2015 hood flex help!!

[Rick U]

My 2015 LE's hood flexing along with the roof and doors bothers me big time. It's so noisy we don't even listen to the stereo on road trips. I'am considering dynomat for the doors. I guess it's "normal" but it sucks.
:violin:

 

[Jetboy]

1708 Fiberglass 45/45 DBM Biaxial 50" Inch Wide - 3 FEET LONG - 1 YARD: Amazon.com: Industrial & Scientific
+
Laminating Epoxy Resin 4:1 Kit (1/2 GL - Base Resin & 1 Pt. - Curing Agent): Amazon.com: Industrial & Scientific

should solve your hood problems. If you've never made composite things before - read up on how to safely work with epoxy - don't get the shit on your body!

If you want to get really fancy, infuse carbon biaxial fabric on the bottom.

Also free tip: dynamat is pretty much the same thing as aluminum roofing membrane. And the roof stuff is a tiny fraction of the cost and available at your local hardware store.

 

[BlackWorksInc]

It flexes in the middle closest to the dash at speeds above 70mph. I don't believe the flex is caused by road vibration… I want to say its wind turbulence. Like I said it doesn't seem to be as bad on the SR5. I know I am being picky here fellow 4runner faithful.. but I bought a brand new car and I would expect more from Toyota as my 2006 was the best car I have ever owned. I guess if I keep it dirty and not shiny it won't bother me as much!:evil:

That's the problem, you bought a NEW car, how do you think they trimmed the fat on the porky 5th gen? Easiest way for manufacturers to meet MPG requirements is to lose weight; easiest place to lose weight is the hood door skins, roof, and back door skin as they typically are not structural in most designs. Also by removing/reducing stiffening brackets and using industrial adhesives help shave weight down and reduce metal used helps as well. Not to mention impact safety standards; you won't find a heavy solid hood like those old cars for at least 20-30 years back, they mandated them to have crush/bend points to prevent decapitating the occupants in a crash and instead to fold/buckle easier, part of why a fender bender ruins hoods now more readily than before. Not to mention if a pedestrian lands on top of the hood it needs to deform some to absorb impact damage (hence why there's a regulation for hood to top of engine if I remember right.)

Basically, if you bought a brand new car expecting it to be as heavy, sturdy, and solidly built as an older vehicle; you'll be disappointed. Most of the strength of new cars is their ability to destroy themselves to keep the occupants inside safe, not being solidly built. It sucks, but that's how it is now. You can try and reinforce the hood if you want, but that's quite a bit of work depending on how you want to do it (i.e. fiberglass, TIG welding reinforcement in, Rhino-Lining the hood, ect.)

 

[Blitzkrieg]

Brother, if this is keeping you up at night, you need to re-evaluate your priorities. ;-)

 

[LawnDart]

Was going over washboards and yes the hood bounce is less than great, but whatever, got me to where I was going and we were screaming down the road at 80mph through shitty terrain.

I'll live.

 

[flighht2k5]

That's the problem, you bought a NEW car, how do you think they trimmed the fat on the porky 5th gen? Easiest way for manufacturers to meet MPG requirements is to lose weight; easiest place to lose weight is the hood door skins, roof, and back door skin as they typically are not structural in most designs. Also by removing/reducing stiffening brackets and using industrial adhesives help shave weight down and reduce metal used helps as well. Not to mention impact safety standards; you won't find a heavy solid hood like those old cars for at least 20-30 years back, they mandated them to have crush/bend points to prevent decapitating the occupants in a crash and instead to fold/buckle easier, part of why a fender bender ruins hoods now more readily than before. Not to mention if a pedestrian lands on top of the hood it needs to deform some to absorb impact damage (hence why there's a regulation for hood to top of engine if I remember right.)

Basically, if you bought a brand new car expecting it to be as heavy, sturdy, and solidly built as an older vehicle; you'll be disappointed. Most of the strength of new cars is their ability to destroy themselves to keep the occupants inside safe, not being solidly built. It sucks, but that's how it is now. You can try and reinforce the hood if you want, but that's quite a bit of work depending on how you want to do it (i.e. fiberglass, TIG welding reinforcement in, Rhino-Lining the hood, ect.)

Actually, newer vehicles tend to be heavier than older. Wish that myth would die. Newer cars are far more sturdy than older cars. Newer cars are far safer than older. "Thick" sheet metal means diddly squat for safety or strength. You need to see the video of the 2010 impala vs the 1959 impala. That will change your mind about older cars are tougher or whatever it is people think.

