I see more guys putting lightening holes in rectangular tube frames and then sleeving them with a piece of round tube thats welded in. I get the look and the idea of the added strength of the round tube welded in...but where is the "Lightening" if the inserted tube weighs MORE than the 2 slugs cut out of the frame ?
Details, details, don't sweat the details. Look at the wicked cool work of guys here like Bass and Harv117, and others. Their work is so awesome, it doesn't matter if weight is shaved, or added!
Lightening holes aren't generally done to really "lighten" anything, they are done more for cosmetics.........they just look cool. And if you don't sleeve them you have an open area where water and dirt can get into the frame, or wishbone, or whatever. Originally, they were done way back when to lighten cars, but not so much anymore. Don
Well the holes are for creating a part that's stronger and lighter. Holes in a tube will do that and do that well. The problem is the tube fills up with shit , solution is to close the hole with a pipe. Do that and now its heavier and not any stronger. Exercises in futility. With holes you can make any part stronger pound for pound .
I have been told that the louvers in the trunk cause a disturbance in the air flow over the trunk. that gives a down force on the rear of the car at high speeds. like the salt flats. making it grab the track better.
Yes, they were lightening holes until the sleeves were added...lol Even though adding the sleeves adds weight they still give the frame a lighter open look, and add strength over just having the open holes with the same look. Thanks VooDoo
A really good Cheese have lots of holes in it! http://www.jalopyjournal.com/forum/album.php?albumid=30451&pictureid=346966 http://www.jalopyjournal.com/forum/album.php?albumid=30451&pictureid=346972 Lighter!
Actually if you poke a hole in an NHRA car and I think a B-Ville car you have to sleeve it. Lots of times the sleeve is not as thick as the metal taken out. Even if you didn't sleeve it we are only talking grams here and it take a lot of swiss cheese to amount to anything. They used to build frame out of conduit as well not so much any more. Rusty they were originally used to let air out. At speed a given vehicle may get a lot of air in the trunk, especially if the trunk floor has been removed to lighten it up and the louvers were used to let the trapped air out.
I would think the holes with the inserts would have much greater torsional strength/rigidity over the totally uncut rail. Might be good for a flexy frame under the engine where an X member can't be placed or for a wishbone, but certainly not lighter. My guess is though, it's mostly just for looks.
Have you checked out Dimple Dies to belle a hole. Cuts weight and adds a lot of strength. More for sheet metal than s frame though. Posted from the TJJ App for iPhone & iPad
Depends upon application of course. Real race cars cut for weight, show cars do it for style. Form vs Function, ya know?
Not intentionally for sure. Think about this, taking a hot rod with open holes and no tubes in various parts of the frame etc., to Bonneville You would have salt in places you never dreamed of and good luck getting it out
From what I have seen , dimple dies came out of the aircraft industry to strengthen holes used to lighten up the aircraft
We used to drill radius rods and not heal them and even cars that normally only get driven on paved roads would end up with the bones packed with mud and gravel. If pavement was clean you would never have to wash your car. Squablow is correct about torsional strength. Healing the holes will ad strength to an otherwise standard boxed frame. I cannot give you numbers it would depend on several variables and I would have to dig deep to find a good usable equation but it does add some strength.
Adding Torsional strength? Much like pissing in the ocean adds to the total volume of water, right ?!?! In a vehicle frame application, which we are speaking of here : If enough force was applied to the frame rail made of box tubing to twist it, that force would also be enough to destroy the car long before the additional tubes in the holes got to prove anything. Look at a factory cross member, its formed channel with plenty of holes and most of them are belled. Holes in tubes lead to tubes full of crap
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