Towing power

[gjones]

So, what's the best way to increase towing power on a '85 CUCV ? My buddy bought a camper, and his CUCV will only do about 50mph going up a hill while towing the thing.

 

[gimpyrobb]

Put a turbo on it.

 

[patracy]

Turbo would certainly help, but if it's a 1008/1010/1028/1031 you're going to be dealing with 4.56 gears. I'm guessing it's one of the pickup variants correct?

 

[Tow4]

Buy a different truck. 50 mph towing up hill with a CUCV doesn't sound bad to me.

 

[patracy]

I would say the same.

 

[CUCVLOVER]

You can turbo it, turn up the fuel, engine swap, or different truck. 50 pulling a camper sounds good. What are the specs of the camper?

 

[tonkasal]

My M1008 top speed is 55 to 60mph with no trailer, Not sure how fast you want to go, but these MV's were built for 55mph. You either have to enjoy the right lane or get a civ truck.

 

[Gunzy]

Replace the engine and trans and regear the diffs. Or just buy a civilian P/U and call it a day.

 

[gjones]

Buy a different truck. 50 mph towing up hill with a CUCV doesn't sound bad to me.

He's towing a 5500 LB tailor (unloaded). Says it'll do 70 mph without the trailor. So, at this point he's going to look in to having a turbo installed.

 

[patracy]

He's towing a 5500 LB tailor (unloaded). Says it'll do 70 mph without the trailor. So, at this point he's going to look in to having a turbo installed.

Does he understand the implications of driving it at 70mph?

 

[porkysplace]

Does he understand the implications of driving it at 70mph?

It shouldn't take to long to find out.

 

[patracy]

I'll give a little more info. If it's still 4.56 geared and on 31" tires. 70mph is about 3600rpm. Which is the governed RPM of the civy 6.2. The military IP isn't the same as a civy and has a higher high idle speed. But the internals of the 6.2 are still the same.

 

[CUCVLOVER]

I am not trying to pee in the oatmeal but my Cucv that have stock drive train will do 80 on the speedo. I know that CUCVRUS does it with his Cucv trucks also. Is it loud, and a little scary at 80 yes it is but a Cucv truck in good shape will hold together.

 

[patracy]

80 on the speedo is one thing. Traveling 80mph on the road is different. (You're going to be turning 4100+ rpm to do that with a 31" tire and 4.56 gear) The 6.2 is a oversquare engine design, so that lends to a higher top RPM. But the original design of the 6.2 was for economy in the 1800-2200 rpm range. Which in the CUCV pickups means about 45mph tops.

Now, will it run at 3-4K? Sure. I've run mine routinely at those speeds. (Mainly I run around 2800rpm) Will it come apart at those speeds? No, probably not. Will it suck the fuel tank dry at high RPMs? YES.

Just because something can, doesn't mean it should.... (At least not all the time)

 

[CUCVLOVER]

80 on the speedo is one thing. Traveling 80mph on the road is different. (You're going to be turning 4100+ rpm to do that with a 31" tire and 4.56 gear) The 6.2 is a oversquare engine design, so that lends to a higher top RPM. But the original design of the 6.2 was for economy in the 1800-2200 rpm range. Which in the CUCV pickups means about 45mph tops.

Now, will it run at 3-4K? Sure. I've run mine routinely at those speeds. (Mainly I run around 2800rpm) Will it come apart at those speeds? No, probably not. Will it suck the fuel tank dry at high RPMs? YES.

Just because something can, doesn't mean it should.... (At least not all the time)

True the speedo is probably off at that speed. Do I run it that hard a lot, no. 55 is usually plenty. I was just posting my experience with my truck.

 

[Lukes_deuce]

A cheap upgrade to get some better top end speed would be adding some bigger tires. Even going up to full size 33s you can gain 5 mph. On the power side of things, I know the 6.2s could use some help. There are some options for that, but the 6.2 is not an engine I am familiar with.

 

[86m1028]

Put a big block in it opcorn:

 

[jpg]

Some M1009 CUCVs are geared for higher speeds than the other CUCVS, so their top speeds are higher. You have to look at the gearing in the differential.

On steep mountain roads, my stock M1010 tops out at 20MPH at full throttle in first gear, without a trailer. Kind of embarrassing... On the highway, I can keep up with highway traffic, but fuel economy suffers greatly. I can sustain highway speeds on most highway grades, but if there is a steep grade with a "slow vehicles use right lane", you're sure to find me in it, at full throttle, unable to maintain highway speeds.

Re-gearing and/or bigger tires will help you go faster at lower RPMs on the flats, but they will hurt your ability to pull a trailer up a steep hill. On the hill, you're limited by the engine's horsepower. A turbo and the corresponding IP tweaks will help that, at the cost of greater stress on all your internal engine parts.

I'm planning on a HD 700R4 transmission swap, to get my highway RPMs down closer to the engine's sweet spot (about 2000 RPM). I'm also planning on a turbo, but that's mostly to keep things moving at high altitude in the mountains. If you think a CUCV is slow on a steep grade, try a steep grade at 10,000 feet!

Fundamentally, your friend is asking the CUCV to do something for which it was not designed. He needs to decide whether to live within the design envelope of the vehicle, and accept the slower speeds, or to modify it heavily. If he chooses the latter path, it might make more sense to just get a different truck. You can pour a lot of money into modifying a CUCV. Afterwards, it's just a hacked up CUCV that's still not as highway-capable as a civilian truck.

Many folks will tell you to either embrace the suck, or get another vehicle. Financially, that's probably the wisest approach.

 

[86m1028]

Many folks will tell you to either embrace the SUCK, or get another vehicle.

Now that's a signature line !

 

[CUCVLOVER]

Put a big block in it opcorn:

Been there and done that.
I'm rocking a big block now, will haul butt and burn the tires with no problems. Gets about 8mph though