Throttle By Wire

[jjackkrash]

I have heard a few complaints about the new boats from several manufacturers being more "doggy" or "piggy" than the older versions of the same model, even through the objective numbers appear comparable, like weight, horsepower, acceleration, etc. I believe that this perception by some may be attributed more to the TBW than weight additions, hull changes, or catalytic converters, as the throttle response is just not as crisp and controlled as a mechanical throttle. Anyone else have any thoughts on this issue?

[68Slalom]

It's not the same, you can tell the difference in TBW from the old Throttle Body with cable, there is always a slight delay but response of the engines hp is the same. I think the other big difference is that the throttle handle is much smoother, in a car the gas peddle is really easy to push. I went from a 2001 trans am to a 2006 GTO and you can tell the difference right away. I'm not sure which one I like better

[zad0030]

When we took our 08 for the first time we were speeding through a no wake zone because the throttle was so sensative. The boat jumps out of the hole. It performs 10 times better than my tige did in all aspects. Im not sure where this "doggyness" is because I have never noticed it.

[WakeGirl]

I've driven several '06 VLXs, a couple of '05s & an '07 & an '09. The '05 feels somewhat old school, although very smooth & responsive. All of the '06s (including mine) feel similar, although you can change the feel with spring rate at the throttle as I understand it (I've just never done it). Of the different years, the '07 feels most similar to the '06. And of the TBW boats, the '09 is by far & away the most responsive.

Peter & I have discussed this a little & I wasn't fully conscious of what it was that I was feeling in my boat (even after more than 200 hours) until he put it into words. On the '06 & many of the '07 models, the TBW system has a very slight delay when you first "hit it". How does that translate into the real world? For most boarders & skiers, it's a non issue. But where it matters (& this is where I really notice it) is when you're in a situation where you really have to time your takeoff right, like pulling someone off of a dock. You almost have to anticipate it a little. The other place that you'll notice it is when you're trying to pull up a beginner, it can really foul things up if you're not aware of it & anticipating things a little. With time in the driver's seat it's definitely something that's manageable, so it's not a deal-breaker IMO. But overall IME & at least in the case of the VLX, I don't think that it translates to a lack of power, just a very slight delay in delivering that power. As far as the '08 boats go, I've never driven one, but I've heard that they corrected it for that year. The '05 (no TBW) & the '09 (newest TBW & SBW) both completely lack this "feature".

Maybe Peter can expand a little on the issue, since he's the one that I've seen that seems to be able to speak most intelligently about it.

[skisix@38]

I think it got a lot to do with the dogginess from my own personal experience. I regularly drive a tbw CC196( club boat) and I think PCM does the worst job of TBW. The issue is that the TBW sends signals to the ECM, the ECM then takes those signals and a variety of other signals( ambient air pressure and temp, throttle position etc...) and has to calculate how much gas to mix in. What Tracie said was noticeable to me, the 06 and 07 versions had a slight delay before they started to react. I wonder if this was due to calculation time and a slow processor. The 08 Bu's I drove were a little too sensitive I thought and they threw in too much gas for the little bit of travel on the throttle but didn't seem to have the delay anymore. The delay was something that someone without hours of time at the throttle of a cable boat would ever notice and if the TBW boat was the one you always drove it wouldn't be an issue becuase you would adapt. The 196's I have driven all rate from totaly suck to almost bareable to me in this category. I think I'm a fast learner and a capable driver but for the life of me I can't seem to get the same start out of the 196 I clocked probably upwards of 100 hrs driving! I think it has to do with the rate that the throttle moves and when the ECM finally figures out where to gas. It's like sometimes the ECM sees that I'm at 50% throttle and sometimes I'm at 25% for the same set and skier. Madenning! When I get behind the wheel of my own boat the first thing I notice is how much more relaxed I am when I go to pull a skier up because I know he's not getting overly yanked and he's not drowning- NICE!

Throw in the cats and all that go along with those and finally we get something that feels totally different than what we were used to. I haven't driven a 197 in over a year so I can't comment on those boats and how they react but the 196 is terrible and the few RLXi's that I drove last year were super sensitive.

I had a along discussion with a Scott( I think that was his name) who is the Texas Malibu rep on this issue last Jan at the Dallas boat show and he said he was going to take my opinion and thoughts back to Dennis Kelly and they would give me some feedback- of course that never happened but Scott was nice enough to mail me a bunch of Malibu stickers.

