Vmax MPG improvement

[3-Max]

I was told it kicks in around 6000RPMS yet I can hold it steady in that area and not notice a increase in power

V-boost isn't all or nothing. The servo controls a butterfly valve between the front & back pairs of carbs. The ecu opens this valve progressively starting at 5,75k to fully open at 8 k (might be sooner). Things really start to ramp up at c.7k - at least on my trike (& it's awesome). I don't notice it at 6.

Just starting to do shakedown runs after majour carb servicing, did mpg calc last time & got 26 / UK gal. so envious of the 35-40 being talked about here but I was into V-boost several times in the 45mile trip & it is a trike so no idea what gearing/dif ratios are or o/a weight. Only ridden it 5-6 times at that sort of distance & not owned anything like this (inc bikes <500cc) before so still on a big learning curve.
5.5-6K is giving me 70mph/110kph in 5th.
+side I've room to fit a much bigger tank. I'll also be fitting a simple make/break toggle switch on the line operating the servo so I can turn it off for motorway cruising to get places (eg. a bike meet) but flip it back should it be required.

 

[Incider]

My 96 uk spec bike gives 32mpg pulling a sidecar, 96 Canadian same set up gives 25 if I'm lucky

 

[Jack Hammer]

Mine does 7.0l/100km with numerous mods. 7.5 when I push it a lot. Basic tank size is ok.

 

[Woody]

My wrist won't allow anything over 25mpg.
Nor will the smile on my face.Everytime I twist the on /off switch.

 

[3-Max]

96 Canadian same set up gives 25 if I'm lucky

Hmmm. My trike base is '98 Canadian. Any idea what the difference is to UK spec?

 

[jpeterguerra]

My 96 uk spec bike gives 32mpg pulling a sidecar, 96 Canadian same set up gives 25 if I'm lucky

Are you in the Toronto area? If you do can you recommend a Vmax mechanic. I have a 2007 which needs the valves adjusted and the Carbs synchronized. Thanks Peter Guerra

 

[Incider]

Are you in the Toronto area? If you do can you recommend a Vmax mechanic. I have a 2007 which needs the valves adjusted and the Carbs synchronized. Thanks Peter Guerra

I'm in , got a lot of imports over here

 

[jpeterguerra]

I'm in , got a lot of imports over here

Thank you for your reply... Hope your day is Awesome.

 

[one2dmax]

Float settings and overall carb settings are primary factors in fuel economy. The stock (smaller) tires at 40psi plus brakes that don't drag. Lots of little things add up.

 

[Redrum]

Float settings and overall carb settings are primary factors in fuel economy. The stock (smaller) tires at 40psi plus brakes that don't drag. Lots of little things add up.

I could see if the Float is set to allow too much gas in and it overflows into the engine or on the ground. Is there something else a float setting being off might do?

I can't see how it would richen up the mix.

I'm 100% not disagreeing but I just don't know.

 

[Jack Hammer]

Float level affects how your emulsion tubes work, how your throttle responds, the transition.

 

[sparky4123]

Yes if you think about it, your carbs work by vacuum lifting fuel out of the float bowl. The higher the fuel level the easier the fuel will be drawn in - richer.

 

[Jack Hammer]

When tuned properly, carbs are better for the engine than fuel injection and less than 5 percent away from the benefit to the owners wallet. They keep the engines slightly richer, which the engines like but the society condemns. I'm not trying to sound old school but that's a fact.

 

[MaxMidnight]

When tuned properly, carbs are better for the engine than fuel injection and less than 5 percent away from the benefit to the owners wallet. They keep the engines slightly richer, which the engines like but the society condemns. I'm not trying to sound old school but that's a fact.

Perhaps you can explain what you mean by 'better for the engine than FI'?
E.g.: less fuel consumption, lower emissions, better torque and power, maintaining synchronisation, more reliable, the ability to react to various changes such as altitude, throttle position, weather condition, atomisation of the fuel, drivability, the facility for diagnosis?

