Mike Stewart Posted May 28, 2005 Share Posted May 28, 2005 I was working on the Ghezzi Brian and had the body work removed and I found a module under the tail section. A little research and what I thought was a capacitive dicharge unit turns out to be a voltage amplifier that takes 12 volts going to the ignition coils and converts it up to 15 amps and 20 volts. You can open the spark plug gap from .028" to .056". All I can say is this bike has the best burning plug I have seen on a big block Guzzi. Anyone else have any experence with one? Mike Link to comment Share on other sites More sharing options...
callison Posted May 28, 2005 Share Posted May 28, 2005 No experience with one. They were offered by Evoluzione for a while, I don't think they do anymore. As far as running them on a standard Guzzi (the GB may be wired differently), I think I would modify the wiring so that the voltage amplifier was not running to the injectors and the fuel pump. Link to comment Share on other sites More sharing options...
Skeeve Posted May 28, 2005 Share Posted May 28, 2005 I was working on the Ghezzi Brian and had the body work removed and I found a module under the tail section. A little research and what I thought was a capacitive dicharge unit turns out to be a voltage amplifier that takes 12 volts going to the ignition coils and converts it up to 15 amps and 20 volts. You can open the spark plug gap from .028" to .056". Anyone else have any experence with one? Mike 52975[/snapback] None whatsoever! But something which has crossed my mind lately after seeing the new 1100 Breva come out w/ dual plug heads and reading the thread on having Mike Rich do the deed to older heads, it strikes me that it would be cheaper and more cost-effective to get an MSD unit and wire it up. Since multiple-discharges from one plug would have much of the benefits of the dual-plug setup [o.k., less the benefit of being able to back off the advance] at a substantial savings over dual-plugging, the idea appeals to me greatly, esp. if there's a noticeable improvement in mileage [ie, the MSD box pays for itself over time.] or power [huuh, huuh, huuh! More! Power! ] The drawback being, that I'm the enemy of choice for almost any kind of electronic device [they all hate me, & find new & unusual methods of failure around me. WTF?!? - am I carrying around my own magnetic pinch? At any rate, one o' these days, I'm going to have to give it a try, unless I come across a negative report from someone else who already did. So far, nothing, but I'll keep my ear to the ground [eyes on the CRT... it's a wired age, after all! ] Link to comment Share on other sites More sharing options...
callison Posted May 29, 2005 Share Posted May 29, 2005 But something which has crossed my mind lately after seeing the new 1100 Breva come out w/ dual plug heads and reading the thread on having Mike Rich do the deed to older heads, it strikes me that it would be cheaper and more cost-effective to get an MSD unit and wire it up. Since multiple-discharges from one plug would have much of the benefits of the dual-plug setup [o.k., less the benefit of being able to back off the advance] at a substantial savings over dual-plugging, the idea appeals to me greatly, esp. if there's a noticeable improvement in mileage [ie, the MSD box pays for itself over time.] or power [huuh, huuh, huuh! More! Power! ] Some of the MSD's are quite power hungry and the somewhat puny MG system may not be able to keep up with the electrical load. You'd just have to do your specifications appropriately. However, the advantage to the dual plug stuff is that the Guzzi combustion chamber (as I understand it) is not a very ideal one and it's difficult to get the flame front cleanly across the entire volume. That's where the dual plugging excels. Just doing a better job of lighting off the mixture in one spot will probably not give as good of results as lighting off the mixture from two locations. I suppose the best analogy would be burning down a forest. It'll burn down faster if each end of the forest is set on fire at the same time vs just one end. MSD's probably work best in combustion chambers where the spark plug is central to the ignition volume like on the 4 valve engines. And again, since I am by no means well acquainted with this stuff, I could be completely wrong. Link to comment Share on other sites More sharing options...
Guest Frankie100Chili Posted May 29, 2005 Share Posted May 29, 2005 what do you think of these? or, would use some "supercoils"? Link to comment Share on other sites More sharing options...
luhbo Posted May 29, 2005 Share Posted May 29, 2005 I would not recommend the use of such spark wonder generators! They are not worth the money and time you spend for it. Maybe there was some reason for them with the old contact ignitions, but also only in some cases. You cannot compare such stuff with dual ignition heads at all . Two valve engines all have disadvantages related to ignition advance, especially those with high compression ratios and big valves as Guzzi has. The resulting combustion chamber is everything else but compact. That's pre-war technology, over here this means from 1930! Dual ignition is the only way to make this anachronistic system a bit more efficient and up-to-date. If you don't go this way the standard ignition gives enough igniting energy. Just look at the housings and names of all this wonder stuff! It's just 'Pimp My Bike', bling-bling for tech-freaks. Hubert Link to comment Share on other sites More sharing options...
