Spitfire Multi-spark - anyone used one?

47 posts / 0 new
Last post
Spitfire Multi-spark - anyone used one?

Supposed to increase the number of sparks made by the plug.
Increases power, economy etc etc.
Easy starting etc.

Anyone know if it's any good?

A plug can only fire one spark for each impulse it gets from the points/dizzy/CDI etc...Would you like to buy some beachfront property in Arizona?

I remember this being fitted to a rallye prepped xtz750 featured in TBM a couple of years ago, they reckoned that they were getting much better economy but cant be any more specific than that. wasnt ever convinced enough to buy one (not even sure if you can) British chap built em IIRC

They've been on the maket for many years, yet are still seen as a gimmick. Iridium plugs caught on immediately, because they are good.That makes me think Splitfire plugs really are just a gimmick.Or is "Spitfire" something else?

ink ink wrote

They've been on the maket for many years, yet are still seen as a gimmick. Iridium plugs caught on immediately, because they are good.That makes me think Splitfire plugs really are just a gimmick.

No this is the spitfire not splitfire. Its a gizmotron on the HT lead that sparks once and then a few more times in very quick succession with the aim being to increase detonation.dont know how it works but thought I should clear this up (unless I got it wrong which is quite possible I assure you)

Why would you give the name of your new product a name nearly the same as a similar product that everyone thinks is shit? Or did spitfire plugs come before splitfire ones?

Periodicaly someone "invents" these things... an extra gap in the HT lead it amounts to, sometimes they are even in transparent tubes so you can see the sparks jumping. Why complicate it!

What's another spark gonna do - Make the fuel burn twice ? Detonation in an engine is a bad thing, so increasing it would also be bad. Worse than bad in fact. Badderer. Gve us a link so we can all see these wonderful new plugs.

Multiple spark sources or repeated sparking would surely be a good thing? I'm not saying this plug isn't gimmicky or that it works better (if it did they would easily be able to demonstrate this) but igniting the entire fuel charge in one go with one spark is not always a simple task, especially in two stroke engines. They can tend to four stroke at low to mid rpm. I would imagine that for this to be effective it would require an increased load on the charging and ignition system for it to produce any noticeable effect. We all know the effects of degraded spark plugs or incorrect plug gaps (ie increased resistance equals weaker spark equals lower fuel economy and poorer performance), getting a single powerful spark to ignite compressed fuel is a big enough job in itself, and spark plugs are relatively sophisticated consumables. This idea either makes several additional weaker sparks which would be of limited effect or by neccesity must draw additional charge, which is not available without further modification to your bike.With regards to detonation, Honda developed a 2T engine that used the effect of detonation to ensure that the entire fuel charge was ignited, thus lowering emissions dramatically. This kind of highlights the fact that all of the fuel in a cylinder per cycle is not nessecarily being ignited, even in a 4T engine a lot of it is inaccesible to the spark or flame front. Anything burning this lost fuel is by definition going to increase performance, economy and lower emissions but getting it to burn is incredibly difficult with a single spark source, hence the use of high pressure detonation (like a diesel engine) by Honda and its resulting elimination of low to medium rev misfires.

Pardon me my friend, but I am Nigerian Royalty, and I need you to send me money!If you believe what they say about that gadget, you will believe the above!

Mr Rooty Tooty wrote

Multiple spark sources or repeated sparking would surely be a good thing? I'm not saying this plug isn't gimmicky or that it works better (if it did they would easily be able to demonstrate this) but igniting the entire fuel charge in one go with one spark is not always a simple task, especially in two stroke engines. They can tend to four stroke at low to mid rpm. I would imagine that for this to be effective it would require an increased load on the charging and ignition system for it to produce any noticeable effect. We all know the effects of degraded spark plugs or incorrect plug gaps (ie increased resistance equals weaker spark equals lower fuel economy and poorer performance), getting a single powerful spark to ignite compressed fuel is a big enough job in itself, and spark plugs are relatively sophisticated consumables. This idea either makes several additional weaker sparks which would be of limited effect or by neccesity must draw additional charge, which is not available without further modification to your bike.With regards to detonation, Honda developed a 2T engine that used the effect of detonation to ensure that the entire fuel charge was ignited, thus lowering emissions dramatically. This kind of highlights the fact that all of the fuel in a cylinder per cycle is not nessecarily being ignited, even in a 4T engine a lot of it is inaccesible to the spark or flame front. Anything burning this lost fuel is by definition going to increase performance, economy and lower emissions but getting it to burn is incredibly difficult with a single spark source, hence the use of high pressure detonation (like a diesel engine) by Honda and its resulting elimination of low to medium rev misfires.