As a matter of fact I'll post the video
https://youtu.be/1_ptUrQOMPs

 

[Blitzkrieg]

Actually, newer vehicles tend to be heavier than older. Wish that myth would die. Newer cars are far more sturdy than older cars. Newer cars are far safer than older. "Thick" sheet metal means diddly squat for safety or strength. You need to see the video of the 2010 impala vs the 1959 impala. That will change your mind about older cars are tougher or whatever it is people think.

As a matter of fact I'll post the video
https://youtu.be/1_ptUrQOMPs

Yep. My dad had a 1960 Chevy Bel-Air. I thought that thing was a tank but that video sort of proved how really good crush zones on modern cars are. Scary what that steering column in the old Chevy would do to your vital organs.

 

[LawnDart]

Yep. My dad had a 1960 Chevy Bel-Air. I thought that thing was a tank but that video sort of proved how really good crush zones on modern cars are. Scary what that steering column in the old Chevy would do to your vital organs.

There's a reason why my 86 E30 BMW 325's insurance cost so much, it was a rolling death trap with no airbags. At least I would have gone quick...or not...

 

[BlackWorksInc]

Actually, newer vehicles tend to be heavier than older. Wish that myth would die. Newer cars are far more sturdy than older cars. Newer cars are far safer than older. "Thick" sheet metal means diddly squat for safety or strength. You need to see the video of the 2010 impala vs the 1959 impala. That will change your mind about older cars are tougher or whatever it is people think.

As a matter of fact I'll post the video
https://youtu.be/1_ptUrQOMPs

You're missing the point I made in my post. Newer vehicles ARE heavier because of all the laden safety, creature comforts, extra crap, ect. As a result to reduce ADDITIONAL weight that would further impinge on fuel economy the manufacturer's need to shave as much weight as they can get away with. One of the easiest ways to do that is to thin up the metal in cosmetic/non-structural areas such as the door skins, hood, and roof panel skin. Theses areas are not typically structural and more often then not designed to just crumple into nothing at the lightest touch (the hood being an example since it is notched to fold up vs. decapitate the occupants in an accident.) I'm not saying the vehicle is any weaker/unsafe; I am saying that the engineers decided that perhaps using a 20gauge sheet steel they would use a 22gauge and open up the support structure more and use less adhesive bond in some places because it doesn't have to be THAT rigid compared to say the A-Pillar and B-Pillar sections which may be made of a 14 gauge steel (these are all arbitrary numbers used for example purposes.) Or even a reinforced polymer in some sections versus steel counterpart (side skirts, front & rear bumper skins, door panels, fender panels, ect.)

A lot of extra junk was thrown into the 5th gen, even though they removed a lot of stuff that was in the 4th gen as well as the cab being slightly bigger than the 4th gens (the frames are dimensionally the same, but the steel is supposedly different in some key sections so that would add mass as well.) It's ALL about shaving weight, reducing engine size (and as a result CO2 footprint... which is a whole other bag of ridiculous garbage I don't eve want to go into), reducing rolling resistance, reducing wind resistance, ect. The weight of the vehicle you see now is a huge ball of compromises made between comfort, reliability, strength, economy, cost, ease of manufacturer, ect. They could have gone with a slightly thicker sheet metal for the hood, with more adhesive in spots or tacked to the hood frame; but that could have added as much as 5lbs on the hood and then if they did that with the doors, it'd be another 5lbs per door, and soon you've added an additional 30lbs to the vehicle just in adhesive and slightly more rigid steel.

 

[flighht2k5]

That's the problem, you bought a NEW car, how do you think they trimmed the fat on the porky 5th gen?

Basically, if you bought a brand new car expecting it to be as heavy, sturdy, and solidly built as an older vehicle; you'll be disappointed. Most of the strength of new cars is their ability to destroy themselves to keep the occupants inside safe, not being solidly built. It sucks, but that's how it is now. You can try and reinforce the hood if you want, but that's quite a bit of work depending on how you want to do it (i.e. fiberglass, TIG welding reinforcement in, Rhino-Lining the hood, ect.)

