Making custom strut brace

[RobertoX]

Yep agreed shiny,

just on the rear brace, on my 2 sprinters, 1 with a 'strut brace' between the shocks and one with a welded seat latch brace. The strut brace did crap all, it helped marginally but not really worth it. The seat latch brace was the most effective chassis stiffening I have felt, deffinately the best bang for buck, it affected the feel of the car much more than a front brace also.

[mic*]

the way i see it, it isn't going to flex enough to break the bar, and 10 inches of mig wire is cheaper than a spherical bearing.

if you wanted to get technical, you could just run a cable/tnesion rod between the strut towers for virtually the same effect (according to the theory that strut braces only work in tension)

Interesting point mate. Do any "tension" beleivers care to explain why we have not seen strut braces done with a nice bit of Bowden cable? I always thought there was more to it than pulling the towers in together.

[MWP]

Interesting point mate. Do any "tension" beleivers care to explain why we have not seen strut braces done with a nice bit of Bowden cable? I always thought there was more to it than pulling the towers in together.

Pulling the towers together??

Strut braces are there to stop the towers moving away/towards each other while cornering.

[roadsailing]

think about it more.

i agree in this way, i would use a bar type brace in case there are compressiove loads, and it won't weigh much more anyway. besides, you can't put a HKS sicker on a cable.

[mic*]

MWP,

Exaclty. The last post of mine was a challenge to those who are of that belief to justify it.

So in terms of cost benefit analysis, i cant see why you would build a brace with rosejoint's. Its only gonna promote independent movement - exactly what the brace is meant to inhibit.

More cost - what benefit?

[puzzle man]

3 things:
as for triangulating... nut-serting a plate to the firewall will provide the same 'strength' in terms of reinforcing the friewall as will welding the plate on. there shear will be different, and possibly welding better in that regard, but considering the forces involved, i doubt it. if you can be assed pulling the dash apart right up to the cabin side of the firewall to move any wiring from possible heat damage, then id weld, otherwise nutserts are your friend.

hay ed or eny body else this is what i was thinking of doing..
sorry bodge pic..


my AE92 has to big pipes on each side (passenger and drivers side)
inside the vent (fire wall) up top
i was thinking of ruining a 36mm thick bar from one side to the other
then ad the rest to it...eg the triangulating thing..
whats your thoughts....
thanks.
Craig

[mic*]

Is an AE92 the same thing as a FTO?

[puzzle man]

Is an AE92 the same thing as a FTO?

i dont have a pic of under my hood so improvise
ps that is an eclipse

[puzzle man]

well here is my atempt.....

can't go strait across not enough clearance between the air filter and hood and my wiper motor arm was in the way for the bar right across from passenger and drivers side.
so we made a plate to go on to the fire wall bit and fabricated to little things to go round the top of the strut.
I will take some more pic if eny one wants them i might do a little right up but i did not take the camera with me so no "in the process pic"
edit for got to mention the price:
old water pipe: $0
old bits of steal:$0
having a brother in-law as a master fabricator: priceles.....

[TurboRA28]

Very good work mate.. And the price is right!

How thick is that water pipe OD?

Cheers
Joel

[puzzle man]

about 24to25mm thick and the thickens of the wall of the pipe (if that makes sense) 4to5mm

[oldcorollas]

brace should be in compression...

ever seen a rally car after a jump where the strut tops bent outwards?? perhaps there could be tension, but my money is on compression (since you have virtually single direction loading at strut top.. ie upwards... and then the body there will rotate around the chassis rail (i suppose, being strongest bit) and then try to go inwards....)

can they be in tension?

[roadsailing]

a strut brace is for tying the towers together during cornering, not for going over bumps (well i guess it works for that too)

draw a free body diagram of a mcpherson strut (including wheel) with road load applied to the tyre and the LCA as a fixed pivot.

i saw a good explanation on a website a while ago, but cant find it now. might draw one myself if i can get time to do it and scan it in today.

again, i do believe that at the very least the brace will be in compression some of the time, so there is no reason to make it work in tension only.

[Toycrash]

As the struts upper points are closer to each other, than lower points, the body tries to flex inwards.

For me the strut bar is only for making sure i wont bend anything on huge jumps
Thats what its used in rallye cars. On streeters and some track cars, its easy way to eliminate flexing on corners, but body what is modified to take serious abuse, only thing makes then flex is jumps.

At stock car i would make tri-bar setup to firewall, it holds on all directions. I've got roll cage for keeping them to not moving backwards.

ps. if i somewhere make you scratsh your head for sayin something stupid or it wont make sense, its just that this aynt my native language. Bare with me

[tricky]

brace should be in compression...

ever seen a rally car after a jump where the strut tops bent outwards?? perhaps there could be tension, but my money is on compression (since you have virtually single direction loading at strut top.. ie upwards... and then the body there will rotate around the chassis rail (i suppose, being strongest bit) and then try to go inwards....)

can they be in tension?

Ideally, you'd think so. Under bump loads that is. But consider hard cornering. With the chassis rail as the fulcrum, the load on the inside corner is pushing the strut top outwards. To counteract this moment, a strut brace in tension would be ideal. The tension could also be calculated specific to the car and intended surface. ie a track car would have a certain level of grip (In, say, lateral g-forces). From this grip, determined through testing, the moment around the chassis rail could easily be calculated, hence the tension required for the counter-moment could be calculated about the strut top.

The only way you could be at all accurate in the above situation is by using a triangulated brace, otherwise the force would be simply transmitted the the adjacent tower, and you probably wouldn't be gaining *that* much.

That level of developement would be entirely unnecessary for a road car though...