 

[Jack Hammer]

Engines like richer conditions by their nature than we want to provide. When I was a kid and older with carburated engines you had to learn the quirks. The quirks in general were how to richen the mixture temporarily in a nutshell. Piston engines are still the same, valves bring mixture in, valves carry residue out.

My point is that if you know how to use carburated engines they won't shy away from fuel injection. Engines have characteristics that you need to learn. If you have fuel maps and electronic throttle every time, you personally will never learn this.

Carbs are very good if they are properly tuned for the application, very close to FI, sometimes more powerful because fuel delivery is based on draft and demand and FI is based on programming and force feed. A responsive human being will always outsmart a computer in the conditions one drives/rides in. Fuel injection made the engine quirks obsolete to the person who doesn't want/need to learn them. Electric throttle was introduced originally because the engines were not able to respond to driver commands fast and efficient enough. Think about it: Why would you want to control throttle pedal movement at the throttle blades? You surely don't want the blades to open faster for a million different reasons. Electronic throttle slows your pedal movement down at the blades to give the engine more time to respond to its programmed parameters with smooth operation.

This is just my opinion. I have no interest in fighting over any of this.

 

[MaxMidnight]

My point is that if you know how to use carburated engines they won't shy away from fuel injection. Engines have characteristics that you need to learn. If you have fuel maps and electronic throttle every time, you personally will never learn this.

Why do you have to learn? That is true to a certain extent for 'old technology' vehicles but it assumes that a) the individual has the ability to assimilate and apply the knowledge (I suspect very few of us have) and b) do they want to know and learn? (again I suspect they may be in the minority).
With modern vehicles doing the 'thinking' for you not only to you get better performance, lower fuel consumption and emissions, it allows the rider to concentrate on enjoying the ride.

Carbs are very good if they are properly tuned for the application, very close to FI, sometimes more powerful because fuel delivery is based on draft and demand and FI is based on programming and force feed.

You are correct that FI is is based on programming (and electronically controlled) which is based on measurements that ensure the optimum amount of fuel is delivered for a given condition. This infinitely variable and can be altered by the millisecond.
Whilst good carbs well set up for the machine can perform well those fitted to the majority of production vehicles are built to a price not in that category.
There is a reason why vehicles in modern motorsport use FI and electronic ignition..........

A responsive human being will always outsmart a computer in the conditions one drives/rides in. Fuel injection made the engine quirks obsolete to the person who doesn't want/need to learn them.

I think we will have to agree to disagree that a human can perform better than a computer. That may be the gift of a select few but for the rest of us that just isn't the case. IMO part of the reason we have ABS, stability control, drive by wire throttles is because most of us don't have the ability to react quickly enough.

Electric throttle was introduced originally because the engines were not able to respond to driver commands fast and efficient enough. Think about it: Why would you want to control throttle pedal movement at the throttle blades? You surely don't want the blades to open faster for a million different reasons. Electronic throttle slows your pedal movement down at the blades to give the engine more time to respond to its programmed parameters with smooth operation.

True, but you also turn that around and say the average driver didn't know how to use the throttle to the best effect?
I think we can agree about the benefit of a electronically controlled throttle. IMO the weak link in a vehicle will always be the person in control.
Systems that can provide safety and efficiency benefits are welcome and as I get older I need and appreciate them more.
My first car (Ford Escort 1300L) gave out some 60bhp and would do just over 30 mpg on a run (this despite being Daytona Yellow with a triple coach line)
My current vehicle Mercedes A Class is also nominally 1300cc and gives 163bhp and averages 44.5mpg.
Now I may be wrong but I suspect that some of this difference will be down to the engine management systems.

This is just my opinion. I have no interest in fighting over any of this.

I completely respect that and I hope you don't see me offering an alternative opinion as fighting.

 

[Jack Hammer]

No no, all good here. I fully understand your points. Very good ones. I'd say we just have different approaches and we are discussing about them. Let's continue. All good.