critters

[idrivejunk]

This will reveal my level of attention paid one way or the other... and test yours.

Was trying to thinkmember but it seems like Bill the current one you made in the what I called sheetmetal style but wait...

it is a fully boxed combo of tubing in straight sections and sheetmetal (same thickness) at kickup / hump areas.

Is that correct? Memory says older builds of yours were all tubing.

Body metal is where my genuine interest stops so naturally the other stuff is not as fully digested although all seen and read.

So has your K/B-O/S architecture evolved or are my observations valid? Wouldn't hurt to talk about that some.

And I concur with the bracing suspicion. If you were a roadster shop about to make available a chassis, do you make a ladder then go pound on it to see where cracks appear like the approach used in locating an H pipe aft of header collectors? Like building a business complex then waiting a year to put connecting sidewalks where foot trails appear.

Because while the underfoot section with the brand laser cut into theirs, after having seen more than one of their designs firsthand... kinda looks like a common reinforcing grid shape that gets plopped between rails to suit the app.

Have they done stress testing? I'd say most certainly. Have they done destructive testing, crashing a handful of frames as OEs would? Hmm, skeptical. I am not aware of any regulations regarding aftermarket chassis that might prompt such but haven't looked for any. NHRA is probably a relevant guideline.

Whether suspension choices or rigidity is the more critical focus is a good question but we are talking vehicles with the  aero of a Frigidaire and on public roads so merely sufficient eyeball common sense rigidity likely serves fine. But observing similarities or differences in different makes of aftermarket chassis would be what I would look to for bracing cues. The RS frames ain't all that dadgum stiff but stockers are like dampened spaghetti. On the scale involved, body-on-frame, yeah I'd say racy stiffness is out the window either way but quantifying how much of that is enough is the question and personally would pursue ride quality and stability over how long can it drift high-horsepowered donuts and figure eights or serve baja duty.


Absolutely yes a question only answered by trying 'em out.


I think they are all, theirs and yours, mild street frames that are yeah probably all OK for running tens or so too. I don't think you'll find many 100K+ mile hard use testimonials on RS frames but theres a lot of OE frames still good enough to hold a quick truck.

I have one more pic of the 51 frame, may post that too. Outdoors. This comment is fluffy enuf as is.

[idrivejunk]

 

[idrivejunk]

Personally, on that one, I cannot stand it having nothing but sheetmetal ahead of block to stop a centered pole. No damage resistance if your light turns green and somebody runs the red catching it ahead of spindles. Theres no bumper. Gimmie a spreader bar... something besides the radiator core, I mean come on man.

[jaybee]

Matt, I took a ride once in a late model Mustang with a 700rwhp dyno sheet. Incredible acceleration anytime he put his boot in it, the thing actually pushed you UP the seatback.

Bill, the frame you built for the new truck looks really sturdy to me. Maybe not quite as much as the hydroformed chassis of a C5, but you're gusseted up, reinforced at the joints, and I think it's going to drive like a sports car.

[kb426]

The chassis is all tubing. Instead of adding cross members, the cab and bed frame are the additional supports. The carriage for the irs is quite substantial. I'm concerned that when it gets weighed when completed that I missed my goal and it will way the same as the last 3.

[idrivejunk]

Jaybee, yessir. Overplenty is plenty. But how usable low speed city grunt compares between say a 400 horse Ponch 400 and a 400 HP Coyote is my curious point. The Pontiac getting the work done in 2/3rds the RPM range of the Ford indicates much different driveability. One is engineered for three gears and one for six. What happens if theres a C4 behind a Coyote or a six speed behind an all iron Pontiac? Nobody knows because its most practical to use the appropriate transmission. Since I don't race and have enough TH400 / 12 bolt to last until doomsday, this is the concern that comes to mind because transmissions are now more expensive than engines in my power level of thought. Stepping to electronics for either has negative appeal for a hobby car in my realm.

Bill, all your thinking might pay off. Remembering that total rigidity is the sum of that from frame and body together. Good point to give a shot at... doing enough without doing too much.

My kneejerk horror reaction to the aftermarket frames is because its all flat stock and corner welds ground flush. My crash side sees rails splitting at seams if crushed and therefore making a more dangerous ride after impact before stop. My rod side sees ease of manufacture and swanky appearance there but wants to use all tubing and get it overwith.

