County fair pull

[Mark Rinker]

Ran the high mile 2002 in the local county fair pull yesterday. Had good results and placed in the top 1/3 of 20+ local trucks, mostly contractors and smart alecks from around town. The fairgrounds is 3 blocks away, I basically put on my shoes and drove up there with the truck that was sitting in the driveway.

We got rain in buckets early in the afternoon, so they scraped off the top 2" with the grader but things were still greasy. Put on a new set of Michelin M/S last week, so lots of good bite for the conditions - tall, skinny and lots of tread to find dry dirt.

Winners were in the 270 foot range - I think a heavily modded Duramax ended up on top. The 'Cummins boys' sure like their trucks, most have a single center 6" or 8" stack in the bed and sound pretty mean. Newer 6.0L Ferds don't even compete - a few old 7.3s did much better. Most of the Duramaxes were quiet but effective at getting the sled down the track. Not much for grandstand appeal - compared to the smoke, noise and hop of a properly crude Dodge shakin its way to the end...leaving parts all the way.

Threw it into 4LO, left it in 3rd gear, tow/haul ON, Kennedy switch on 'performance'. Got the chain tight, mashed the brakes and did a full throttle brake stand for 2-3 seconds to get the hot exhaust rolling and turbo boost maxed out...then let off the brake and and let 'er buck, wheels spinning at full throttle letting the Allision take care of two quick upshifts. To me, thats the most fun part - when your holeshot and wheel spin is translating to mid-track speed and you can feel the tires finding traction and getting ahead of the sled. Its a rush!!!

Went 252 feet - about 40 feet further down the track than I have ever seen before. It was a good, long ride with no wheel hop and just a little drift, looking for traction. The old LB7/Allison had no problem making and holding ~3 grand rpms from shortly after launch until I let up at the other end. I assume there was constant wheel slip from launch to landing, but mid-track it felt hooked up and 1:1 with the ground for awhile - like a Sunday drive with impending doom chasing you.

I didn't add any weights out front and could have been 1000# heavier and still legal in the class. Hook was a clevis through my receiver tube pintle hitch, a full 4" lower than legal max. Did top off the 80 gallon transfer tank 'mid-ships' for ~600# of 'ballast'. This year I went for a 5 mile warm-up romp before my class started and had the engine and transmission up to full operating temperature, left the truck idling with A/C on max to help maintain underhood heat and I think this translated to a much harder launch and better speed.

Someday I am going to combine all the lessons learned, plan ahead and assemble a truck that will pull that damn sled out the other end.

Most likely candidate: K3500 SRW long box crew cab with 100+hp custom tune, weight maxed out to class limit, new skinny rubber with 1/2 inch of flexible block tread...and maybe a sneaky shot of nitrous mid-track to get ground speed up over 20mph ...

Pushing 300K miles and pulling with the new trucks. Like a rock.

[DieselDavy]

Way to go Mark! I'll bet that was quite a ride!!
Dave

[More Power]

Great Job! Maybe a locker in the front diff? Maybe some competition tierods? The longer traction bars (longer than the Caltracs) seem to be the preference for pullers. You'll only need nitrous if the engine can't pull without losing rpms. Do you have a built Allison?

Jim

[Mark Rinker]

Agreed on the nitrous. One thought however, is that a small extra 'bump' (+50hp?) might allow for a 4th gear pull, rather than 3rd in 4LO.

Its all about mid-track speed, as the ending is inevitable. Anyone else out there pulling in amatuer ranks (stock 8500# or 9000# class) this summer? If so, in what gear and (allowable) mods are you running? I have Timbren springs in the rear - have always run them but technically they are illegal, and I am sure they help by stopping suspension travel and reducing rear 'hop'.

(Moderator - can you move this thread to the "Duramax Diesel Performance" forum, please? Maybe I'll get better responses to these questions there.)

[Kennedy]

Tires: Something a bit wider and more aggressive would help a lot in most cases. The BFG AT in 285 would be what I suggest. There are a lot of other choices, but the BFG AT is excellent all around, MT for muddy tracks. New rubber is not necessarily better. A flatly worn tire at 50% will put more rubber to the ground with less squirm. I like Michelin runbber, but it's nowhere near as aggressive as one should have if this becomes a habit/addiction and you want to be competitive.

You'll need a lot more ponies, or maybe less hitch (less bite) to run 4th effectively. At least 500RWHP but 700 would be much better.

[Mark Rinker]

Not interested in competetive pulling - simply like to take what works on the street and for business and see how it stacks up to the rest of the world! Thanks for your help with the tune.

As for traction, I think the snotty track due to rain was my advantage - not too much power on tap, good tires for the conditions.

Sometimes its okay to be more lucky, than good.

[rustyk]

I'd like to give that a try - with 10,500 lbs. on the rear axle, I suspect I could pull the sled and a Duramax dually pulling against...

[Mark Rinker]

Ummm...no offense, but I suspect you'd go about 50 feet. Maybe 70.

With the Duramax pulling in the other direction...backwards.