Power Flat Spots

[Phil A]

John,

 

1. I would expect the three holes to ingest warmer air than the snorkels. Suppose the snorkels were simply cut off the airbox. What would you expect the result to be?

1.

(a) as you bellmouth the snorkel you actually considerably improve the throat of the snorkel. The snorkel is not quite as bad as it seems as the id is fairly large due to the original reservoir shape in there.We just utilise it better.

(b)the snorkel protrudes down into the faster moving air flow than at the top of the air cleaner lid itself.

Does this make sense? Therefore "scooping" air up into the cleaner lid area.

( c ) A hole simply drilled into, say, the front of the airbox will not flow anywhere near as much as a hole fed by a bell mouth.

 

2. I gather from your studies, that unless the ECU is remapped to add fuel at high throttle openings, there would be little change in HP. Moreover, if one were lucky enough to be able to spend any length of time at full throttle, the protracted lean condition could cause piston damage.

2. Strangely enough, the top end performance of a standard bike, given the limitations of aircleaner snorkels/mufflers, airbox design, exhaust etc is actually half reasonable.

I believe this to be so, because it is these figures that are advertised to sell or market the bike. eg 85hp at 7500rpm etc.

When we improve things it is more difficult to get big gains, top end, due to the original effort spent in actually getting the top end right in the first place.

In answer to your question. yes, the factory settings are already nicely lean to maximise performance, so further airflow yields very little gain if you retain the original fuel settings.

 

3. At cruise throttle openings, there would be no reason to change the mapping, because the relatively low air flow rates would not be affected by the reduced restriction provided by the modifications to the airboxl, agreed?

3. In this area we achieve greater gains than you would believe possible. In fact we get a 4% (approx) gain from idle. I found this hard to believe at first, however I guess that the same decrease in resistance that gives us the top end must also give us better flow from the bottom up. In fact I have improved torque at 2800rpm by approx 25%! which is way more than we get in the top end. Therefore this mod to a std bike without correcting the fuel delivery, will give you worse stalling/surging/hicuping than original.

 

Greg,

the initial mods were round holes as described however as I supply this design with my maps I figured it is all around the world by now. You will be surprised how much difference it makes.

 

Please excuse my ignorance, What is the BMC?

 

Ciao,

[Greg Field]

BMC is an Italian brand of gauze filter, like a K&N.

 

So the teardrop shape allows significantly more power than the round holes do?

[motoguzznix]

Thanks Phil for your explaining!

 

I think max power will not increase on a V11 when performing your mods with the airbox because of the limited breathing of the V 11 intake port. Supposedly the V10 4V design flows significantly more air and therefor can make use of the better capability of the modified airbox.

This might be different for gains in the lower rpm area.

 

When I was on the Dyno with my KR V11, I compared the stock airbox with the snorkels to a modified one with 6 holes of 25 mm on the top and could not measure any difference powerwise. The mixture on the top was almost the same and got richer from 6000 to 8300. This lead me to the conclusion that the airbox was not the bottleneck in the V11 system. Here is the graph whith the two Leovinci measurements with an without holes in the airbox.

 

Exhaust was an open leovinci cans with Stucchi Xover.

 

I will give your mods a try, but first I want to fix the intake port issue.

[Ryland3210]

John,

1.

(a) as you bellmouth the snorkel you actually considerably improve the throat of the snorkel. The snorkel is not quite as bad as it seems as the id is fairly large due to the original reservoir shape in there.We just utilise it better.

(b)the snorkel protrudes down into the faster moving air flow than at the top of the air cleaner lid itself.

Does this make sense? Therefore "scooping" air up into the cleaner lid area.

( c ) A hole simply drilled into, say, the front of the airbox will not flow anywhere near as much as a hole fed by a bell mouth.

2. Strangely enough, the top end performance of a standard bike, given the limitations of aircleaner snorkels/mufflers, airbox design, exhaust etc is actually half reasonable.

I believe this to be so, because it is these figures that are advertised to sell or market the bike. eg 85hp at 7500rpm etc.

When we improve things it is more difficult to get big gains, top end, due to the original effort spent in actually getting the top end right in the first place.

In answer to your question. yes, the factory settings are already nicely lean to maximise performance, so further airflow yields very little gain if you retain the original fuel settings.