I'm ready to see yours come together, I know that.

[idrivejunk]

Was trying to shut the door of my car after lunch yesterday but this bee flew in and got shooed out four times before I could barely manage to shut the door. No doubt I appeared to be insane but fortunately no observers were present.

[jaybee]

Matt, I recently deleted the link because it's broken, but I bookmarked a conversation on the most recent version of RRT. It was a discussion you played a big part in about the need for crush zones in cars. You had noticed that some of the aftermarket frames appeared to be too strong clear to the ends of the frame rails, potentially transmitting more force to the occupants to the extent of injury or death. What you say above reminds me of that, in that the damage you fear could happen at anyplace in the structure. The rails at the ends of the chassis could well hold together, driving the force back into the area of the passenger compartment and splitting the welds in the most critical zone instead. It would be the worst possible outcome if, for example, impact at the front of the car pushed the engine compartment area rearward intact but destroying the passenger area in the process.

Somewhat related matter, I have a recent interest in the GMT400-OBS-C/K1500 pickups made from 1988-1998, or 2002 for the Tahoe and Surburban. Unlike earlier pickups, these have a kick up behind the cab. It seems that stress and bending loads concentrate in this area, and can even crack or break the frame. When new, these trucks sometimes even suffered from complaints of shaking caused by frame beaming in resonance with undulations in the pavement or expansion joints.

The obvious solution is boxing plates for that part of the frame, with fish mouths at the front and rear of the plates if the whole frame isn't being boxed.

But, I'm also curious about something I saw on one of the Hot Rod Garage episodes about the pickup they swapped onto a Crown Victoria frame...the Crown Hick. Going in, I acknowledge their theme is often doing things the wrong way but having fun with the car anyway. What they found in this case is a lot of flex in the axle kick area, because as Bill is doing in his latest build, the Crown Vic body and frame work as a team. The pickup tended to bend between the cab and bed. They did a couple of things to help, but I want to mention one of them. They put hockey pucks as improvised body mounts between back of the cab and the front of the pickup box.

They demonstrated a lot less flex as indicated by far less variation in the cab/box gap as the car was jacked up. What's your position on something like this? Inexpensive but ingenious? Rat rod nonsense? Likely to create other issues? I think the answer may be different for a lowered street burner than for a flexed out 4x4.

[58 Yeoman]

We have a very small possum in our area that can't use its hind legs; looks like it was either hit by a car or an animal got to it.  It climbs the (at least) 25' hill from the dry creek to our yard to feed on the seeds that the birds drop.  He really gets around the yard. I throw extra food out for it if I see it looking.

The last couple nights, I've seen a large raccoon milling about eating the seeds, etc.  I have to set out two live traps, because the possum usually comes first and gets trapped. But since it has trouble walking, it hasn't been going into the traps anyway.  I saw the raccoon out there tonight milling around the traps, and finally got greedy and went into one.  Bad move. He's already in the trash dumpster for tomorrow's trash pickup.

[idrivejunk]

Phil, you've shown a balance there. Good sportsmanship. Obviously the handicapped opossum has been around the block and learned things.

Its funny to watch especially a couple weeks ago then the wanuts fell. Mourning Doves see the car coming and stay until the last moment positioning the nut of choice so you'll run over it cracking it for them. Bless their hearts, they think the tires go all the way across. If I see that scenario I try to oblige them but they place them in line with the whole car, not a tire. So its hit n miss for them. Bird brains. Or rather... dinosaur brains.

[idrivejunk]

Due to using a phone to forum, I've made one small inadvertent tap and put myself in a cut and paste situation I can't back myself out of within the available time. Was reading to try to get back to sleep, now the alarm clock is going off. Crap. Been trying to go to bed early for my job's sake but it always backfires.

So, pasting my response below and it starts over in I think the 13th paragraph. Sorry. The space I have to type in is about 1 3/4" x 1 1/2" and backspace, no arrow keys. Soft keyboard area is about the same size. Constant typos.

Best I can do:

Jaybee the idea for a frontal crash is to start slowing the impact down, absorbing energy, before the centered phone pole contacts engine and stops all at once.

