Aftermarket Crossover with stock exhast cans

[lavrgs]

Would changing just the crossover improve performance? For example I'm thinking about replacing the stock crossover with a Mistral, which has been touted as something to help reduce the torque dip in the 4K region. Has anyone done this leaving the stock cans in place? A seat of the pants, ballpark or other guesstimation about benefits would be welcome.

[Guest ratchethack]

In a word, yes. As confirmed by the dyno pull comparo's by Doug Lofgren. The Stucchi crossover with stock cans makes a noticeable improvement in midrange poke over the stock crossover. It also gives a deeper sound to the stock exhaust. I ran my bike this way for a year before installing FBF oval carbon mufflers.

[dlaing]

In a word, yes. As confirmed by the dyno pull comparo's by Doug Lofgren. The Stucchi crossover with stock cans makes a noticeable improvement in midrange poke over the stock crossover. It also gives a deeper sound to the stock exhaust. I ran my bike this way for a year before installing FBF oval carbon mufflers.

The Lofgren dyno pulls were not done with stock cans.

http://www.visi.com/~moperfserv/report.htm

Motoguzzix did dyno pulls comparing the crossover while using modified stock mufflers

http://www.v11lemans.com/forums/index.php?...=stock+mufflers

[Guest ratchethack]

If you look at the last of Doug's dyno charts on the page here: <a href="http://www.visi.com/~moperfserv/more_mg.htm" target="_blank">http://www.visi.com/~moperfserv/more_mg.htm</a>

 

This is the one that confirmed to my satisfaction what all the other charts had indicated about what to expect from the Stucchi crossover with stock mufflers. Note that the top end differences are negligible (stock air box, Agostini mufflers, Stucchi crossover). Since effects of the stock cans vs. freer-flowing aftermarket cans are least at low RPMs and greatest at high RPMs, and most non-racing riders (can we just say "all road riders" here and be considered accurate?) don't ride at sustained WOT (myself included), I focused on what was going on at the stock 4500 RPM dip and the improvement made here. My seat-o'-the pants dyno says this is where the improvement was after I installed the Stucchi crossover -- with stock mufflers -- as expected.

 

NOTE: The absence of the "dip" in the torque curve means there's no sudden "climb" out of it on the far side. This is the first thing I noticed after replacing the stock crossover ONLY -- more poke and smoother torque spread. After a year of riding this way I installed FBF oval carbon mufflers. By my seat-o'-the-pants dyno, there was another improvement in midrange that's sustained in upper RPMs.

[lavrgs]

I looked at the link for the Lofgren runs and what he concludes is that with the cross over (Agostini) you lose the dip at 4500 AND lose 10 HP over the stock crossover - both runs had Agostini Slip ons. He obviously recommends riding away from the 4500 RPM zone. Later runs with the Stucchi lost the dip and got the 10 HP back but I interpreted that out of the box you would not get those results. I would have liked to see what the stock set up could do. Are we being hornswaggled into getting expensive exhaust systems that only add noise and require extensive tuning - i.e. more $$$$? Interesting to note that he spent alot of time adjusting the timing to get the best results not just fuel mapping.... I'll have to go follow the other links to get more data....

[wheelsucker]

Don't want to hijack the thread but it might be useful to others, which is the better crossover for mid-range power and durability, the Stucchi or the Mistral?

[dlaing]

Don't want to hijack the thread but it might be useful to others, which is the better crossover for mid-range power and durability, the Stucchi or the Mistral?

Which is better for mid-range is clear in the Doug Lofgren's graph.

Note these are two seperate bike, so exact performance differences will vary.

Other people who have dyno'd with Mistrals have gotten more high RPM power with Mistrals than this graph indicates.

Mistral in Red and Stucchi in Blue.

But as for durability, I think it would take years of R&D to answer that.

Do V11 five speed Tontis outlast V11 Sixspeed spines? If we knew that, that might give us a clue, but of course differences like the sump and oil cooler might make a difference, too.

[lavrgs]

To me the graph says Mistrals win for low end torque improvement...almost 10ft-lb better...right?

I read that the torque and HP curves should cross at 5252 RPM can someone explain the math to me? And why have I seen variance in a couple graphs but the "torque dip" was still around 4500RPM

 

The Mistrals seem like a better buy as they were cheaper than the Stucchi and while the Stucchi was double walled I was told the "siamese" set up was subject to cracking. The siamese part means the two main parallel pipes are joined in the middle

 

Mistral in Red and Stucchi in Blue.

[wheelsucker]

To me the graph says Mistrals win for low end torque improvement...almost 10ft-lb better...right?

I read that the torque and HP curves should cross at 5252 RPM can someone explain the math to me? And why have I seen variance in a couple graphs but the "torque dip" was still around 4500RPM

 

The Mistrals seem like a better buy as they were cheaper than the Stucchi and while the Stucchi was double walled I was told the "siamese" set up was subject to cracking. The siamese part means the two main parallel pipes are joined in the middle

 

Mistral in Red and Stucchi in Blue.

 

Yeah, that's what I got as well. It looks like the Mistral is the better bang for the buck and the better low end power is exactly what I would want.

[Greg Field]

Here's the dyno charts for my '04 Ballabio:

 

 

This is for a bike with an airbox modded per Phil A.'s earlier pattern, Mistral corssover, and Mistral cans. It also has the front crossover. No torque dip and still has decent top end.

[wheelsucker]

the Mistral has two models for the V11, with or without a Lambda sensor. How can I tell if I have the Lambda sensor? Please no Nerds jokes:)

[v11cafe]

the Mistral has two models for the V11, with or without a Lambda sensor. How can I tell if I have the Lambda sensor? Please no Nerds jokes:)

Lambda sensor is a small cylinder shape thing that seats on the crossover (upper side).

and there is a cable going upwards to the ECU.

You can"t miss it , if it is there.

[lavrgs]

Lambda sensor is a small cylinder shape thing that seats on the crossover (upper side).

and there is a cable going upwards to the ECU.

You can"t miss it , if it is there.

 

 

It's also possible to plug the hole. Moto International supplied a plug for mine...Thanks Greg!!!

[JoeV11]

I installed a stucci crossover with stock mufflers and noticed a deeper sound and smoother running. The smoother running may also have been from a quality first tune-up by the guys at Marsh Motors. They really liked the way the bike ran, too. I eventually added aftermarket mufflers. Joe

[Greg Field]

WS: None of the US V11s have the lamba sensor.

 

It seems every piece of evidence agrees that if you want ultimate top-end, the Succhi is the best choice. This meshes exactly with what a one-day comparison by feel, and not dyno, showed me. I would love to have the xtra top end of the Stucchi. It would be a boon on some of my rides, but for the other 90 percent of the riding, I like the no-torque-hole performance the Mistral provides.