Anyone dual-plug a V11?

[Cliff]

Pretty weird cliff. That implies that the tach is teed off of the injector drive in the same fashion that the old Guzzis had the tach driven off of one coil. In a word - cheap, it doesn't say much for isolating the ECU from problems caused by external components.

No I don't think thats it.

This was happening with the WM ECU and my ECU.

I think its was more to do with system voltage fluctuactions that the short was producing

[al_roethlisberger]

So Cliff,

 

To clarify, you recommend just finding the correct dual-tower/output coils and connecting them directly to the ECU?

 

Another question, what "range" of impedence variance from the measured .7 Ohm should be safe? Would an impedence range of say, .5 Ohm to 1.5 Ohm be OK?? ..and which way along the scale is better/safer, more or less(I would suspect more) impedence, hence 1.5 versus .5 Ohm would be better??

 

thx!

al

[Cliff]

There are two things I see the ECU caring about, the maximum current and the kickback voltage.

 

The current has to be handled by the driver of the ECU. In addition to being within spec for the driver, more current will also mean more power has to be dissipated whilst energising the coil. A coil is just like any inductor. When turned on the current starts at 0 and ramps up ( in an exponential decay sort of way ) towards a maximum value dictated by the DC resistance. Apart from determining the final current the DC resistance determines how quickly the current ramps up.

 

The kick back voltage on the primary is dictated by the voltage generated on the spark plug and the ratio of primary turns to secondary turns. To throw a few loose numbers if the spark voltage is 30kV and the ratio of turns from secondary to primary is 100:1 then 300V will apear at the ECU. The ECU will have addition protection built in to protect its output stage, perhaps 400V. Ideally this will not come into play as the voltage is limited by the secondary side. You want all the stored energy at the spark plug, not back in the ECU. If you don't have enough turns on the secondary, or your spark gap is too great some of the energy will be back into the ECU.

 

Fortunately things aren't as exacting as it sounds, don't go less than your current coil resistance. Measure both of them. Don't go too high either or the ECU may not energise them long enough to store sufficient enery in them. The ones JohnIIS suggests are probably ok as would probably most coils off a Jap 4. They're usually dual output also aren't they?

[al_roethlisberger]

Thanks Cliff... a very technical perspective for sure

 

I'm going to give Dyna a call tomorrow as well.

 

thx!

al

[callison]

I can check the parts numbers for the Sport 1100i and California and see if the coil part numbers are the same, but I'm pretty certain they are and that MG hasn't changed coil specs since they went FI. So, if Dyna says that the 1.5 ohm dual tower coils are the appropriate coils for dual plugging, then I would go with their recommendation.

[al_roethlisberger]

OK,

 

Well I just got off the phone with Dyna, and they recommended to me that I use their DC9-1 dual-output coil, which is what Jason originally thought as well.

 

This is a .7 Ohm primary resistance coil, and the tech at Dyna was surprised that Dyna had recommended a 1.5 Ohm coil to John. While it would work, he stressed that if the manufacturer specified a .7 Ohm primary resistance, the coil they make is designed around that specification, and hence I should stick with the impedence the ECU expects.

 

That he said, was the DC9-1. He also said that since this is a dual-output coil(as opposed to a dual-coil in-one design like a Crane, which gets closest to spec at 3 Ohm... so no banana there )... I will have to squish the plug gap a tad, maybe to .025

 

So does anyone have any opinion on the choice of the DC9-1(.7 Ohm) versus the DC2-1(1.5 Ohm) that John ended up using?

 

Also, any opinions on Dyna coil reliability?

 

And finally, I was looking at the following to try to keep the spark gap stock/consistent and maybe add a little "punch":

 

Ignition Amplifier at Evoluzione

 

Any thoughts? Ken says they have been using tons of these on the Ducati Monsters, and a handful of V11's for two years with no problems, and "good results".

 

I think we're getting close

 

thx!

al

[Cliff]

I'm sure it will improve the spark and perhaps performance a little, but I don't think it would be good bang for buck.

 

CDI and such are more important in the single coil/multicylinder environment where there is limited time to charge up the coil. For our application there is plenty of time. I don't see the ignition of the FI bikes being lacking.

