I think the goals need to clearer for any of us to discuss this properly, very big difference between towing 5000lbs in the Midwest and towing 10,000lbs through the rockies. Regardless of that I'm sure it can be done and I'm planning on doing it and willing to make some sacrifices. Is it gonna tow like a Cummins or duramax , no way. I'm thinking stock 4.8 , cast 7875 , stock converter, 4l80e . 3.73 gears and 28-29 inch tire , towing in 3rd @ 3000 ish rpm for hills , maybe 5 psi with small w/m nozzle ( washer fluid ) and a large reservoir. Conservative tune , pulling timing for high iat and ect. Not going to set the world on fire but if it can produce say 400 ft/lbs @ 3000 rpm through 1:1 gear and 3.73s should pull fairly well and last . I'm building the truck anyway - 66 c10 , will be quite a while before it tows anything but I'm thinking possibly 5000 lb travel trailer . As far as durability goes , the only thing cheap about a diesel truck is the fuel , and the ecoboost- since when has any ford had 100,000 mile durability? Lol about 40 years I figure. Just my thoughts on the subject

 

That tow mode reduced timing is a great idea.

 

I don't see why it wouldn't be possible, it's gonna be an experience finding the weak parts. If Ford can do it, why not?

You're gonna want to pay close attention to cooling, in it's entirety.

 

I would not use a cast 7875 on a 4.8 if you're wanting peak torque somewhere in the 2500-3k range.

 

Was thinking it would be good to reduce back pressure , doesn't need to be instaboost like it is on a 6L , and I already have it . Doesn't need to be peak torque at 3000 , just enough to do the job. Just an idea at this point , truck is still in pieces. Towing wouldn't be the main goal , just a good , cheap daily that CAN tow and be a tiny bit of fun. I agree though , wouldn't be the best for all out towing set up

 

Trying to round out the replies now that I can... I see many miscommunications, which may be my fault, but i've been posting responses to everything so far pretty much.

Were on a fairly similar page here, including the idea of making some sacrifices.


Is there any way to help that occur/should I not trust the factory computer to be fighting detonation as it is?


Your commentary IS useful I just think there's still some miscommunications occurring. It's probably my own fault so i'll take another shot at it:

I'm pretty darn sure I would use a 5.3 at least, I just didn't see anything functionally different about using a 4.8 with a little more boost. Everything I understand about engines just tells me that the physics of boost should not be radically different, or at least not worse, than just cubic inches. 400hp in a V8 meaning 50hp per cylinder whether it's gotten from 100% cylinder filling on a 6.0 or 125% cylinder filling on a 4.8 or 113% cylinder filling on a 5.3. 400lb/ft at 3000rpm in any of the three engines should have about the same load on pistons, rods, crankshaft. IF I'M WRONG and I may well be i'd love to be pointed to some reference where I can correct this, some physics book or engine builders manual. Reading past hot rod books on forced induction always focused on how turbos seemed to be one of the gentler ways to increase engine power.

Boost by itself should not be pushing the engine harder than other methods, my understanding is "wanting 400hp instead of 300hp" is what is pushing the engine harder. It's just a question of how much harder, at what rpm, focused on which specific parts of the engine over others. There's multiple ways to get there besides turbos - more rpm, wilder cams and heads, nitrous, superchargers.

An LS seems like a tough engine based on what hot rodders do to it, all i'm trying to do is wanting to optimize that bottom end so that it pulls more like a 383 smallblock than a 305 smallblock for comparison, since that's literally part of the origin of this mindset. Guys on the GMT400 boards when voting for the engine they thought was best as an upgrade always chose a 383 for it's low end torque over modern 4.8/5.3 LS engines but that's because it's better for doing work.


