spark plugs

[John]

anyone seen these Brisk spark plugs? they have
a surface and air gap spark. depending on version,
2 or 3 sparks PER ignitor pulse.

I guess similar principal to Mikes plasma coil
that was mentioned a week ago...the one that
creates 10 or so ignitor pulses (but of diminishing
amplitude) instead of just one pulse.

The life expectancy of the Brisk plugs are about half
of that of a normal single spark per single ignitor pulse
plug. That makes sense.

They also give A BIG FAT WARNING. Paraphrased: "if your
engine is already quite modified, e.g. uprated cams,
custom ignition timing, etc., then application of these
spark plugs must be determined on an invividual basis"
"otherwise SERIOUS engine DAMAGE may result".

Ok, I have some plots showing how the "colder" vs. hotter plugs
affect the boarderline between good ignition and detonation.
This is just general info though.

Lets say you already have a high spec motor and are looking for
new plugs, besided the common ones we already know about.
Who can tell you which one is correct AND safe?
Some plugs from Brisk e.g., run wider gaps or protrude further
into the chamber. All of that has an effect. Im running
surface gap plug like they did in the old days, it is RECESSED
so nothing is protruding into the cylinder chamber like on
a street spark plug.

Increasing spark energy is another subject.

I think once you have custom ignition, highly tuned engine,
it is critical.

Also, Im not sold on the idea of 10 sparks per ignition pulse.
With high compression you already need lots less ignition advance...
If my ignition is already well tuned, I dont want to change the
speed of the burn. To increase efficiency, the only thing
interesting is to ensure a more complete combustion.
if you have a stock car, then changing the spark to achieve a
change in timing increases power. much like, if you cant tune
fuel curves, but found some more airflow, you can just increase
the fuel pressure. so you found an easy knob to turn to
find some power. tuning the fuel directly is perhaps too time
consuming. in tuning fuel, you see this argument all the time:
bigger injectors or higher fuel pressure etc. messing with
spark is the dual to this? now having a system that has sufficient
spark energy to ensure "ignition misses" do not happen, is good.
as long as that is not happening, why mess with the spark as opposed
to tuning ignition directly?
Thats my current view atleast. ideas?

John

[Jeff J.]

Do the Brisk plugs explain the warning? I can only guess they have the warning for a highly tuned motor that might experience detonation/pinging if the speed of burn is increased. Like you say, if your ignition tuning is timed well there might not be a benifit to a faster burning mixture from an ignition advance standpoint.

Isnt there a direct power benefit to a faster burning mixture though? I thought that it lead to a more instant and powerful force against the piston.. How is fuel octane related to rate of burn? I can see your point that if you have control over ignition timing anyway, how would there be any efficency improvments with a faster burn but I think there are probably other factors.

When talking about a more complete combustion, I think a stronger initial spark discharge and then secondary sparks would have a big improvement compared to a standard weak single spark setup. The Coils and booster box by Ignition Solutions do this. Here are charts comparing stock to the IS coils:

Stock:
http://www.ignitionsolutions.com/ima...condaryOEM.gif
IS:
http://www.ignitionsolutions.com/ima...aryBOOSTER.gif

A stronger spark and then additional sparks should lead to a more complete burn. On a highly tuned motor I think this is critical.. Multi-sparks per ignition pulse more completely burns the fuel mixture which is a considerable efficency improvement! Thats why the torque improvment is non-rpm dependent when you look at some of the dyno charts. I cant see a downside to this multi-spark idea, but I think it might be better to have this handled by a coil or piggyback box rather than the spark plug..

[EVOIIIM3]

John, do you have any pics or a web page for that setup?

It may be that the plugs are physically longer? Or it changes spark advance, or will burn to hot and cause problems.

I just ordered the ignition Solution "Plasma Booster" This piggybacks the stock coil. they do not offer a coil for our cars.

I talked to their lead Engineer, and he told me to get a coil pack off of a 90 Merc 500sel, he told me this is a powerful coil and better then just about everything else. he also knew that my car was a 4-pot! That speaks for it's self!

Now, the plugs life will go down due to having more spark over the same time, then having a hotter spark.

Simple physics states that as compression goes up, you need MORE spark to just the gap. We both spent a LOT of time and $$ building our engines, only to leave ignition stock.

I also want to use a surface gap plug, but I'm not willing to change out plugs every time I start the car. My thought was to try the X5TDC multi electrode plug, as it's a side gap.

I got 40 XR4CS plugs in the garage, I may mess with a set and try to side gap them, this is a old muscle car trick form some more HP.

Multi spark makes a LOT of since, for throttle response and more complete burn. This will also add low end torque. The faster and more complete the fuel/air burn the more HP produced!

Then it also cuts down a LOT on emissions.

The kit I got was only $165 delivered to my house, it should be here early next week. I'll post pics and do a little write up on it.