You're missing the point I made in my post. Newer vehicles ARE heavier because of all the laden safety, creature comforts, extra crap, ect. As a result to reduce ADDITIONAL weight that would further impinge on fuel economy the manufacturer's need to shave as much weight as they can get away with. One of the easiest ways to do that is to thin up the metal in cosmetic/non-structural areas such as the door skins, hood, and roof panel skin. Theses areas are not typically structural and more often then not designed to just crumple into nothing at the lightest touch (the hood being an example since it is notched to fold up vs. decapitate the occupants in an accident.) I'm not saying the vehicle is any weaker/unsafe; I am saying that the engineers decided that perhaps using a 20gauge sheet steel they would use a 22gauge and open up the support structure more and use less adhesive bond in some places because it doesn't have to be THAT rigid compared to say the A-Pillar and B-Pillar sections which may be made of a 14 gauge steel (these are all arbitrary numbers used for example purposes.) Or even a reinforced polymer in some sections versus steel counterpart (side skirts, front & rear bumper skins, door panels, fender panels, ect.)



A lot of extra junk was thrown into the 5th gen, even though they removed a lot of stuff that was in the 4th gen as well as the cab being slightly bigger than the 4th gens (the frames are dimensionally the same, but the steel is supposedly different in some key sections so that would add mass as well.) It's ALL about shaving weight, reducing engine size (and as a result CO2 footprint... which is a whole other bag of ridiculous garbage I don't eve want to go into), reducing rolling resistance, reducing wind resistance, ect. The weight of the vehicle you see now is a huge ball of compromises made between comfort, reliability, strength, economy, cost, ease of manufacturer, ect. They could have gone with a slightly thicker sheet metal for the hood, with more adhesive in spots or tacked to the hood frame; but that could have added as much as 5lbs on the hood and then if they did that with the doors, it'd be another 5lbs per door, and soon you've added an additional 30lbs to the vehicle just in adhesive and slightly more rigid steel.

I must be reading something else then because this is what I read

Basically, if you bought a brand new car expecting it to be as heavy, sturdy, and solidly built as an older vehicle; you'll be disappointed. Most of the strength of new cars is their ability to destroy themselves to keep the occupants inside safe, not being solidly built. It sucks, but that's how it is now.

In the paragraph above you said that new cars are not as heavy sturdy or solidly made as old cars.

I corrected you and then you said that new cars are heavier and are safer.
Maybe I should take a reading comprehension class.

 

[BlackWorksInc]

[MENTION=113291]flighht2k5[/MENTION] You're interpreting a causality between "Heavy, Sturdy, and Solidly Built" and "Safety" which isn't what I am talking about. What I am talking about is the progression of automotive technology, engineering principle, crash safety, and fuel economy; and how they compare to people's expectations based on an older generation of vehicles built around slightly different design ideals.

A vehicle does not have to be "Heavy, Sturdy, and Solidly Built" to be "Safe," modern cars have proven that time and time again. By making large critical sections of the vehicle literally cave in on themselves and result in massive damage to the vehicle in an attempt to absorb as much kinetic energy as possible before it reaches the occupants; modern vehicles are incredibly safer than their typically "Heavier, Sturdy, and Solidly Built" elders. Much of that is done through a combination of lighter (but stronger) high strength steel in areas surrounding the occupants and certain key areas; while the rest of the vehicle is typically made with lower grade steel, polymers, adhesives, ect. that are designed to break, bend, crush, and/or deflect in the event of an accident to absorb as much energy as possible.

Take for example the bumper on a 1960's car: a big hulking bar of chromed steel that is basically bolted to the frame (some vehicles had hydraulic dampeners to mitigate impact damage in low speed collisions.) The whole thing probably weighs as much as a ShrockWorks bumper if you look at all the components. Now look at the bumper on your 2015 4Runner: A flexible and light polymer bumper skin bolted & clipped in place over foam & plastic support structures over a simple aluminum bumper bar that is bolted via notched/pre-bent support structures designed to crumple. The whole assemble probably weighs about 30lbs less than the 1960's bumper and feels far more weak; you can push/pull/flex the bumper skin, hell in a light fender bender the outer corners will just pop-off from their clips! Maybe even ripping the screws & damaging the clips on them (something you'd just "buff out" on the 1960's vehicle.) But the reality is that the 2015 4Runner is far safer than the 1960's vehicle, despite having a much weaker/flimsier looking bumper than the 1960's heavier, sturdier, and more solidly built counterpart.

Make sense now?

