'04 Cafe Sport Dyno Run

[luhbo]

...

 

Usually, when we map/tune for midrange, it's at a slight loss to top end power, at least 5% or more, and vice-versa. ....

 

Could you explain this, please? Does it mean, with the same equipement, means inlet - outlet, I have the choice between top end or midrange power?

 

Hubert

[Ryland3210]

Could you explain this, please? Does it mean, with the same equipement, means inlet - outlet, I have the choice between top end or midrange power?

 

Hubert

 

Since mapping of the midrange and and top end are independent, I do not see any cause for a tradeoff between them or a need to choose. I suspect that by "tuning" Kevin is including inlet, outlet, valve opening, valve timing, as examples of variables which could create a such a trade off.

 

Of course, Kevin will no doubt speak up on what he means.

[Pierre]

... "Mapping" was not the best word to use. I meant setting up an engine completely, as in valve size, inlet size, exhaust size, venturi (carb or TB) size, valve timing. The rest of you are correct, as with altering timing, AFR, whether via carburator (needle/needle jet, main jet) or mapping software, the circuits are independent. Sorry for the mis-speak.

 

Engines that are set up for low end power/torque, typically sacrifice some peak RPM output and vice versa.

 

The one benefit to electronic systems is that we can alter timing in certain areas, whereas this was not possible (to my knowledge) with older mechanical advance.

With that revision / explanaiton, I pretty much agree with Kevin on this. However, there is one modification that in my experience substantially increases mid range without harming (though not helping much either) top end, and that is to increase the CR. Of course, then you do have to deal with timing and so forth.

 

It's a mixed bag of trade offs. Cam, then head work, yield the biggest gains in peak HP IMHO, while adjusting a/f ratio and timing are secondary but absolutely necessary to accommodate cam and head work.

[dlaing]

Retarding the timing has the same end result as richening the AFR. If the mixture was lean to begin with, then retarding the timing would improve output. Another generalization: advancing timing leans mixture, retarding does the opposite. That's what's nice about the older distributor Guzzis, like the Eldo...You can nudge the timing a few degrees and do a plug reading to observe the result, then test ride it. Their simplicity allows one to learn the fundamentals of engine tuning.

Generally retarding the timing has a similar result to enrichening the AFR.

You can get more power by retarding for more reasons than a pre-existing lean condition.

For Motoguzznix, retarding ignition could have helped because it was too lean to begin with, or it could have helped because the timing was simply wrong.

I got the impression that Motoguzznix optimized fuel before determining that retarding would produce more power. I am not sure if he re-optimized fuel after retarding timing, but it would have made sense to do so, if he could afford enough dyno time.

[Ryland3210]

The one benefit to electronic systems is that we can alter timing in certain areas, whereas this was not possible (to my knowledge) with older mechanical advance.

 

That may be true for Guzzi's, but timing curve modification of mechanical advances is certainly possible. Changing springs, filing the slots and so on are ways of controlling maximum advance, the RPM at which advance begins, and even two different slopes of the degrees versus RPM within the curve. Then there is the vacuum advance, with similar curve modification possibilities. Lots of flexibility there.

 

Speaking of vacuum, I understand that the fuel pressure regulator is referenced to atmosphere, and at one time the intention was to connect that to the vacuum port on the throttle body. The purpose was to increase fuel pressure when the throttle was opened wide to accelerate, and consequently temporarily add more fuel until the RPM caught up, and vacuum increased again, similar to an accelerator pump. I recall reading one post offering the opinion that it's better not to connect it because the resulting exercising of the regulator every time the throttle was moved would result in earlier failure of the regulator.

 

To review, one of the reasons accelerator pumps are used is that with sudden throttle opening, some fuel can condense as a result of the sudden increase in absolute pressure in the intake passage. The pump makes up for the temporary lean condition. My bike seems to have no such hesitation, so I imagine the mapping must be deliberately over rich to compensate.

 

It seems to me that if I simply connect it to the vacuum port, it will lean out the cruise mixture, while leaving the WOT mixture where it is. Viola! Longer range, same full throttle mixture. I'd have to be alert for pinging, and change timing if ncecessary.