[Jake]

I've been meaning to get in on this thread but time seems to be at a premium over here lately. So I'll just keep this short.

I've wanted to learn more about surface gap plugs and now that we're talking about it, I may as well ask. I know what they look like but I don't know or understand the advantages. Could someone please explain it?

I like the cleaner design of surface gap plugs but what’s the disadvantage? Spark just not far enough into the chamber to support cold start?

What could possibly be the disadvantage of increasing spark energy? I understand plug life may be compromised but who cares about that, right? :p

Multi spark set ups, again, are there any disadvantages?

I'm not an engineer. I can't test concepts. Because of this I have to rely on a crude logic that if it can't hurt, but there may be benefits, then that's reason enough for me.

Cheers,
Jake Larsen

[EVOIIIM3]

Originally posted by Jake
I've been meaning to get in on this thread but time seems to be at a premium over here lately. So I'll just keep this short.

I've wanted to learn more about surface gap plugs and now that we're talking about it, I may as well ask. I know what they look like but I don't know or understand the advantages. Could someone please explain it?

I like the cleaner design of surface gap plugs but what’s the disadvantage? Spark just not far enough into the chamber to support cold start?

What could possibly be the disadvantage of increasing spark energy? I understand plug life may be compromised but who cares about that, right? :p

Multi spark set ups, again, are there any disadvantages?

I'm not an engineer. I can't test concepts. Because of this I have to rely on a crude logic that if it can't hurt, but there may be benefits, then that's reason enough for me.

I'll keep it brief...

Surface gap plugs make the best flame, there is NOTING in the way to distort the flame kernel. Then the whole ground becomes the electrode. This will produce a better spark, and put it in the right place. Thus giving more power and a better burn. On the M3 they are a COLD plug, so they foul, just like the XR4CS plugs.

Disadvantages are, price, and heat ranges, usually need a higher voltage to work well.

Multi spark boxes, are suppose to burn more of the A/F mixture giving more power, it really helps with throttle response and low end torque. I believe they also compound the burn to give added thrust to the piston. They also lower emissions.

Down side, need more control over spark, plugs wear a lot faster.

[Jake]

So going with a surface gap plug and multi spark ignition is a no brainer. Just do it. With extra juice going to the plug anyway, fouling won't be much of a problem. Sound good? Please shoot it full of holes. It's time to "get my learn on".... as they say. :D

Cheers,
Jake Larsen

[EVOIIIM3]

Originally posted by Jake
So going with a surface gap plug and multi spark ignition is a no brainer. Just do it. With extra juice going to the plug anyway, fouling won't be much of a problem. Sound good? Please shoot it full of holes. It's time to "get my learn on".... as they say. :D

Cheers,
Jake Larsen

Yea, that is kinda it. But the plug heat range has more to due with fouling then plug type.

[ADA///M]

I think the warning that they note might have to do with the multiple firing....they might be worried as to how the car is setup....and if this multiple firing might cause a mis fire...aka early detonation...somehow catching the incoming mixture and igniting that if there is some intake/exhaust overlap in the cam timing and the plug is still firing as new unburnt mixture comes into the chamber...

Did that make any sense? It makes sense in my head...

ADA///M

[UofOm3]

So then... we are saying that going with an upgraded coil pack and some sort of a booster is a good idea, and i understand why... i'm a bit foggy on the topic of plugs... are you saying run this upgraded setup with say a set of standard Bosch platinum plugs w/a different gap? Or is there some sort of "upgraded" spark plug other than the xr4cs that can be run without the constant fouling problems. Also, i'm not certain if i read this right or not.. but running the upgraded coil w/ the booster would decrease the likely hood of fouling the plugs?
Ted

[Jeff J.]

Ada///m, I thought about that same thing at first, but if you think about it I dont think it would ever be possible to ignite the incoming a/f charge. Even with the most long duration intake cam, the intake valve wont stay open long enough into the compression stroke for the flame to travel up into the intake. For obvious reasons this would be very bad...

I think with most of the multi-spark ignition setups (like the Ignition Solutions coils and booster boxes) the secondary sparks happen after the much larger initial primary spark. So this shouldn't make the ignition timing change. Its more the issue of rate of burn that would need a change in timing to prevent detonation/pinging.

[ADA///M]

Jeff...i agree with you also...

But i think that is there disclaimer just in case someone is running some overlap or even close to it...

There is a possiblity at least in their minds....that the exhaust valves may be closed while the sparking is still occuring...just a possibility...you never know...and they need to be cautious...

[EVOIIIM3]

Originally posted by UofOm3
So then... we are saying that going with an upgraded coil pack and some sort of a booster is a good idea, and i understand why... i'm a bit foggy on the topic of plugs... are you saying run this upgraded setup with say a set of standard Bosch platinum plugs w/a different gap? Or is there some sort of "upgraded" spark plug other than the xr4cs that can be run without the constant fouling problems. Also, i'm not certain if i read this right or not.. but running the upgraded coil w/ the booster would decrease the likely hood of fouling the plugs?
Ted

On a stock car not so much. As cylinder pressure goes up, you need more voltage to make the spark. The stock system is good for this. But once you add 11.25 pistons, things change.

