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1995- 2000 (1990-1994?) LS400's use stamped braces (labeled #52295 in Lexus exploded parts diagram) to increase rigidity and reduce flexation of the rear suspension cross member (labeled #51206A in Lexus parts diagram)
The project here is to box in the brace therby increasing it's torsional rigidity.
Some images depicting the brace on vehicle.
Lexus parts diagram depicting front and rear crossmember. and rear suspension member brace.
The rear suspension member brace is a stamped part that is prone to twisting. Boxxing in trough will significantly increase torsional rigidity without much expense. Will post after images. May elect to fill the modified brace with automotive grade closed cell foam for NVH reduction....in fact, the rear crossmember assembly appears comprised of large diameter formed hollow tubing that could be filled with automotive grade foam to reduce NVH ..
no disrespect to your knowledge or expertise, but if such a simple operation would yield such a positive result, wouldn't toyota have already done it in this car that they so needlessly over-engineered?
no disrespect to your knowledge or expertise, but if such a simple operation would yield such a positive result, wouldn't toyota have already done it in this car that they so needlessly over-engineered?
My Grandfather used to ask me the same thing...and it is a fair question.
When Toyota determined these supplemental braces necessary to fortify the rear suspension carrier,, they elected to use a stamped part which is cost effective, but ino where near the rigidity of a boxxed part when stressed..
It adds cost to box in the brace...so that is my answer.
Boxxing was employed by me on rear differential swing arms of my 1969 GTO. the arms were essentially stamped U channels with bushings in one end, which connected the differential to the frame...and the design was a poor one..lots of flex which I rectified by simply boxxing the channel.which would have added $1 to the cost (!!)
Of course there are now numerous aftermarket suppliers offering this fortified design.for GM "A" bodies of that era.
no disrespect to your knowledge or expertise, but if such a simple operation would yield such a positive result, wouldn't toyota have already done it in this car that they so needlessly over-engineered?
Examples of GM "A" Body rear control arms...
Major flex with this rear control arm due to unboxed channel
A screenshot depicting afterrmarket part with discussion on improvement.
i have no doubt that a 50 year old pontiac has LOTS of room for improvement across pretty much any aspect of its design, but i'm going to go out on a limb here and say the LS was much more meticulously designed than a 1960s GM. i'm not faulting the thinking here, i'm just a bit skeptical that it'll really make a huge difference. i mean don't let me talk you out of anything here... if it really helps i'd consider doing it to mine as well.
Have you done any FEA on that part to see if there's an actual improvement to be made? Toyota spent 1 Billion producing and developing this car with some of the best engineers in the world. I doubt boxing it is going to do much but add weight and add NVH. Plus, how do you know that that part of the suspension is purposely made that way to "give" when the suspension cycles?
If everything was rigid, you'd get much more NVH into the cabin. Take the poly bushings that people like to swap in place of the rubber strut rod bushings on the front arms....horrible choice because people think they can get a part that lasts 3x as long but don't think how bad the vibrations are when the suspension cycles over small bumps that normally wouldn't have been felt with the factory part.
Also, on your photo, it looks like the mounting point is starting to get pretty rusty, I would address that before strengthening anything, as that could be another possible failure point. Need to cover all your bases first and make sure that suspension member is structurally sound first.
i have no doubt that a 50 year old pontiac has LOTS of room for improvement across pretty much any aspect of its design, but i'm going to go out on a limb here and say the LS was much more meticulously designed than a 1960s GM. i'm not faulting the thinking here, i'm just a bit skeptical that it'll really make a huge difference. i mean don't let me talk you out of anything here... if it really helps i'd consider doing it to mine as well.
It will not make a huge difference...and no comparing 1960's technology to 1990's...simply presenting incremental improvements and why boxxing works
Enough small improvements yield discernible results.
As an FYI, the 2001 LS430 increased torsional rigidity over 2000 LS400 by 30%
no disrespect to your knowledge or expertise, but if such a simple operation would yield such a positive result, wouldn't toyota have already done it in this car that they so needlessly over-engineered?
Cost is ALWAYS a factor,these arent low run cost is no concern Lambo's for example. IMO yes,the bean counters do factor in.
My Uncle was a Big Dog bean counter for a major parts manufacturer,pennies matter...a lot! And a company as big as Toyota,they matter.
