Straining Pulling Roo 17

[LiDAR4U]

Hi,

In our first tow experience we towed on relatively flat terrain I found our Sienna straining in 4th gear often dropping into 3rd on false flats (light hills) in Eastern Ontario.

Details...

Roo 17 single axle with rubber suspension weighing 3065 lbs dry with options excluding the weight of the propane and deep cycle battery. No water in tank, moderate food and cargo inside. Me, my wife and 3 small kids... I did have my cargo box on the roof of the van which acted like a deflector in my opinion. For a 340km trip it took approx a tank and half of fuel. :o

Freeway speed were where it strained the most at speeds ranging between 90-110km/h. I found between 90-100 to be worse as 100-110 allowed me to keep momentum. On by-ways 80-90km/h I had no issues even going up relatively big hills. RPM in 4th was a tad under 3K and 3rd closer 3500-4000rpm.

I am at loss as I see quite a few of you pulling much bigger trailers and I don't hear much complaining.

I am worried about my big trip from Eastern Ontario to Florida causing damage to van or it will take so much fuel that it will put me in the poor house!!!

I went shopping today for an F150 supercrew 4X4 5.0l V8 that can pull 10,000lb, even with employee pricing it is still fair chunk of change with trading my Echo... Although it sure is nice.

Any advice would be greatly appreciated.

Thanks,

Claude

[tcp]

Our Bantam F-18 was pretty much the same as your Roo. We have since gone to a slide out, two axle funfinder. I think sticking around 90km/h when towing is always your best bet (trailer tires are rated at 65mph, 105km/hr maximum so you're aware).

You are pulling an sail through the air and fuel economy will be about the same with the F150 while towing, but with a much higher consumption when not towing, compared to the sienna, especially in city driving.

Spinning the engine isn't a problem. You aren't driving a diesel with huge low-end torque. Don't be afraid of 2500-3000rpm. The engine will do that without issue.

The only time I really have problems is pulling in southern alberta when there is a 50-70km/hr headwind. I usually sit around 80km/hr and the van is working hard. On the other hand, with the same tailwind heading home, the sienna will do 100-110km/hr in 5th gear and never need to go into 4th on the hills.

Anyway, remember that wind drag increases 4 times for a doubling of speed. 90km/hr is your friend and let the engine spin.

[brian_bp]

I agree with tcp's assessment. In our case, our 3000 lb (loaded) trailer is easier to pull because it is likely narrower and likely has a better shape (for aerodynamics).

I never cruise as high as 110 km/h, mostly due to the fuel consumption; I like around 105 km/h on a flat highway. In general through-the-mountains towing, not holding up traffic, I would be shocked to use 120 litres of fuel (that's a tank and a half) in 340 km... that should be good for 700 km.

I have not noticed any effect on fuel economy of a large rooftop cargo box - or a canoe - while towing; I think the net aerodynamic effect is about zero.

Speed kills... fuel economy.

[komondor]

If you do go with the F 150 give the EcoBoost V6 a hard look I have it in my Flex and am getting about the same MPG as my AWD Sienna around town and better by about 1 MPG 21 vs 22 at highway 80 mpg 9128 KPH) Much better at hills too

[shineysideup]

Hi,

In our first tow experience we towed on relatively flat terrain I found our Sienna straining in 4th gear often dropping into 3rd on false flats (light hills) in Eastern Ontario.

Details...

Roo 17 single axle with rubber suspension weighing 3065 lbs dry with options excluding the weight of the propane and deep cycle battery. No water in tank, moderate food and cargo inside. Me, my wife and 3 small kids... I did have my cargo box on the roof of the van which acted like a deflector in my opinion. For a 340km trip it took approx a tank and half of fuel. :o

Freeway speed were where it strained the most at speeds ranging between 90-110km/h. I found between 90-100 to be worse as 100-110 allowed me to keep momentum. On by-ways 80-90km/h I had no issues even going up relatively big hills. RPM in 4th was a tad under 3K and 3rd closer 3500-4000rpm.

I am at loss as I see quite a few of you pulling much bigger trailers and I don't hear much complaining.

I am worried about my big trip from Eastern Ontario to Florida causing damage to van or it will take so much fuel that it will put me in the poor house!!!

I went shopping today for an F150 supercrew 4X4 5.0l V8 that can pull 10,000lb, even with employee pricing it is still fair chunk of change with trading my Echo... Although it sure is nice.