I'll re-explain my own perceived use case to see if that changes any of the perception of what i'm doing. Feel free to highlight the point you think i've gone off into the wilderness:
- I'm not looking to be towing 90% of the time or a big block/diesel becomes more appropriate, i'm not an HD chassis guy, this is not a full time tow vehicle, and this is NOT something i'd recommend for someone hotshotting and such. I'm looking to tow the way that modern Ecoboost guys are towing - 10% of the time, with good performance, and reliability while doing so. Most of us don't drive around with full throttle all the time and if I did i'd expect life to rapidly shorten. Even because I want to have a chassis that can tow up to 10,000lbs through the rockies doesn't mean i'll be doing it every single time (most of what i've hauled is more 4000-7000lbs running deadhead, project vehicles on flatbed or construction materials), just that I want the reserve of that big capacity - if the loads of that are just plain too darn much, the limit is learned, and I either upgrade what failed on the next swap or I stop running it so hard.
- 4.8 and 5.3's are super common and come with stronger stock parts than any small block i'd find, I can build a 383 and tow with that but i'm not convinced it will be stronger or cheaper
- Instead of spending an extra $800 to get a 6.0 I figure why not spend that on the turbo and piping?
- Just because this isn't a high dollar project doesn't mean it's a delusionally low dollar project, i'm willing to spend money where it matters but $800 for a 6.0 and another $800 for a turbo is still $800 more than I thought should help round out the torque some. :) Especially since I might still have to upgrade pistons and rods in the 6.0 anyways if they're no stronger. For the higher figures ie 550lb/ft i'm just trying to capture the interest of other people asking this question, i'd have less confidence doing that on stock rods and pistons. 360-400lb/ft i'd probably try stock rods/pistons to start with water/meth injection and watching timing especially if cores are another $250 from the junkyard. 450lb/ft i'm starting to feel uncomfortable on stock everything if the load is meant to go on for minutes but if i'm opening an engine to rebuild and freshen stuff up i'm tempted to upgrade pistons/rods and first tune it for that goal to see how it holds up.
- Altitude compensation of turbos is nice, even big blocks run out of steam as the altitude climbs. No big block feels real strong in the rockies though.
- To me it's a question of where best to spend the money: gas for the big block? Parts upgrade for the LS? Turbos? Even a Vortec 8100 is probably 'easiest' but I suspect the 90% unladen at 10mpg will add up to more over time.
- "If using a turbo makes the engine unreliable I just go back to not using any turbo and driving slower." If that's the only way to tow more reliably so be it, i'll continue to howl along in 2nd gear then like I do now. An LS swap still has the power to replace any 1990's small block or big block or even pre-Duramax diesel, it's just tuned higher than I like. There is SOME aspect of experimentation in this - it IS a "project" - but if this project ends up lasting more durably than I thought, it switches from shop truck increasingly to daily driver. If i'm running it hard on tows and it holds up amazingly, i've proven something I hope and just share my results with others who want to do something similar.

Do my goals make ANY sense or still seem completely out of touch? :-/


Last part didn't fit again...

 

I think we all want big tow power, but this is not a hot shotting rig, this is a similar use case to modern 'super half tons' that tow big but whose users aren't towing big 90% of the time. I think that's the biggest miscommunication. If I cant have it, it reverts to a nonturbo LS with 255hp or more just doing what it does in a heavier chassis, that's all. I wanted to learn about LS's already, instead of a hot rod i'm wanting to modify a tow vehicle. If I break a few and "it just doesn't work" i'll post and share those details the same as if I can make it work.

And no no no no no no no I don't want to spend $250-500 for the "engine", I want to spend that for the CORE, if I spend another $1200 on a rod/piston kit from Summit and with a turbo that gets me to 550lb/ft, that's fine. If I refresh things and i'm only shooting for 380lb/ft that's still "big block power" but now with altitude compensation keeping that power to 10,000ft. What I dont want to do is to have to drop $3500 on a crate engine meant for hot rod loads that I don't know will last any longer in tow use or even more on some turbo crate engine. A $250-500 core means if I break down cross country it might suck, but I could park at a friends place, grab some wrenches and throw in another non-turbo core to limp everything back home probably without touching the engine internals, and then go back to modifying once home. Also when I talk about 100-200k miles i'm talking about something I rebuild life not radically shortened by tow use - not pulled from the junkyard as is and having the power jacked up 40%.

When I hear of guys with diesel breakdowns dropping 5-10 grand to fix their truck and get back home I cringe - I have more time than money, my projects are more part time than full time, even if i'm using some tows to make money it's not something that I lose if it takes me a few more days to get home it's more like bringing home a car to part out. I'd rather break down "ten times as much" as some brand new $50,000 truck because most of what i'm doing is hobbies, small side hustles for money, and simultaneously using it as a project to learn about LS's, swaps, turbos, welding and everything else anyways. Nowhere am I trying to suggest this is the equal of someone's new $50,000 pickup meant for hotshotting - anything i've towed so far has been with 80's and 90's beater trucks worth maybe $3000 and just lacking power. To me it seems an LS swap with a little boost to round out the bottom end would be just the ticket and the big blocks just cost too much to drive when not towing when it's just a bunch of crap in the bed.

 

Just jumping in to the what-if mind set here..
For low RPM bigger = better cylinders are better,, look at Aircraft engines,, 4 cylinder 5.7L , Or boat motors on bigger fishing boats,, 6 to 800 CI but never spin much over 2000 rpm. Massive torque..

