truck tracs with 2600 rpm converter, hoosier slicks, and stock 3.55's got me a 1.59. without the truck tracs I got a 1.69 that day 30 minutes before, installed them at the track. NICE!

that 1.59 happen to be the run I blew my monster box out on, so who knows what that would have been for me.

 

I run the JLP bars. I get pretty consistent 1.7X 60 FT times on Nitto 555R drag radials, adj. shocks and a Pro Torque 2400 stall converter. I am sure at a good track I can easily see 1.6's. One of the main things is track prep. On a side note.....the peace of mind that you get with bars makes them all worth it. I no longer have to worry that awful noise coming from under my truck again. Driveshafts aren't cheap either unless you have a dealership that will warranty them for you. I do! -Mat-

 

"I run the JLP bars. I get pretty consistent 1.7X 60 FT times on Nitto 555R drag radials, adj. shocks and a Pro Torque 2400 stall converter"

What type of adj. shocks do you all use with them need part #'s please?

Peace, Suavy [IMG][img]

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I believe most guys are useing Q1s. See Ruslow for the proper 'ends'.

Dan

 

Okay, let's take this "lift" theory one step futher.

(1) If I drop the back of my truck another 2", would the resultant added rear weight bias (actually reduced front wieght bias) demonstrably change my off-the-line traction?

(2) And wouldn't ANY traction bar give exactly the same amount of lift, so long as it arrests all axle wrap and is attached to the frame (or in the case of CalTracks or Truck Tracks, so far towards the front of the spring that it might as well be on the frame)? As a matter of fact, so long as I prevent the axle from wrapping up--no matter what device I use--doesn't that necessarily result in that force which would otherwise twist up the leafs to cause lift?

(3) With a true 4-link with equal length bars and mounting points perpendicular to the ground plane, the pinion angle remains the same relative to the ground through the entire range of suspension travel. The Metco bars I have hook to the front spring eye, creating roughly the same geometry as an equal-length 4-link. However, since the transmission tailshaft is not moving with the diff, this means that the pinion angle actually changes as the axle moves up. For those traction devices which attach well ahead of the front spring eye, what happens to the pinion angle? Does it stay better aligned with the tranny? Which is better?

Yup, more bench racing.

 

Tim, I'll try to answer your questions.

A 2" drop shackle will definitely affect the static weight transfer. It will transfer a small mount of weight rearward, giving you a slight traction advantage. The same goes true with the front of the truck. The higher it is, the more weight is transferred to the rear.

A traction bar is basically a lever. It harnesses the rotational force of the rear axle, and uses it to lift the front of the truck. In doing so, it also pushes down on the rear axle.

The amount of force is dependant on the length of the bar, and where it connects to the frame. If the end of the bar contacts very high in the chassis, it will apply a large amount of vertical force. However, it will usually lift the rear axle with it.

The amount of lift is also dependant on the angle. If the bar angles steeply upward, it will apply force quickly and violently. If the bar has a shallow angle, it will react more slowly, but provide traction for a longer period of time.

Any traction device is good for the driveshaft. A little rotation won't hurt it.

Now, onto a 4 link. This is a whole different system. All components are adjustable, so you can adjust the amount of lift, and squat. You can put the "contact" point of the traction device virtually anywhere in the chassis.

As with other bars, the front end lifts, and the rear has a tendency to squat, due to the large amount of weight being transferred rearward. In effect, the rear end is being pulled upward, away from the track surface, reducing the effectiveness of the weight transfer.

The 4 link can be adjusted to counteract these forces.

No traction device can absolutely maintain the pinion angle. As you go through the travel, you will change the position of the driveshaft, so small changes are inevitable.

 

Jay, what do your bars (I have a set) do on a road course? Do they help or hurt? Sorry if this seams like a dumb question. I had your bars on my truck running the road course at TMS in a SVT on track event and was not sure if that was good or bad.

Jerry

 

Jerry, as with any traction bar, they will change the handling of the vehicle. You might want to check with Daniel (the pawn). He was using them on the autocross course for a while.

One thing that they will do, is affect the steering under power. When you accelerate, the Truck-Traks will lift the front of the truck. This will make the truck understeer under power.

I found that by changing my driving, I could work around this problem. I try to get the truck as straight as possible before putting the power down.