 

There'll always be those that can hear the difference with gold $100/metre speaker cables though.

[callison]

Drat! Now I'm going to have to start using gold plated speaker wire to upgrade my bike. Cliff, you fiend - how are we ever going to keep up?

[al_roethlisberger]

BTW, for those not on the MGCL email list, Cliff measured the primary resistance on his OEM 1100i coils and it measured .7 Ohm.

 

If anyone else with a V11 Sport/LeMans has an opportunity to double-check the resistance of theirs, that would be great(I'd check myself, but the bike is still in the shop). I'm just trying to perform due-diligence before buying the Dynas

 

Oh, and anyone with any experience or opinions on the reliability of these type of Dyna coils is much appreciated. I'm looking for them to be "at least" as reliable/long-lived as the OEM set.

 

Thanks all

 

al

[callison]

As I replied to your post on the MGNOC list Al, the part numbers for the ignition coils for a California are the same as those for the Sport 1100i and I'll bet all of the other EFI Guzzi's as well. Even with different computers, the output coil driver designs are unlikely to differ. Cliff measured both of his coils in parallel giving a reading of .7 ohms. That would make the individual coil resistance 1.4 ohms (and this is the way they operate). That means the notes on the guzzitech page for the dual plugged Bassa are correct and you should be looking for a 1.5 ohm dual tower Dyna. I'm not certain the ECU could survive a .7 ohm load, especially at sustained upper rpms.

[al_roethlisberger]

Cliff measured both of his coils in parallel giving a reading of .7 ohms. That would make the individual coil resistance 1.4 ohms (and this is the way they operate). That means the notes on the guzzitech page for the dual plugged Bassa are correct and you should be looking for a 1.5 ohm dual tower Dyna. I'm not certain the ECU could survive a .7 ohm load, especially at sustained upper rpms.

 

OK, now you guys are confusing me, Cliff told me just the opposite

 

Here is yours and Cliff's thread from MGNOC, and Cliff's response where he maintains that the coils are still .7 Ohm each:

 

>[Carl] Yeah, but they don't run in parallel through the ECU, so the

> [Carl]http://www.guzzitech.com/HRBassa-John.html note specifying a 1.5 ohm

> [Carl]dual tower coil would be the more correct choice.

>

 

The two ignition coils are common on the +12 side, along with the

injectors

and fuel pump.

 

I measured from the negative of one coil to the negative of the other

as they

were convenient to get at from the ECU.

 

Each coil was 0.7 ohm

 

Cliff

 

 

Let me know what you guys figure out

 

al

[Cliff]

It is getting confusing and these multiple boards don't help.

 

Carl is incorrect when he says I measured the coils in parallel. I did measure both coils together, but they were in series. Combined impedence was 1.4 ohm which means each coil was 0.7 ohms.

[Guest Jaap]

Although I like this techtalk and appreciate the knowledge of you guys, personally I'd still would leave twin sparking to the specialists. Like TLM:

 

 

We make the perfect second sparkplug into your big Guzzi. The burning-time of the mixture will be reduced to almost half the original time and that will bring you a more efficient engine. You will get a higher torque, more horsepower, lesser chance for detonation and cleaner exhaust-gasses. This concept we use since 1979 (Lava-Racing). The bigger the cylinder-bore the bigger the effect of a second sparkplug. So the newest models will gain the most with this execution.We will take care of the complete installation of twinsparkplugs, but spare cylinderheads are also welcome.

[biesel]

"Cylinders are like Martini's & tits - one's not enough and three are too many."

 

*LOL* !!!

[callison]

Actually, and I hate to admit this, I have a spare coil because I didn't do a wonderful job troubleshooting a bad connection last year. What I didn't want to do is dig around in my box of ill gained goodies to find it. But I just did. And the answer is...

 

1.4 ohms.

 

All by it's little lonesome. No bike attached.

 

These suckers aren't cheap either. $80. That's why I don't like to be reminded that I goofed and bought one for the wrong reasons. But that ought to settle the question on the coil resistance anyway.

 

If that's a copacetic answer for everyone, I have another question. Al, did you get the heads decked to raise compression, are you changing the pistons or is all of that the same as before and you're dealing only with the ported heads and dual plugging?