Yes, it's a good idea, smoother power, more complete burn, more torque, lower emissions, better start, etc..

NEVER, NEVER, use platinum plugs on a modern BMW! They are multi electrode, you don't gap em.

I have been running the XR4 plug since I got my car! I have NEVER had any problems, even on my stock engine. It's more of a function of how you drive, then the plug. If you do all stop & go, and never warm the car up, there really bad! I you take it out for longer drives, rev it and generally take care of it, they are not a problem.

The hotter spark of the aftermarket system will not keep a plug from getting fowled, but they do provide more spark energy, this will be able to fire when a plug starts to foul, where the stock system will not work.

[TeamM3]

I'd be very sceptical, I personally can't see it happening without an actual ignition modification similar to Ignition Solutions, etc.

Without actually seeing the info you're referring to it kind of reminds me of the Splitfire plug marketing BS
may just be a lack of understanding though, hope you can post more info

[UofOm3]

mike...
I understand what you are saying and I have become more concerned about this department as i am now going to be running the 11.25 pistons on my 2.5. I am just trying to clarify, the XR4 is a different plug than the XR4CS correct? Secondly... is this coil pack that you previously refered to a Bosch part? I would assume that getting that piece through an independent bosch dealer would be MUCH cheaper than going through my MB parts counter... I remember their prices being insanely expensive when i had my 190 amg. I plan on warming the car up and actually driving it, not just stop and go and never let it warm up. Thanks for the clarification.
Ted

[John]

Well, I have to say Ive not tried the ignition solutions
"booster". From the plot, the firt peak spark, which
starts the flame front, is about the same as a normal spark plug/ignitor setup. I looked at the plots of some guys
e36 M3 with and without ign. solutions, and that was
how his plots looked. After this comes a series of sparks
that decrease in amplitude over time.

Im dont know if this will have an effect on the dwell time up
to very high rpms e.g. up to 9000 rpm. the e36 M3 certainly
doesnt rev that high. Im not sure if anyone at that company
has taken this into consideration.

I would be tempted to try it out. But, Im a little worried.
First of all, playing with ignition and spark in this manner
is a typical "entry level mod" done by people who usually dont mess with their
actual ignition and fuel maps. This is IMO the target audience
for such aftermarket stuff. For people who have changed basically
everything on their motor, I think caution is advised, and this
is also what Brisk says. If you tune the igntion properly,
mainly you just need to verify that the ignition system is adequate
for your plugs and the plugs may not be too hot. Better too cold
than hot.

I am especially skeptical, because I run 12.3:1 compression AND
have long duration cams. That means I have a lot of cylinder filling
and together with the high compression ratio, I have a much higher
than normal cylinder pressure. I cant actually get in there
and see what is going on, but you can see misses in the AFR readings
if they are frequent. Unburned gas leads to increased CO and HC
values. With my surface gap plugs, Ive not been able to detect
misses via AFR guage.

Whether multiple sparks is actually a real plus overall, Im not sure.
Perhaps there is an SAE paper on this? Brisk makes it sound that
there is an effective change in burn rate, and hence the overall
ignition advance would have to be modified on a very highly tuned
engine that is already close to the edge. But, if it really comes
down to burn rate, then there is your power advangtage -- thru
the ignition setup you have achieved an effective advance, something
that can be done directly in the motronic. How that burn rate is
achieved (with Brisk) is not clear -- they have a protruding electrode setup AND multi-spark. Why arent other manufacturers
of medium to high end cars doing somthing so simple?
I guess if the first spark misses, then a following spark
will still ignite the mixture, whereas in the normal single spark
setup, it would be a miss.

On surface gap plugs, the only advantages I know about are
that the plug is flush with the cylinder head so nothing
protrudes, they are colder (less isolator is exposed to
the heat) and thus transfer more heat to the head thereby
makeing pre-ignition less likely, the spark can go in
any direction (360 degrees). The downsides is you can
fuel foul them easily. Ive fuel fouled my plugs only 1 time
and that was because I had changed my alpha N idle to very
rich to test a signal and forgot to change it back. So when
I started the engine...it went right out and could not restart.
In all other instances, Ive not had a cold start problem.
I think as long as the idle mixture is not too rich it will be ok.
But, I do carry a set of stock plugs with me just in case.
When I first pulled them they showed they were burning very very
nicely. I do know also that most people overhere running
over 12 compression are running similar plugs with success.

More ignition energy probably is nice. Multiple sparks Im less
convinced. With an airbox setup, you will never hear high
rpm detonation. Also something to think about...
Maybe Im just too conservative?

John