Truck/Tractor Pulling

[496Cubes]

I'm going to enter my truck in a local truck pull Sunday. Does any one have any pointers or advise. I have 285/75R16's, DMI bumper, and Wester's Reprogrammed ECU otherwise everythings stock. Any idea what gear I should run in and if I should run in 4HI or 4LO.

 

Right now the only thing I have planned is to put 93 octane in and maybe mix it with racing fuel if I get my hands on some.

 

I have the 8.1/ZF6 combo with locking differential.

 

Thanks guys.

[BDBWTE]

Hopefully you'll will do better than my buddies pulling the sled. My buddies truck has the power to pull it but the clutch keep slipping on him. Plus IFS don't help you once your nose goes up.

 

Depending on the track and how compacted it is and water I would definately start off in 4lo for the torque multiplicaton of the transfer case but don't start off in 1st try second or third so you can have the torque and at screaming high r's you can have some speed for momentum. out of a 300ft track my buddies truck pulled the sled 198ft. My 6.0HD NV4500 with 284's pulled 180ft. So I wasn't impressed by the 8.1..

[Jersey Tahoe LT]

Thee only advice I can give is don't breake your truck. Other than that get some action shots.

 

Later,

Brandon

[BadBowtie]

Advice, You want to stay in the peak of your power band. If it starts at 2k, then powerbrake up to that and launch from there, if you can wind it up, leave it in one gear. Many times any momentum is lost when shifting gears. Id probably want to be in 4lo, and start in 2nd maybe 1st would work, might even be able to keep the r's higher in first... Good luck!

[1BADHD]

I pulled my first sled last year. I learned a lot from that one pull. Since you have big cubes and a manual. I would use 4 lo and start in second gear. Dont shift. Keep the RPM's up. When I first hooked to the sled I got the sled moving then pinned the throttle. I was spinning the whole way. Never did torque out just lost traction. So.........thry to roll into the throttle. The farther the weight comes up, the farther you push the gas. Try to keep traction and you'll pull it outta the arena. My 6.0 with 4.10's and 285 Mastercrafts, pulled 215' in the 6200 class. And 245' in the 7200 class. I now have a 6" lift and 35" X-terrains. I will be hooking to the sled again this Sunday. Should be interesting. Anyway, good luck and have fun.

[496Cubes]

Well I pulled yesterday. I went in the 6,000 and 6500lb class. I use 2nd gear 4LO and had to slip the clutch at about 3,000 RPM to get the load moving. I got it up to 5,000 RPM within about 30 ft. I spun a little for about those first 30 ft and then I just cruised until I spun out. The engine never pulled down or dropped from the 5,000 RPM mark. I got 278 feet on the first pull and then 256 feet on the second pull. I ran about in the middle of the pack both times at 8th and then 9th out of about 15 trucks in each class.

 

I ran in the 4WD Street Class, but I wouldn't have called anyone of them trucks stock. Almost all of them were homemade and some even had weights hanging off the front end. If I knew that would pass I think I could have rigged up some kind of bracket to bolt up to where the tow hooks mount.

 

Anyway, I had more than enough power, I just need to find a way to make some more traction. That's where I lost. Well maybe I can go to 4HI 1st gear or 4LO 3rd gear and get the momentum going. I think I want to use the highest gear I can and still be able to get started. I won't have much of a clutch left though.

 

I'll probably have to try this a few more times. Your definitely the star of the show, nobody can believe someone would take their new truck into a pull. As far as I could see there's nothing your going to hurt, except wearing out the clutch pads a little early.

 

If anyones got some ideas for improving the traction let me know. Later.

[1BADHD]

I forgot to menthion this. But.........lower your air pressures. makes for a larger contact patch on the dirt, making better traction. I cant tell you what psi to use. It all depends on the tires you have an what size. I pull this Sunday. I have 35" X-terrains. I think I am going to put 20 psi front and 25 psi rear. My normal psi's are 35 front and 28 rear. Since most of the weight is in the back I will keep the rear higher than the fronts.

[496Cubes]

That's a good idea BADHD, I didn't think of that. Max pressure on my tires are 65psi on 285/75R16's. I was running 50 psi all the way around. One other thing I did that I can suggest to you is to turn down your torsion bars. Everyone said I was running pretty level down the track. The only draw back is my front tires rubbed, so I had to do an Austin Power's to turn around it tight places. Good Luck.

[1BADHD]

What will cranking the bars down do? Soften the front suspension?

[BadBowtie]

Leve the front cranked up, or right where it is, and hang 5-10 of those tractor weights on the front end to bring it back down. That'd work better than lowering it, this way you add more weight to teh front, not just alter the ride height.

[Firetiger(MN)]

Some ideas I read over on the diesel page were to leave the air up in the rear tires. They also mentioned strapping the IFS too keep the wheel hop to a minimum. Not sure how they do strap them though.

 

The Duramax/Allison would be a different animal than your configuration, but they pull in 1st and 4HI and keep the pedal to the floor. Wheel speed is ground speed.

 

I'd like to try it sometime but a little nervous about abusing a $40k+ truck for 300 ft. Little different than pulling a trailer nice and easy to get it moving.

 

Sounds like you had fun though! Now you're (as they say in pulling), hooked!

[496Cubes]

BADHD, Someone who had pulled before recommended turning down the torsion bars to me. The idea is that as you go down the track the sled is putting more weight on the rear end. This is squating down the back end and raising the front end of your truck. This is taking weight off your front wheels and giving you less traction up front. By cranking down the torsion bars you are lowering the front end and keeping more weight up front giving your front tires more traction. Hope that helps.

 

BadBowtie is right about the tractor weights though, if you can keep under weight and its legal.

 

Firetiger thanks for the info about what the D/A's are doing. I'll have to figure out what gear ratio that is and compare it to my set-up. I'm not sure how strapping the IFS is going to help wheel hop though...

[496Cubes]

Okay, I'm confused. If duramax/allisons are pulling in 4HI 1st gear I must be calculating something wrong. All Duramaxes have 3.73 rear ends, so 3.10(1st gear)*3.73 (rear end) = 11.563. I was running 2nd gear 4LO, 3.31 (2nd gear) *4.10 (rear end) * 2 (4LO) = 27.142. I was going about 15 mph down the track. That means they are going about 35 mph down the track. There's no way. If I ran in 2nd gear 4HI I still wouldn't have as high as gear ratio as that. I made an assumption that the transfer case is a 2:1 ratio, but that's pretty close. Can someone straighten me out.

 

Allison

First 3.10:1

Second 1.81:1

Third 1.41:1

Fourth 1.00:1

Fifth 0.71:1

Reverse -4.49:1

 

ZF-6

Gear Ratios:

First: 5.79

Second: 3.31

Third: 2.10

Fourth: 1.31

Fifth: 1.00

Sixth: 0.72

Reverse: 5.23

[96Z71asskicker]

all i can tell ya is do everything the oppisite my friend did with his truck. he's got a 2002 chevy duramax and got 4th out of 4 trucks he sucked big time didn't air down just put a new exhaust on his truck 5in. thought it would help. Then got a chip which took away his low end tourqe. the other 4 trucks were all Powerstrokes one had a full pull that truck was amazing to watch since all he had done was a chip and the banks kit. loud as hell goin down the track too.

[Firetiger(MN)]

Are you considering wheel spin in the speed calcs? 35 mph doesn't mean the truck is actually going that fast, but the wheels are. Like I mentioned before, wheel speed translates to ground speed. Get those tires spinning and the load moving.