 

[flighht2k5]

[MENTION=113291]flighht2k5[/MENTION] You're interpreting a causality between "Heavy, Sturdy, and Solidly Built" and "Safety" which isn't what I am talking about. What I am talking about is the progression of automotive technology, engineering principle, crash safety, and fuel economy; and how they compare to people's expectations based on an older generation of vehicles built around slightly different design ideals.

A vehicle does not have to be "Heavy, Sturdy, and Solidly Built" to be "Safe," modern cars have proven that time and time again. By making large critical sections of the vehicle literally cave in on themselves and result in massive damage to the vehicle in an attempt to absorb as much kinetic energy as possible before it reaches the occupants; modern vehicles are incredibly safer than their typically "Heavier, Sturdy, and Solidly Built" elders. Much of that is done through a combination of lighter (but stronger) high strength steel in areas surrounding the occupants and certain key areas; while the rest of the vehicle is typically made with lower grade steel, polymers, adhesives, ect. that are designed to break, bend, crush, and/or deflect in the event of an accident to absorb as much energy as possible.

Take for example the bumper on a 1960's car: a big hulking bar of chromed steel that is basically bolted to the frame (some vehicles had hydraulic dampeners to mitigate impact damage in low speed collisions.) The whole thing probably weighs as much as a ShrockWorks bumper if you look at all the components. Now look at the bumper on your 2015 4Runner: A flexible and light polymer bumper skin bolted & clipped in place over foam & plastic support structures over a simple aluminum bumper bar that is bolted via notched/pre-bent support structures designed to crumple. The whole assemble probably weighs about 30lbs less than the 1960's bumper and feels far more weak; you can push/pull/flex the bumper skin, hell in a light fender bender the outer corners will just pop-off from their clips! Maybe even ripping the screws & damaging the clips on them (something you'd just "buff out" on the 1960's vehicle.) But the reality is that the 2015 4Runner is far safer than the 1960's vehicle, despite having a much weaker/flimsier looking bumper than the 1960's heavier, sturdier, and more solidly built counterpart.

Make sense now?

Nice trying to recover
A bumper is not what saves you in an accident. Having a "sturdy" thick heavy bumper is once again irrelevant in an accident unless its a 5 mph and less. The 4runner having a "weak plastic bumper" as you even pointed out is still safer. So your comment about how super strong and thick an old cars bumper is is pointless. I think you are just trying to save face and not admit you were wrong by typing long pointless responses trying to sound like you're an automotive engineer when its obvious you're not. Now that this thread has completely derailed from the OPs objective I'm done

 

[BlackWorksInc]

Nice trying to recover
A bumper is not what saves you in an accident. Having a "sturdy" thick heavy bumper is once again irrelevant in an accident unless its a 5 mph and less. The 4runner having a "weak plastic bumper" as you even pointed out is still safer. So your comment about how super strong and thick an old cars bumper is is pointless. I think you are just trying to save face and not admit you were wrong by typing long pointless responses trying to sound like you're an automotive engineer when its obvious you're not. Now that this thread has completely derailed from the OPs objective I'm done

You're the one who took my comments to imply the vehicle is less safe than older ones. I am simply pointing out that older vehicles tended to have heavier, sturdier, and more solidly built parts than today's vehicles. Much of it is done in the name of safety, cost, and fuel economy. It's not that the vehicle is any less reliable or durable (that can be debated), but that a plastic part is typically not as heavy, sturdy, or robust as solid steel part and that affects factors such as fuel economy.

All I said is that non-structural areas like the hood tend to be made of thinner materials and often are "fluttery" at high speeds because they are among the choice parts to chop for weight reduction in a final design. While older vehicles tended to have heavier, thicker hoods, and other components that in the grand scheme of things didn't really jive with weight savings and fuel economy. So I'm not sure where you took your left turn into thinking I'm saying older cars are safer since in many of my posts I point out that modern cars are much safer BECAUSE they are designed to crumple/crush in key areas while other areas are made of stronger steel. :noidea:

Most members on here know me to be pretty good about admitting when I am wrong in the face of evidence, but you're basically trying to take my posts as implying that I am saying modern cars aren't safer, which isn't true.