Any advice would be greatly appreciated.

Thanks,

Claude

As several other posters already stated, speed is your enemy. Especially on 401 type roads. The more you tow the more you'll be able to anticipate when your sienna is going to downshift. Letting off on the throttle slightly will avoid this, you will lose a little speed likely but this will help. From my experience cruise does not work very well when towing heavier loads...(read: I don't use it)

Your Roo has a nearly vertical front and sits quite high off the ground. For example my surveyor has a height of 8'-6" while your roo has a height of 9'-2" (5+ more feet of frontal drag above the back of your van). Your trailer is also the full 96" wide, the same as mine (forest river website info). This just makes your trailer that much more of a power robbing sail, trailer weight isn't the only thing that matters. Aerodynamics really kick in above 70 km/hr in my experiences.

I recently towed my brother's trailer 250 km with his '08 entourage. His trailer, rolling down the road is pushing 3200 lbs. I towed the whole way (West of Toronto to London) in 4th gear with cruise on (when I wasn't sitting in traffic!), never downshifted once, occasionally the torque converter came out of lockup. I was quite impressed. His trailer has a round shape to the front which seems to make a huge difference. It is also only 7' wide.

slow down and enjoy the scenery, your sienna won't let you down!

[LiDAR4U]

Hi,

Thanks for all the great posts --- I will slow it down to an average 90km\h and the box is coming off. Yes the 401/416 highways are the culprits for the high gas consumption. No cruise control has ever been used as that is a bad idea.

I agree the Roo is a big sail but there is nothing I can do about that other than possibly put a deflector on the roof.

I'll report my consumption once I make these adjustments.

Slight off topic...

I am now pondering a F150 SuperCrew 4x2 3.7l V6 as a replacement for my Echo (not the Sienna) as it showing it's age/getting small. The F150 price is inline with a Mazda5 and consumes 12.6l City 8.8 Highway and can tow 5700lbs. This would become my tow vehicle and it is one of the reasonable priced vehicle other than a van that can safely fit 3 car seats.

[shineysideup]

Hi,

Thanks for all the great posts --- I will slow it down to an average 90km\h and the box is coming off. Yes the 401/416 highways are the culprits for the high gas consumption. No cruise control has ever been used as that is a bad idea.

I agree the Roo is a big sail but there is nothing I can do about that other than possibly put a deflector on the roof.

I'll report my consumption once I make these adjustments.

Slight off topic...

I am now pondering a F150 SuperCrew 4x2 3.7l V6 as a replacement for my Echo (not the Sienna) as it showing it's age/getting small. The F150 price is inline with a Mazda5 and consumes 12.6l City 8.8 Highway and can tow 5700lbs. This would become my tow vehicle and it is one of the reasonable priced vehicle other than a van that can safely fit 3 car seats.

For the difference in price I would opt for the ecoboosted 150. Don't forget that the truck weighs a lot more than a van etc. It makes the 420 ft/lbs of torque almost off idle. All you hear about is torque from diesel owners, I'm sure this would be an awesome tow vehicle for you now and for future considerations ( over 11,000 lb. tow rating when properly equipped ). I believe that the gas mileage numbers are also very similar!

Skip the deflector, I've heard from people with years of towing experience that it isn't worth the initial investment.

happy camping,
shineysideup

[sfpcservice]

Headwinds cause us to run about 10 MPH slower sometimes in order to keep the transmission from hunting. I'd rather run a bit slower than downshift to 3rd and keep a higher speed. I can hear it sucking fuel now...

[07sienheaven]

Whenever I do any towing with my 07 Sienna, I run on 91 octane. It really makes a difference as the engine advances the combustion and provides a boost in power. Also make sure your maintenance is up to date, especially the air filter as this is a huge aspect in how efficient your engine will run :-)

[sfpcservice]

Forgot to mention the 91 octane! I fully agree. The 1st time we towed I didn't use it and there was a lot more gear hunting from the transmission. When I use 91 octane it seems like the engine can dig in a bit deeper and pull without downshifting so much. It has a deeper sound and what feels like more power under a heavy load.

[brian_bp]

Any effect of higher octane will likely vary significantly between individual Siennas. All the higher octane does is allow the engine to run more advanced timing without knock, which may make more power available at high loads and/or high engine speeds (which are towing conditions)... but only if the timing which is ideal for power can't be reached without knock on regular octane. In previous discussions of octane, it was clear that some people had knock issues and others did not.

