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5.7 towing 9800lbs for 400 mountainous miles

11K views 38 replies 25 participants last post by  dadriva  
#1 ·
Just wanted to make a quick report on a recent trip we made. I posted this on a boating forum but then thought that it would be well served here on TS as well. Maybe should be in the towing section but thought it would get more exposure here. :thumb:

Trailered a 2007 Donzi 29 zfc from Maryland to Ohio ~400 miles of mostly mountainous terrain.

I knew it would be close so I calculated the numbers over and over...and then a few more times. I prefer to use the 80% rule when it comes to the limitations of towing and went into this knowing I would be out of my personal comfort zone but within the manufacturers published limitations.

Here are my calculations -

2007 Toyota Tundra 5.7
Curb weight - 5570lbs
Me - 150 lbs
My buddy - 200 lbs
our junk / misc / fudge factor - 100 lbs
= 6020 lbs

29 Donzi ZFC - 6000lbs
2 x 250 Verados - 635 lbs each
90 gal fuel on board - 558 lbs
Trailer - 2000 lbs
= 9828 lbs

= 15,848 GCVW

Max towing - 10200 lbs
GCWR - 16000 lbs

The truck was most definitely working hard. I'd love to say "you couldn't even tell it was there!" but that would be very far from the truth. It stopped ok (triple axle trailer with disc brakes on each axle) sagged a bit but was compensated for with Firestone airbags, and actually accelerated pretty well (at 0.9 mpgs
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!!!!!!!!!!!!!)

That being said the engine temp and tranny temp gauges DID NOT BUDGE at all through the mountains on the PA turnpike.

The only real downfalls were the engine noise (mostly in 4th gear at 55 mph in the mountains and 5th gear at 65mph on the flatter portions) and we averaged 6.5 mpgs over the ENTIRE trip for 400 miles which absolutely sucks! I exponentially increased my carbon footprint and am now a prime contributor to global warming
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All in all I was VERY impressed with this truck's capabilities. I do not plan to ever do this again or make a habit out of long hauls with this rig but must say that if needed to rise to the occasion that I have utmost confidence in this truck.

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#2 ·
all i can say is... WOW! nice boat, nice setup, nice story! i can't say that i would have had the cajonas to try it, but glad to know it can be done. thanks for posting this.
 
#3 ·
Impressive speed through the mountains. I've towed a heavy trailer (about your weight, maybe a few hundred pounds less) with my 02 F250 diesel and in the mountains, I'm constantly look'n at my pyro gauge keeping things in check and running in third gear at 50-55 MPH tops. Anymore and the pyro gauge starts creeping into the hotzone. My 7.3-Powerstroke was an awesome engine but in the hills pull'n, it didn't get great mileage either. 9-10 MPG with that kind of weight.
 
#6 ·
Very nice... The boat pretty much swallows your truck.
Nice boat as well... I was at first turned off with Donzi's with their narrow beams... But not but two years ago, I got the opertunity to fish a 36'(I believe) in some 3-6' seas, and man!! What a sweet rig... Dry and likes to fly!!!

I guess flat land pulling would be a no-brainer?
 
#7 ·
eather way thats a huge load alone, plus the drag from the boat its no wonder it got that mileage, hell i'd give it props
 
#8 ·
For towing, I'd put this against any 3/4 ton gas or diesel. Personal experience.
 
#10 ·
damn, talk about a load to tow...damn nice boat too

I'm on a boat!
 
#13 ·
Towed my 8500lb toyhauler (wind sail) from AZ to CA and back and avg 7mpg for the entire trip. The truck pulls very hard even with the trailer. Even ended up traveling a little faster than I probably should.

Can't complain. I have been impressed with the towing of this 1/2 ton gasser.
 
#14 ·
Towed my 8500lb toyhauler (wind sail) from AZ to CA and back and avg 7mpg for the entire trip. The truck pulls very hard even with the trailer. Even ended up traveling a little faster than I probably should.

Can't complain. I have been impressed with the towing of this 1/2 ton gasser.
Yeah Imdone, I have to agree with you. Even at that load, it still had plenty of passing / merging / etc.. power.