It also wasnt 'needlessly over-engineered',it was built to beat the competition,that is all.No MORE,and no LESS.
IMO.That and 5 dollars will get you a needlessly over-engineered cup of coffee at Starbucks.
Cost is ALWAYS a factor,these arent low run cost is no concern Lambo's for example. IMO yes,the bean counters do factor in.
My Uncle was a Big Dog bean counter for a major parts manufacturer,pennies matter...a lot! And a company as big as Toyota,they matter.
It also wasnt 'needlessly over-engineered',it was built to beat the competition,that is all.No MORE,and no LESS.
IMO.That and 5 dollars will get you a needlessly over-engineered cup of coffee at Starbucks.
well i guess i must've misread all the numerous publications that cite the LS development process as having "no specific budget or time constraints" and misheard the employees at the lexus dealer that told me LS didn't turn a profit... come on man do some research before you make these claims. the slogan was the relentless pursuit of perfection, not the casual pursuit of adequacy. i don't know of any other car where one of the actual design parameters was that "an LS 400 with 50,000 miles should not look, sound, feel, or perform noticeably different from a new one." just watch this:
and for the record, i've ridden in a gallardo and a murcielago and they're both giant piles of crap when it comes to quality and refinement. they are very sexy and awesome sounding though.
It may be true they had an open DEVELOPMENT budget,that doesnt mean they have an unlimited PRODUCTION budget.You dont design a car to lose money or price it out of the market so it doesnt compete in price.Thats called bankruptcy. And nobody is immune to that reality,not even mighty Toyota,and nobody knows that better than they do.
They have to make a profit,and they have to compete on price. Business 98,not even Business 101.
As for history,look at the Japanese color tv model.....bring out a fine product,sell at a loss,take over the market. I also notice Lexus had a rapid price rise,now go for whatever excuses you may want to make to explain that,thats the Japanese business model of the day. Actually thats Amazon's model today,and Walmart's before it.Still true.
=Stroock639;10167070 - I don't know of any other car where one of the actual design parameters was that "an LS 400 with 50,000 miles should not look, sound, feel, or perform noticeably different from a new one."
I do.Read a 1971 MB 280SL owners manual.Where they state dont be concerned that the car sits a little higher in the rear end.This is normal,the suspension wont fully settle until 100,000 miles.
And dealer maintained its still an INCREDIBLE car at that point.Back when MB truly cared about engineering the best in the world.
It may be true they had an open DEVELOPMENT budget,that doesnt mean they have an unlimited PRODUCTION budget.You dont design a car to lose money or price it out of the market so it doesnt compete in price.Thats called bankruptcy. And nobody is immune to that reality,not even mighty Toyota,and nobody knows that better than they do.
They have to make a profit,and they have to compete on price. Business 98,not even Business 101.
As for history,look at the Japanese color tv model.....bring out a fine product,sell at a loss,take over the market. I also notice Lexus had a rapid price rise,now go for whatever excuses you may want to make to explain that,thats the Japanese business model of the day. Actually thats Amazon's model today,and Walmart's before it.Still true.
well of course not, toyota wouldn't have been in business very long if they always lost money. obviously 99% of the cars they sell turn a profit since that's why someone goes into business in the first place. i'm pretty sure toyota is the most profitable car company in the world in fact... and because of this fact, they can afford to undertake projects that won't necessarily become immediate profit makers. this also wouldn't be the only time toyota did something without profit as the main goal, just look at the LFA. it's known that they took a HUGE loss on every single car, even with it's "excessively high" price tag.
and yes the old benz's were tanks. one of my favorite cars ever is the mercedes 600 with its hydraulic everything, and that was also built with a similar take all the time and money you need, just build the best car you can way.
And yes the old Benz’s were tanks. One of my favorite cars ever is the Mercedes 600 with its hydraulic everything, and that was also built with a similar take all the time and money you need, just build the best car you can way.
Isnt that the truth,then we have the LS400 taking that niche,the best out there.Great era's,eh?
In the end it all depends on the use of the car, if it needs a bunch of engine or suspension mods. Is it for some form of competition? Then yeah maybe. But then some mods can also add unnecessary weight as well. If its to be used as a towing vehicle then yeah the suspension may need some big time mods as well as the whole drive train.
But for a car to drive here and there, its all such a waste of everything.
04-07-18, 09:24 PM
Fortifying rear suspension crossmember braces
