hey everyone, a buddy of mine had given me a driveshaft loop but no mounting directions..ive heard different locations and measurements. some say 6 inches from fron u joint other say between 2- 6 inches from rear u joint..any help is appreciated..thanks
I think you'd want it near the front u-joint. If the front joint breaks, the driveshaft can drop down and "polevault" the car. If the rear joint breaks, it drops and either drags or pulls out of transmission; no real harm done.
DS loops are to be near the front u joint no more than a foot. As mentioned its main feature is to keep the DS from digging into the track.
If you drag race, check your rules from the sanctioning group. Like NHRA, AHRA, IHRA. These rules are specific for the guidelines. I think NHRA says no more than 8", maybe 12" behind the front yoke.
Welded mine to the floor support closest behind the front u-joint. That way no holes in the floor of the car.
With the Metco loop you'll find there's two places you can mount it. Fore or aft the floorboard support brace. Both will work, but fore the floor brace will allow less circular travel of the drive shaft if it breaks. Only problem is if you have a bucket car, the holes you drill for this mounting location will require one of the holes to go through the passenger left side front portion of the bucket seat mounting pad.
FROM THE NHRA RULE BOOK http://www.nhra.com/UserFiles/file/2010RuleBookAmendments-5.pdf 2010 NHRA Rule Amendments As of August 11, 2010 DRIVELINE (January 26, 2010) Driveshaft meeting SFI Spec 43.1 mandatory. Each end of driveshaft must have round 360-degree driveshaft loops within 6 inches of U-joints. Full 360-degree driveshaft tube mandatory over yoke, extending from transmission tail shaft a minimum length of 9 inches. Minimum thickness of tube housing is .050-inch chromoly or titanium. Two-piece accepted with minimum 6 3/8-inch Grade 8 bolts. See General Regulations 2:4
That spec is for pro mod. They also have a spec for cars with slicks. You don't have to have one with street tires, I don't think.
As per the 2010 NHRA rule book: 6" max from the center of the front U-joint and the loop must be a minimun of 2" wide. Driveshaft loop required on all cars running 13.99 (8.59 1/8 mile)or quicker and utilizing slicks except vehicles running 11.49 (7.35 1/8 mile) seconds or slower equipped with street tires.