What utter bollocks, The first spark would ignite the fuel surrounding the electrode of the plug so if there was a second spark a split second later there wouldn't be any fuel there for it to ignite as the flame front would have already moved away from the plug.

If you listen carefully you can hear the engine designers weeping.... if it works and its cheep , why haven't all bikes and cars got them from new?

What I mean is that ignition relies on the propagation of a flame front to all areas of the cylinder, this does not happen in actuality. Some areas (especially the boundary layer in contact with the inside surfaces) are never ignited except in extreme cases, such as when detonation occurs.I'm saying these plugs wouldn't work but that in theory multiple ignition sources are desirable and that ignition by an abundance of hot pressurised particles acting as spontaneous ignition sources (as in detonation) is one of a few ways in which the full fuel charge is completely burnt in a two stroke engine.

A lot of people thought that Mr Fords trembler coils, as fitted to Model T, were better than single spark devices. A 'long lingering spark' was one way of describing it.A trembler coil is one similar to a door bell, in that the contact breaker made and breaked all the time. This by means of an armature and spring contacts, no rotating parts at all. The resulting sparks were fed to the distributor and thus to the cylinders. Therefore the plug was fed a short succession of sparks so if the first one did not fire the second might.From above comments not much has been considered about turbulence in a combustion chamber. Turbulence can come about from squish bands, offset inlet tracts and down draft tracks. Therefore there may be a combustible mixture near the plug after the intial start of combustion.I would certainly like a ignition system that gave more than one spark, mainly for a more certain start - with uncertain mixture strength, low crank speed, low volatile fuel, etc. all of which makes starting engines difficult.The sparking plugs with multi points is another ball game alltogether. As a passing thought I've used, succesfully, a plug with six fine wire centre electrodes and one round earth electrode.

IIRC it was suggested this device was most effective in large cylinder bikes like the R30 and aforementioned XTZ750 which I guess are fairly inneffecient combusters. Few people here with way more knowledge than me here about whats happening to my fuel air at combustion so will leave it for them to dispel or explain why this may beAnd just to reiterate it is not a spark plug!

Rapdon wrote

A lot of people thought that Mr Fords trembler coils, as fitted to Model T, were better than single spark devices. A 'long lingering spark' was one way of describing it.

Probably worked great when engines revved to 1500rpm i doubt they would last long at 15,000 or even 18,000rpm. Mulitple spark technology has been around for a while MSD ignitions for example but even they drop to single sparks at higher rpms. The same igniton source sparking away is pretty pointless in a modern engine, multiple ignition points in a chamber is a good thing though

maddog wrote

Probably worked great when engines revved to 1500rpm i doubt they would last long at 15,000 or even 18,000rpm.

I'd love to see a 600cc single cylinder bike revving anywhere near that!. Im assuming R30 in his handle implies hes on a CCM with either suzook or rotax lump, neither are big hitters in the rev stakes so does the above imply there's some benefit to such a device?

It would be interesting to know if the coil trying to produce more sparks in the limited time available actually ends up with a lesser initial spark... just a thought..

maddog wrote

multiple ignition points in a chamber is a good thing though

You might know more about this than I do but I remember reading about GS thou racers that had a twin plug setup because they also had two valves per cylinder, now that most bikes have four or five valves its simpler to have a centrally located plug that ignites the fuel more evenly.Can't remember who's bike it was though, does Mick Grant and XR51 mebbe 69 sound right?Fairly sure I read it in Performance Bikes in about 89-90.Does anyone use twin plug setups for old Z motors?

To ignite unburnt fuel outside of the range of the coil release ... possibly ??