I believe you need a turbo if you want economy when your not pulling hard.. You want the energy savings the supercharger has a hard time matching.. (not impossible just a little harder... )

Cold side cross over/Bypass might be a thing in this use case.

I would look at things like a Diesel engine radiator+intercooler fro the same model year diesel chassis if available so the core support fits your chassis and maximizes the capability,,, good thing is the diesel tuner boys sell off the old parts when they upgrade.

Go BIG on the tranny,, more gears = engine staying in the sweet spot of the power band. might make the $$ for a gear vendor Over Drive unit make sense.. a 4 speed 4L80 with a 2 speed splitter would get you a lot of flexibility.
Or a 6L80 + a OD from the right builder. d

Pick the right tires, to really pull and get effieiency some skinny tall high pressure tires with street friendly tread.

To get life you need to keep the cylinder pressure from spiking, points back to a 6.0 in my mind.

VVT is a good thing on wide application engines,, as long as you maintain the system its a win..

Since this isn't a drag vehicle,, a heavy flex plate is probably your friend to help with the load surges as you start up a hill or just for starting off, I've seen guys use a machined ring that bolted to a flywheel to put weight where it will do the most good and was not an expensive option..

Get the DEF tank off a Duramax and use it for meth, the one that goes in the side of the pickup bed by the fuel door.

Find a dual tank truck and use one side for E85 and the other for regular gas. Lot of the heavier trucks have two tanks..
Then run the electric fuel switch off the ECU with tuning so it switches between tanks/octane and adjusts all the timing..

Biggest trans cool that will fit.

Sacrifice top end speed (in the gearing) so you have the max number of gears from 0 to 90..

Try and pick an axle with the largest diameter bearing you can get, they roll easier and cooler.
(Dualy axle with singles in the rear.. )

there..

 

Wow a few clever ideas I hadn't thought of before, including the DEF tank for water-meth and buying a diesel rad off other guys. (are rad upgrades common on diesels actually? I dont know.) Thanks for indulging me... i'm always looking for clever little tricks there that save $100 here and $200 there, it all adds up.

Could you explain what you mean by "Cold side cross over/Bypass might be a thing in this use case."? If it's what I think i've often wondered if just having a complete turbocharger bypass like the way exhaust cutouts used to work (but stronger due to heat) would be a way to get power on demand without having the normal seeming loss of a few mpg in normal driving. Some of the newer superchargers do this too unladen - but my preference for turbo is more low used cost (nothing except Eaton M90's are really cheap and theyre too small and need alot more fabbing or special manifold and such) plus just wanting the 50-75hp that might be spinning it going down the driveshaft instead.

Using E85 not for all towing but for critical points of towing... thats an interesting possibility... since detonation is the killer and the turbo is mostly there for the long heavy hill climb? Alternately water-meth (not just water) should boost octane as well, blue washer fluid here we come I guess! I dont like running engines flat out for hours at a time, this isn't meant to be a build that constantly tows at max boosted power in gear - the power is for safety not holding everyone back, keeping up with traffic. I've been underpowered in heavy traffic before and it can be scary and unsafe, even if you stay furthest right!

Would the dually axle running SRW really make that much drag difference?? I would have thought it fairly negligible...

I'd explored the 'more gears' option wondering about even the Ford 5R110 trans in a different posting but I don't know if anyone else will indulge me in that topic. To me it seems like a budget Allison for cheaper than any built 4 speed let alone 6+....


To all others I know it's possible i'd be asking too much to gain torque on the bottom "for the money", going way back to the guy who said 333lb/ft higher instead of 500lb/ft lower. In that case this just turns into a more midrange optimized build and we use the gears - i'm exploring this topic to try to push some thinking and solutions brainstorming is all. I have my preferences for that seat-of-your-pants jolt stabbing the throttle and the feel of the engine seeming like it's barely working - but more important than feel is actually getting the work done. I still think even a mildly turboed 4.8L from like 255hp with even a 30% torque boost to reach 330hp or so and i'd like to see if it would do that with stock parts. "But what about a cam or stroking a 5.3 or or or..?" Yes power fine but I want altitude compensation - guys who haven't towed at 10,000lbs wont know, even with a big block you feel it run out of breath - I still think even a turbo 5.3 would be better than an NA 6.0 at altitude especially if making the same power and let alone power-at-altitude where the 6.0 is dropping too. I dont mind a car winding up through the gears it can feel like it's faster than it is which is fun, but for a truck to be constantly gear hunting and winding out to the top rpm every time to me is stressful to drive.

