v7 Classic exhaust crossover, mistrals, power commander etc

[chrisk]

Hi, I'm thinking of fitting Mistrals (or Arrows if they ever turn up) to a V7 classic and have a few questions -

1) What's the advantage of fitting the mgcycle crossover (link below) ? It looks as though the 02 sensor will still be fitted, so I'm wondering what the difference is, whats in the original to make it so big ? I understand the catalytic convertors are in the silencers.
http://www.mgcycle.com/product_info.php?products_id=1721

2) There is a fatduc device discussed in Cafe Racer mag, and discussed here somewhere. I'm guessing this either fits between the physical 02 sensor and the loom connector or does it just connect to the wiring loom? If it's the latter I guess you need to blank off the 02 sensor in the crossover?

3) If you fit a Power commander does it come with a connector for the 02 sensor or do you need a Power Commander and a fatduc?

Comments appreciated.
Chrisk

 

[Holt]

I can only give a bit of an answer to question 1.
The cross over shown is very like the Stucchi-crossover that I have. The advantage is one, as I'm concerned: You get access to the sump drain plug...
Also it's said to produce alotta hp. Doubt it.
And give a new exhaust note. Probably. I can't hear it, because I'm always driving using earplugs.

DanR mounted Mistrals, as I remember.Go search for his postings.

 

[GuzziMoto]

As for #2, the FatDuc tries to modify the signal from the O2 sensor to the ecu. So you still fit the O2 sensor and the FatDuc plugs in between the O2 sensor and the ecu.
Some have had good luck with it and some have not. It is very low tech but that does not mean it can't work.
I don't know if you can get a power commander for the V7 and if you can what version it is, but if you can get one it would likely give you better results then the FatDuc (although it does cost a lot more $) as it allows you to add more fuel in areas it needs it and to take away fuel where you have too much where as the FatDuc is only a add or subtract fuel device.

 

[draidt]

No need to search for DanR's post that is me

As Anders (Holt) said the biggest advantage is the clearance for the gearbox drain plug I the ordered the crossover from MG when I tried to get the plug out for the first time. There is no improvement in performance nor sound that I could detect.

These will though

http://www.mgcycle.com/product_info.php ... ts_id=2576

I went to the reverse cone Mistral's after having the Slash cuts on for a year strictly for aesthetics (I am so vain :mrgreen: ) both give an honest seat of the pants boost in HP and mid range torque how could they not without the cat's blocking the exhaust. I found that running with the DB killers in gives better performance on both types of Mistral's. I do like the sound of the reverse cone better then the slash cuts. It does truly make beautiful Guzzi music without being obnoxious or popping on decel . I see no need to revise the fueling on the V7C via a fat duc or Power Commander the fueling right out of the box is spot on. This coming from someone who went the full Guzzitech monty with my Norge, Power Commander, Auto Tune, Stepper Motor, Open Air Box and K&N filter. Now the Norge run's like it should have right out of the box, If the V7C needed it I would be the first in line but it doesn't. I also am running the stock air filter on the V7C and have no plans to mess with the air box or change to a less restrictive filter.

 

[NOLAGuzzi]

RE #3
I have, but don't have it on the bike, a powercommander for my breva. It comes with a little black box that you plug into the 02 sensor harness to fool the ecu into thinking all is well in the lambda world. The fueling is controlled by the map overlay in the PC so I don't think you would need a fat duc too. The breva and the V7C have the same ecu, at least I think they do, so a powercommander should be available if wanted. I know that DanR has mistrals on his V7 C and did not need to alter anything with the FI.
I want the arrow exhaust too. I wonder if it would work on a breva :?:

 

[GTM®]

RE #3 I have, but don't have it on the bike, a powercommander for my breva. It comes with a little black box that you plug into the 02 sensor harness to fool the ecu into thinking all is well in the lambda world. The fueling is controlled by the map overlay in the PC so I don't think you would need a fat duc too. The breva and the V7C have the same ecu, at least I think they do, so a powercommander should be available if wanted.

Correct on the fact that if you have a PC w/02-optimizer, you do not need anything else for proper fueling. Happy to get you one ->HERE<-click.

The under transmission crossover is a pre-muffler or sorts... You will get more sound, cooler running and easy access to the trans drain plug.

 

[sign216]

I can only give a bit of an answer to question 1.
The cross over shown is very like the Stucchi-crossover that I have. The advantage is one, as I'm concerned: You get access to the sump drain plug...
Also it's said to produce alotta hp. Doubt it.
And give a new exhaust note. Probably. I can't hear it, because I'm always driving using earplugs.

DanR mounted Mistrals, as I remember.Go search for his postings.

The aftermarket crossovers give you much better access, but the factory must have made the stock x-over that wide for a reason. To block the plug like that, it must have been built on purpose. Or am I ascribing Intelligent Design to where there is none?

 

[GuzziMoto]

Exhaust parts are often built for noise and/or emissions standards reasons and not because it is better for performance or access. I don't have a V7 but I have three Guzzi's and not one of them came with a crossover/collector that was designed very well. The Daytona was the worst as it came with what has been best described as a colostomy bag for a crossover. Two of the three, including the Daytona, have had their crossover/collector replaced with a better designed aftermarket piece and the third will likely have its replaced sometime in the future when I have the time/money.

