Triumph Speed Triple Forums banner
1 - 20 of 31 Posts

·
Registered
Joined
·
2,832 Posts
Discussion Starter · #1 ·
I rode a Benelli TnT 1130 Cafe racer today and it had this cool useless gizmo that reduces -10hp (or adds 10hp, depends on how you look at it) by pushing one button. You can do it on the fly, no need to stop or restart the bike or anyhthing like that.

Of course there's ways to do this otherwise, but I guess this is done by adjusting the mapping in the ECU?

Benellis are tuneboy compatible so I guess the ECU unit is kinda similar to Speedy. So I was thinking could something similar be done with Speedy? It would be cool to have separate hooligan and economy mapping that could be switched by pushing a button.
 

·
Registered
Joined
·
8,252 Posts
The 2007 GSX1000R has the same feature. The service manager at the dealership said it was like having the entire GSXR line in one bike. 600 in "C" 750 in "B" and 1000 in "A" modes respectively. (I think that was the order) He also said the easiest way to power wheelie the bike is to accelerate in "C" mode and bump it to "A" on the fly. Instant power wheelie. :smitty: If the S3 had the same feature I could definitely see the benefit of a economy and hooligan mode. ;D ;)
 

·
Registered
Joined
·
2,832 Posts
Discussion Starter · #3 ·
Word! :d:

I think the first thing would be to find out how it's done. Changing the mapping would be an obvious solutions but how do you do it? Upload a new tune? That can't be it, it would require "rebooting" the bike?

Other option would be having two different maps in the ECU and let the ECU do the change. This however needs to be built in feature in the ECU. So it's not gonna happen with Speedy. Or at least Tuneboy doesn't show this option. Is Tuneboy's features all there is to our ECU's?
 

·
Registered
Joined
·
4,658 Posts
It is simple.
The ECU has several maps in memory and the switch simply lets you change between them on the fly. My F250 has an added chip that does the same thing - not from the factory. :eboy: I only use the economy setting for towing.

My question to you all is this: If you had the cruise rpm/throttle range tuned for economy, and WOT tuned for best power, why would you want to ever switch between tunes and limit power? I have ridden several bikes and driven several cars with the ability to switch maps on the fly. I never did.
 

·
Registered
Joined
·
2,832 Posts
Discussion Starter · #5 ·
Well I think it's simple. If most of my riding is normal paced commuting there's simply no need for all the power Speedy has to offer. So I can use a tune made fuel economy in mind and save a good amount of money. And when I go hooligan and want to use everything speedy's got I can I just hit the button and go nuts.

I haven't ever had this possibility so I don't know if I would actually use it, but I'm thinking it would be useful.
 

·
Registered
Joined
·
2,832 Posts
Discussion Starter · #6 ·
Btw. What kind of differences in MPG could you expect with a tune made for optimal fuel economy? If there's little difference in the fuel economy between an optimal power/torque tune and optimal fuel economy tune there's no point even thinking about this.

This whole fuel economy thing might seem a bit strange to you guys, but remember that stuff actually costs something over here (we get fucked with fuel taxation big time).

:devil:
 

·
Registered
Joined
·
1,186 Posts
What Devi is saying is that if the bike is tuned for economy at part throttle openings, then tuned for power at bigger throttle openings, the button is obsolete. When cruising at part throttle, you have the economic mapping, but when the throttle is twisted farther open, the mapping would favor power over economy. Think exponential throttle. I think the switchable maps are pointless on a street bike. On a track when you want consistent laps rain or shine, switchable maps make a little more sense.
 

·
Registered
Joined
·
1,186 Posts
The part throttle parts of the map would be the same. Full throttle would not feel like full throttle anymore, so why?
 

·
Registered
Joined
·
4,658 Posts
If you are truly after good mileage, then you don't need to use wide open throttle (or even more than about 80%). If you tune the mapping under this throttle position so that it runs leaner and maximizes mileage, you can tune above this for best power. All it takes is restraint not to give it all that throttle.

A lean burn condition in the cylinder is good for mileage, but hesitates when the throttle is suddenly twisted wide open. An engine wants fuel to accelerate. Lean burn is hard to ignite. And when the throttle is suddenly opened, it goes leaner causing hesitation and even misfires in many cases - unless the acceleration circuits/maps are tuned well.

;D
 

·
Registered
Joined
·
729 Posts
How do you cut power from an injected engine safely?

