I mainly wanted to post that pic but I do see straps on street cars at shows and events that are not alky's (the cars, I don't know about the owners).
Just like wheelie bars; if it's obvious the car doesn't need it.........it's obvious it's obviously................
I do. Or I did. Car hasn’t moved in 4 years, but when it did, I was required by the ECTA that it have straps, but not current certification, which saves a lot of money. Went 205 just like that.
I personally only run restraints or a bag on my street driven vehicle or Drag engine unless I am 7,000 engine Rpm's & over 12 pounds of boost with static compression of 11 to 12 to 1, My last full race was close to 70% OD @ 9,700 engine rpms Alky . Here are Rules ,,, NHRA Supercharger Restraint Rules Overview of Restraint Requirements The NHRA has implemented specific rules regarding supercharger restraints to enhance safety in drag racing. These rules are particularly relevant for cl***es like Pro Mod and Top Sportsman. Key Restraint Specifications CL*** RESTRAINT SYSTEM REQUIREMENT ADDITIONAL NOTES Top Sportsman Minimum six-point (SFI Spec 16.1) or seven-point (SFI Spec 16.5) Must be updated every two years from the date of manufacture. Top Dragster Same as Top Sportsman All belts in open-bodied front-engine supercharged methanol-burning vehicles must have a fire-resistant covering. Implementation Date These new restraint rules will take effect on July 1, 2025. This change aligns the requirements for Top Sportsman and Top Dragster with existing rules for other NHRA cl***es, ensuring a higher standard of safety across the board. Importance of Compliance Adhering to these new rules is crucial for racers to maintain eligibility in compe***ions. The updated restraint systems are designed to provide better protection and comfort for drivers, ultimately enhancing their racing experience.
Big difference between Required and or Needed for safety reasons and having the pieces on in hope of impressing the mouth breathers. Case in point on the wheelie bars, I doubt many of us would falt Finnegan if he finally showed up at a drag strip with wheelie bars on the 55. Some of the spectators might get upset because they aren't going to get that wheelie shot they were hoping for but the guys who run in the other lane will think it was a great idea.
Nitro and alcohol need them, gas doesn't. I did run them on my 41 but when I made up new valve covers the straps interfered with the breathers, both physically and visually. I did move the straps to a spare setup on display in the house. As far as wheelie bars, how does one just look at a car and know it won't pull the wheels ???
@Mr48chev Finnegan's 55 would be Faster with bar's But He likes dragging bumper , Bars also a tunning option one tire speed & other , back in Pre 70's Most did not know what Bars could be used for , Most where used just to keep vehicle off the bumper and fenders. @swade41 68 motion Camaro's where known to Carrie the wheels 1st & 2nd on street on street with tires of time , Back in mid 60's family friend drove A Sedan 4 speed DD & school onto 70s He could leave with tires in air 12 inches & when really showing off drag fenders after tearing them up a few times he bobbed them . Here quite a few street cars could carry the tires before 1975 , Mags @ time only showed very little what was going on around the US or other countries.
On a street application, if you have a corrrectly sprung pop off valve, the chance of lifting the blower lessens. What you will do is probably bend the rotors and ruin it. With some of today's tech and the alum studs, it might come lose. On the old v belt drives, the belt would slip and lessen the damage.
When I was trying to get the preliminary fire up of the flathead I had a few backfires under the blower, got to see those plates in action. What a mess they made of my polished intake! I ran a toothed belt rather than V belts mainly because everyone around here was running the multiple V belts and I don't like being like other people.
Thanks! I hope to get it back out there one day. I hear ECTA is going to run 1/2 mile events at Maxton again.
I’m thinking about restraints in my FED. 40’s vintage I6, vane supercharger running ****-through, alky injected. There are only six 1/4” bolts holding the manifold to the head… and a large volume of fuel/air mix upstream. The blower manufacturer from the 60’s notes that banging the blower in this setup can be “of nuclear proportions” It runs two relief valves, but they may not be enough. cheers, Harv
Wild set up on the IL6. If that thing no nuclear it is going launch at the spectators. Like they say down under "tie that kangaroo down mate".
It’s got a brace either end of the supercharger that go down to the ch***is. If it bangs, it would indeed launch sideways, but would pivot off that brace and dig the blower and injector into the track. Not fun. I figure two straps from the top of the blower, over the rocker cover to the exhaust studs. cheers, Harv
It was a high power motor for a gas coupe and/or daily driver when finished. A 671 supercharger with a new Isky-Gilmer belt kit plus an Edlebrock manifold. It was a new kit not yet shown at the local speed shops, back then. Hello, We ran one of the first Isky-Gilmer blower belt drive systems for a 283 Chevy motor. Isky cams had the original one. At the time, they came with a pop off valve on the Edlebrock manifold. No other manufacturer had made a manifold for the 283 block, so this one was matched to the new Isky-Gilmer Belt Drive System. When we picked up the whole system in Los Angeles, our friend had known both Isky and Vic Edlebrock way back when they were younger. So, he had insight into the new kit not on the market as yet. This was late 1959-early 1960. He was able to get kit #2 that included the whole Isky Gilmer Belt Drive, pulleys, adjusters, brackets and the Edlebrock Manifold. On the back of the Edlebrock Manifold, was a pop off valve with springs. That was sufficient enough to allow any blow back misfires. The springs allowed any extra power to exit when they were compressed and it opened up slightly. We never had a misfire or a blow back from the 671 supercharger system and it ran perfectly, once we got the 6 Strombergs tuned and adjusted. Jnaki The owner of the Bill Moxley Slicks Company always parked next to us in the Lion's Dragstrip pits and had his photo taken back then. Surprisingly, we noticed our Willys Coupe with the 671 on top in the back of the photo. How nice... Yes, earlier prior to the Willys Coupe build, he had parked next to us while we were racing the 1958 Impala. And, my brother bought a set of cheater slicks for racing. They lasted several weeks as those slicks were deemed "not stock," and were banned from eliminations. Trial runs, yes, but not for cl*** eliminations during the day/night. We sold them to another racer and for time trials, we used our original Bruce Slicks on the Impala. Luckily, the Bruce Slicks also fit neatly under the wheel opening of the Willys Coupe...problem solved. Note: As our friends at Reath Automotive told us the pop off valve on the manifold would be sufficient if the backfire took place. But, with a powerful gas motor built with specific blower spec parts, not high potent fuel powered motor, we would be ok with what was provided. The manufacturer, Edlebrock, knew the inherent possibilities. The different manifolds for the GMC superchargers have their own pop off design. For those that have other superchargers, they usually have a pop off valve for safety, on manifolds. No one runs fuel on the daily driver streets in a hot rod or even a family station wagon. So, no straps necessary/...YRMV
The Jalopy Journal