If I could go back and add to the poll to "do a midrange turbo build instead" I would.

 

Was referring to 100K to 200K reliability goal, not max tq.

 

Op, let us know when you get to the build specs and parts list based on the input provided.

 

I will, though the build is probably next summer at the earliest because I have to move to the twin cities outskirts before I can replace or modify my tow vehicle. However i'll be shopping for parts hopefully early next year. Until then it's research and brainpickings... I realize those nudging me to midrange power instead of low end may win the argument.

The main things i'm sort of settled on though for anyone not following the whole talk:
- Trying to start with a vehicle already set up for heavy tow instead of overworking a half ton and having to upgrade everything incl cooling, like one someone pulled a big block or duramax out of for their project.
- Planning on a 5.3L (I wanted things to work with a 4.8L too but that's because other guys trying to do the same might have a 4.8L and I wanted them to be able to do it too)
- Turbo ideally with a bypass, water-meth injection with a LARGE tank (probably a used DEF tank, I liked that idea), conservative tune to start 380lb/ft goal on stock pistons/rods and eventually 550lb/ft on aftermarket probably 4340 rods/forged pistons, "doing this to learn"
- Upgrades to the 5.3L incl overhaul might happen before or after the turbo is added, but since I dont like to gamble until the combo is better worked out I might just dial the boost down to 0psi on a long trip for the first trips. EDIT: i've decided once I have access to a 2nd tow vehicle (like through a friend) i'll turn it up to the power goals and see what happens. If it breaks it breaks, someone gets a call and there's two long trips back home - one for my load and one hauling my broken truck.
- Trans either a built 4L80/4L85 or possibly a Ford 5R110 (sacrilege!) if anyone will ever engage me in that discussion where i've posted elsewhere. Lower first gear would be nice without touching axle ratios or losing overdrive ratios and as tough as an Allison with cores on a budget. They can be tuned on a laptop using an OEM computer now.

 

Fair enough. However he did not say that was max torque. He just wanted 500lb-ft at 2000 rpm. At least as far as I can tell. A power goal at a certain rpm with a reliability goal does not take a paragraph (referring to OP) to explain or state. I am still somewhat confused as to the OP's end goals, Just to be clear, 500 lb-ft @ 3000 rpm is not the same power/towing ability as 500lb-ft at 2000 rpm. It is 50% more power/towing ability. BTW, does anyone know of a good synonym for the word "goal"? I would have have used it in an earlier sentence.

 

I'm very wordy i'm sorry! XD I'm never sure if people need to understand WHY or not and tend to over-explain but I thought every answer was in my walls of text. I love the feel of old big blocks, stab it right off idle and it feels strong even at part throttle. I rode in an Ecoboost too and it was great. High altitude same power.

Stronger towing within a budget is one of the goals. I'll quote from the Sloppy Mechanics page "ALL OF THESE ENGINES ARE EXCELLENT, quit being weird about needing a 6.0 only, or LS1-2-3 only. Listen, you have a budget, and you don't have a motor, Just get one and put it in the damn car." An LS with mods outlast a smallblock doing the same or be more readily replaced for the same budget once in and is just a more modern solution.

 

We're talking like a 60-75hp increase here with 3psi.

I'm telling you from experience, most of the replies are over complicating what needs to be done here. I've stuck a 68mm turbo on a 5.3 half ton that runs it at 3-5psi. It's really no more stressful on the damn thing than a simple camshaft change which also nets an average of 60hp on a 5.3.

WMI, not a bad idea if it's hot as hell were you are at. But a small intercooler would be good too, like a 400hp sized air to water. But the truth is the factory radiator and everything except the injectors and the fuel pump are fine for a 5.3 towing on 3-5psi. Been there, done that. I didn't even need to really pull any timing out of the tune. It runs 15* at 5psi on 90 octane and will tow 26" boat 750 miles like it came from the factory the way it is. No water/meth, just the small intercooler.

Worry about your transmission if it's a 4l60e, that's what will **** the bed and leave you stranded.

 

I would use E100 for the cooling charge,, you can buy a 50Gal drum from most chemical suppliers of fuel depots, (< $400 last time I looked)
The trick would be to use a good enough injection system to switch between gasoline and pure alcohol.
On a 3/4 ton with dual tanks you'd run on the left side and use the right side for the E100/E85. (The tank switch fails to the left if it goes bad.)