[Woodski]

One item that might make a difference, it was done on some cars, is to have a non linear throttle opening setup. The old 3800 V6 actually opened the throttle faster at lesser throttle positions (approx 50% throttle at 30% pedal position) then flattened out at the higher ends. Result was a very responsive feel to the driver. There might be differences in throttle application across the different marine engine upfitters (Indmar, PCM, etc).

[WakeGirl]

Yeah, the '09 that I drove was really responsive. I think that I could probably get used to that given some time behind the wheel, but my first impression was that it was too responsive. Couple that with the newer throttle knob that shifts with the button at the top.....it was definitely different.

I still think though (& this is my own seat of the pants opinion, not really based on anything) that the delay has more to do with the programming of the computer telling the engine when to go, & not as much with the rest. Doesn't it seem like the issue of how much gas/air to mix would be a separate one? I mean, when to go engage & how much to engage that is, 2 separate issues. In an EFI engine, it has to do those air/fuel mixture calculations either way, whether it's getting the data from TBW or from a traditional throttle cable. And I know that that is not an exact science, after all idle flair was somewhat of an issue at one point in time. (Not the same issue I realize, I just wonder if we have 2 separate problems going on.) What do you think? Am I missing something on that?

[Woodski]

Yeah, the '09 that I drove was really responsive. I think that I could probably get used to that given some time behind the wheel, but my first impression was that it was too responsive. Couple that with the newer throttle knob that shifts with the button at the top.....it was definitely different.

I still think though (& this is my own seat of the pants opinion, not really based on anything) that the delay has more to do with the programming of the computer telling the engine when to go, & not as much with the rest. Doesn't it seem like the issue of how much gas/air to mix would be a separate one? I mean, when to go engage & how much to engage that is, 2 separate issues. In an EFI engine, it has to do those air/fuel mixture calculations either way, whether it's getting the data from TBW or from a traditional throttle cable. And I know that that is not an exact science, after all idle flair was somewhat of an issue at one point in time. (Not the same issue I realize, I just wonder if we have 2 separate problems going on.) What do you think? Am I missing something on that?

Yes, I would agree, different issues with each of the comments. "Dogginess" and lack of initial response on throttle engagement could be different issues. Even some non DBW boats exhibit a different initial throttle response characteristics, but when you couple a non direct activiation system, it can certainly become more apparent. Fine tuning the system to get the correct response takes a few software revisions.

[skisix@38]

Yeah, the '09 that I drove was really responsive. I think that I could probably get used to that given some time behind the wheel, but my first impression was that it was too responsive. Couple that with the newer throttle knob that shifts with the button at the top.....it was definitely different.

I still think though (& this is my own seat of the pants opinion, not really based on anything) that the delay has more to do with the programming of the computer telling the engine when to go, & not as much with the rest. Doesn't it seem like the issue of how much gas/air to mix would be a separate one? I mean, when to go engage & how much to engage that is, 2 separate issues. In an EFI engine, it has to do those air/fuel mixture calculations either way, whether it's getting the data from TBW or from a traditional throttle cable. And I know that that is not an exact science, after all idle flair was somewhat of an issue at one point in time. (Not the same issue I realize, I just wonder if we have 2 separate problems going on.) What do you think? Am I missing something on that?

I've often wondered if someone were to take a new boat, say 09, and put a cable throttle on it what would it feel like? I wonder if the program that replaced the cable adds gas more slowly. So, I'm wondering if the engine really has the same potential to do work but the program that tells the engine how much gas to add and when to do it is the difference.

I agree the mixture is controlled seperately from the timing on when to add more gas. I was getting at the possibility that the processor is lagging a bit due to having extra calculations to do in the same amount of time. I don't know that, just wondering.

[WakeGirl]

Yeah, I see that. The '09 was so different in that the power came on a lot faster than in a traditional cable setup. It was so touchy that it was hard to get used to at first. For people that may not understand, it's an issue of when the power comes on, not the actual raw power that's available.

That's a good point on the throttle cable on a new boat. That really would be an interesting point.

[Bake's Marine]

Personally I think the fly & shift by wire throttle (2008-2009) is awesome, very responsive with minimal throttle movement. It takes some getting use to because it's very different than the fly by wire alone (2006-2007) Those years still had a cable for the transmission and the ECM did not talk with the transmission other than transmission temp. Now when you look at the ECM under scope the engine sees everything, even lake and air temp so all factors are taken into consideration. The new MEFI5-5A ECM's in 08-09 are the latest and greatest when it comes to what it does to get over all performance.