[dlaing]

That may be true for Guzzi's, but timing curve modification of mechanical advances is certainly possible. Changing springs, filing the slots and so on are ways of controlling maximum advance, the RPM at which advance begins, and even two different slopes of the degrees versus RPM within the curve. Then there is the vacuum advance, with similar curve modification possibilities. Lots of flexibility there.

But not nearly the flexibility of the ECU map.

And without vacuum advance, centrifugal timing adjustment is two dimensional and limited.

 

Speaking of vacuum, I understand that the fuel pressure regulator is referenced to atmosphere, and at one time the intention was to connect that to the vacuum port on the throttle body. The purpose was to increase fuel pressure when the throttle was opened wide to accelerate, and consequently temporarily add more fuel until the RPM caught up, and vacuum increased again, similar to an accelerator pump. I recall reading one post offering the opinion that it's better not to connect it because the resulting exercising of the regulator every time the throttle was moved would result in earlier failure of the regulator.

I thought connecting to the airbox might give better feedback, and the vacuum would not be too great, but a complete remapping might be necessary.

 

To review, one of the reasons accelerator pumps are used is that with sudden throttle opening, some fuel can condense as a result of the sudden increase in absolute pressure in the intake passage. The pump makes up for the temporary lean condition. My bike seems to have no such hesitation, so I imagine the mapping must be deliberately over rich to compensate.

I don't know for sure, but I think the ECU has built in throttle pump emulation.

So, it was not deliberately mapped over rich.

 

It seems to me that if I simply connect it to the vacuum port, it will lean out the cruise mixture, while leaving the WOT mixture where it is. Viola! Longer range, same full throttle mixture. I'd have to be alert for pinging, and change timing if ncecessary.

Could be an interesting experiment.

It would be good to do it with a WBO2 sensor.

The deceleration could be a problem. I would expect lean popping.

[guzzi jon]

Looks great.

 

Do you have any AFR plots to go with it? Was it corrected for temperature, barometric pressure and humidity?

 

Louie set the AFR around 13/1, there was no correction on the dyno, he assured me the guzzi sensors adjusted for barometric pressure. I do know that on the way home from this tune, on one of the straights in the mountains, I hit a bit over 130mph in no time. it wheelied just rolling on the throttle... sucker absolutley smoked, idled like a sewing machine, started perfect, ran perfect in 0 degrees or 115 degrees. It was absolutely the best running guzzi I have ever ridden, my cal SS dyno linked by louie is also perfect running... and it ran great pre PCIII Anyone who doubts the value of a PCIII has never had one properly tuned... It is matched perfectly to the minor variations and nuances of your bike, no other method to do this... I'll have my Cal SS at the So Cal National this year, anyone who wants to experience a perfect fueled guzzi is welcome to try it

[Ryland3210]

I thought connecting to the airbox might give better feedback, and the vacuum would not be too great, but a complete remapping might be necessary.

 

Think in terms of absolute pressure: as the throttle is opened, it increases on the intake side of the butterfly, but decreases on the airbox side, so they are the inverse of each other. The variation in pressure on the intake side is also far greater than the airbox side.

 

Assuming the post I referred to is correct, then since the increase in absolute pressure is supposed to make the mixture richer, connecting that to the airbox would make the mixture leaner as the filter becomes contaminated. That's OK, I suppose, although if the regulator is designed to be sensitive to the much larger variation on the intake side, connecting it to the airbox would probably have a negligible effect.

[Ryland3210]

Louie set the AFR around 13/1, there was no correction on the dyno, he assured me the guzzi sensors adjusted for barometric pressure. I do know that on the way home from this tune, on one of the straights in the mountains, I hit a bit over 130mph in no time. it wheelied just rolling on the throttle... sucker absolutley smoked, idled like a sewing machine, started perfect, ran perfect in 0 degrees or 115 degrees. It was absolutely the best running guzzi I have ever ridden, my cal SS dyno linked by louie is also perfect running... and it ran great pre PCIII Anyone who doubts the value of a PCIII has never had one properly tuned... It is matched perfectly to the minor variations and nuances of your bike, no other method to do this... I'll have my Cal SS at the So Cal National this year, anyone who wants to experience a perfect fueled guzzi is welcome to try it