The more I think about it the more I am truly impressed with this rig. I actually tapped the engine / coolant temp and xmission gauges a couple times to see if they were stuck. The fuel gauge was the only one that was moving. :crazy:The only thing that would have made it better is the now available 48 gallon tank for better range. But to be frank, after ~150 miles of towing that sled in the mountains I was ready for a break.

Thanks for the comments. :tu:
 
#15 ·
Well, now I feel much better. Just finished trailering my new 34ft. TT weighing 7800 lbs from Albany,NY to Richmond Va. I averaged about 9 mpg.
Oddly enough, my second trip from Va. to Myrlte beach loaded up with camping gear at about 9000lbs got me around 7.5 mpg.
Indeed, the truck pulls just fine. Won't keep up with my friends Duramax diesel on the hills but can easily do 65-70 mph all the way. Geesh the gas mileage sucks.
So now I'm looking at anything to improve the mileage even if just a little.
Anyone have any luck with K&N Air filter, Uni Chip etc.?
 
#16 ·
For towing, I'd put this against any 3/4 ton gas or diesel. Personal experience.
I'm with you tundrabay.

It looks like i just might finally get my opportunity with my cousin. He just bought a 30' fifth wheel, that will be towed with his stock 08 dummax. I beleive my tundra will pull as good or better than his dummax, but we shall see i guess.

Hopefully i will know this summer, so be sure to be watching for my post's.
 
#17 ·
I'll post my own write up when I get a chance, but I just towed a 2001 Focus on a U-Haul dolly + all my brother's crap from Ohio to LA by the southern route (Louisville, Nashville, Little Rock, Dallas, El Paso, Tucson, Phoenix, LA). I estimate 4000-5000 pounds towed and cargo weight. I checked my mileage every tank, I got 11.2 to 16.97 MPG. Like others have noted, you've got to keep it below 1800 RPM if you really want to economize. Keeping the speed lower than the limit isn't enough.

I started the trip out with ~1700 on the clock, and i've now got 4425. I drove the truck around the block after dropping the whole package, and I think I warped a rotor. The dolly didn't have any brakes (or suspension) and i'll never be renting one again. I'll try the heat fully and park it for a half hour method tomorrow, if not, it's due for the 5000 mile service interval before I make the trip back to Ohio.
 
#18 ·
Last year, I pulled my 5,000 lb Aeorlite Cub with my wife and 3 kids from Cypress, TX to YellowStone National Park and back. Took a couple of weeks and covered about 4,500 miles round trip. We took a route through my old stomping grounds (Durango, CO >> Silverton >> Ouray >> Grand Junction, CO) so the kids could see how beautiful the Colorado mountain ranges are. The first thing you hit out of Durango is two ~11,000 passes. The Tundra held up great throughout the trip and my average gas mileage when we got home was 9.8 I believe. I was very happy overaell (other than nearly $4 gas at the time.) Oh yeah, and I did have to the rotors turned -- my dealership did it under warranty.
 
#19 ·
I'm curious, the hitch says w/d gear is needed for tongue weight over 500lbs...your weight would have been around 980 at 10% of the trailer. I was wondering how you would use w/d with a heavy boat since most have surge brakes?
 
#20 ·
I'm curious, the hitch says w/d gear is needed for tongue weight over 500lbs...your weight would have been around 980 at 10% of the trailer. I was wondering how you would use w/d with a heavy boat since most have surge brakes?
The tongue weight is much more adjustable with a boat. (move forward on trailer = greater tongue weight / move aft on trailer = less tongue weight)

I was there for the adjustment of the trailer and we stopped making adjustments at 660lbs.

Are you asking about sway control? or a weight distributing hitch?

I used the stock Toyota hitch and no sway control.
 
#21 ·
The tongue weight is much more adjustable with a boat. (move forward on trailer = greater tongue weight / move aft on trailer = less tongue weight)

I was there for the adjustment of the trailer and we stopped making adjustments at 660lbs.

Are you asking about sway control? or a weight distributing hitch?