Skisix@38

Some early 07's had issues with Tournament skiers having a laged or a sticky response, they did get addressed though. The pedal position sensor on the throttle needs to be re-torqued (don't quote me but i think it was 4 lbs). The manufacture of the control put them on too tight bending the sensor making it not work correctly. I think it was Denis Kelly that released a calibration to help with the lag problem going around a turn island (i think the calibration allowed some more flexibility for a few filters)

Hope this helped

-Paul

[Lance B. Johnson]

Fuel/ Timing calculation is not done any different than it was before. The real name for throttle by wire is "Throttle Actuator Control". TAC just takes the place of the cable and makes our speed control systems much more reliable. Theoretically if done right TAC systems will not affect the way the boat drives in any way except for the fact that precision pro speed control should be more responsive than Perfect Pass systems that utilize cables. (not sure as I have not driven one)

TAC systems utilize a motor with integrated gear reduction (located on the side of the throttle body), Multiple Accelerator Position Sensors (redundant), and the Engine Control Module or separate TAC module. This system uses inputs from multiple sensors in order to calculate throttle angle. Don't confuse the Accelerator Position Sensor with the Throttle Position Sensor. The TPS is still used and also located on the side of the throttle body.

[WakeGirl]

Theoretically. In reality though TBW in this application is very different from a traditional cable system.

Observation: people that don't like the TBW system or at least have more difficulty adapting to it are typically the ones that have a lot of time at the wheel of ski boats. The ones that like it or are indifferent are often times new to boating or at least new to driving boats. No judgment there either way, I just think that it's something that people are more likely to pick up on if they like what they know & know what they like. If they have very little or no frame of reference on that, then they won't know what to like.

[zad0030]

Another thing about the new throttles is they have a very short throw, Which eliminates all the play out of the throttle which my tige had quite a bit of. Also you can easily get anyone up just by using your thumb.

[Chappy]

I have an 08 VLX with the new throttle and I have some buddies with older Bu's. Although it takes some getting used to because it is so much more sensitive and responsive; I love the new throttle. It is very smooth and resposive. No more dropping the throttle all the way to your knee then pulling back to level the speed off. I did have an issue with the replacement throttle after the recall but my dealer threw another one in and it has worked great. Happy New Year!

[FIC]

Fuel/ Timing calculation is not done any different than it was before. The real name for throttle by wire is "Throttle Actuator Control". TAC just takes the place of the cable and makes our speed control systems much more reliable. Theoretically if done right TAC systems will not affect the way the boat drives in any way except for the fact that precision pro speed control should be more responsive than Perfect Pass systems that utilize cables. (not sure as I have not driven one)

TAC systems utilize a motor with integrated gear reduction (located on the side of the throttle body), Multiple Accelerator Position Sensors (redundant), and the Engine Control Module or separate TAC module. This system uses inputs from multiple sensors in order to calculate throttle angle. Don't confuse the Accelerator Position Sensor with the Throttle Position Sensor. The TPS is still used and also located on the side of the throttle body.

The first systems that were drive by wire with the mefi 4 system had a tac module, the mefi 5 ecm eliminated the tac module. The way the systems works is, at your throttle is a pps sensor their is 2 internal sensors in one howsing, as you move your throttle handle the pps request the ecm to move the electric motor on the throttlebody, which opens the flap letting air in, as the flap opens there are 2 tps sensors inclosed with the electric motor which tells the ecm how much the flap is openning, all of your spark timing and fuel injectors will respond inconjunction with the throttle openning. As far as the transmmision goes pertaining to electronic versus cable there is no gain in performance or response time . As far as drive by wire everything responds in miliseconds , hard to beat for fuel efficiency or excelleration.

[68Slalom]

Fuel/ Timing calculation is not done any different than it was before. The real name for throttle by wire is "Throttle Actuator Control". TAC just takes the place of the cable and makes our speed control systems much more reliable. Theoretically if done right TAC systems will not affect the way the boat drives in any way except for the fact that precision pro speed control should be more responsive than Perfect Pass systems that utilize cables. (not sure as I have not driven one)

TAC systems utilize a motor with integrated gear reduction (located on the side of the throttle body), Multiple Accelerator Position Sensors (redundant), and the Engine Control Module or separate TAC module. This system uses inputs from multiple sensors in order to calculate throttle angle. Don't confuse the Accelerator Position Sensor with the Throttle Position Sensor. The TPS is still used and also located on the side of the throttle body.