Depending on the impact's proximity to rail end, without a  frame x member of sorts in front of engine... if it hits on a rail end, kickup behind engine is probably absorbing energy at the start of the crash crush. Miss the rail end and slow down less until wham, solid contact with the heavy stuff. With frame horns tied together, that center impact can be slowed down a lot before that happens and transferred to a greater amount of bending metal that can give, softening the blow.

I have seen a truck or two damaged in transport, where frame becomes bent between cab and bed, and wondered if it happened during tie down or during the ride due to how it was tied down. Truck frames are long. Theres a great deal of leverage involved along that length.

Stiffening within the torque box area urges the frame to bend more at kickups, making two bend points rather than the one in the center. Arguably a riskier take if its a work truck driving through ditches at a work site. The concentration of fatigue out closer to suspensions by boxing the middle under the cab / box gap could cause unforeseen increased flex hotspots at kickups / susp mount points.

But the overall reduction in flex would help to keep front and rear suspensions in their unstressed, proper orientation relative to one another and for a corner carver thats the ticket.

For best payload tolerance, I think allowing the full length flexing probably generates the least fatigue.

Obviously an arch, like a foot or doorway, bracing over the middle of a pickup frame could be of light construction and have a similar effect to boxing but there again it creates fatigue points where attached. The models mentioned having a dip instead does seem counterintuitive but facilitates comfortable entry/exit with a lower cab position.

My understanding is that the 88-up GMT introduced hydroformed rails. At least the front section. Obviously, in pursuit of one thing, another thing which takes time to show up was compromised. Resulting in the rhythmic destructive bouncing as might occur over road expansion gaps.

So absolutely, yes the intended usage comes into play. If you could haul a load without cab or bed, I don't think frames would mind much. Pickup bodies are more of a seperate entity from chassis.

By using cab and box as part of the structure, creating two stiffer areas, of course more strain is placed between the two. Engineering guesswork then trial and error required to calculate how much stiffness is enough. Wheelbase could certainly be a factor in how that proves out.

But OEs are out to walk a fine line, rodders can build in plenty of rail strength there and not have to nail the guesswork on keeping a frame from folding in half.

That gets into trying to make a truck body work like a car, which is the direction to take on a light or no duty sport truck. And for a load toting truck, flex to spread fatigue would be the path to follow.

When wanting to turn the latter into the former, why heck yeah a higher-up bed / cab connection (or just cushion) is a gentle way via body mounts, to lessen and spread any middJaybee the idea for a frontal crash is to start slowing the impact down, absorbing energy, before the centered phone pole contacts engine and stops all at once.

Depending on the impact's proximity to rail end, without a  frame x member of sorts in front of engine... if it hits on a rail end, kickup behind engine is probably absorbing energy at the start of the crash crush. Miss the rail end and slow down less until wham, solid contact with the heavy stuff. With frame horns tied together, that center impact can be slowed down a lot before that happens and transferred to a greater amount of bending metal that can give, softening the blow.

I have seen a truck or two damaged in transport, where frame becomes bent between cab and bed, and wondered if it happened during tie down or during the ride due to how it was tied down. Truck frames are long. Theres a great deal of leverage involved along that length.

Stiffening within the torque box area urges the frame to bend more at kickups, making two bend points rather than the one in the center. Arguably a riskier take if its a work truck driving through ditches at a work site. The concentration of fatigue out closer to suspensions by boxing the middle under the cab / box gap could cause unforeseen increased flex hotspots at kickups / susp mount points.

But the overall reduction in flex would help to keep front and rear suspensions in their unstressed, proper orientation relative to one another and for a corner carver thats the ticket.

For best payload tolerance, I think allowing the full length flexing probably generates the least fatigue.

Obviously an arch, like a foot or doorway, bracing over the middle of a pickup frame could be of light construction and have a similar effect to boxing but there again it creates fatigue points where attached. The models mentioned having a dip instead does seem counterintuitive but facilitates comfortable entry/exit with a lower cab position.

My understanding is that the 88-up GMT introduced hydroformed rails. At least the front section. Obviously, in pursuit of one thing, another thing which takes time to show up was compromised. Resulting in the rhythmic destructive bouncing as might occur over road expansion gaps.

So absolutely, yes the intended usage comes into play. If you could haul a load without cab or bed, I don't think frames would mind much. Pickup bodies are more of a seperate entity from chassis.

