towing a toyhauler with a 4.6L?
 

I have an 02' scab with a troyer tuned 4.6L (112K) new 4r70w (100K warranty) and 34's with stock gearing right now. Me and a buddy are thinking of picking up a toyhauler as they are really cheap right now. My question is with regearing/bigger additional tranny cooler/ebrake controller and helper springs will my truck tow a 6000-7000 pound loaded toyhauler well?

Also I just got back from pismo, I towed a 20 foot carhauler full of toys plus the bed was full. I am guessing 800lbs in the bed plus prob 3500lbs for the trailer. The truck did it fine but could barely hold od on the flats and I would turn it off for any kind of grade, I always hear dont tow in od but when I lock it out it is turning between 2500 and 3k rpms @ 70mph is this ok for the engine? If I was pulling a toyhauler I would def slow down but I am just concerned if I regear it may turn to many rpms?

Leave that OD *OFF*. Running that engine at anything under 5000 rpm continuously is fine, it will just suck gas like there's no tomorrow.

A 7000# trailer is likely to exceed one of the max ratings. It will tow it though. You *WILL* want a weight distribution hitch. I'd use air bags instead of helper springs, it will ride a lot better when you aren't loaded.

Definitely change your rear. Those 34" tires are going to kill your trannie if you don't. And yes you will definitely be over at least one of your weight limits.

I would definitely stay below 7k, and make sure of your weight before you buy.

I will def be changing the rear end...I was thinking 4.10's originally but if we end up getting a trailer that heavy and my truck is the main tow vehicle I am wondering if 4.30's may be a better choice. I know I will be towards the max capacity but I am thinking with the right equiptment it will handle it?
(I think I actually read 7200? that seems crazy to tow with this truck but who knows)

so you think its safe to turn that many rpms on a motor with over 100K? It runs perfect but it just has me nervous to work it this hard! eventually I want to drop in a 5.4L running boost and maybe a 4r100 (eventually want to turn it into a long travel prerunner)

The air bags are another good idea...we put them on our durango to help tow our big trailer to and from storage. from what I have heard helper springs are sopossed to ride good unloaded too but Ill have to look into the airbags more too!

also would use a wieght dist. hitch for sure!

Does anybody else on here with a similar truck or atleast a 4.6L tow any of the smaller tow haulers? I am hoping to be able to go with a 20-24ft ultralite model that is (half-ton towable). Obviously the bigger the better but I dont want to over do it and kill my truck!

I don't have a 4.6 or a heavy TH, but my 190,000 + mile 5.4 tows my #5000 TT just fine at 2500 rpms all day long and nets me about 10 mpg towing..

I don't have any worries about taking my rig on a long trip either... I keep all the fluids fresh and don't usually tow more then 65 mph. 60 mph is my rigs 'sweet spot' in 3rd gear. On the grades, it'll downshift into 2nd and I slow down to 50-55 mph only because the engine is 'screaming' at around 3000-3500 rpms, but I'm only about half way into the gas pedal... I can go faster, but no point in that, as when it starts getting to around 4000 rpms, I can actually watch the gas gauge go down!

Actually, when you are in OD and towing, I feel you are working the engine harder by lugging it down below it's peak power rpm and you have to press the gas pedal deeper, dumping more fuel into the cylinders, but not really gaining any more rpms...

Try riding your mountain bike up a hill in say 10th gear and how long is it before your legs start burning? Do the same hill in say 5th gear, and sure, you are peddling faster, and going slower, but your legs don't burn as bad, right?

There is also a huge wind resistance factor to consider with the TH compared to the car hauler you towed.... Try holding a 4x8 piece of plywood up going 60 mph! Compare that to laying that same piece of plywood flat and that's the difference your truck has to make up to cut thru the air. The faster you go, the resistance goes up exponentially too!

I have 31" tall tires with 3.55 gears and it's actually a good combo for my rig... If I had 4.10's, I might be able to hold OD more, but I'd still be reduced to 3rd and then I'd be pulling around 2700 or so rpms to go the same mph. Unless I could hold 3rd on the grades, I'd still be in 2nd and again, pull more rpms to go the same mph with say 4.10's...

I'd go with 4.10's if I had 33" tires however... That'll keep me about the same as I am now for the most part.. You want to match your gears and tire size to keep your engine in it's 'sweet spot' while cruising to get the best towing performance IMO..

With a true 34" tall tire (have you physically measured the height of your tires and that's just not the 'size' stamped on the sidewall?) you might do well with a 4.30 gear?

Anyway, your 4.6 only has a 8.8 rear end and a 4r70 trans, so all the power adders and spring or air bags will still take it's toll on these items in the long run...

In my case, my #5000 TT puts my truck over it's #6250 GVWR by several hundred pounds when it's all hitched up and loaded for a long weekend of camping! I'm still under the rear axle rating by a tad and under the trucks GCWR by over a 1000 pounds, but since I'm over my GVWR, I don't want to tow any heavier, that's for sure! Sure, the truck will handle it and move a heavier trailer down the road, but not give me the performance I want and just wear out the truck that much faster...