Had a look at their website, doesn't really tell you much. TBH it looks like they sell "Gadgets", but I'm not totaly cynical, and would like to know if anyone has used any of ther products. for exapmle, the Formulapower Fuelblaster sparkpugs sound great, but do they actually do anything ? Does the Deisel Booster really "inhibit bacterial growth", and will it honestly work on my 2 stroke engine (they said it) ? And finally, do they really think anyone's going to beleive that the Fuel Cat will "eliminate most carburation flat spots and...pinking". Fuck this stuff must be magic. Going on what they say, if I fitted all of their products in the right order my bike would do twice the MPG, go faster without producing any poisonous gases whatsoever, and can be run on chip fat.

I've bought a set of these, and I'm going to try them on my Yamaha TRX 850. Assuming that they give performance no worse than stock, I will then try them on my light aircraft with a Norton-based MidWest twin-rotor engine.

It seems to me that the Multispark is a sort of capacitor that is able to split the spark voltage into five different bursts. Of course, each spark may well have only one-fifth the power of a single spark; but if there is enough energy for five sparks, what is the problem? The multi-spark should be particularly appropriate on a rotary engine because: (i) it is slow revving (at cruise the rotors spin @ 2,000 rpm); and (ii) the combustion shape moves past the plug, so that each spark should occur at a different phase of rotation.

I will report back with my results; but I do know that some microlight flyers already use this device.

(Someone has posted: "if it works and its cheap , why haven't all bikes and cars got them?". Well, it is a fact that twin plugs improve combustion, but very few cars or bikes use twin sparks. Yet ALL aircraft piston engines use twin sparks per cylinder. A pre-flight check is to switch off one and then the other plug circuit; and each time one will notice a small drop in revs because of the poorer efficiency. Twin sparks are easy to arrange on a 2-valve, 3-valve and 5-valve head. On a 4-valve head the second plug cannot be ideally placed, but the 4-valve layout gives efficient combustion even with a single plug.)

There's a massive difference between a combustion chamber that incorporates two separate spark plugs and one with a single spark plug that claims to 'split' the spark, which it won't.

"There's a massive difference between a combustion chamber that incorporates two separate spark plugs and one with a single spark plug that claims to 'split' the spark, which it won't."

True; but I cited the example of twin-plug head purely to show that industry does not always adopt proven solutions, even when they are simple, cheap and effective. (Another case of ignored technology is the electric cooling fan on liquid-cooled engines. Now these are a universal feature; but for years one had to buy a Kenlowe unit to enable one's car to run at an optimum temperature).

Back to the Multispark: I have seen it demonstrated, and it does work, at least on their test jig! Of course, the way a spark-plug fires in clean atmosphere may be be different to how it behaves in a combustion chamber filled with a highly-compressed fuel-air mix; but I am prepared to give it a go, because in theory at least, it should benefit a wankel engine, where the combustion chamber shape is far from ideal.

x

arriviste wrote (see)

 (Someone has posted: "if it works and its cheap , why haven't all bikes and cars got them?". Well, it is a fact that twin plugs improve combustion, but very few cars or bikes use twin sparks. Yet ALL aircraft piston engines use twin sparks per cylinder. A pre-flight check is to switch off one and then the other plug circuit; and each time one will notice a small drop in revs because of the poorer efficiency.

Aircraft has two magnetos/sets of plugs simply as a safety measure (double redundancy), if you get a big drop when you switch on or the other off then there is a problem.

I fitted a Multisprk unit to each of the plug leads on my Yamaha TRX850, and the simple answer is: They don't work! Instead of running smoothly, the engine popped and banged and misfired.

The supplier has agreed to give a full refund (though I doubt I will get postage repaid); and he rather peevishly said that the failure was probably because I had "fitted them wrongly"!

Although I am not entirely surprised that they are useless, I am disappointed, because had they worked they might have been beneficial on the rotary engine, given that (unlike a piston engine) the combustion chamber sweeps past the plug; so five sparks should have aided combustion.

sounds like a good idea

arriviste wrote (see)

I am disappointed, because had they worked they might have been beneficial on the rotary engine, given that (unlike a piston engine) the combustion chamber sweeps past the plug; so five sparks should have aided combustion.

 I think your theory is flawed.  Why will it make any difference? For a succession of sparks or a prolonged spark to make any difference implies that either the first spark didn't work (in which there is a bigger problem than something that can be fixed with a later spark), or you expect to be able to ignite any unburnt fuel with a later spark.  There may be unburned fuel still in the chamber but suggesting that you can ignite it when it failed to burn in the first explosion is rather over simplifying the problem. 