By using cab and box as part of the structure, creating two stiffer areas, of course more strain is placed between the two. Engineering guesswork then trial and error required to calculate how much stiffness is enough. Wheelbase could certainly be a factor in how that proves out.


le gap flexing over the entire chassis length. But might require some "stoutening" at said cushion area. Factories probably avoid this method due to the added vibration transfer to inside the cab but it is a neat idea and the concept seems logical.

Ever heard of an el Camino frame bending in the middle? Of course not. Ever hear of a unibody truck that had a long production run? Nope. For trucky truck use, I say take the flexy approach. For car-like truck use, go rigid. And make sure the wheelbase doesn't match expansion joints on interstates.

[idrivejunk]

*. I would have trouble sorting that out even on a PC with a mouse. Hope I didn't lose any of the content, theres no time to proofread. Like I said I hit paste instead of copy one of the times I tried to copy because of the timeout. Good luck!

[58 Yeoman]

We live about 500' from a state highway, and the farther south we take it, we will see turtles crossing the road from east to west, heading for the parallel river. Many times, we will stop and pick up the turtle and put it on the side that it's heading for. A few years back, I had stopped and got out, but before I could reach the turtle, an * in a PU came and aimed for it, just hitting the side of its shell. That sent the turtle flying down the road like a wheel, obviously killing it. That's the mentality that we have to deal with here.

Matt, you know way more than I do about frames and crush zones.  The picture I posted shows a Monte Carlo that slid sideways into a large power pole about two blocks from where I used to live, on a state highway.  I wasn't able to get a pic of it until after it was towed to the local Ford dealer. Don't know what happened to the occupant/s, but OUCH on the car.

In late '68, I was working for that Ford dealer when we got a wrecker call to pick up a new GTO that had slid sideways into a tree about three miles away. It was a construction worker that lived in one of the apartments next door to the Ford dealer. He missed the first part of an S curve and slid sideways into a large tree. The local wrecking yard was already there with a flatbed, where they loaded the front of the car from the firewall forward onto the flatbed. They also loaded the dash and both doors as one piece onto their truck.  We wrapped our cable around the rest of the car and picked it up sideways.  I'd never seen a wreck like that, the car broke into three pieces.  Wish I'd had a camera then.

The best part was we talked with the ambulance crew that told us the driver of the car had been wearing his shoulder/seat belts. When the car stopped moving, he was still sitting in his seat, feet sitting on what was left of the floor, looking out where the whole front of the car had disappeared. He walked to the ambulance. Obviously, crush zones wouldn't have helped either of those cars being hit from the sides like they were.

[idrivejunk]

Man, its gonna be a long day.

I saw a C5 vette that had taken that kind of hit. Pole stopped at the transmission.

I always enjoy the original Gone in 60 Seconds scene where they knock an obviously pre-sawed Dart convertible in half.

When it comes to T-bone side impact, no matter the vehicle, the body metal is all there is to slow down the hit. If it makes it to the frame rail you are probably already deceased.

A Harley can toss it's rider and penetrate a tri five clear to the driveshaft tunnel with only a couple layers to stop it.

Observe on modern construction how door intrusion beams AND door jambs overlap significantly. On old stuff the door opening is the size of the door leaving the possibility of shoving door through door opening in body. Thats the kind of side impact protection improvement that counts as far as statistics.

Like the pole hit on the original Eleanor, a pole hit just behind front wheels is one of the few ways feet can get hurt in a wreck. Its an Archilles' heel on any vehicle.

But yep, if you are wearing your seatbelt in a car-ripping-apart impact, chances of survival are improved simply because the floor pan / rocker box is the core and farthest from impact in any case. If hunks are being torn off, staying put in the seat is the best bet for sure.

[enjenjo]

There is a snapping turtle that has been crossing my yard and road for 50 years, twice a year. In the spring from the creek to the swamp behind me, and in the fall from the swamp to the creek. When I first saw it, it was just bigger that a small plate. Now it's about 24" across.

in the early 70's there was a guy that fell asleep at the wheel driving a full size 70 Pontiac wagon, and hit a Jersey Barrier guard rail in front of my house head on. It was clear through the car and stuck out through the tailgate. He was unhurt.