what to expect out of a cucv?

[bigredneck61088]

i want to build a cucv pickup in the next year because they are cheap, and a great drivetrain is already in place(dana 60, locked 14 bolt, np205, 4.56 gears) Where i live all we got to wheel is mud, my question is will the 6.2 have the power to spin the tires (prob 39.5) and go decent in the mud, or what mods can i do to make it, or should i just go for a 1 ton gasser(really dont want to)

 

[metto]

they dont have 205's, IIRC all of them are 208s. 6.2's are definately known as being dogs, ive heard that a banks turbo will liven them up a good bit. you could do propane injection too, its like nitrous for diesels

 

[original balzer]

my 84 6.2 diesel k5 was a turd then i put a $2000 ATS turbo on it and about another $500 into other performance mods and it still didnt have enough power to get out of its own way and that was with d44 front and 14b rear with 4.56 gears and smallish 32x11.50x15 (grinder+calipers+15" 8 lug white spokes) it could be my 6.2 was just plain worn out being the odometer didnt work

 

[OffRoad]

i don't think the diesel is gonna have the power you're looking for. i would consider smaller tires. something in the 37-38 range.

on the other hand, if you're set on 39s and are just mudding, put in 454 and be done with it. i think you'd be a lot happier in the long run.

banks makes a kit for your engine (6.2), but it still won't have the power of a big block or even a built smallblock.

of the trucks i've seen in the mud, the ones that worked the best were truck with high horsepower gas engines and small tires. 31s, 33s, etc. the reason for that is the smaller tires are easier to spin. the tires weigh less and can be spun at 50-60 mph.

last year i was at a mudbog with many different types of trucks. from stock to 44s. excluding the buggys with paddle tires, the best truck there was a fullsize blazer with 33s and a 300 hp 350. it was spanking everything else cause he could so fast. that's the key.

i'm not sure what your exact situation is and can only go from my experience.

 

[ksmeltzer]

The 6.2 suffers from a multitude of problems most of which are easily remedied but some are not. A stock 6.2 is not stellar and will not impress many with the exception of getting great fuel mileage. However they can be modded to perform quite well. In saying that though the 6.2 suffers from a few design flaws that will always keep it from being a performer like say the Cummins. Anyway here are the problems as I see them most of which can be remedied to create a fairly good powerhouse.

1. No turbo, if you want any performance out of the 6.2 you must put a turbo on it. Many suggest the banks turbo but at 2K you could swap in a Cummins with the turbo already on it, so this route is not a solution in my opinion. In my opinion the best possible solution is one of two things. Either get the turbo and manifold of a 6.5 or get a turbo off an old Mercedes diesel and fab it into your exhaust system.

2. Intercooler, the 6.2 is susceptible to higher temperatures quickly when you add a turbo in an effort to increase boost while keeping your egt’s down you must add an intercooler. It is pretty easy to do especially if you are fabbing the turbo piping yourself.

3. The exhaust on the GM diesel trucks flat out sucks, a diesel should have at minimum a 3” exhaust. Most GM’s are 2” which restricts air flow. You have to put a larger exhaust on the 6.2 or it will choke on its backpressure.

4. Manifolds, if you are getting the CUCV then this is not as much of a problem as you will have what is referred to as the J manifolds which have better air flow characteristics. I would still recommend doing a port and polish on them to get as much air flow as possible.

These mods will put the 6.2 at about 275 to 325 in horsepower with about 450 ft lbs. of torque depending on your setup. If you modify you injectors and upgrade your pump you can easily see the mid to high 300’s in a 6.2. It will spin the tires and climb almost anything in its path but you are not going to see the 400’s and 500’s that the Cummins hits with the turn of a screw. Diesels are restricted by how much air you can get into them, increase the air flow on a diesel and you will increase the power it is pretty much that simple. The bitch is the torque by the time you get a diesel into the HP band you want you have blown past the torque ratings for the tranny. So in the end plan on beefing up the tranny.

 

[shaun]

I will say that my stock 6.2l can spin my 37's. And that is w/ a detroit in the back. So they dont suck but it isnt a tire spinning monster either. If you want mud drags then lean towards another motor (gm 8.1L one day) But for mud with your friends with a set of 39.5's and 4.56's w/ lockers front and rear you can walk through alot of stuff and w/ a set of 38.5x14.5x16.5 boggers I was going everywhere my friends with there nice sbc and bbc and the occasional ford was going. I have since turned up my IP (black smoke is cool) and will be installing 3" duals w/ 40 series single chamber flowies. I am also working on a better air intake as this will make a difference also. The turbo though is your best gain. So I will be picing together a turbo kit and we will see how that goes.

 

[project84k5]

my 6.2 has a few mods, its got 6.5 injectors, a ported j code intake, timing gears, bored .030 over, a single 3.5" exhaust, and a turned up injector pump, it has zero problem spinning my 42's down the freeway with 5.13s and a built 700r4. it doesnt spin them, but i am about to lower the truck back down and put 39's back on it so im sure it might get a little chirp, but it makes enough power that i can pull anyone of my buddys with superdutys out and will crawl over everything at a little more than idle. still not a blown big block, but enough to amaze most people. i would keep the 6.2, dont go gas, its not as fun.

Ryan

 

[tRustyK5]

I have no trouble spinning my 39.5's with my 6.2 and SM465. It doesn't get the 100 mph wheelspeed that you need for mud drags, but it cleans out the tires easily enough.

I still run puny single exhaust but the intake has been port matched and polished up. IP is set stock as far as I'm aware, but was rebuilt along with the injectors. The IP may have been turned up slightly when rebuilt...

I honestly never use the last 30% of the gas pedal, in fact I currently have a throttle stop installed. The throttle stop got me through emissions testing with flying colors (prevented the tech from over-fueling it while lugging it on the dyno) I'm in no hurry to remove the throttle stop...so maybe I'm in the minority that feels the 6.2 is fine for power

Rene

 

[joez]

so maybe I'm in the minority that feels the 6.2 is fine for power

Rene

Nope, your not. I feel that for what it was designed for, it does just fine.

 

[original balzer]

wow after reading the rest of you with 6.2's posts i realy think my 6.2 was just plain worn out even after the turbo it easnt even close to a stock 350 kinda makes me wish i would have kept the turbo and find a differnt 6.2 or rebuilt the one i had i always herd bad things about them and figured mine was common given the chance id like to try one with a sm465 and some tune up items you all have sugested

maybe find a 6.5 in a wreaked truck??? are they simular engines?

balzer

 

[tRustyK5]

Most trucks with the 6.2 got really stupid gears...with decent gears they pull just fine IMO. Even with the Detroit and the 39.5's it takes very little effort to pull a quick 180 on wet pavement.


Rene

 

[ksmeltzer]

are they simular engines?

Virtually identical, the 6.5 is a better engine in my opinion. It had a better fuel pump, turbo from the factory, and it addressed some weak points of the 6.2. Just watch out for the PMD get a cooler or a relocation kit for it. If you are going to go out and get an engine, I would spend the couple extra bucks to get a 6.5 the price is not that much difference and it is getting easier to find a 6.5 than it is to find a 6.2.

 

[muddog]

they dont have 205's, IIRC all of them are 208s. 6.2's are definately known as being dogs, ive heard that a banks turbo will liven them up a good bit. you could do propane injection too, its like nitrous for diesels

3 models had 205's..covered it in anothe post