 

The reason I asked about the correction factor was to normalize it to other dyno charts. When it's done right, the actual horsepower developed is corrected for the local barometric pressure, temperature and humidity, all of which affect horsepower developed. That's separate from the correction made by the Guzzi ECU. For example, on my dyno run the actual horsepower was reduced by 1%. Without knowing the local conditions on your run, we don't know what the HP would be under standard conditions. It could be more or less than what the dyno chart indicates. Also smoothing the curves can be done to filter out peaks and valleys which are often artifacts of the dyno's electronic signal conditioning.

 

Sounds like a great running bike. If I make it to the SoCal Rally, I'll be looking for you to take you up on that invitation!

[guzzi jon]

The reason I asked about the correction factor was to normalize it to other dyno charts. When it's done right, the actual horsepower developed is corrected for the local barometric pressure, temperature and humidity, all of which affect horsepower developed. That's separate from the correction made by the Guzzi ECU. For example, on my dyno run the actual horsepower was reduced by 1%. Without knowing the local conditions on your run, we don't know what the HP would be under standard conditions. It could be more or less than what the dyno chart indicates. Also smoothing the curves can be done to filter out peaks and valleys which are often artifacts of the dyno's electronic signal conditioning.

 

Sounds like a great running bike. If I make it to the SoCal Rally, I'll be looking for you to take you up on that invitation!

 

I dont believe the bhp was corrected for altitude as the sole purpose was to enhace performance and driveability. Louie could do that, but I was not looking for a chart to post, just a sweet running bike. I do not belieive and correction factors were involved, or smoothing, it was simple race type tuning, pure data, no bs, no effort to maximise the appearance of the results. It as spooky as my Lemans ran perfect when I arrived, and ran much more perfect when I left, huge gains in the powerband, and big gains on top.. having the bike wheelie during low gear roll ons was a real surprise.

[Ryland3210]

I dont believe the bhp was corrected for altitude as the sole purpose was to enhace performance and driveability. Louie could do that, but I was not looking for a chart to post, just a sweet running bike. I do not belieive and correction factors were involved, or smoothing, it was simple race type tuning, pure data, no bs, no effort to maximise the appearance of the results. It as spooky as my Lemans ran perfect when I arrived, and ran much more perfect when I left, huge gains in the powerband, and big gains on top.. having the bike wheelie during low gear roll ons was a real surprise.

 

OK, but it's not a matter of maximizing the appearance of the results, just me being my usual inquisitive nerdy self. This is the kind of thing that happens to us northerners with too much time on our hands, and not enough good riding weather.

 

I was curious about what the performance was compared to others on an apples to apples basis. For example, it could be that even though the altitude was high, which would normally reduce power, barometric pressure might have been high enough that day that it was actually as if the bike was below sea level. Similarly, higher than standard temperature would have reduced HP. Humidity also affects HP. Applying the correction factors would make the chart more informative on a scientific basis.

[motoguzznix]

Generally retarding the timing has a similar result to enrichening the AFR.

You can get more power by retarding for more reasons than a pre-existing lean condition.

For Motoguzznix, retarding ignition could have helped because it was too lean to begin with, or it could have helped because the timing was simply wrong.

I got the impression that Motoguzznix optimized fuel before determining that retarding would produce more power. I am not sure if he re-optimized fuel after retarding timing, but it would have made sense to do so, if he could afford enough dyno time.

Unfortunately my efforts in remapping were stopped last year and will hopfully continue this year when my house with workshop is ready to live in it.

Yes, I first optimized the fuel as it was a lot too lean in most areas except above 7000 rpm. Then I did retard the ignition by 3° and got gains of 1-2 HP in most areas.

In the meantime I reoptimized the fuel again but I neither have dyno nor A/F measurements done since then.