 

3. In this area we achieve greater gains than you would believe possible. In fact we get a 4% (approx) gain from idle. I found this hard to believe at first, however I guess that the same decrease in resistance that gives us the top end must also give us better flow from the bottom up. In fact I have improved torque at 2800rpm by approx 25%! which is way more than we get in the top end. Therefore this mod to a std bike without correcting the fuel delivery, will give you worse stalling/surging/hicuping than original.

 

Ciao,

Thanks Phil.

On 1 ©, Yes, there is a big difference in flow efficiency between a sharp edged orifice and a venturi. However, I was looking for your thoughts on the difference between relatively cool air from the snorkels, versus warm air from hole in the airbox. To the extent the holes in the airbox suck in warmer air of lower density, it should reduce performance, all other things being equal. On the other hand, are you saying that the bellmouthed snorkels still cause enough restriction that the holes in the airbox are a plus, even though the ingested air is probably significantly warmer?

2. OK, understood.

3. With your remapping out the extreme lean condition around 3,000 RPM, I have no difficulty believing in a substantial increase in midrange torque (at full throttle). Once again, am I right to assume there was no remapping of part throttle settings, and that the snorkel/airbox mods do not call for any changes in cruise throttle settings?

[Greg Field]

I looked at my dyno charts again this morning. I can see no torque hole at all. By 2500 rpm, it's reached 56 lb-ft. and just goes up gradually, leveling off at 60 lb.-ft. until 4300 rpm, which point it rises to its peak of 67 lb.-ft at 5200 rpm. WIth the guaze filter, the chart is basically the same, except that it begins the rise at 3600 rpm and peaks higher, at 70.7 lb.-ft.

[Ryland3210]

I looked at my dyno charts again this morning. I can see no torque hole at all. By 2500 rpm, it's reached 56 lb-ft. and just goes up gradually, leveling off at 60 lb.-ft. until 4300 rpm, which point it rises to its peak of 67 lb.-ft at 5200 rpm. WIth the guaze filter, the chart is basically the same, except that it begins the rise at 3600 rpm and peaks higher, at 70.7 lb.-ft.

 

Very interesting.

 

Excuse my ignorance, Greg, but please supply the basic conditions:

 

Mod's to the bike, mod's to the mapping, etc.

 

Thanks,

[dlaing]

One of these days, I'll figure out how to post the charts.

Please do

Here are Jaap's instructions on how to post images

http://www.v11lemans.com/forums/index.php?showtopic=1767

I like to use imageshack

http://www.imageshack.us/

They invite you to register but it is not necessary.

Browse to file

Upload

copy link under heading "Direct link to image"

The links with php in them don't work on this forum...as far as I have figured out.

When you post on the forum simply paste the link, highlight it and then click on the green icon labeled 'insert image'. This surrounds it with the appropriate code.

 

If you are stymied because the charts are in some weird format, you might be able to take screen shots and save them as jpegs or gifs, but detail will be lost.

[Greg Field]

Conditions are '04 Ballabio, all stock expcept Mistral crossover and mufflers, airbox modified per Phil A.'s earlier round-hole pattern, and PC III.

 

I did mapping runs with the paper filter and modified box, and then I replace the filter and box lid with a BMC filter and cut-off lid. That gave immediate power and torque gains at between 3500 and 7800 rpm. Outside these limits, the Phil box and paper filter perfromed better.

 

It's not posting I'm having a problem with. It's scanning the graphs and getting a usable image from them. I 'r' a retard.

[Guest Phil_P]

Although not a V11, you guys might be interested to read about the dyno results I got on my 1100 Sporti here on Wild Goose Chase;

 

http://wildguzzi.com/forum/index.php?topic=13632.0

 

The bike in question is fitted with Raceco crossover, which I think is similar to the Stucchi version, K&N pod filters and Leo Vinci straight through pipes that were originally destined for a Gixer but with some new flanges fitted beautifully.

 

The most noticeable feature of the custom mapping that I had done for the power commander were the amounts of change to even a modified map, with the extreme being an additional 86% fuel added at about 4500 RPM at part throttle.