The advantage is the amount of reduction you get in combustion temps its HUGE like cylinder head temps being 20% or more lower..
Especially if you have E100 pumps in your area, E85 would be my second choice.. I worked on a track car road racing that was running E100,
If the outside air temps were under about 70, I had to cover about 80% of the radiator to get the motor to warm up at all.. And the car made 600+ N/A

The Alison automatics would be great if you could find a ECU for a gas engine set up to work with an Allison,
The Allison transmissions are cheaper than you might think if you look outside the box, IE they come in bread trucks, delivery vans, school busses etc..
It would be a scavenger hunt..

You might also look at the marine rods and pistons ,, IIRC they are a little taller skirt and are designed to pull in the 3500 range.
Not as light weight but more for that specific high "power level" setting.

 

If you have to fill with anything other than straight up pump gas then this is a fail.

 

Wait nobody told me that rule! LOL yea, I'm thinking the E* tank is for bad pulls, like the grapevine..
Of course replacing 1 tank with Propane would work too.. At least its available all over..

Btw at least around here ,, the farmers Co-OPs are another source for grain fuel...

 

Just how much weight are we talking about? I towed my 26 foot Haulmark w a 1500 Suburban all over the place and all I did was put fresh 96 Vortec motor with a 4.11 gear an d worked 700 trans! My buddy w a 454 GMC dually and same trailer couldn’t keep up with me. I don’t see why a small turbo on a 5.3 wouldn’t be fine with the right gear & set up.

 

Diesel guys already have to fill with DEF. I'm not 100% opposed to filling up something simple - E85 is all over minnesota where i'm from, but it's not coast to coast. This is why i'm for using either straight water or I suppose it's like 33% alky for the blue windshield washer stuff available in fall/winter months in the north. The DEF tanks even come with a built in heater if I have to use water when it's freezing and just trying to pull the whole fender insert for the 'double fuel filler' diesel/DEF tank opening could make it even more convenient to refill outside so big thanks to pdxmotorhead for his clever idea. Ddnspider suggested pulling timing while towing, but in the tuning boards others disagreed saying it would cause overheating if done for minutes (not temporarily like for racing) so that's probably out.


I'm looking to pull up to a maximum of 10,000lbs of trailer. But trailering at all is only a 10% of the time job so using a big block constantly wastes gas.

I thought E100 might be overkill, E85 is all over my state but it's not national and the hardest tow would be out of state - yet even plain water cools alot and "E33" commonly known as -20F blue washer fluid cools while also being more convenient to find, store and such. (I wouldn't hesitate having a full shelf of blue washer fluid in the garage or jugs thrown in the trunk but wouldn't do the same with gasoline or normal fuels.)

I dont know if the Allisons can handle the RPM and wasn't sure where to ask the question, though I thought they came with the Vortec 8100 in some cases. I also have no idea about how one is tuned and theyre the most expensive of transmissions to build. I WAS very curious about the Ford 5R110 which is like a budget Allison with comparable strength and people have home tuned those with a laptop - I know purists retch but everyone else loves putting an LS into non-chevy vehicles and that 5R (which has come with both gas v10 and diesels) is a heck of a trans. It's a slower shifting transmission (they have to use full declutching between gears which slows down 0-60) but so is the Allison. Fallback is a 4L80 or 4L85 though.

I have not seen the 1000 series Allisons in those uses (if you have could you enlighten me?), only the other models like 2000 series or older direct drive 4 speeds that are sort of too big heavy slow-shifting and parasitic drag-ey for a light pickup thru one ton van chassis.

Whats this about marine rods and pistons? Is this something available for a better budget than aftermarket stuff?


That's still my thinking, whether the power is from nitrous or turbo or cam shaft, the physical loads shouldn't be much different if its the same torque and RPM without detonation. I'm all for the intercooler - I still think i'd like water or water-meth on top of it. Especially in combination I have less need for E100 or E85 for charge cooling. My needs aren't extreme, though my specific application is a bit different than normal. I just want a smaller LS to turn into more of a tow god, that's all. Ecoboost does the same job in 3.5L, once forged rods/pistons are put in the LS I think it would keep up pretty good not just in power but lifespan/reliability. (minus whatever miles already used up with a used core)


For what it's worth from postings elsewhere the plan just refines itself based upon feedback. The first build will probably be a stock internals 5.3L with some boost added to get to 380lb/ft, the minimum of early 90's big block power. This will hold me over as I work on a second build where I plan to upgrade rods and pistons (and other parts) to try to hit 550lb/ft while actually towing the hard loads - RPM still open to negotiation just preferring low as feasible. Thats the biggest of what the 1970s big blocks ever hit (the Cadillac 500 in 1976 put out 400hp and 550lb/ft gross) which is why it's my high number/not reaching for the stratosphere.