Exhaust system

[Lars Le Mans]

Hey everybody

I am a happy owner of a V11 Le Mans 04 with Mistral Carbon cans (no cat.),open airbox with a KN filter and Power Commander III. On the 04 model the cross over is placed on the down pipes. I have decided to make a new exhaust can, aluminium,placed under the gearbox. So my question is this: which effect will it have if i make a second cross over ind the Can ?

By the way .This forum is great. My wife dont think so cause Im spending to much time here

Greetings from Denmark Lars

[Tom M]

Hey everybody

I am a happy owner of a V11 Le Mans 04 with Mistral Carbon cans (no cat.),open airbox with a KN filter and Power Commander III. On the 04 model the cross over is placed on the down pipes. I have decided to make a new exhaust can, aluminium,placed under the gearbox. So my question is this: which effect will it have if i make a second cross over ind the Can ?

By the way .This forum is great. My wife dont think so cause Im spending to much time here

Greetings from Denmark Lars

 

Greetings to you Lars. Installation of a muffler under your gearbox will change the power characteristics of the engine, probably similar to what the Quat D users have seen assuming the construction of your muffler is similar. Your really should consider having a custom PC map made after you install your custom exhaust.

 

Good luck with your project and be sure to share some pics with us when you're done

[motoduck]

I too would really like to see and hear more about this exhaust upgrade. Currently I'm running the same Mistral/KN/Powercommander set up as you on my '00. Although, mine has a custom map for more top end and terrible fuel milage

 

^S^

[Lars Le Mans]

I too would really like to see and hear more about this exhaust upgrade. Currently I'm running the same Mistral/KN/Powercommander set up as you on my '00. Although, mine has a custom map for more top end and terrible fuel milage

 

^S^

Thanks for your reply.I still dont know if a second crossover in the Can will do more harm than good.And by the way my fuel milage is also terrible <_ ihave made a few other on my v11. db-killers in lafranconi design and black round led tail lights i have tried to post some pic but am better metal works than pc. src="%7B___base_url___%7D/uploads/emoticons/default_cool.png" alt="B)">

[GuzziMoto]

The 04's and other bikes with a front cross over usually also have a cross over further back. As I don't have a later model bike I don't know the details of yours. But exhaust theory is the same on all.

The crossover at the front of the motor is mainly there to reduce noise. It will change the power characteristics but not entirely for the better. You would be better served to eliminate it and have a proper cross over at the normal spot, somewhere just in front of the rear wheel. A stock Guzzi cross over (at the proper spot, just in front of ther rear wheel) is not ideal but it is better then nothing. A Stuchi cross over is better yet, but no one that I have seen makes one that is perfect. Part of the problem is the lack of space down there. Another is the angle of the head pipes as they come around the block. You can buy a proper two into one collector or cross over but making it fit is another story alltogether.

There are lots of causes for bad mileage, ranging from bad temp signals to throttle body sync, valve lash, or the crappy stock fuel map. The problem is figuring out which problem (or problems) is yours.

[Guest ratchethack]

Hey everybody

I am a happy owner of a V11 Le Mans 04 with Mistral Carbon cans (no cat.),open airbox with a KN filter and Power Commander III. On the 04 model the cross over is placed on the down pipes. I have decided to make a new exhaust can, aluminium,placed under the gearbox. So my question is this: which effect will it have if i make a second cross over ind the Can ?

By the way .This forum is great. My wife dont think so cause Im spending to much time here

Greetings from Denmark Lars

Lars, according to Todd Eagan at GuzziTech, who's probably pulled as many V11 dyno runs as anyone on the planet, and was largely responsible for single-handedly getting DynoJet to develop a PCIII for our bikes, the front crossover makes no perceptible difference on the dyno whether it's there or not. My Pal's '04 LM suffered ZERO perceptible change when he finally welded the header spigots shut on his in utter frustration after years of grief dealing with sealing problems.