[pete roper]

I can't really contribute anything to this as I have minimal experience but I can assure people that if Phil talks you are very well advised to listen. Mad as a balloon he may well be but he's done a lot more succesfull tuning, especially flow work, on more motors than most of us have had hot dinners. Chances are if Phil reckons it will make an improvement it will. He doesn't make claims he can't substantiate and he's far to modest to mention the speed records he's achieved over the years or at least I've never seen him do so.

 

He's currently building a Hi-Cam for the salt and hoping to bruise a few egos next year out in the desert in SA. A very sage man, although I do worry about that beard getting sucked into motors sometimes

 

Pete

[Guest Phil_P]

I can't really contribute anything to this as I have minimal experience but I can assure people that if Phil talks you are very well advised to listen. Mad as a balloon he may well be but he's done a lot more succesfull tuning, especially flow work, on more motors than most of us have had hot dinners. Chances are if Phil reckons it will make an improvement it will. He doesn't make claims he can't substantiate and he's far to modest to mention the speed records he's achieved over the years or at least I've never seen him do so.

 

He's currently building a Hi-Cam for the salt and hoping to bruise a few egos next year out in the desert in SA. A very sage man, although I do worry about that beard getting sucked into motors sometimes

 

Pete

 

Can I add, just in case folks didn't realise, Pete is talking about Phil_A not me, Phil_P

[Pierre]

...

A very sage man, although I do worry about that beard getting sucked into motors sometimes

Pete

That would explains his obsession with keeping the air box in place.

[Ryland3210]

Conditions are '04 Ballabio, all stock expcept Mistral crossover and mufflers, airbox modified per Phil A.'s earlier round-hole pattern, and PC III.

 

I did mapping runs with the paper filter and modified box, and then I replace the filter and box lid with a BMC filter and cut-off lid. That gave immediate power and torque gains at between 3500 and 7800 rpm. Outside these limits, the Phil box and paper filter perfromed better.

 

It's not posting I'm having a problem with. It's scanning the graphs and getting a usable image from them. I 'r' a retard.

 

No changes in the mapping?

[Greg Field]

No changes in the mapping. The only thing that changed was the filter element and the top portion of the box. I wanted, on the cheap, to see if Phil was correct that you could make as much power with his modified box and a paper filter as with gauze. He is correct in that. Perhaps the gauze could make more peak power than the paper if a map were made specifically for it. I didn't want to spend the money to try that, as I plan to stick with a paper filter because I like to explore dirt roads and know how poorly gauze filters are in catching dirt (spare me the arguments; I've had two of my bikes ridden side-by-side on the same dirt roads on the same day, one with paper, one with K&Ns, and I've seen how much the paper caught vs. the gauze; there is no comparison).

 

I actually expected the gauze to stomp the paper filter at high rpm, and the paper to stomp the gauze at low and mid. The opposite proved true.

 

I salute Phil for making what appears to be a very marked improvement in the Guzzi airbox.

[Ryland3210]

No changes in the mapping. The only thing that changed was the filter element and the top portion of the box. I wanted, on the cheap, to see if Phil was correct that you could make as much power with his modified box and a paper filter as with gauze. He is correct in that. Perhaps the gauze could make more peak power than the paper if a map were made specifically for it. I didn't want to spend the money to try that, as I plan to stick with a paper filter because I like to explore dirt roads and know how poorly gauze filters are in catching dirt (spare me the arguments; I've had two of my bikes ridden side-by-side on the same dirt roads on the same day, one with paper, one with K&Ns, and I've seen how much the paper caught vs. the gauze; there is no comparison).

 

I actually expected the gauze to stomp the paper filter at high rpm, and the paper to stomp the gauze at low and mid. The opposite proved true.

 

I salute Phil for making what appears to be a very marked improvement in the Guzzi airbox.

 

So what I gather is that between 3800 and 7500 RPM, the gauze filter and cut off lid gave immediate power and torque gains at between 3500 and 7800 rpm compared to Phil's modified airbox with a paper filter, even without optimizing the map for the former.

 

For me, that's the range of primary interest.

 

I still prefer the paper filter with Phil's modification for the reasons you state, but want to clear up my understanding. BTW, I like dirt roads too, but worry about riding on tires designed for the Autobahn.