I used the stock Toyota hitch and no sway control.
I was just curious how heavy the tongue weight was, I know I feel a big difference when I used w/d over 500lbs of tongue weight vs. not using it. I didn't realize that the tongue weight of a boat was adjustable.
 
#22 ·
I'm with you tundrabay.

It looks like i just might finally get my opportunity with my cousin. He just bought a 30' fifth wheel, that will be towed with his stock 08 dummax. I beleive my tundra will pull as good or better than his dummax, but we shall see i guess.
I haven't driven any gas engine (except maybe the old big blocks) that can match the mid-sized diesels for towing. I have no doubt that the 5.7 will pull the load, but the Duramax will be running 1800 rpms while the 5.7 is running 4k+ rpms, to do the same job---not to mention the heavier frame/springs on the 2500. I pull a 5k+ load with my 5.3 behind a friend w/ a 12k lb 5th wheel & Duramax, and he pulls away from me uphill without breaking a sweat. Zero to 60, the 5.7 should win, since the Duramax has a *lot* of torque management on the low end, but once up to speed the diesel just hums along.

All of that said, I'd much rather drive a gas engine day-to-day. I guess we can't have it all.
 
#23 ·
I haven't driven any gas engine (except maybe the old big blocks) that can match the mid-sized diesels for towing. I have no doubt that the 5.7 will pull the load, but the Duramax will be running 1800 rpms while the 5.7 is running 4k+ rpms, to do the same job---not to mention the heavier frame/springs on the 2500. I pull a 5k+ load with my 5.3 behind a friend w/ a 12k lb 5th wheel & Duramax, and he pulls away from me uphill without breaking a sweat. Zero to 60, the 5.7 should win, since the Duramax has a *lot* of torque management on the low end, but once up to speed the diesel just hums along.

All of that said, I'd much rather drive a gas engine day-to-day. I guess we can't have it all.
Well, my dad dumped his old HD 454 GM for the tundra and pulling his 9k lb fiver the tundra does much better. The 454 had like 250 hp / 450 tq or something llike that, and our old 4.7L tundra's kept up with his old HD pullling our 8k lb fiver pretty well. And the 4- speed 4.7's were nothing to shout about my any means.
Although it was really close back when my bro had his 2003 5.3 tahoe vs. our 02 sequoia. Small hills (without dropping down to 2nd), the sequoia held speed better thanks to the TC lock/unlock feature. The tahoe didn't have that feature in 3rd gear, so it fell behind. But once we dropped to 2nd, the tahoe did pull away slightly. Both had 70 series flowmaster exhaust and CAI.

I maybe doing 4k r's going up a hill to maintain speed (which doesn't bother me at all) but on the flat i'm in 5th humming along at 2600 r's @ 70 mph.
 
#24 ·
I was just curious how heavy the tongue weight was, I know I feel a big difference when I used w/d over 500lbs of tongue weight vs. not using it. I didn't realize that the tongue weight of a boat was adjustable.
I would venture to say, that most boats ARE NOT adjustable from my experience anyway. I know my Epic 22 isn't adjustable, but it don't need to be either. My brother's 23' Crownline isn't either.

Sounds like some larger boats may be though, i don't know.
 
#26 ·
Well, my dad dumped his old HD 454 GM for the tundra and pulling his 9k lb fiver the tundra does much better. The 454 had like 250 hp / 450 tq or something llike that, and our old 4.7L tundra's kept up with his old HD pullling our 8k lb fiver pretty well. And the 4- speed 4.7's were nothing to shout about my any means.
A key difference is the Alison 6-spd mated to the Duramax, vs the 4L80 mated to the old big blocks. The big gas engine I was referring to is the 8.1L, which was mated to the new 6-spd in 2007.

Take a look at the power/torque curve for the Duramax, and then imagine that through a 6-spd rated to pull 16k lbs.
http://media.gm.com/us/powertrain/e...wertrain/en/product_services/2008/HPT Library/Diesel/2008_66L_LMM_SierraHDf.pdf

It's impressive. I'm not knocking the 5.7 or any other gas engine (the GM 6.2 and 6.0 engines are powerful too), but the raw low end torque of a diesel is hard to compare with the small/mid-sized gas engines.