spark only jumps across one gap so the other three are then redundant??
 
Hi guys,

yes Nash - the aero plugs have two electrodes and are uber expensive so get cleaned and gapped a lot! They are mainly made by champion.

I remember reading somewhere that the spark only jumps across one gap so the other three are then redundant??
 
ON multi-electrode plugs the spark will only jump across one gap on any particular firing. However, they will tend to jump around between electrodes due to temperature, vortexes, and such. There are plenty of marketing hype videos showing this on youtube.

Anyone tried Halo plugs? They may have even more displacement and increase your compression ratio from 8.995 to 8.995001!!
 
ON multi-electrode plugs the spark will only jump across one gap on any particular firing. However, they will tend to jump around between electrodes due to temperature, vortexes, and such. There are plenty of marketing hype videos showing this on youtube.

Anyone tried Halo plugs? They may have even more displacement and increase your compression ratio from 8.995 to 8.995001!!
 
new pics of old plugs

30csl said:
Last time i removed them they were more white in colour.
They are Bosch W78 - what is that like for heat range etc?
Click to expand...

Here's more for you guys to chew on. These are pics of old plugs. Guesstimate of 4700 mi on the W8DC and 5700 on the 4479 +4 platinum. These were used for test purposes on another vehicle for a short while and on an csi M30 - but spent most of their time on csi. Currently using W7DC's.




 
This is going slightly off topic from the original question however:-
As allready posted by jhjacobs a spark will only jump to one electrode at any one time. There are a number of advantages to having 2,3 or 4 electrodes the first being longevity. Every time a spark jumps it removes a tiny ammount of metal off both electrodes which is why old spark plugs have rounded off electrodes. So if we have 4 electrodes the plug will in theory last 4 times as long.
The next advantage is that as the plug now has more than one earth electrode they can't all be placed over the centre electrode so they are placed at the side, this (in theory at least) improves combustion because the flame isn't sheilded (covered by the earth electrode) from the rest of the combustion chamber. Due to the fact that the slowest part of the combustion process is from the point of ignition to the flame becoming a ball approximatly 0.1 inch in diameter (after this point the flame spreads rapidly) in reality the benefits are miniscule you could probably reduce the required ignition advance by 0.5 degree (tongue in cheek) and not feel any loss in power!
Platinum plugs (the ones with the tiny centre electrode) work on the same theory except platinum work by having a larger air gap therefore the spark is bigger thus igniting more fuel at the point of ignition and because of that the overall process is slighly faster. Another advantage of platinum is that it is highly resistant to errosion so the centre electrode can be made very thin, sparks like to jump from and to sharp points. To a spark the centre electrode on these plugs always appears to be a sharp point as its so thin to start off with.

From my point of view the benefits are so small it is not worth the added expense. As enthusiasts we all change our plugs,oil + filters etc way before they have given their best so the benefit of longevity is never reached. As for faster combustion like I said the improvement is tiny and most people never retard their timing to suit any way so in actual fact they just advanced their timing making peak pressure occur to early so once again any benefit is never reached.
 
This is going slightly off topic from the original question however:-
As allready posted by jhjacobs a spark will only jump to one electrode at any one time. There are a number of advantages to having 2,3 or 4 electrodes the first being longevity. Every time a spark jumps it removes a tiny ammount of metal off both electrodes which is why old spark plugs have rounded off electrodes. So if we have 4 electrodes the plug will in theory last 4 times as long.
The next advantage is that as the plug now has more than one earth electrode they can't all be placed over the centre electrode so they are placed at the side, this (in theory at least) improves combustion because the flame isn't sheilded (covered by the earth electrode) from the rest of the combustion chamber. Due to the fact that the slowest part of the combustion process is from the point of ignition to the flame becoming a ball approximatly 0.1 inch in diameter (after this point the flame spreads rapidly) in reality the benefits are miniscule you could probably reduce the required ignition advance by 0.5 degree (tongue in cheek) and not feel any loss in power!
Platinum plugs (the ones with the tiny centre electrode) work on the same theory except platinum work by having a larger air gap therefore the spark is bigger thus igniting more fuel at the point of ignition and because of that the overall process is slighly faster. Another advantage of platinum is that it is highly resistant to errosion so the centre electrode can be made very thin, sparks like to jump from and to sharp points. To a spark the centre electrode on these plugs always appears to be a sharp point as its so thin to start off with.

From my point of view the benefits are so small it is not worth the added expense. As enthusiasts we all change our plugs,oil + filters etc way before they have given their best so the benefit of longevity is never reached. As for faster combustion like I said the improvement is tiny and most people never retard their timing to suit any way so in actual fact they just advanced their timing making peak pressure occur to early so once again any benefit is never reached.
 
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