1. retard the ignition (and burn the exhaust valves if someone rides TWO with the limiter)? No no
2. make the mixture very lean or rich? No no
3. Cut the fuel and spark randomly from cylinders? Runs rough. Not a perfect idea but won't hurt the engine.

How is it done in the real world?
By limiting the air supply to the engine so the mixture is ok all the time and the engine runs fine but only with limited power. With diesels it is even simpler by only limiting the fuel.

Corvette ZR1 closed half of the ports in the 16 channel manifold by turning the key. GSXR, Rocket 3 and Benelli limit the opening of the secondary butterflies. It is simple and does not need any complete mapping change. Just push the button or turn the key and the maximum opening of the servo operated butterflies is limited.

My conclusion is it cannot be done in the S3 with single cable operated butterflies and the feature is pretty much useless anyway unless you loan the bike for some jackass (which is not a bright idea anyway). It is sensible with corvettes and high end cars considering wifes, sons, daughters (and their boyfriends), valets etc.

Devi is right about tuning the low throttle to economy and the rest for power. With small throttle openings you do not want much power. Otherwise you would have twisted it more. With stock gearing the bike goes 130km/h at about 20% throttle position. I have usually tuned the sub 25% for better economy.

There is something fucked up with these injected bikes. My 1998 Bandit 1200 was heavier, with bigger engine and more power than the S3 but it drank considerably less. Modern precise fuel metering should get better mileage. Most people think it is meaningless because the biking is so expensive anyway and because the engines are powerful it is ok or even cool to drink like a camel even when going slowly. On Finnish bike forums if someone talks about fuel economy, people laugh at him/her. You are not supposed to nitpick about that even with the $7/gal gas.
 

·
Registered
Joined
·
32,016 Posts
HarriS said:
There is something fucked up with these injected bikes. My 1998 Bandit 1200 was heavier, with bigger engine and more power than the S3 but it drank considerably less. Modern precise fuel metering should get better mileage. Most people think it is meaningless because the biking is so expensive anyway and because the engines are powerful it is ok or even cool to drink like a camel even when going slowly. On Finnish bike forums if someone talks about fuel economy, people laugh at him/her. You are not supposed to nitpick about that even with the $7/gal gas.
HarriS, there's actually an explanation for this and it's quite interesting. dr_gallup would be the one to question on this issue, but here is how I understand it. (Please correct me anyone if I am off base here)

Basically it's this, Fuel Injection is a mixed blessing as it is right now. On the one hand it produces more HP and better emissions because it more accurately maintains Air/Fuel ratios and is more adjustable to environmental conditions- particularly temperature. It's difficult to tune a carburetor for an engine (such as a air cooled Harley) that has high variations in engine temperature. You end up having to tune very rich for the engine to perform properly, which is very bad for emissions. Fuel Injection solves this problem by continuously monitoring the temperature and adjusting (at least that's the theory, and the reason why Harley has moved to FI.)

On the other hand, the electronic fuel injectors used on modern cars and bikes have a serious down side in comparison to carburetors. It's concerned with fuel droplet size and fuel vaporization. Carburetors actually do a very good job of diffusing the fuel into the air as a very fine mist, but they have difficulty making changes to the A/F ratio on the fly. Electronic fuel injectors do a good job of maintaining A/F ratios, but are particularly poor at diffusing the fuel into the air. It's all about droplet size. This is one of the reasons why most fuel injectors are oriented to spray the fuel onto the back of the hot intake valves: it helps evaporate the fuel for better mixing in the combustion chamber (due to "squish" and "swirl" characteristics inside the combustion chamber.) The other reason is (of course) to help keep the valve cool.

So, what we have is a situation where carburetors give the engine an A/F charge that burns more efficiently thus giving better fuel economy, while the Fuel Injection allows us to tune to higher horsepower at the cost of burning more fuel less efficiently.

Does that make sense?

An interesting wrinkle is that there are experiments now with high-pressure fuel injectors like those used in direct injection Diesel engines which decrease the droplet size considerably. These experimental fuel injectors have both flexible tuneability, and good A/F mixture capabilities. However there do seem to be some technical difficulties with implementing them on petrol engines that I'm not too clear on.
 

