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At what point is a driveshaft loop required?

Kern Dog

Kern Dog

Life is full of turns. Build your car to handle.
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Hey guys,
I have yet to run my car at the strip with the current combo but a guy last week asked me if I had a driveshaft loop in my car. I do not.
Sacramento Raceway is having their annual Mopar show/race/swap THIS weekend and I was hoping to make a few passes.
Thanks
 
Kern, I put in the same class of blowing a trans/ flywheel failure or the rear end failing at speed. Even though I have good equipment in my 64 I still have a shaft loop. I got my education on this topic when I was in my teens and my best friends dad lost the driveshaft at the local 1/8 strip probably about 60/80 mph and it got a good bite in the pavement and exploded the car in a way that made a major impression on me that has stuck with me and I will never forget. It broke numerous bones and his back and neck and he was straped in a cage and was in the hospital for a hell of a long time and then he was done. They ain't to bad in price but I like making my own.
 
At what point is a driveshaft loop required?
Right before you have a driveshaft or U-joint failure..
:lol:
Actually I'm glad you brought this up. I should get one. Thanks!
BTW- can you recommend the strongest/best U-joint for street/strip, a loop too, and a source? TIA!
 
They're cheap insurance against a potential nasty occurrence. I'd never heard of them before I rebuilt my 440 to a 494 with considerable additional hp. Someone mentioned them to me and I bought one right away. I don't recall what you're running - but they don't cost much and if your running at the strip at all or just laying into it occasionally on the street I would still install one.
 
Thanks guys but the question still stands.
Maybe I should have asked: Is there a universal guideline that states at what ET index a driveshaft safety loop is required to pass a tech inspection?
I understand that seat belts, a radiator catch can, having no fluid leaks and all the lug nuts in place are basic requirements. A battery hold-down too.
Years back, I recall a helmet being required if the car ran faster than a 14.0.
My car is a stock body, all steel 1970 Charger. 440/493, 727, 8 3/4 with 3.55 gears. Approx 4000 lbs without me in it. I run a 295/45/18 tire with a 200 TW rating. My launch skills are not good, I either go up in smoke or walk it out and ease into it. Either way, I don't expect an impressive 60 foot time. With a slightly warmed 440 in 2002, I ran 14 flat at 101 with a 2.2 60' time. I have more cubes, less gear than before but the weight is about the same.
 
I thought it varied by track. Had to add a second throttle return spring just to race at the hokey Reno gig. Think it was less than 1/8.
 
I want to say NHRA standard is 11.49 and quicker a loop is required, I'll double check later today when I get home I have a 2017 rule book
 
Generally required with sticky tires or slicks. However local track rules may require it at a certain ET level, 13 seconds or quicker.
Doug
 
Don't know the rules or if there's a universal hp # at which you should but I'd just do it.

When I was a teenager I was driving a Polara down a fairly rough state route when it dropped the driveshaft at the tranny, could have easily been catastrophic! Imagine cruising along at 70mph and hearing a bunch of thumping, followed by a big bang sending the *** of the car up in the air! I could have sworn the tranny fell out and I ran over it it was so violent, we were lucky but never found the shaft. Best I could tell the shaft fell and thumped around briefly before stabbing into the asphalt catapulting the *** of the car while ripping the shaft off of the rear pinion. Scary!
 
Its different from track to track ive personally have had a driveshaft twist and it sat the car up on its nose it dont matter if you fall asleep at the light or have the best launch ever if your running it down the strip anything can happen its just added saftey so you and the guy your racing make it home at the end of the night good luck
 
My recollection is that NHRA requires it if you are running slicks. That is what my home track required and they referenced the NHRA safety standards.
Cheap insurance. Should you decide to make your own, be aware that the NHRA book specifies dimensions (metal thickness, etc.).
 
I have one in my car if you run slicks you need a loop summit sells them for 25 bucks and install it six inches past the end of the trans
 
I put one of these loops on both my cars. No drilling required. Bolts to the trans cross member.
mancini-racing-front-drive-shaft-loop-18.gif

http://www.manciniracing.com/mabebofrdrsh.html
 
If you run slicks. You will be fine if on street tires. If they want you to have one they will (most tracks) let you race the first time, if you are running street tires.
 
Kern Dog said:
Hey guys,
I have yet to run my car at the strip with the current combo but a guy last week asked me if I had a driveshaft loop in my car. I do not.
Sacramento Raceway is having their annual Mopar show/race/swap THIS weekend and I was hoping to make a few passes.
Thanks
Click to expand...


I took this from a older NHRA rule book. I believe this rule still stands.

13.99 1/4-mile (8.59 1/8-mile) or quicker:

-A driveshaft safety loop is required when you run slicks (not drag radials or street tires). With street tires or drag radials, no loop is required until 11.49 1/4-mile (7.35 1/8-mile) and faster.
 
I wouldn't run without one at any et on the track. If the track is sticky even cheap radials will hook hard enough to break things.
 
there worth the investment its good insurance :thumbsup:
 
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