"I think your theory is flawed..."

Your scepticism may be appropriate for piston engines, but NOT for vvankels. Rotary engineers have struggled for years to attain complete combustion. Difficulties include the odd shape of the combustion chamber which is not ideal for a flame front; and the large surface area of the rotor face and side walls which reduces volumetric efficiency. It is known that having multiple plugs is beneficial, whether they are side-by-side or in-line down the chamber. A rotary engineer supported my experiment; so it's a shame that the Multispark doesn't seem to work in practice.

I'm not questioning the validity of multiple spark sources, but I do doubt that it will be possible to ignite unburned fuel with a second spark even if it is a rotary engine.  I would expect that the cause of the fuel being unburned is likely not due to a lack of an ignition source, seeing as there would have been a pretty decent one.  I appreciate that this is not a simple problem but if the multi-spark doesn't work in practice that might suggest something.

When you ignite the combustible mixture the flame front spreads out from that point. Petrol combustion is a deflagration, not a detonation, so the flame front takes quite a long time to spread - hence why more power can be attained by using two spark plugs on larger combustion chambers. If the flame front doesn't reach some parts of the mixture whilst conditions are still right for combustion, then those parts aren't ignited. In an ordinary piston engine the only places this tends to happen is near the walls -wall quenching removes too much heat to sustain combustion so the last bit of mixture is left unburnt.In a wankel engine with the combustion chamber moving past a a static wall, the flame front is moved away from the spark plug by the sweeping action of the rotor. This effect can actually move the flame front forwards from some areas faster than it can spread backwards to ignite them. This is why you can get a lot more unburnt mixture.Providing a second spark could potentially provide another initiation point to ignite this unburnt mixture. By this time the combustion chamber around the spark plug would be quite a flat shape and not very good for full combustion, but it could still ignite previously unburnt mixture.

I entirely agree with tappy's remarks.

For the record, I fitted the Multispark to my TRX NOT to get an improvement because (especially with iridium plugs) the standard TRX ignition is fine. Rather, I wanted to see if the Multispark would work on a road vehicle before I tried it on an aircraft. However, even though the Multispark devices failed to work on the bike, I may still try them on ground runs on the aircraft, although my expectations are low.

A problem with the Multispark is a certain lack of credibilty. The sales brochures make claims for it, but don't say what it is. An amplifier? Capacitor? The brochure says "Many, many car and motorcycle clubs have used with success our unit..." but there is only a single testimonial. The RRP is said to be gbp40, the ebay price varies between 12 and 25, butI paid 40 for six! To his credit, the seller has good eBay feedback from people who have bought the unit, which suggests that it has worked for them!

If the Multispark were upgraded to be a reliable, credible & sophisticated device, it might still be the answer on a wankel. Or else it might be possible for the engine's ECU to be programmed to put out multisparks. I'm not giving up on this project just yet!

(If you are interested, the aircraft is G-ORIX, an ARV Super2 with a MidWest twin-rotor wankel. See: http://www.caa.co.uk/application.aspx?catid=60&pagetype=65&appid=1)

Good luck with the project.  I understand exactly what Tappy is saying, but I still think that it's an oversimplification of the problem, and it's quite hard to believe that the solution lies in a cheap product the claims for which are questionable, but if they prove to work then fine.If they are cagey about what exactly the device is, then it might be interesting to ask the supplier/manufacturer for some information showing the voltage vs time trace of a before and after system. If it is at all credible then they must have tested it.  Alternatively you could open one up.  

I'd agree - to burn any unburnt fuel you'd need several strong sparks, not one decent spark divided up into several smaller bursts (if that's actually what it does). Something like the igniters used on jet engines may be - more or less a constant stream of spark.

Well if it's simply a device in the existing line, which the Multispark items I've seen for sale are, then it can only modify the existing spark.  What I mean is it cannot add any power. 

Although I am not an engineer (I am a lecturer in maritime law!), I work within the Engineering Department of a university; and I am hoping to get some bench testing done of this device. This may include dismantling one completely. I suspect it is a very simple item. I will report back.