I have never used "premium" fuel, but I have typically used Husky/Mohawk regular fuel, which until recently was a couple of points higher in octane (89 versus 87) than most regular gasoline, due to the addition of ethanol. Now that 10% ethanol is required here, the base regular gasoline stock has been degraded so that even with 10% ethanol it is only at 87.

With the price premium of higher-octane fuel, and little if any fuel consumption benefit, I doubt that I would spend the extra to save a minute of hill-climbing time even if I found that there were a difference, but that's an individual choice and with my trailer I am not concerned by a lack of performance.

This will presumably also vary between 1MZ-FE (1998-2003), 3MZ-FE (2004-2006), and 2GR-FE (2007-2011) engines.

[07sienheaven]

Any effect of higher octane will likely vary significantly between individual Siennas. All the higher octane does is allow the engine to run more advanced timing without knock, which may make more power available at high loads and/or high engine speeds (which are towing conditions)... but only if the timing which is ideal for power can't be reached without knock on regular octane. In previous discussions of octane, it was clear that some people had knock issues and others did not.

I have never used "premium" fuel, but I have typically used Husky/Mohawk regular fuel, which until recently was a couple of points higher in octane (89 versus 87) than most regular gasoline, due to the addition of ethanol. Now that 10% ethanol is required here, the base regular gasoline stock has been degraded so that even with 10% ethanol it is only at 87.

With the price premium of higher-octane fuel, and little if any fuel consumption benefit, I doubt that I would spend the extra to save a minute of hill-climbing time even if I found that there were a difference, but that's an individual choice and with my trailer I am not concerned by a lack of performance.

This will presumably also vary between 1MZ-FE (1998-2003), 3MZ-FE (2004-2006), and 2GR-FE (2007-2011) engines.

Good point there. I should have been more specific to say that I can only confirm the 91on octane benefit for the 2GRFE engines as the OP has. This is the engine I have and can confirm the power difference and fuel economy difference between 87 and 91 octane. Toyota also confirmed this info as well which is part of the reason they recommend their Lexus brand vehicles with the same engine to run on premium fuel. For example, a comparable Lexus RX350 with the same Sienna engine has 275 hp versus our 266 hp and 257 lb/ft versus our 245 lb./ft of torque both at the same rpm and compression ratio. I'm sure the Lexus computer has been massaged a little bit to squeeze out the extra power, but according to Toyota, it also has to do with the advanced timing coming from the premium gasoline. Now to verify your statement, I can't say that this situation would /could apply to the 1mz or 3mz engines.

[LiDAR4U]

91 Octane for better consumption? I would have to do test and a cost benefit analysis to see if the gain in economy is compensates for the ~10% cost premium. Worth noting that I have experienced any engine knock in towing, otherwise I would have put in premium.

On another note the F150 is on hold for a year , two car payments while my better half is on extended mat leave is not going to happen...

I'll do more tests and log my results to see if I get better consumption.

Thanks for the help and happy camping!

[LiDAR4U]

Hi,

So I took off the Skybox, reduced my average to 90km/h and for about 220km it took about 50 litres of fuel, with equates to about 22 litres per hundred km on flat terrain :o... At 90kph, in 4th gear my RPM is at 2500, at 80kph it is 2400RPM and on perfect flats at 100kph is 2600RPM. Is this normal considering my trailer is acting like big sail (8 foot wide, 9.5 foot tall)?

Any thoughts?

[shineysideup]

Hi,

So I took off the Skybox, reduced my average to 90km/h and for about 220km it took about 50 litres of fuel, with equates to about 22 litres per hundred km on flat terrain :o... At 90kph, in 4th gear my RPM is at 2500, at 80kph it is 2400RPM and on perfect flats at 100kph is 2600RPM. Is this normal considering my trailer is acting like big sail (8 foot wide, 9.5 foot tall)?

Any thoughts?

It sounds close to what I am getting, depending on the wind. Like I've said, the 401 is the worst for gas mileage. Your trailer is lighter but would likely have more drag than mine (shape of the front of the trailer and the roofline is quite a bit higher). I do run premium gas, I want to give my van every bit of horsepower I can. I do find that it doesn't need to downshift as much running premium compared to regular gas (IMHO). As it has been mentioned that individual results will vary, you will form your own opinion. I also have heard on more than one occasion that people feel they get better mileage with american gas! :o