The first systems that were drive by wire with the mefi 4 system had a tac module, the mefi 5 ecm eliminated the tac module. The way the systems works is, at your throttle is a pps sensor their is 2 internal sensors in one howsing, as you move your throttle handle the pps request the ecm to move the electric motor on the throttlebody, which opens the flap letting air in, as the flap opens there are 2 tps sensors inclosed with the electric motor which tells the ecm how much the flap is openning, all of your spark timing and fuel injectors will respond inconjunction with the throttle openning. As far as the transmmision goes pertaining to electronic versus cable there is no gain in performance or response time . As far as drive by wire everything responds in miliseconds , hard to beat for fuel efficiency or excelleration.

Very well explained, but if you truly get into how the TBW works compared to the older TB and flap air intake induced air units you'll find that most of the TBW response is not as accurate as the older systems. Most TBW sensors tap out before the full true throttle response has been achieved, example: if you take the the newer TBW systems, you can achieve full acceleration way before your throttle is maxed out or pegged and you'll notice no less power advantage because there is a huge difference from the sensor control position to throttle acceleration position. Most TB systems bypass the MAF sensors for true throttle response because of air restriction or lack of the signal to the PCM knowing how much more air is being flowed through the TB, but you can get true linear control of the air flow based on how much of the flap is open or closed (or just how much air/vacuum is being w is incalled for) much harder to explain verbally that in theory. But, true bottom line, if you have been truly tuned TB versus a stock TBW you can get much better response from the TB versus the TBW. They don't even use them in the racing world as this point because there is much more fine tuning that needs to be done befor e it compares to the old TB systems.

[Lance B. Johnson]

Theoretically. In reality though TBW in this application is very different from a traditional cable system.

Observation: people that don't like the TBW system or at least have more difficulty adapting to it are typically the ones that have a lot of time at the wheel of ski boats. The ones that like it or are indifferent are often times new to boating or at least new to driving boats. No judgment there either way, I just think that it's something that people are more likely to pick up on if they like what they know & know what they like. If they have very little or no frame of reference on that, then they won't know what to like.

By feel yes, by the way the engine runs no. I did notice a small misplaced word in my post that might have made you think otherwise.....

I imagine they tune the responsiveness similar to changing the "ramp up" on a non linear cable actuator.

I guess the best way to explain it is that what you are experiencing is the speed at which the throttle plate opens, not engine performance.

[WakeGirl]

Yes, I think that we're saying the same thing. It comes down to how the TBW system acts & is tuned, right? Not the engine or its management systems, at least for the discussion at hand.

[Sixball]

It has been a long time since I was working on TBY and it was early in the development. One of the things we worked with was you may give a full throttle request but the ECM would only give you the best possible case. I don't know if you understand what I am trying to say but Maximize torque over H.P. if it offered a better scenario. I know it was odd in a vehicle it felt slow some time may be its what we feel in the boats? As said in other posts the response time is very adjustable and can be very different what one person thinks is good is too much for another. Its hard to make ever one happy.

[FIC]

Fuel/ Timing calculation is not done any different than it was before. The real name for throttle by wire is "Throttle Actuator Control". TAC just takes the place of the cable and makes our speed control systems much more reliable. Theoretically if done right TAC systems will not affect the way the boat drives in any way except for the fact that precision pro speed control should be more responsive than Perfect Pass systems that utilize cables. (not sure as I have not driven one)

TAC systems utilize a motor with integrated gear reduction (located on the side of the throttle body), Multiple Accelerator Position Sensors (redundant), and the Engine Control Module or separate TAC module. This system uses inputs from multiple sensors in order to calculate throttle angle. Don't confuse the Accelerator Position Sensor with the Throttle Position Sensor. The TPS is still used and also located on the side of the throttle body.

The first systems that were drive by wire with the mefi 4 system had a tac module, the mefi 5 ecm eliminated the tac module. The way the systems works is, at your throttle is a pps sensor their is 2 internal sensors in one howsing, as you move your throttle handle the pps request the ecm to move the electric motor on the throttlebody, which opens the flap letting air in, as the flap opens there are 2 tps sensors inclosed with the electric motor which tells the ecm how much the flap is openning, all of your spark timing and fuel injectors will respond inconjunction with the throttle openning. As far as the transmmision goes pertaining to electronic versus cable there is no gain in performance or response time . As far as drive by wire everything responds in miliseconds , hard to beat for fuel efficiency or excelleration.