Good luck and 'choose wisely' when shopping for TH... They are designed to be 'light' when empty, but have huge CCC ratings and when loaded up with all your toys, it'll get really heavy fast!

Mitch

hey mitch thanks for your great info...the tires are listed at 33.8 inches tall. I'm a little nervous about pulling that much weight with this truck especially since I will also have to climb hills pretty much anywhere I would go

It will pull it, as long as you leave OD off and aren't in a hurry. The 4.6 was designed as a car engine, and high revs aren't an issue.

I really don't think you are going to get away with one that big. I would say maybe a 16 foot at the most. Even the new 19 foot Weekend Warriors are like 4300lbs. Start throwing toys, wood, and all the other crap and it adds up fast.

Toy haulers generally have a lot of tongue weight which means 1/2 ton pickups are over GVWR often before loading up any toys, passengers or gear in the bed. THat's why I say leave the TH for 3/4+ ton trucks.

The 4.6L sings sweetly at 3000rpm all day long, though, so let it free if you must.

they do have a ton of tongue weight empty,but as soon as you throw 2-3K worth of toys in the back you change the ballance of the trailer and its not quite so bad. Our bigger stacker trailer is the same way until we load it up conciously putting the heavier stuff in the back (it is primarily for our sandcar which has the motor in the back so it helps even it out). I am primarily concerned about how much wear and tear it will put on the motor and trans towing that kind of wieght up hills if I set the truck up the best I can, especially with over 100K on the engine.

I would say you need gears to help the truck the most. I turn 2800rpms at 60mph, 35's with 4:56's and the 5.4. I can push it up to 65 @ almost 3k and then hit OD then RPM's drop to 1900 and I can hold it there. But like you said any little hill and I am back down to 3rd. And the big hills 2nd @ 3k @45mph. And its not a problem of power, its the TQ that I can't keep locked when I come to the hills.

And a WD hitch will take care of any tongue weight issue...

bigdad, what are you towing with yours? Do you think going up big hills at 45mph in 2nd gear at 3k will overstrain it or as long as I can be patient and just go slow it wont be a problem?

I'm pulling a 21 foot toybox that is 4900UVWR with a EX300, Raptor700 and Raptor80. Plus 1/2 bed full of firewood, tools, parts, 100 gal of water, plus the ton of crap my wife puts in there. I gotta be pushing 7 to 8k with just a little math. I think I am doing fine down in 2nd, I am only pushing about 1/2 throttle. It's really the stop and go in town that is the hardest, once you get it moving its cool. Now we did go just camping one time, no toys, no water, I was doing like 80 like it was nothing. If I was you...16 foot, but what are you going to put in there???

3 or 4 full size bikes maybe a couple of quads or a RZR S. That or a couple bikes and a few standup jetskis plus food, wood, etc...and of coarse as many people as possible!

Bigdad, have you ever hit the scales? You're probably at 5000 pounds over the rear axle.

A WD hitch does not make up for heavy tongue weight. It does not turn 1200 pounds into 600. It is required and useful over 5000 pounds for the trailer, but is not that dramatic on the scales. It helps in bumps and dips more.

4.6 + heavy 34" tires will suck. I have the 5.4L 3.73 gears and heavy 33" tires and wish I had 4.56 gears even empty. Have you considered a hybrid TH with open cargo space? Something like the Rockwood Roo 232 or 232L.

not really...we will be looking for a few year old used one as you can pick them up so cheap right now. I am not totally opposed to those style but they arent my first choice. I think Im gonna start by gearing it and rebuilding the factory ls when its apart. from the sound of the other posts on here it will be like a whole new truck! I just need to decide to go with 4.10s or 4.30s as I really dont want to over do it, but with a trailer that heavy it needs all the help it can get!

What axle ratio do you have now and how many miles do you drive per year?

it has a 3.55LS stock (8.8). I prob between 15-20K per year on it...used to be a lot on the freeway but not to much anymore (that may change next year when I transfer though). I was looking today and it is only turning about 2K at 80mph! the speedo is sopposed to be corrected but I think it might be a bit high. I typically drive about 75mph sometimes 80 on the freeway and dont want the thing spinning too high, but then again I dont even remember where it was originally since its been so long since it has had stock size tires on it.

4.10 would be a good gear for you. The 4.6L makes peak torque somewhere around 3500rpm. It just costs more fuel.

You can always keep the 3.55's and turn OD off when towing (which you should do anyway).

I've only got 31" tall tires and only haul a #5000 'soaking wet' TT and in third, I'm pulling less then 2500 rpms going 60 mph... With 34's, #7000 trailer and a low torque 4.6, I don't know about that????

