V11 dual Plug Conversion

[al_roethlisberger]

Moto Guzzi V11 Sport/LeMans Dual Plug Head FAQ

 

****************************************

 

Introduction:

-----------------

 

Due to the design of the hemispherical stock Moto Guzzi V11 Sport combustion chamber, domed piston, and offset(not centered) spark-plug, the flame-front and efficiency of the combustion process is not ideal. During the compression stroke, and subsequent spark, the domed piston creates a "shadow" that delays the smooth and uniform spread of the fuel/air combustion. For this reason, over the years, many owners have added a second plug to the opposite side of the combustion chamber via various dual plug conversions to balance and increase the efficiency of the combustion process.

 

Although many older Moto Guzzis have been converted to dual plug heads, very few current generation V11 Sport/LeMans have been done in North America, and until recently not much information was available. This lack of late model conversions is because the newer bikes are equipped with electronic fuel injection and ignition systems, and many shops do not have the expertise to fully convert these systems. However, in Europe, it is more common as dealers such as TLM in the Netherlands have a complete package available off of the showroom floor.

 

The benefits of dual plugging the heads is increased efficiency, smoother power delivery, less detonation(pinging), and the potential for slightly more HP and torque.

 

 

The primary components of the conversion are:

 

1) Converted machined heads that relocate the oil-supply fitting, and create a second spark plug socket

2) Dual output coils

3) Modified ignition map

 

 

Head Conversion:

-----------------------

 

Conversions can be performed by various machinists with experience, although it is highly recommended that one choose a technician or shop with specific experience converting V11 Moto Guzzi heads. The two shops that are known to perform quality work are:

 

North America:

Mike Rich Motorsports

www.mikerichmotorsports.com

21 Jerusalem Hollow Road

Manorville, New York 11949

(631) 874-7032

(866) 676-7767

 

Europe:

Teo Lamers

www.tlm.nl

Nijverheidsweg 26

Nijmegan

6541 CM

31.24.37.11.111

 

Costs for the conversion can vary dramatically depending on the shop, however, as a bench-mark, Mike Rich charges(as of 2003) an extra $150 per head while performing head porting. In the case of Mike Rich's conversion, high quality work, extensive machining, and relocation of the oil supply warrant the high cost.

 

 

Coils:

------

 

Also required for the conversion are new dual-output coils to energize the now required 4 plugs, versus 2 plugs as stock. The single output stock V11 Sport coils are OEM supplied by various manufacturers such as Champion and Marelli, but although only come as a single tower/output, have the capacity both electrically and physically to support a second output tower.

 

Although some reported conversions have used various aftermarket coils, relays, and non-standard or non-OEM wiring solutions, dual-output versions of the OEM coils are available, and will plug directly into the stock wiring harness with no modifications required.

 

These coils are available from TLM, and are a direct bolt-on replacement. As of 2003, these coils were available for about 103 Euro each(2 required), TLM model number 307165000010

 

 

Ignition Advance:

-----------------------

 

Finally, although the engine will run fine with the stock ignition map as supplied on the M15 ECU, to maximize the benefits of the dual plug conversion, the ignition curve should be retarded. This modification is required, because as stock, the ignition is advanced through the ignition curve in order to fire the spark early enough in the compression stroke to allow the flame front to propagate through the combustion chamber. With two spark plugs firing on opposite sides of the piston dome, there no longer is a shadow effect, so less ignition advance is required to fully burn the charge before top dead center(TDC).

 

However, in North America, there are few if any shops with required sofware such as FIM Ultimap and/or the experience and willing or able to remap the ignition map on the Marelli M15 ECU. Although this ECU is shared with several Ducati models, and many shops that service Ducatis do have this expertise, they have seemed reticent to perform this work on the Moto Guzzi due to lack of experience with the brand and/or dual plug conversions and ignition remapping.

 

But, as mentioned, the stock ignition map will work fine, with no detrimental effects to the engine. This reassurance has been made by TLM's experience with dual plug conversions over time. Again though, some inefficiencies will be introduced by not changing the ignition curve, so ultimately the ideal solution would be to adjust the timing.

 

As of 2004, the easiest way to have the ignition curve remapped is the current service provided from TLM where one exchanges the stock ECU for a remapped unit. The service is available for 250 Euro, and takes approximately 2 weeks.

 

 

 

With all three modifications performed, results from the conversion of Al Roethlisberger's 2002 V11 LeMans seem promising so far as of Spring, 2004.

 

Although due to other modifications it is difficult to quantify performance improvements specific to the dual plug conversion in regard to HP and torque, it does appear that the engine runs more smoothly and detonation is definitely reduced.

 

After installing the ignition curve remapped M15 ECU, and tuning the air-fuel mixture via a custom mapped Dynojet PCIIIusb, maximum power is 84.36 rear wheel HP, and 64.9 lb-ft of torque.

 

 

V11 Forum Topics:

--------------------------

 

Forum Dual Plug Thread

 

 

FAQ Administrative Contact:

--------------------------------------

 

Please feel free to contact this FAQ's administrator via email or a Forum Private Message to submit new information or suggest corrections.

 

Al Roethlisberger