Moto Guzzi V11 Sport Exhaust System Testing
The new V11 Sport uses the Weber-Marelli 1.5M computer which uses no replaceable EPROM, or chip, like it's predecessors. (1.6M, P8, P7)
The new maps for the 1.5M can be uploaded with the use of Ultimap diagnosis software. For more about Ultimap products, go here; FIM
In the last two weeks, we've scheduled re-mapping for two V11 Sports. The first had the air-box removed, K&N filters and 'Mistral' slip-ons and cross-over.
The mapping produced more torque, more peak HP, and great driveability. See the before and after dyno chart below.
However, 72HP just doesn't sound right. I don't do enough Guzzis to know off-the-top-of-my-head just how much they should make, but looking at the chart tells me that the engine could peak at a higher RPM. It is, after all, a 7500+ RPM engine. It was my guess that the aftermarket cross-over, which has the balance tube about 5 inches farther along the pipe than the stock cross-over, might be making the engine peak at 6500 RPM instead of higher. I thought that a few hundred RPM would help the power a lot.
Along comes the second V11 Sport, and the customer asked me if he should eliminate his air-box too. This bike has the Agostini slip-ons and cross-over, which according to the customer, is the same component as the 'Mistral'. The ensuing discussion highlighted the questions I had, so the customer dropped off his stock crossover to try. Might as well learn something while we're at it.
This example had more power than the first one (the stock air-box?) but it didn't want to improve peak HP with mapping. A bunch of fuel adjustments and timing adjustments later I had a good map but no more HP than when I started.
Below I've compared it with the previous one (in red).
The difference around 6500 RPM is probably due to air-box resonance on the later one. You can see that the one with the air-box (blue) has a dip at 6700 RPM while the one without has it's peak there.
OK, there is a little more peak torque but the peak doesn't look very good.
The graph above is after good maps were developed for each of the bikes.
The next step is to replace the Agostini cross-over with stock one.
I could hardly believe the difference!
Ten HP!! The dip at 4600 RPM was accompanied by a very rich condition, with a lean condition at 7500.
After a complete redo of the map, including timing changes at the torque dip, I got a pretty good map with good driveability.
Now there is a flat-spot in the power curve at 4500 RPM, but if you want to go fast you shouldn't be hanging around at 4500 RPM.
The engine peaks at 7500 RPM as it was designed to and the pay-off is 10 HP!
There is, actually, more torque below 4000 so the driveability isn't significantly compromised.
Take your pick! I'll go for the power!