Gph Comparison

[ahopkins22LSV]

If they aren’t using the latest models with the latest drive trains is this even worth the test? That’s like taking a new 1/2 truck and doing a tow test against an older competitors truck and the saying look! My truck is better! Well, duh!

Now don’t get me wrong, I’m noting saying that Malibu would some how miraculously  jump to the top because I do agree that SG and the Wedge create a lot of drag but I just ran an event with a 2017 24MXZ pulling wakeboarders and surfers from 11am to 5:30pm. Full ballast plus plug n play the whole time with about 25-30 different riders. No engine off time and there was still a 1/4 tank left I believe. It was the polar bear event so I wasn’t doing hard math calculations for my full consumption during the day. Mainly was just trying to keep warm and get back to riders as quickly as possible. 

Just would be much more interesting and realistic if they did a more apples to apples test. 

[billjames]

Reading the post on Wakeworld from the OP, the goal was to show that the new Centurion Hull was great for gas consumption. Starting with this goal in mind, the OP can do all the tests he wants, but it will always leave a smell of bad test regarding independence. If he would have started with the goal to compare gas consumption on different scenarios for different boats, then it would have been more credible and we can discuss the scenario chosen for the test.

I am not sure anyone is interested in such a test when the boat cost north of $100K, and the saving for an average Joe with such boats might be in the $1000 per year. Average Joe, might be better off spending more time at the negotiation table  or just consider you just Burn Another One Thousand...

[TenTwentyOne]

In that case, I think it would have been best for them to compare a Centurion without opti v, and one with it......

[shockthis]

I have a friend that had a 2015 G23 with the 550 1.50 transmission and then had a 2017 g23 with the 450 and a 2:1 and he said that the new on was way more fuel efficient . So if they are using the old model with a 550 then they need to make an apples to apples comparison.

[TallRedRider]

5 hours ago, billjames said:

Reading the post on Wakeworld from the OP, the goal was to show that the new Centurion Hull was great for gas consumption. Starting with this goal in mind, the OP can do all the tests he wants, but it will always leave a smell of bad test regarding independence. If he would have started with the goal to compare gas consumption on different scenarios for different boats, then it would have been more credible and we can discuss the scenario chosen for the test.

 

In research speak, I think that is not often the case.  Many good research articles start with a hypothesis in mind. 

Also every GOOD research article these days has a conflict of interest statement.  Given they are Centurion dealers, that is a conflict of interest.  That does not automatically mean that the research is biased.  Personally, I think the methods used are very good and the conclusions are likely to be pretty valid, unless there is some straight up falsification going on.  

2 hours ago, shockthis said:

I have a friend that had a 2015 G23 with the 550 1.50 transmission and then had a 2017 g23 with the 450 and a 2:1 and he said that the new on was way more fuel efficient . So if they are using the old model with a 550 then they need to make an apples to apples comparison.

The 550 got the 2:1 transmission in 2017, and I think they said the G was a 2017.  There are guys at Planet Nautique that have experimented with prop choice with the supercharged engine and have found that there are prop choices that are a lot more fuel efficient than the stock prop.    But spending $900 on a new prop to save 20% on fuel may not be the most cost effective use of money.  

[TenTwentyOne]

1 hour ago, TallRedRider said:

 

The 550 got the 2:1 transmission in 2017, and I think they said the G was a 2017.  There are guys at Planet Nautique that have experimented with prop choice with the supercharged engine and have found that there are prop choices that are a lot more fuel efficient than the stock prop.    But spending $900 on a new prop to save 20% on fuel may not be the most cost effective use of money.  

Was actually 2016 that the 550 got the 2:1.

I went from 9gph average, down to 6gph. I usually put on about 150hrs a year. I paid for that prop, with my fuel savings, way before the end of just one season. Smartest $900 I spent on a boat. Not to mention, the added benefit of a better cruising speed, and a much quieter engine while surfing.

 

Edited January 9, 2018 by TenTwentyOne

[skurfer]

15 hours ago, TenTwentyOne said:

In that case, I think it would have been best for them to compare a Centurion without opti v, and one with it......

It's been done. Claiming 50% more efficient. More like 55-60%, but 50 to be conservative.

Edited January 10, 2018 by skurfer

[The Hulk]

Glad I spent 20yrs gas savings for a future proof boat lift capable of handling the ri257. Ha

I think the test is awesome somebody actually doing something although obviously not Apples to Apples..

At least somebody took some initiative to actually do some test even if it may be a bit skewed to Brand and testing procedures..  I mean it's sad they just did more testing in one day then all of the boat manufacturers combined have done in the past decade.. 

Now could you imagine a prop company doing a test on all these boats each year.. you can knock out numerous boats in one day with a few different scenarios and setups and different props and post the data..you don't have to get all crazy just a few scenarios on each boat.. the data would fill in the gaps... They couldn't make props fast enough!!.. 

Edited January 10, 2018 by The Hulk

[wakebrdr94]

I’ll just leave these here...

https://www.boatingmag.com/malibu-wakesetter-25-lsv-1#page-5

https://www.boatingmag.com/centurion-ri257-1

[IXFE]

26 minutes ago, wakebrdr94 said:

I’ll just leave these here...

https://www.boatingmag.com/malibu-wakesetter-25-lsv-1#page-5

https://www.boatingmag.com/centurion-ri257-1

Shocking...