Mitch

ya I atleast want to do 4.10's even for eveyday driving...i think the truck will drive a lot better and the tranny will thank me! I just dont wanna go with 4.10's and regret them not being enough, or vice-versa with the 4.30's. Also it sounds like anywhere from 2500-3K is safe and makes enough power to cruise at 60-65 while towing so that is what I think Im shooting for

I don't think there is a 4.30, but maybe that's for the 9.75" gears. 4.10 or 4.56. I'd love 4.56 with my combo (5.4L 33" tires), even for DD.

Yeah, I'd check on the availability of 4.30's for the 8.8 diffs.... Something in the back of my head says that they don't have them for the 8.8's... If you have 4x4, you will need to do the front too, and maybe that's where the 4.30's don't exist, because they have to be a different grind up front?? I think they call it a 'reverse cut' gear for up front?

Then it's either 4.10 or 4.56... With the 34's, I'd personally go with the 4.56's and not look back! :)

Mitch

thanks for the responses guys! Im only 2wd and with the 8.8 which I think is actually the only combo they make the 4.30 ratio for...I think its probably a ratio used by mustang guys. I would think 4.56 is overkill but what do you turn rpm wise on the freeway at 60-65 and at 75? I will never get bigger tires that what are already on it (atleast if its still a street truck) so I really just dont want the thing to turn too many rpm. Im gonna try to go play with my truck on the freeway and write down what rpm's Im at certain speeds and see if I can calculate where it would be with the other ratios and see what looks like it would work best.

a quick calc from here http://www.bncoffroad.com/tire_gear_cal.html

Shows that at 65 mph with 4.56 gears you'll be spinning at 2,929 rpms in third (1:1) in OD, it will be about 2,050 rpms (.7:1)

Mitch

where do you guys mount your brake controllers? I am thinking of putting it in the little cubby below and to the right of the steering wheel so it is kinda hidden and wont get in the way. Also I need to get the harness to plug into the oem plug and not sure where to get it or what it costs.

That's where I'm gonna put mine. It seems like that's what that cubby is for anyway....
You should be able to get the harness where you get your controller.
The Prodigy has been highly recommended, and that's what I'm getting.

Letting the 4.6 rev high when towing seems a little scary to me...
Then again, I'm used to towing with a 7.5L.....

6100 lb truck, 4K camper, and maybe another 1K in the bed....2000-2100 in OD at 70...

That's the hardest thing for me to get used to with the 4.6, having to turn the OD off. My 7.5 would laugh at hills even in OD.

The only thing I don't miss about my old truck is the broken springs in the seat and the single digit MPG's....

The 7.5 is a low revving pushrod truck engine with a ton of torque. The 4.6 is a high revving OHC car engine.

I wish they would use more low revving, pushrod truck engines in these new trucks. These new v8s are like rice rocket engines put together with how high they rev. Including the 5.4l v8.

Why do you think I'm happy with my V-6? It's a pushrod engine designed for a truck.

I love mine... or else I wouldn't have went back to it... :thumbsup:

I was reading a good article on OHV and OHC engines, and not only did they say it was better for trucks to have low revving OHV engine, but so did a lot of the critics.

I love engines that have an OHV setup... :drool:

OHC should stay in cars and especially those little rice rockets/Hondas. :lol:

The torque peak for both the 4.2L V6 and the 5.4L V8 are at the same RPM, so there goes your low revving OHV engine theory.

Also, the Dodge Hemi which is OHV makes peak torque at 4400 RPM. The Chevy 5.3L also peaks at 4400 RPM, and the 6.0L peaks at 4200 RPM, both OHV engines. Their HP peaks are also at significantly higher RPMs.

Now the Ford 5.4L OHC engine produces peak torque at 3750 RPM, and peak HP at 5000 RPM. Hardly high revving. :coffee:

Those are new OHV's... I'm talking like 460 big blocks... 1400 rpms at 390 ft/lbs of torque... Now that's smokin'... :smoke:

Ore even better, the old 300 I6. THAT was a real truck engine. Slow as snails but would pull anything.

The engine torque curves and peak torque are not inherently part of the valve design. SOHC, DOHC, OHV, does not matter. One can design/tune the peak torque for whatever engine speed he wants. I don't see any problem with the Ford Triton V8's. They have more peak torque, broader torque curve, and get better fuel economy than those engines of yesteryear. If these new engines spin at 3500rpm, they are still quieter and get better fuel economy than the old school big blocks at 1500rpm.

One problem these new engines face is they are pulling 30-50% more weight in their trucks than 20+ years ago.

I wasn't aware of the 460 ever being available in a 1/2 ton. :rolleyes:

Anyway, you wanna compare that to the 6.8L OHC V10? It's said to make 80% of it's peak torque, which is 457 ft/lbs, by 1000 RPM. So at 1000 RPMs the OHC V10 is making ~366 ft/lbs. It'd be a safe bet that it at least matches the 460 through the entire powerband, and beats it through most of it. But that can't be since it's an OHC rice rocket motor. :coffee:

I believe the 460 was a 1/2 ton option from 1973 to 1979.