Predator powered vehicles

By now we've all seen tractors, karts, wagons, pedal cars all powered by the Harbor Freight 6.5hp Predator motor, but now it seems some people have upped the game.

https://www.youtube.com/embed/7DCpUs0cnt0 This truck was the first one I saw, and it has a sibling video showing off it's true power. https://www.youtube.com/embed/Z12gbY3nTm0 Which I think is pretty impressive just as it is. 4 wheel drive, those big heavy tires, with the predator motor and a big sprocket. He does have a second motor on the back just for the tow crane.

But I saw this third one. And it confuses me. predator motor, to regular 5 speed transmission and 4wd. Claims 70mpg https://www.youtube.com/embed/WSc9CVyje5Y All the information I've found on the builds is in the descriptions on youtube, but I'll summarize below.

6.5 HP predator, a 12 inch sprocket, magic happens, and 4wd awesomeness results.

So what magic happens? I understand the size of the sprockets and the length of the chain can make torque and fun stuff happen, but is it just math to tie it all together?

With enough gear reduction you can move just about anything. If you half the rpm, you double the torque. Do that enough times and pulling a truck is easy. Just don't be in a hurry.

Um, Ok?

In reply to Toyman01:

I do understand that. What I don't understand is how the predator gets tied to an actual transmission, or powers a 4wd system.

I'm guessing figure out the right size pulley, weld it to the input shaft, and bobs your uncle. That just seems to easy to work.

Vehicles like this had been the subject of many many drunken debates and arguments amongst myself and some friends for years, so seeing them in action is great. It just leads to more questions for me.

Looks to me like the transmission is present on both vehicles, just no bellhousing on the first one. You can see both sprockets in the still on the third video; there's a small one on the engine, and one about the diameter of the bellhousing below. Looks like the large sprocket is on a shaft that's supported by the trans input at the rear, and presumably a mount on the chassis at the front, hung off the same plate that's spanning the frame rails as an engine mount, since that larger pulley is way too far from the trans input to just be supported at the trans end, given the input was never meant to support radial loads.

Looks like that's how it's adapted to the trans, and of course from there the rest of the 4WD system is already present.

6.5hp is 6.5hp. Gear it low enough and it'll move a Euclid dump truck, but the wheels may make sundials look speedy. The length of the chain is irrelevant, it's just the ratio of the smaller engine sprocket and the larger input sprocket. That reduction is multiplied by all the other reductions (I'm guessing you only use 4-low).

In reply to Ransom :

Check out this dude. He used an old Wisconsin 18hp engine with a 1:1 drive ratio to the transmission, and he can move around in 2H! It's crazy how little power it takes to actually do that.

https://www.youtube.com/watch?v=ur-NZlPFM8I

I like this one:

https://www.youtube.com/watch?v=7PoKLJym_qc

I saw a predator swapped Ranger with the centrifugal clutch of the predator on a belt(chain?) to the input shaft on the M5OD. Seemed to mome okay.

This one is a little more purpose built, but still roughly based on an automotive drivetrain with a Predator engine.

The whole build series is pretty cool, I would suggest checking it out.

https://youtu.be/Tbfd7szvSTA

I love the first one so much. I would like to build that..

Not a Preditor but in the same vein.  David’s Farm (old classic YouTube) had a fairly decent sized front-end loader powered by a 305 SBC.  Worked good.  There are several videos of it moving around school buses, crushing cars and the like.

https://youtu.be/1-Eu2J7j6TI

So, who's going to be the first one to make one fly?