Post Note-

Hell why not have a jury of my peers condemn me if I am wrong:

[MENTION=66316]1engineer[/MENTION] [MENTION=96008]Engineer[/MENTION] [MENTION=60018]CXS[/MENTION] [MENTION=78273]Jeremy556[/MENTION] [MENTION=50591]gaterose[/MENTION] [MENTION=92049]LandCruiser[/MENTION] [MENTION=1032]NoDak[/MENTION]

 

[flighht2k5]

You're the one who took my comments to imply the vehicle is less safe than older ones. I am simply pointing out that older vehicles tended to have heavier, sturdier, and more solidly built parts than today's vehicles. Much of it is done in the name of safety, cost, and fuel economy. It's not that the vehicle is any less reliable or durable (that can be debated), but that a plastic part is typically not as heavy, sturdy, or robust as solid steel part and that affects factors such as fuel economy.



All I said is that non-structural areas like the hood tend to be made of thinner materials and often are "fluttery" at high speeds because they are among the choice parts to chop for weight reduction in a final design. While older vehicles tended to have heavier, thicker hoods, and other components that in the grand scheme of things didn't really jive with weight savings and fuel economy. So I'm not sure where you took your left turn into thinking I'm saying older cars are safer since in many of my posts I point out that modern cars are much safer BECAUSE they are designed to crumple/crush in key areas while other areas are made of stronger steel. :noidea:



Most members on here know me to be pretty good about admitting when I am wrong in the face of evidence, but you're basically trying to take my posts as implying that I am saying modern cars aren't safer, which isn't true.



Post Note-



Hell why not have a jury of my peers condemn me if I am wrong:


[MENTION=66316]1engineer[/MENTION] [MENTION=96008]Engineer[/MENTION] [MENTION=60018]CXS[/MENTION] [MENTION=78273]Jeremy556[/MENTION] [MENTION=50591]gaterose[/MENTION] [MENTION=92049]LandCruiser[/MENTION]

Cool story bro. I don't care anymore.

 

[1engineer]

Nice trying to recover
A bumper is not what saves you in an accident. Having a "sturdy" thick heavy bumper is once again irrelevant in an accident unless its a 5 mph and less. The 4runner having a "weak plastic bumper" as you even pointed out is still safer. So your comment about how super strong and thick an old cars bumper is is pointless. I think you are just trying to save face and not admit you were wrong by typing long pointless responses trying to sound like you're an automotive engineer when its obvious you're not. Now that this thread has completely derailed from the OPs objective I'm done

It doesn't take an engineer to figure who is blowing smoke and who actually knows what they are talking about. Don't choke on the smoke dude and if you want to debate automotive structural design and the physics of force and mass as it pertains to said structures then I'll be happy to start a thread just for me and you. Just say the word. Ready?

 

[Jhalko]

Jeez I got what [MENTION=66389]BlackWorksInc[/MENTION] was trying to say with his comments. My first car was a 76 Mercury cougar wagon (the year I was born, she was a beaut even with the wood panels and rust) It was huge, built like a rock, felt sturdy, and heavy as hell, I bounced it off a fence post once and when I bent the bumper used a sledge hammer and a jack to bend it back. Zero safety features outside of seatbelts.

Black works has probably forgotten more about cars than I know, chillax...

 

[flighht2k5]

It doesn't take an engineer to figure who is blowing smoke and who actually knows what they are talking about. Don't choke on the smoke dude and if you want to debate automotive structural design and the physics of force and mass as it pertains to said structures then I'll be happy to start a thread just for me and you. Just say the word. Ready?

Ooohhh scary . Meat you outback at 3 o'clock high.

 

[flighht2k5]

Jeez I got what [MENTION=66389]BlackWorksInc[/MENTION] was trying to say with his comments. My first car was a 76 Mercury cougar wagon (the year I was born, she was a beaut even with the wood panels and rust) It was huge, built like a rock, felt sturdy, and heavy as hell, I bounced it off a fence post once and when I bent the bumper used a sledge hammer and a jack to bend it back. Zero safety features outside of seatbelts.



Black works has probably forgotten more about cars than I know, chillax...

And once again. Old cars are not heavier than new cars. Feeling sturdy is not the same as being sturdy. Take that "tank" and get into a head on accident and see how you feel after. Guarantee that sturdiness isn't what you thought it was.

 

[Bevo]

op2:

 

[ouscubagrad]

I think it's a Toyota thing. My 15 Trail does this and my wife's 13 Rav4 also does it, as does my nephew's old Rav4 and 15 Limited...