[gorilla]

Only problem with Boating Magazine.....they don't have the correct info. Since 2017, the 25LSV has run a 17" prop no matter what motor is it running. 

[shawndoggy]

1 hour ago, wakebrdr94 said:

I’ll just leave these here...

https://www.boatingmag.com/malibu-wakesetter-25-lsv-1#page-5

https://www.boatingmag.com/centurion-ri257-1

These basically validate the video, right?

[store934]

So if I am reading everything correctly the ri257 is like the Prius of boating?

Congratulations.  

I hope everyone drivIng one feels a little bit better about themselves and planet.

Edited January 15, 2018 by store934

[MadMan]

9 hours ago, wakebrdr94 said:

I’ll just leave these here...

https://www.boatingmag.com/malibu-wakesetter-25-lsv-1#page-5

https://www.boatingmag.com/centurion-ri257-1

GPH look about the same up to 35mph, where the Centurion tops out, above that the 575 in the Malibu starts making some boost, the air/fuel goes richer and it starts sucking some fuel.

[IXFE]

11 hours ago, shawndoggy said:

These basically validate the video, right?

Actually no. This data says slight edge to the 25 LSV, but they weren’t surfing. 

[shawndoggy]

5 minutes ago, IXFE said:

Actually no. This data says slight edge to the 25 LSV, but they weren’t surfing. 

For the Malibu I'm seeing 13gph @ 4000 which is basically the exact same as the video, isn't it?

and the centurion burns 4gph less at 4000...

Edited January 15, 2018 by shawndoggy

[IXFE]

16 minutes ago, shawndoggy said:

For the Malibu I'm seeing 13gph @ 4000 which is basically the exact same as the video, isn't it?

I’m looking at the comparison of both boats at optimal cruising speed.

It says Malibu achieves lower RPM, lower GPH, while cruising at a higher speed. 

Like I said though, they’re not surfing.  Once you add all the weight, wedge, trim tabs, surf gates, list, etc that’s a whole new set of variables. But this baseline test shows that like for like, the Malibu isn’t any less fuel efficient than Centurion.

Edited January 15, 2018 by IXFE

[shawndoggy]

I just figure we all know that that "optimal cruising speed" thing is totally prop dependent, whereas fuel burn seems to be directly correlated to RPMs.  At every step in the rpm range the Di motor appears to burn less fuel.

 

[MadMan]

The fuel used at a specific MPH is the important number here.  Fuel used at an RPM can vary significantly with engine loading.  The fuel used at 4000 rpm in neutral will be vastly different that that at wide open throttle fully ballasted.

It take "x" horsepower to push a boat at a particular MPH.  The prop and gearing determine what RPM the engine is at.  One prop may put the engine at 3000 rpm, another may put it at 5000 rpm, for the same MPH, but it still take the same horsepower to push the boat at either rpm.

Edited January 15, 2018 by MadMan

[shawndoggy]

18 minutes ago, MadMan said:

The fuel used at a specific MPH is the important number here.  Fuel used at an RPM can vary significantly with engine loading.  The fuel used at 4000 rpm in neutral will be vastly different that that at wide open throttle fully ballasted.

that would be an interesting test.  But not real helpful, I don't think.

The malibu clearly has a higher final drive ratio than the centurion in the test (5600 rpm at 34 mph for the centurion, 5400 @ 40.8 rpm for the malibu).  If fuel used at a specific MPH is important, isn't it also important to recognize the gearing? 

Unless you think a corvette gets the same mpg in second gear @ 55mph  that it does in 6th?

[Cole2001]

So basically what we can say is Malibu is a great runabout but put 3k ballast and wedge down and it’ll suck up all the fuel. 

Am I wrong? 

[MadMan]

31 minutes ago, shawndoggy said:

Unless you think a corvette gets the same mpg in second gear @ 55mph  that it does in 6th?

Exactly, that Corvette at 140mph @ 4000 rpm in 6th gear will be burning a heck of lot more fuel the 40mph @ 4000 rpm in 1st.

[MadMan]

28 minutes ago, Cole2001 said:

So basically what we can say is Malibu is a great runabout but put 3k ballast and wedge down and it’ll suck up all the fuel. 

Am I wrong? 

I think the wedge, being in the prop wash, burns a lot of fuel.

[JasonK]

If the car engine is turning 4,000 rpm it's burning x amount of fuel. If you put a big gear on it or a small gear on it, as long as the RPM is steady, it's going to use almost the same amount of fuel (unless there's a big change in torque applied). Looking at gph, not mpg. Maybe I'm totally wrong.

Now talking boats, imho yes more weight means more torque needed. More torque=less gph.

Edited January 15, 2018 by JasonK

[MadMan]

2 minutes ago, JasonK said:

madman- if the engine is turning 4,000 rpm it's burning x amount of fuel. If you put a big gear on it or a small gear on it, it's going to use almost the same amount of fuel. Looking at gph, not mpg.

Fuel maps are load (derived of the MAP sensor) dependent.  It takes "x" amount of fuel at 4k rpm to make 100 horsepower, it take more fuel to make 200 hp.  This is what happens when you are cruising, then decide to open the throttle and accelerate.