 

The front crossover serves an entirely different purpose than the rear crossover, and one does not replace any function of the other. Without getting into black arts too far beyond my own relatively meager grasp -- and a few beyond the grasp of many experts -- Exhaust gas flow dynamics are extremely complicated. Lots of interdependent factors are involved with reflected wave harmonics and positive-negative pressure wave interactions at various RPMs and loads. Even a small change to a heavily engineered system can make a big difference.

 

What the effects of a yet-to-be-made crossover exhaust can would be are nearly impossible to predict with any degree of accuracy, with the possible exception of those who've actually designed and tested them for a specific application like the V11.

 

Based on my understanding of existing crossover/box designs (the "checkered" performance history of the Quat-D comes to mind), starting from scratch, and working to fit available space and for appearance alone, you're far more likely to come up with something that hammers the torque and power curves into a mere shadow of their OE peaks and desirable curve shapes than make any improvement wotsoever. Sound quality, being "in the ear of the beholder", and not having much of any direct relationship with power or torque curves, is all but a crap-shoot.

 

But o' course, that's just my take. I'd be more'n interested in your progress with anything you can cook up.

[dlaing]

Quat-D made a few versions of the Guzzi Ex-box.

The one I previously had made a little more power below 5000 RPM but quite a bit less power above 5000 RPM.

But it was more fun to ride.

From the few dynos I have seen, and the Rosso Corsa I test rode, the newer Quat-Ds increased high rpm power significantly compared to the early ones.

You could save effort and buy the Quat-D, but If you build your own, please post photos, results, etc., here!

Someday I want to have my own, custom built with dual ports, for stereo sound, but that may never happen. Best of luck

[Lars Le Mans]

The 04's and other bikes with a front cross over usually also have a cross over further back. As I don't have a later model bike I don't know the details of yours. But exhaust theory is the same on all.

The crossover at the front of the motor is mainly there to reduce noise. It will change the power characteristics but not entirely for the better. You would be better served to eliminate it and have a proper cross over at the normal spot, somewhere just in front of the rear wheel. A stock Guzzi cross over (at the proper spot, just in front of ther rear wheel) is not ideal but it is better then nothing. A Stuchi cross over is better yet, but no one that I have seen makes one that is perfect. Part of the problem is the lack of space down there. Another is the angle of the head pipes as they come around the block. You can buy a proper two into one collector or cross over but making it fit is another story alltogether.

There are lots of causes for bad mileage, ranging from bad temp signals to throttle body sync, valve lash, or the crappy stock fuel map. The problem is figuring out which problem (or problems) is yours.

My 04 LM has the front cross over and I belived it was there because of the cat. under the gearbox. I like the ideer and the look (and the sound ) of the "Quad-box" ,but I am just a poor working man who can do something with metal. So I am playing with the ideer of doing it my self (in aluminium) and make a cross over in the can. My wifes knee angle will be improvet to.

But there is more to it than this. I bourght the bike 1 year old,with Mistral´s,no cat.,KN filter in the original housing and PC III.Last fall it began to backfire out of the throttle´s when I give it a quick twist. This problem has grown cause now it backfires at cruiser speed belowe

3000 rpm. And if have to pay a bike mecanic (if I can find someone who knows anything about V11 ) I would like to have changed the exhaust first. I have read the throttel body sync. in this forum,but my english aint good enough to do it my self.

And what is this Tuneboy stuff? Can it replace the PC III or ???

[Skeeve]

But there is more to it than this. I bourght the bike 1 year old,with Mistral´s,no cat.,KN filter in the original housing and PC III.Last fall it began to backfire out of the throttle´s when I give it a quick twist. This problem has grown cause now it backfires at cruiser speed belowe

3000 rpm. And if have to pay a bike mecanic (if I can find someone who knows anything about V11 ) I would like to have changed the exhaust first. I have read the throttel body sync. in this forum,but my english aint good enough to do it my self.