 

[Holt]

Probably for noise emission purpose only. The EU homologation rules have become quite strict concerning noise and exhaust emissions. A vehicle homologated in one EU-country is automatically approved in all other EU-countries as well.
Compliance and control vary some from state to state. In Sweden the authorities doesn't seem to care much about the specific sound emission level unless you're driving with open pipes, but I do suspect that, for example in Germany, it won't be possible to run with other than the original system - if not a replacement system has an approval and that the change is introduced into the vehicles registration papers.
As Guzzi is a really small manufacturer - what are the numbers of smallblocks produced in a year? - 1000? 2000 max? - they'll probably not put too much efforts in finding the most optimized system, by financial reasons mostly.
And don't forget that the smallblocks mainly are a late 1960's - very early 1970's construction, based on what was requested back then.

 

[chrisk]

Hi all, well that answers all I needed to know so thanks. Decisions are -

- Buy the mistrals or wait for the arrows... (anyone got pics of the mistral slash cuts and reverse cones on a bike ? )

- Is it really worth getting the PC? (draidt thinks not) I'm tempted to but they are not cheap and I wonder what you'll really achieve. Difficult to know unless you can see a dyno sheet for the pipes with and without the PC.

My first service (700miles) is due in a week or so, I'll get that over with and will have hopefully decided by then.

 

[draidt]

Hi all, well that answers all I needed to know so thanks. Decisions are -

- Buy the mistrals or wait for the arrows... (anyone got pics of the mistral slash cuts and reverse cones on a bike ? )

- Is it really worth getting the PC? (draidt thinks not) I'm tempted to but they are not cheap and I wonder what you'll really achieve. Difficult to know unless you can see a dyno sheet for the pipes with and without the PC.

My first service (700miles) is due in a week or so, I'll get that over with and will have hopefully decided by then.

Reverse cone




Sound Bite Reverse cone

[youtube]z2_sUPt479w[/youtube]

Slash Cut





Sound bite Slash cut

[youtube]vlj-RGTYhGw[/youtube]

 

[russ in pa]

I have the Pwr commander on a Breva750. +7 HP & +4 ft-lb. The curves are up on the MG_750 forum on Yahoo. The increase is only for the PwrCommander as baseline was done with new slip-ons already in place. Does not sound like much but going from 38 to 45 is almost 20%.

 

[sign216]

Below is a link to the group for the dynometer runs for Russ's bike. We have several different dyno runs with varying modifications, all in the Files section.

Dyno chart now posted here; https://www.guzzitech.com/forum/202/4473.html

Would like to hear of more modifications.
Joe

 

[Martin]

The aftermarket crossovers give you much better access, but the factory must have made the stock x-over that wide for a reason. To block the plug like that, it must have been built on purpose. Or am I ascribing Intelligent Design to where there is none?

I was thinking of making sort of a Stucchi x-over, but having the x-over removed I saw that it is empty. . . also wonder why it's made that way. Replacing would not alter the sound I think?

 

[Holt]

The aftermarket crossovers give you much better access, but the factory must have made the stock x-over that wide for a reason. To block the plug like that, it must have been built on purpose. Or am I ascribing Intelligent Design to where there is none?

I was thinking of making sort of a Stucchi x-over, but having the x-over removed I saw that it is empty. . . also wonder why it's made that way. Replacing would not alter the sound I think?

Both the OEM and the Stucchis are empty. I guess the OEM tincan works as a kind of a silencer, by the volume.

 

[sign216]

The OEM crossover is oddly shaped and big. It's got to be that way on purpose. There is little explanation for it otherwise. In my heart I hope it is that way because it has been tuned and intelligently designed to assist scavenging and increase benefical exhaust harmonics to increase performance.

Maybe I dream.

Joe

 

[GuzziMoto]

It is likely the way it is for a reason. That I would agree upon. But you are assuming that the reason is for improved performance and that I do not. I would not be surprised if the reason for the design of the crossover was for noise and/or emissions reasons or cost/production reasons and not improved performance. In fact I would think that out of all the possible reasons for the design that maximum performance is the least likely.
But that is just my opinion based on my experiences with Guzzi's, Ducati's, and jap bikes.

 

[Martin]

I would not be surprised if the reason for the design of the crossover was for noise and/or emissions reasons or cost/production reasons and not improved performance.

For sure it isn't for cost/production reasons, because a straight pipe would be easier to make and so less expensive. Is it possible that it is for the lambdasonde, I guess it measures something different than with a straight pipe (Stucchi).

 

[draidt]

I was the first in the US to put in the Stucchi crossover, I can assure you that there was no difference in performance and sound that I could detect and no issues resulted in the conversion, except getting out the gearbox drain plug is not a nightmare anymore, besides that piece of polished Stainless Steel looks way better then the appendage that came from the factory.

 

[sign216]

Regarding the crossover, I checked parts manuals. The older carbureted Nevadas had the large bulged crossover, even though they weren't using a lambda probe! So the large crossover has no emission purpose, although it might have a sound reduction or performance purpose.

Straight tube crossovers were used on the V50, V65 Lario, and the Lemans T3. Large crossovers were used on the Breva, Stone, and the Daytona. The parts manuals call these crossovers an "expansion chamber." Remember expansion chambers from your dirt bike days? Expansion chambers are used on 2 cycle exhuasts to increase positive pressure waves to fill the chamber, and the negative wave to scavange the exhaust out. On 2 cycle engines expansion chambers have a great effect, but supposedly on 4 cycle engines the effect is small.

Guzzi went out of it's way to go from a straight pipe on the early bikes to the large chamber on later machines. They call it an expansion chamber, and I think that is their intent.

Joe