Alh/bew fuel mileage pulling 10k lbs

What do yous think the reliability would be of an upgraded bew or alh engine pulling 10000lbs - including vehicle curb weight. The aim is fuel economy - but I understand it’s going to be less especially at 300~ Hp and 450~ torque which is what I suspect it’d need to comfortable tow up hills. Anyone wanna hit me with some reality?

jimbote said:

why? slow and dangerous pulling that kind of weight... there are already trucks made for that kind of pulling... please stay off the same roads i travel on

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So what you’re saying is you have absolutely zero to actually contribute

The idea is to tow a trailer so your combined weight while on the road is 10,000 pounds, so the Jetta weighs ~3100, you can put 800 in it, plus you for 4,000, then a 6,000 pound trailer? so you are into 2 5/16" hitch ball territory there, and you can't get a trailer hitch for an 05 VW that is rated for 6,000, not even 5,000.

Assuming you did modify the car notably to be capable of having 6,000 hooked up to it, you would not be able to run "300 HP" out of an ALH for more than brief periods without it melting down. At 90 HP you can just about run them WFO all day long and they won't hurt themselves, but you will run into EGT issues very quickly if you mod an ALH to 300 HP AND tow 6,000 pounds with it....

Ackilys said:

So what you’re saying is you have absolutely zero to actually contribute

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you asked to be "hit with some reality" so don't ask if you're not ready for the blow... i have lots to contribute because i daily drive a modded ALH converted tacoma, but i won't waste any more time on this thread

jimbote said:

i won't waste any more time on this thread

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The idea is thoroughly absurd, I posted in the hopes of talking him out of it...

Ackilys said:

So what you’re saying is you have absolutely zero to actually contribute

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I think you do need a reality check. You asked an idiotic question about the exceeding the GRVW by nearly double!

Reality is that a VW doesn't have the power to stop that load in a reasonable distance, look at your door frame for the GRVW what does it say?
If you actually got pulled over, the vehicle will be towed to the nearest, most expensive, tow lot awaiting a truck to haul one, or both

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In terms of power, 150 hp is enough, but you'll want a lot more than that. The trick is being able to sustain 150 hp without overheating and warping the head. The older versions of the Cummins 6BT only had 160 hp from the factory, but they were designed to be able to sustain that power for hundreds of hours without service.

Towing 10,000 pounds in a car that weighs a third that?? Really? Is it April 1st?

This request is comical at best BUT I just happen to happen across it and had to chime in.

I'm finishing a frame-off restoration of 9-ton equipment trailer to move my excavator and the truck was too long to back it under my carport to keep it out of the rain before the new decking was treated SO I lowered the pintle lunette over an upside down drop hitch to back it in with the Jetta.

This trailer weighs 5840 Lbs. I'm not sure what the tongue weight is but the ALH/auto trans does move it but even at creep speed less than 1 MPH the brakes are overwhelmed and the car gets shoved around by the mass of the trailer.

This would NEVER work on the road. It's dangerous, illegal, and the potential for catastrophic loss would be higher than VERY high.

Over the road trailers are governed by FMCSA (Federal Motor Carrier Safety Administration) and further by your State DOT. This trailer is normally pulled with my F450 dump truck with a USDOT number.

The short answer is DON'T DO IT. Don't even think about it. You'll probably end up in jail and/or killing someone, be legally liable for more damages than you could fathom, be abandon (in a heartbeat) by your insurance company, and live the rest of your life wishing you'd paid someone to move your load or set up a vehicle properly and safely do it yourself instead of taking lives of innocent people while trying to save $100 in fuel with the $3000 you put into a turbo, tune, clutch, and intercooler.

My 84 Van weighs about 3800lb with full tank.

I've pulled a 1200lb camper with about 250lbs of stuff inside it as well as deep cycle battery & propane, 250lbs of camping gear/luggage in the back of the Van and four adults (average about 175). That would be about 6200lbs, give or take a few pounds.

Anyway, the ALH with a Stage 1 tune did just fine............... Stopping could have been a big problem in an unprepared situation. So, I was always mindful of what was going on in front of me.... kept my distance!~

Since this post is in the conversions thread I don’t think it is a given that the PO is intending to tow 10,000 with his Jetta.

I towed a big car hauler with a 35 hp Kubota once. Off-road obviously, but power wasn’t an issue. I came to a stop uphill on gravel with all 4 wheels spinning. After a short downhill I nearly had to change my shorts.

For a point of comparison, a heavy duty Fiat Ducato / Ram ProMaster has a GCVW in the range suggested in the original post. The diesel version with that GCVW uses a 3.0 litre 180 hp engine. The lesser versions with the 2.3 litre 130 or 150 hp engines (in Europe) have lower ratings.

An undersized engine is not going to use any less fuel than a bigger, right sized engine.

There was a thread on Pirate (2005?) from one of the well known regulars who got into an accident pulling overloaded.


He was pulling a large toyhauler with a 3/4 ton truck, lost control, went into oncoming traffic and killed 2 people as I recall.


The insurance paid whatever their max was and dumped him. The Civil part of the judgement still had him owing 7 figures in damages.


The criminal portion had him in prison from whence he was writing the story.


There was never any mention of drugs or alcohol.


I'm out on pulling overloaded after that story.

I've thought on putting some small motor in my F350 a few times. the 7.3 in there is really only good for 100hp if that, and it only winds out to 3k RPM, hard starting because of how big it is with the tiny automotive starter that ford used...

Seems like just about anything would be better.
Remember that ford put their 60hp flathead v-8 in EVERYTHING for years and years.

your mention of 300hp is a mistake, you want to get it breathing good, and then limit the tune to 90ish hp after massaging the smoke maps to get it a little more lively. Leave the torque limit maps largely alone except up high. Maybe get 120hp or so out of it. Shift at 5k and don't bother with anything below 3k.
ETA: and you're going to want a transfer case for low range, even if you don't have a front drive axle

An undersized engine spinning fast and working hard is not going to get better mileage than a slightly bigger and mildly tuned one that doesn't have to thrash itself to get out of it's own way.

In the absence of a known BSFC map, for most automotive type engines, best BSFC is usually at a third to half of rated revs and around three quarters rated torque. It follows that the rated power should be 3 or 4 times more than what it takes to roll down the road at whatever highway speed.

GoFaster said:

An undersized engine spinning fast and working hard is not going to get better mileage than a slightly bigger and mildly tuned one that doesn't have to thrash itself to get out of it's own way.

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but the littler motor is easier to push start, and you can start a tdi on a group 51 battery, two 31s struggle to start my 7.3 IDI

Easier to do an engine on the side of the road, too.