·
Registered
Joined
·
729 Posts
Actually it makes perfect sense. This is only speculation since I do not know it in depth. Lets face it, S3 has pretty much power/cylinder. About 43hp that is. With 3 cylinders you need the injectors of the size of a 180hp four cylinder car. A bike needs maybe 12hp to travel at steady 65-70mph. The injector open time is so little that the fuel atomization might not be the best.

The liter twins like Moto Morini, KTM Super Duke etc have turned out to be highly uneconomical. They have like 60hp per cylinder and need even bigger injectors than the S3.
 

·
Registered
Joined
·
4,547 Posts
Actually, fuel injection has very little impact on fuel economy by itself. Fuel economy is mostly determined by combustion chamber shape, valve timing, gearing, ignition timing, aerodynamics, friction, etc. Carbs can be setup to give you good power, good drivability, good fuel economy or good emissions, but not all at once. With fuel injection and the miracle of closed loop feed back control, it is possible to get it all. Of course, the engine/vehicle designers still have to decide what kind of trade offs between performance and economy they want to make. On most bikes they have obviously gone heavily toward performance and given fuel economy very little emphasis. Motorcycles have been able to get away with carbs until very recently because their emissions requirements have been much more lenient.

I have done a lot of testing of injector sprays and they make virtually no difference in efficiency (fuel economy) in typical port injection installations. They make a bigger difference in emissions. Smaller droplet sizes are not necessary in port injected engines at operating temperatures to get complete combustion. There is enough time and energy available to get the fuel completely mixed and vaporized during the inlet and compression strokes. Smaller droplets are helpful during cold start conditions in port injected engines. I have tested ultrasonic injectors and heated injectors. There have been a lot of fancy SAE papers written about them but the supposed benefits of their "better" atomization are very hard to find. In fact, I have seen a lot of engines where a more dense, narrow spray can improve emissions and performance because it reduces wall wetting in the intake tract which is a very bad thing.

Direct injected engines must have much smaller droplet sizes because there is much less time and motion available between injection and ignition. The fuel economy benefits of direct injection are not due to the smaller droplet sizes but to several factors depending on the schemes the engine designers have chosen to use particularly lean burn stratified charge. It is pretty hard to get direct injected gasoline engines, especially lean burn ones, to meet EPA emissions requirements. It has taken over 10 years for the technology to move from the Japanese domestic market to Europe and finally just recently to the US. That is almost entirely due to differences in emissions requirements and the general indifference toward fuel economy in the US market until gas prices shot up 2 years ago.
 

·
Registered
Joined
·
32,016 Posts
What I tell you? The Doctor is in!

Most of my understanding of the issue was from books I've read 20 years ago. Go figure if they're not quite up to date theory wise!

Now, if I understand it correctly the new dual injector setups on the new hyperbikes are for low and high intake air speeds? The close injector is for low intake velocity (i.e. low RPM) and the far injector is for high intake velocity? Thus giving the fuel more time to vaporize?

Are any of them using variable inlet geometry like some of the new sports cars?
 

·
Registered
Joined
·
4,547 Posts
crashmasterd said:
What I tell you? The Doctor is in!

Most of my understanding of the issue was from books I've read 20 years ago. Go figure if they're not quite up to date theory wise!

Now, if I understand it correctly the new dual injector setups on the new hyperbikes are for low and high intake air speeds? The close injector is for low intake velocity (i.e. low RPM) and the far injector is for high intake velocity? Thus giving the fuel more time to vaporize?

Are any of them using variable inlet geometry like some of the new sports cars?
One thing I should add is that most of my work has been with automobile engines at lower engine speeds. An R6 turning 16000 RPM obviously has a lot less time to vaporize the fuel than a small block Chevy or even my 350Z. Although I did work on some pretty high RPM engines like the McLaren F1 street car, various BMW's and of course the 955i, Aprillia Mille, etc.

Yes, the upper injector is used at high RPM & load. The primary reason for two injectors is the dynamic range requirement is too great for a single injector. When they get the injector sized properly for max power & RPM they can not get it to deliver a sufficiently small quantity accurately enough for good idle and part throttle response. The aforementioned McLaren F1 had 24 injectors for it's 12 cylinders. We originally quoted them at $100 apiece because they wanted special designs in low volume. In the end I think we sold them for about $25 each, double what most OEM injectors cost back then. The C4 Corvette ZR1 also used 2 injectors per cylinder.
 
1 - 20 of 31 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top