 

One thing to consider is that I raised the CR by ~0,5 points and that means the fuel burns faster. Thats why retarding the ignition was to be tried. But I really think that the max advance of 44° is too much for Guzzis. The old Lemans never had more than 34° advance from 5000 rpm onwards. I suppose that much advance was applied to make the engine burn completely the lean mixture combined with the restrictive exhaust to meet the emission standards.

If you enrichen the fuel and apply an open exhaust the volumetric efficiency climbs and the engine can burn this better mixture faster thus requiering again less advance.

 

first on the plan for my V11 is to increase the intake flow above 8 mm valve lift to get it flat at 11 mm.

next is to raise the CR further 0.5 to 0.7 points by milling the chamfer completely off the gasket surface to get a real squish.

and eventually remapping of fuel and ignition is necessary

If that does not satisfy me torquewise a camshaft with shorter timing and more lift (maybe Scola OSS) will be applied.

[dlaing]

Thanks for the clarification. I had missed that you had increased the compression.

I am looking forward to your progress reports! ( please )

Sounds like a great plan!

[raz]

Speaking of vacuum, I understand that the fuel pressure regulator is referenced to atmosphere, and at one time the intention was to connect that to the vacuum port on the throttle body. The purpose was to increase fuel pressure when the throttle was opened wide to accelerate, and consequently temporarily add more fuel until the RPM caught up, and vacuum increased again, similar to an accelerator pump. I recall reading one post offering the opinion that it's better not to connect it because the resulting exercising of the regulator every time the throttle was moved would result in earlier failure of the regulator.

 

To review, one of the reasons accelerator pumps are used is that with sudden throttle opening, some fuel can condense as a result of the sudden increase in absolute pressure in the intake passage. The pump makes up for the temporary lean condition. My bike seems to have no such hesitation, so I imagine the mapping must be deliberately over rich to compensate.

 

It seems to me that if I simply connect it to the vacuum port, it will lean out the cruise mixture, while leaving the WOT mixture where it is. Viola! Longer range, same full throttle mixture. I'd have to be alert for pinging, and change timing if ncecessary.

I have thought about that one back and forth too. As I have a WBO sensor I could try it and datalog the results.

 

This is from my WHB:

The pressure regulator is needed in order to maintain a constant pressure difference on the injectors.

The pressure regulator is a membrane differential type that is set to 3 ± 0.2 bar during the assembling.

If the fuel pressure exceeds the setting an internal duct is opened and the fuel in excess re flows toward the tank.

Remember that in order to have a constant pressure difference on the injectors, the pressure difference between

the fuel pressure and the intake pressure must be constant.

I'm not sure about that last sentence but are they not saying we should connect that port to the manifold? But unlike in the older P8 manual no such hose is showed on any picture or mentioned except for that cryptic sentence.

 

The regulator will simply set the fuel pressure to 3 bar above whatever pressure is in that reference port. So, anyone have any clue on the range of intake manifold negative pressure? Is it peaking like 0.1 bar or 1 bar or what? And one thing really bothers me: anyone that has tried to synch the TB's without a LOT of damping in the hoses will know what I mean... what would the fuel pressure at the injectors look like with that shock-waves as regulator input?!

 

But not nearly the flexibility of the ECU map.

And without vacuum advance, centrifugal timing adjustment is two dimensional and limited.

The ECU doesn't have a MAP sensor so it's limited too. On the other hand, it does know the throttle position, so it can make a good guess I suppose.

 

I don't know for sure, but I think the ECU has built in throttle pump emulation.

Not the OEM I think. Not the WM16 anyway. The PCIIIUSB have it (can be downloaded for free) and MyECU has it.

[Skeeve]

I'm not sure about that last sentence but are they not saying we should connect that port to the manifold?

 

I think they're saying the port should be connected to the airbox. "Intake pressure" would be the air pressure inside the airbox; "intake vacuum" would be intake in the manifold next to the injectors.

 

As for how quickly or not the pressure regulator would fail getting the rather substantial pressure fluctuations fed into it, I have no idea. Maybe the addition of a pinhole restrictor a la' the little brass units that come w/ carb stix [mercury manometers, whatever you want to call'em...] would be in order? Easy enough to try it out, but to me

so it's all just theoretical AFAIC.