luhbo Posted May 29, 2005 Share Posted May 29, 2005 Some of the MSD's are quite power hungry and the somewhat puny MG system may not be able to keep up with the electrical load. You'd just have to do your specifications appropriately. However, the advantage to the dual plug stuff is that the Guzzi combustion chamber (as I understand it) is not a very ideal one and it's difficult to get the flame front cleanly across the entire volume. That's where the dual plugging excels. Just doing a better job of lighting off the mixture in one spot will probably not give as good of results as lighting off the mixture from two locations. I suppose the best analogy would be burning down a forest. It'll burn down faster if each end of the forest is set on fire at the same time vs just one end. MSD's probably work best in combustion chambers where the spark plug is central to the ignition volume like on the 4 valve engines. And again, since I am by no means well acquainted with this stuff, I could be completely wrong. 53003[/snapback] Sorry, I didn't read Carls posting. He already had said everything! Hubert Link to comment Share on other sites More sharing options...
Skeeve Posted May 29, 2005 Share Posted May 29, 2005 ... the advantage to the dual plug stuff is that the Guzzi combustion chamber (as I understand it) is not a very ideal one and it's difficult to get the flame front cleanly across the entire volume. That's where the dual plugging excels. Just doing a better job of lighting off the mixture in one spot will probably not give as good of results as lighting off the mixture from two locations. I suppose the best analogy would be burning down a forest. It'll burn down faster if each end of the forest is set on fire at the same time vs just one end. MSD's probably work best in combustion chambers where the spark plug is central to the ignition volume like on the 4 valve engines. And again, since I am by no means well acquainted with this stuff, I could be completely wrong. 53003[/snapback] No argument that an MSD wouldn't be as efficient as dual-plugging, if we had the ability to adjust the spark-advance appropriately. To use your analogy, since we want the forest to complete burning when the piston is exactly at TDC+1deg of rotation, dual-plug heads need 1/2 the advance of single-plugged heads. Since we don't [readily] have that level of tuning control to hand*1*, what does dual-plugging the standard V11 engine give us? Better fuel economy, greater resistance to pinging [ie, the ability to use cheaper fuel w/ higher energy content, which brings us back around to economy], & smoother running. What would we expect an MSD [multiple spark discharge] unit to provide in a single plug head? Since the purpose of the device is to provide multiple ignition events during the combustion process, it's expected behaviour would be similar to that derived from the tuning-limited dual-plugging scenario as I decribed above: better combustion efficiency, improved resistance to pinging & smoother running. Why is this? Since virtually any high performance engine design subsequent to 1928 sought to take advantage of Ricardo's theories of the combustion process, increased swirl of the cylinder charge promotes smoother combustion. Even a V11 engine has substantial swirl of the burning cylinder contents during the power cycle, and an MSD serves to ignite different parts of that swirling charge, which may not have already been ignited, as they move past the end of the sparkplug. Since the V11 uses such a large amount of advance in comparison to other engines of the present time, it would stand to experience even greater benefit from an MSD than most other applications in which it is seen in current use. This would be even more pertinent when running FBF or Mike Rich high compression pistons, due to their greater squish (& hence, increased swirl imparted to the compressed charge...) In short, (& returning to your previous analogy): Since the particular forest we Guzzi firebugs are trying to get lit off is haunted and the trees have legs and are all running about, standing in our one spot on the forest's edge and lighting several trees as they run by is not as effective as lighting both sides of the forest at once, but should prove measurably more effective than just lighting one tree as we presently do... [And as Luhbo pointed out, the question isn't one of using our present can of gasoline and a match to light one tree vs. using a flamethrower to light one tree... ] Ride on! *1* - Yet! Goooo TODD! Get Dynajet to offer the spark-advance tuning to the PC-III unit! Link to comment Share on other sites More sharing options...