Very well explained, but if you truly get into how the TBW works compared to the older TB and flap air intake induced air units you'll find that most of the TBW response is not as accurate as the older systems. Most TBW sensors tap out before the full true throttle response has been achieved, example: if you take the the newer TBW systems, you can achieve full acceleration way before your throttle is maxed out or pegged and you'll notice no less power advantage because there is a huge difference from the sensor control position to throttle acceleration position. Most TB systems bypass the MAF sensors for true throttle response because of air restriction or lack of the signal to the PCM knowing how much more air is being flowed through the TB, but you can get true linear control of the air flow based on how much of the flap is open or closed (or just how much air/vacuum is being w is incalled for) much harder to explain verbally that in theory. But, true bottom line, if you have been truly tuned TB versus a stock TBW you can get much better response from the TB versus the TBW. They don't even use them in the racing world as this point because there is much more fine tuning that needs to be done befor e it compares to the old TB systems.

Part of what you are saying is correct, however both systems in your boats are air density , there is no mass air flow, remember all calulations in the software is a compromise, the computor can make better decisions than the cable operated system as pertaining to opitimom fuel effiecencey and emisions , so they have to sacrfice some response.

[SmoothWaterMan]

Indmar switched over to econtrols for engine management, and in doing so gained some performance, better tune-ability, the best fuel injection control (each), and got rid of some of the "delay" or "lag" found by the experienced drivers in certain scenarios. (such as show skiing)

My personal opinion and I have no information to back it up is that the responsiveness/touchy-ness of the throttle in the new boats is from a non-linear acceleration rate in the control path. (either manually in the throttle control or programmed in the ecm) This provides (again, in my opinion only) some of the kick in the pants holeshot that we all love to feel. No one has been able to provide data to confirm or deny that to me, so it's just my opinion at the moment. The beauty of the econtrols is that it can do so and still be silky smooth in both engine management and driver tolerance. It's like driving an turbine engine with no spool up time needed. With some time in the seat you learn to love it.

In some regards boats are catching up with the electronic world. Like the iphone, Zero-off has an accelerometer in it. When you ski behind it you really control the boat's throttle with the ski handle. Dig your ski in and haul back for all your worth and you'll think the driver just stood up on the throttle control. Ski very technical and smooth and you'll never feel the boat pull change. (Of course, in doing so it's upset every power skier out there...) But the point is that it is so advanced that it happens instantly, before the driver can sense the pull (although you can anticipate it), zero-off is adding in power. I'm going off on a tangent and I don't know if it's the right answer or not, but don't be surprised if we find more of this technology in our boats. Bluetooth-readable ecms should be around soon for diagnostics.

The only negative I have found so far is after driving a VTX last summer, the customer hopped into the an iRide (with cable shift) and man did that feel archaic! What was once so very nice was antiquated in an instant.

Peter

[Toby]

Like the iphone, Zero-off has an accelerometer in it. When you ski behind it you really control the boat's throttle with the ski handle. Dig your ski in and haul back for all your worth and you'll think the driver just stood up on the throttle control. Ski very technical and smooth and you'll never feel the boat pull change.

peter, could you please extend on ZO having an accelerometer in it? this is news to me. why, and how does the computer use its data/output to assist in the pull and control of boat speed? thanks.

[skisix@38]

I don't think that the TBW systems are more sensitive or more responsive that the cable systems. I think thath they are less linear and that results in the lack of "expected" results for those of us who logged 1000's of hours with the cable throttles.

Peter, I too would liek to know more about this accelerometer in ZO. If it has one then it has to be in side the ECM... There is nothing else with that system except the GPS sensors on the top deck.

[jjackkrash]

I don't think that the TBW systems are more sensitive or more responsive that the cable systems. I think thath they are less linear and that results in the lack of "expected" results for those of us who logged 1000's of hours with the cable throttles.

Peter, I too would liek to know more about this accelerometer in ZO. If it has one then it has to be in side the ECM... There is nothing else with that system except the GPS sensors on the top deck.

I think "linear" is the key concept. I don't agree that a boat is more "responsive" when it acts like you have buried the throttle when you have only advanced the throttle 10%. 10% throttle should get you 10% throttle. This is especially true when pulling kids and new skiers. I also don't need the lag you described on the 196. I still think TBW has a way to go before it is a superior to the cable throttle. So I guess I'll stick with the Pig for a little while longer and put up with my old non-gps PP.

Edited January 2, 2009 by jjackkrash