And what is this Tuneboy stuff? Can it replace the PC III or ???

 

Yes, the Tuneboy is an alternative to the PCIII, but instead of a box that intercepts signals to/from the ECU, Tuneboy is a software&cable solution to reprogram the ECU: more powerful, but more dangerous too [screw up the PCIII map; unplug the PCIII & you're back to stock. Screw up w/ Tuneboy & it's new ECU time if you really messed up...]

 

If you're backfiring, it would seem that you need to do a valve adjustment...

[Lars Le Mans]

Yes, the Tuneboy is an alternative to the PCIII, but instead of a box that intercepts signals to/from the ECU, Tuneboy is a software&cable solution to reprogram the ECU: more powerful, but more dangerous too [screw up the PCIII map; unplug the PCIII & you're back to stock. Screw up w/ Tuneboy & it's new ECU time if you really messed up...]

 

If you're backfiring, it would seem that you need to do a valve adjustment...

Valve adjustment? I did that 1000 km ago. Are they to tight? It just comes to my mind, its after the adjustment that it started backfirering at higher rpm.

[Lars Le Mans]

Valve adjustment? I did that 1000 km ago. Are they to tight? It just comes to my mind, its after the adjustment that it started backfirering at higher rpm.

And by the way only when it is warm. I will start by making a new "holder" for the temperatur gauge in the cylinder head. Brass or aluminum.

[GuzziMoto]

Whooaa. Don't be so quick to go re-engineering things when there is something fundamentally wrong with the state of tune of your bike. Fix the back firing issue before you go redesigning things like the engine temp sensor or the exhaust system. There is no reason other then something mis-adjusted (valves could be too tight), leaking (air leak), or otherwise. Deal with that before you go changing things like that. If the bike doesn't run right to start with and you do something that extreme, and it doesn't run right after you are done, you won't know if what you did was an improvement or not.

The bike should be able to run fine stock. You need a solid baseline before you go re-engineering the bike. But once it is running right, by all means build your own exhaust. What the hell, if it doesn't work well you can put the stock one back on (and try again knowing more then you knew to start).

[Lars Le Mans]

Whooaa. Don't be so quick to go re-engineering things when there is something fundamentally wrong with the state of tune of your bike. Fix the back firing issue before you go redesigning things like the engine temp sensor or the exhaust system. There is no reason other then something mis-adjusted (valves could be too tight), leaking (air leak), or otherwise. Deal with that before you go changing things like that. If the bike doesn't run right to start with and you do something that extreme, and it doesn't run right after you are done, you won't know if what you did was an improvement or not.

The bike should be able to run fine stock. You need a solid baseline before you go re-engineering the bike. But once it is running right, by all means build your own exhaust. What the hell, if it doesn't work well you can put the stock one back on (and try again knowing more then you knew to start).

HHmmm.... you are right.I am going to fast.OK... I need to check and adjust the throttle opening angle, I just dont know how to messure the angle inside the throttle housing... I checked the valve clearens yesterday and it seems ok. And I tightened everything on the intake side,nothing loose there. And thank you for bringing me down to the ground again I´m not a totaly rookie with engines but I get carried away when my "Bella Moto" dosen´t feel good

[GuzziMoto]

There are threads on this site that will teach you how to do just about anything your Guzzi will need done.

Take your time and read thru the threads on adjusting the TPS and syncing the throttle bodies.

Also, when you say "I checked the valve clearens yesterday and it seems ok", what were the clearances?

[Lars Le Mans]

There are threads on this site that will teach you how to do just about anything your Guzzi will need done.

Take your time and read thru the threads on adjusting the TPS and syncing the throttle bodies.

Also, when you say "I checked the valve clearens yesterday and it seems ok", what were the clearances?

It´s 0,10mm on the intake and 0,15mm on the exhaust. According to my maintenance book that´s about right