BrianG Posted May 30, 2005 Share Posted May 30, 2005 No argument that an MSD wouldn't be as efficient as dual-plugging, if we had the ability to adjust the spark-advance appropriately. To use your analogy, since we want the forest to complete burning when the piston is exactly at TDC+1deg of rotation, dual-plug heads need 1/2 the advance of single-plugged heads. Sounds to me like the multi-spark units are more like throwing 10 matches into the same pile of tinder. Link to comment Share on other sites More sharing options...
al_roethlisberger Posted May 30, 2005 Share Posted May 30, 2005 Keeping in mind all the various electrical "gremlins" we've run into at various times with the Guzzi system, I'd personally be a bit concerned about splicing "any ole ignition amplifier" or "super coils" into the V11 harness But if you are really interested in checking out an ignition amplifier(although not necessarily MSD), as previously mentioned, Ken Zeller at Evoluzione had a specific ignition amplifier made specially to install into the Guzzi harness, etc... but it was pricey. Even though Evoluzione(evoluzione.net) doesn't sell Guzzi accessories anymore, you might give Ken a call and see if he's still got some lying around, or can get one ordered for you. He also may have some thoughts on how well they worked in the cases his shop installed the system. al Link to comment Share on other sites More sharing options...
callison Posted May 30, 2005 Share Posted May 30, 2005 Keeping in mind all the various electrical "gremlins" we've run into at various times with the Guzzi system, I'd personally be a bit concerned about splicing "any ole ignition amplifier" or "super coils" into the V11 harness But if you are really interested in checking out an ignition amplifier(although not necessarily MSD), as previously mentioned, Ken Zeller at Evoluzione had a specific ignition amplifier made specially to install into the Guzzi harness, etc... but it was pricey. Even though Evoluzione(evoluzione.net) doesn't sell Guzzi accessories anymore, you might give Ken a call and see if he's still got some lying around, or can get one ordered for you. He also may have some thoughts on how well they worked in the cases his shop installed the system. al 53067[/snapback] The Evoluzione thingy (same as Mike's GB module) is a DC-DC converter. It took the battery voltage and boosted it to something like 17V or so (very cloudy recollection). As an input to the entire ECU system, this probably wouldn't be good (for the ECU especially) and it probably wasn't all that kind to the injectors and maybe even the fuel pump. For the coils, it probably didn't really do any harm. Depends upon where and how it was wired into the system. I'd say, coils only - ok, anything else - rethink just what it is you're trying to accomplish. Even with coils, there may be a problem. If you take the transformer ratio of a coils input to output, it should be somewhere in the neighborhood of 1666:1 if you're getting 20 kilovolts from a 12 volt saturation voltage. A change to a 17 volt saturation voltage is going to yield an appreciable 28 kilovolts - but the coil insulation may not be capable of handling a voltage that's 8 kilovolts outside of its nominal specification. It may take a while to break down too, rather than doing it right away (such is the nature of things high voltage - take it from me, I used to be an electronics tech on an 18 megavolt linear accelerator). If it broke the coil right away, you'd just be sitting there fuming about having to pay a ridiculous price for another coil. If it broke in the middle of nowhere, you'd do just a little bit more than fume... Link to comment Share on other sites More sharing options...
luhbo Posted May 31, 2005 Share Posted May 31, 2005 Just to keep things burning Aren't you talking about two different things, some about one single monster spark and some about three or even more tiny sparks shortly one after the other? This multi spark solution sounds logical and well working, but I know these multi sparkers only as capacitor based units. The big disadvantage here is that they create only very very short lasting sparks, not suited for big 4-stroke engines, the more as these engines nowadays tend to run a bit on the lean side. Hubert Link to comment Share on other sites More sharing options...
al_roethlisberger Posted May 31, 2005 Share Posted May 31, 2005 Yes, we are talking about two different things... MSD versus an "amplifier". The Evoluzione unit, and I assume the one Mike found on his Ghezzi, are an "amplifier" not an MSD. ...and yes, your description of the issues with MSD are what I too have heard mentioned before. But there are lots of opinions/camps on this topic to be sure. al Link to comment Share on other sites More sharing options...
Mike Stewart Posted June 1, 2005 Author Share Posted June 1, 2005 The only advantage of the Volt Amplifier is that you can run a larger gap of the spark plug. I doubled the 28 thou gap to 56 thou and the bike runs great. Just did a two day track day and the bike ran flawless. Well, it did have the normal ping at 3 to 4K, but an adjustment with the powercommander helped greatly! Mike Link to comment Share on other sites More sharing options...
jrt Posted June 1, 2005 Share Posted June 1, 2005 Well, normally electronics are "supposed" to spec'ed at about 2X the operating point.........but this is a Guzzi, I suppose. I'm only referring to the spark plug wires here- I totally agree with Carl that the rest of the electronic equipment should be isolated from a 17 V operating point. Couple o' questions- for the capacitive discharge and swirling- wouldn't the combustion front dampen the swirling because it is an isotropic expansion? For the MSD unit or for dual plug heads- wouldn't you need to retard the timing in order to take advantage of this? Link to comment Share on other sites More sharing options...
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