<!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } --> Saab have used multi spark for more than 10 years. If you see a SAAB engine with the Red top or newer Black top ignition module they all use this system. When you switch off the engine you can hear the automated spark plug cleaner burst a stream of sparks for 5 seconds to clean the plug ready for the next time you start the engine. I believe (if I remember right) the computer "reads" the ignition of the fuel via the resistance of the spark and adjusts the spark to ensure complete combustion. This is why SAAB engines emit less pollution out of their exhausts then there is in the air being draw into the engine (in a City like London) TRUE! Perhaps an interested electrical engineer could adapt a SAAB module or cut one down to run on your rotary engine?Also could the coil on your TRX is geting a bit weak and was simply unable to provide enough power to provide the muliple spark with enough energy to let your engine run properly?

I had difficulty starting my 1965 Rolls Royce Silver cloud III. The problem being they don't sell the fuel that the engine was designed for (5 Star leaded). One day after cranking for some time, the was a loud explosion and I had just blow away the last silencer, an expensive job on a RR. I purchased the 'Spitfire Multispark' off e-bay, I felt for the price it had to worth a try, certainly cheaper than a new exhaust. Well, it's fantastic!!! i cannot believe the difference. The old car fires up now after about three turns, and that's in the dead of winter. I guess the multispark will never fix your engine's mechanical problems, as no doubt some might expect it to, but in my case it certainly made up for the lack of the correct fuel grade.

I think youll find that octane rating has nothing to do with poor starting, even in a four year old thread.And Saabs clever coil system has nothing to do with multispark stuf either.

I think you will find that they do in both cases..When 4 star and 5 star leaded petrol went out of use we had to get our cars re-timed to run on the lower grade fuel. In some cases having the cylinder heads retro fitted with hard valve seats to stop regression as a result of the missing Lead in the Fuel. The Saab system allows the use of fuel with an octane rating of 90 to 100 + by automatically adjusting the timing to suit.. (93 min recomended)The problem with the Roller was almost certianly as a result of the car not being retimed for the lower Octane rating fuel.I remember a chap with a highly tuned Norton Dominator trying to get it started after filling it with 4 star instead of 5 star.. it just did not want to know.It was however good fun to watch him getting thrown over the handle bars as the bike kicked back (he was only about 5'2" tall and had to kick start it on the center stand.)I have run A Saab Turbo on 87ish Octane once in an ex communist country just to see how it ran.. (perfectly if a little lower on top power levels)  The Saab system dose not give multiple sparks as such in normal use but dose extend the length and power of the spark as required to get the best "burn" in the cylinder.

I recall, many years ago, witnessing a device manufactured by a Polish gentleman and sold by him at a car show at Stanford Hall in Leicestershire. This was called 'CT Spark' (standing for Constant Teeming Spark). The device produced a spark shower for the entire time the points were open. This was not apparently multiple individual sparks but a constant shower that buzzed.The demo jig was set up in such a manner that the contact set could be left stationary in the open position with the spark shower occurring the whole time. It was fascinating to watch. The gent also fitted his kit, very quickly I might add, to a prospective customers car which the owner then took for a short test drive. On his return, he reported much smoother running, better accelleration and smoother pick-up from low revs. This was back in the '70s and, needless to say, I have been unable to find any information whatsoever on the world wide interweb!Brooky.

Hello there, I purchased a couple of mono at Stanford show Hall in Leicestershire, last April, with the aim to fit them on my Triumph Daytona 500cc, twin cylinder of 1969. Though I doubt it 'll work, I paid 10 pound each: worth to try.I went yesterday for a tour, the result was just astonishing: smoother run in law speed, more power on the highway.I'am definetly going to purchase more for my other oldtimers.Yes, it did work!Arsim

I just found this forum as a result of a search on Google, to see what others have said. Well, I bought one today - fitted it on a '73 Karmann Ghia with 1600 type 1 engine - and the drive back home (1.5 hours on the motorway) was a joy. I felt I could go 10mph faster with comfort. I overtook multiple cars in the fast lane, something I never do. I'm going to buy another one for my camper van, without a doubt.

http://dtec.net.au/Multi

http://dtec.net.au/Multi%20Spark%20Ignition.htm
This could help explain multi spark usage

Log in or register to post comments