Chassis stiffening...

[CMF_sodaniel]

To stiffen the chassis, most of us do the odd front strut bar, swaybars, lower arm bars etc... But what they do in Japan in pretty interesting...

Hmmm here's some food for thought...

Auto Shop Aspect in Japan

This is nuts:

C-pillar bar + Rear tower bar

2 rear tower bars

Aspect Rollcage

From Mullholland - Rollcage!

Don't know but this is from japan too, absolutely nuts.

What have you done to stiffen your chassis? Was it effective?

Has anyone here fitted a rear strut brace? What brand? Any difference?

 

[CMF_turbo march-rolling shell]

yeah. i've fitted a rear strut brace. made it myself, busted out the tig and knocked one up. made absolutely no difference wat so ****in ever. looks cool but .... that rear hatch cross brace is expensive as, looked at getting one, but would be $1000+ buy the time you get it here. you would hope it would do something

 

[CMF_sodaniel]

Hey turbo, I didn't think it would make a difference since there is f**k all weight in the rear anyway haha, but besides that... do you have a pic of it anyway? I was going to DIY one up with an old strut brace I have... Where did you mount it to?

Cheers

 

[CMF_turbo march-rolling shell]

just mounted it across the back strut towers, sorry, i got no pictures... i doubt that big cross brace thing would do much either,..its right at the back of the car, i think it'd have to be a little further forward perhaps to improve the chasis significantly.. might be usefull to tie down a baby seat to..

 

[CMF_sikK11]

front sway bar springs and a adjustable pan hard rod workded really well now i go round corners with all wheel on the ground instead of the inside rear in the air

 

[CMF_Yom]

turbo march-rolling shell WROTE:

"just mounted it across the back strut towers, sorry, i got no pictures... i doubt that big cross brace thing would do much either,..its right at the back of the car, i think it'd have to be a little further forward perhaps to improve the chasis significantly.. might be usefull to tie down a baby seat to..

Of course it wont make a difference - the strut towers are insulated from the body with rubber. They're not structural areas - they're just there to hold the shocks.

A strut brace has to be bolted firmly to the body/chassis in order for it to stop chassis twist.

On this topic..

I always felt the front strut brace effectiveness on k11 will vary somewhat depending on the fatigue already in the chassis (they dont last forever). As it is the strut towers are very close to the structural firewall meaning they have a fair amount of natural strength. I still think it would be worth fitting the strut brace if you can afford it. You're likely to make the vehicle safer in an accident by doing this as well.

But I reckon the lower control arm brace will make more difference on the k11 than a strut brace. The k11 has no big heavy subframe to mount the suspension to - all forces are exerted directly to the chassis. Anything to strengthen it down there will make a difference to the suspension geometry staying the same during extreme cornering (and even braking). Anyone who's actually used one might want to comment on this.. I never got around to it unfortunately.

The other thing I would have liked to see on the k11 is an under car Z brace like on the Honda S2000.

A big triangulating brace between the rear pillars like on that jap k11 will improve body stiffness but whether it'll do anything is pretty questionable in my eyes - the 5 link rear beam axle will absorb alot of cornering forces.

An internal rollcage would have been just awesome - and it turns out that in QLD they are legal for road use providiing they're properly engineered and do not obscure vision or the abilty for emergency services to remove you from your vehicle in the event of a serious accident (ie: no side bars), just pillar and roof bracing.

For those repainting their k11 - a fully seam welding the body will probably improve things out of sight. the panel pressings just don't hold tight after 10 years/150,000km.

 

[CMF_turbo march-rolling shell]

Yom WROTE:

"turbo march-rolling shell WROTE:<BR><BR>"just mounted it across the back strut towers, sorry, i got no pictures... i doubt that big cross brace thing would do much either,..its right at the back of the car, i think it'd have to be a little further forward perhaps to improve the chasis significantly.. might be usefull to tie down a baby seat to.."</DIV><BR><BR>Of course it wont make a difference - the strut towers are insulated from the body with rubber. They're not structural areas - they're just there to hold the shocks.<BR><BR>A strut brace has to be bolted firmly to the body/chassis in order for it to stop chassis twist.<BR><BR>On this topic..<BR><BR>I always felt the front strut brace effectiveness on k11 will vary somewhat depending on the fatigue already in the chassis (they dont last forever). As it is the strut towers are very close to the structural firewall meaning they have a fair amount of natural strength. I still think it would be worth fitting the strut brace if you can afford it. You're likely to make the vehicle safer in an accident by doing this as well.<BR><BR>But I reckon the lower control arm brace will make more difference on the k11 than a strut brace. The k11 has no big heavy subframe to mount the suspension to - all forces are exerted directly to the chassis. Anything to strengthen it down there will make a difference to the suspension geometry staying the same during extreme cornering (and even braking). Anyone who's actually used one might want to comment on this.. I never got around to it unfortunately.<BR><BR>The other thing I would have liked to see on the k11 is an under car Z brace like on the Honda S2000.<BR><BR>A big triangulating brace between the rear pillars like on that jap k11 will improve body stiffness but whether it'll do anything is pretty questionable in my eyes - the 5 link rear beam axle will absorb alot of cornering forces.<BR><BR>An internal rollcage would have been just awesome - and it turns out that in QLD they are legal for road use providiing they're properly engineered and do not obscure vision or the abilty for emergency services to remove you from your vehicle in the event of a serious accident (ie: no side bars), just pillar and roof bracing.<BR><BR>For those repainting their k11 - a fully seam welding the body will probably improve things out of sight. the panel pressings just don't hold tight after 10 years/150,000km.

i was counting the seconds before your response tom. personally, i think, even a front strut brace is a waste of time, any car i have driven with one fitted, then removed, makes absolutely no difference in cornering/stiffness, i reckon there just a bling wank factor to add more weight to the car. seam welding would be mad but. and the brace i have is bolted through the strut towers using 2 10mm bolts either end.... looks good, thats it.

 

[CMF_frank2]

turbo

i agree that strut braces are purely cosmetic (unless you do rally jumps)
link shows a rig to test for flex (half way down the page) and his cable tie moved 1/2mm under hard cornering !
http://www.ppcmag.co.uk/forum/topic.asp?TOPIC_ID=1416

 

[CMF_sportsclassic]

strut braces can be effective, if mounted properly as yom stated, i have seen many cars with rock hard suspension and over time it has moved the strut tower. Front strut braces stop the towers pulling away from each other and towards each other. me and my dad own a micra rally car which the chassi has been stiffened to stop the towers from cracking under hard jumps and over rough, but even with a roll cage and seem welded cracks still appear around shock towers and cross members. i will post up some pics of the cage and welding done on the car.

 

[CMF_turbo march-rolling shell]

frank2 WROTE:

"turbo<BR><BR>i agree that strut braces are purely cosmetic (unless you do rally jumps) <BR>link shows a rig to test for flex (half way down the page) and his cable tie moved 1/2mm under hard cornering !<BR><A title=http://www.ppcmag.co.uk/forum/topic.asp?TOPIC_ID=1416 href="http://www.ppcmag.co.uk/forum/topic.asp?TOPIC_ID=1416" target=_blank>http://www.ppcmag.co.uk/forum/topic.asp?TOPIC_ID=1416</A>

lol, that has got to be the best read i've had in a while! he's got good ideas but!

 

[CMF_Yom]

Some cars have an excellent reponse to strut braces. Pulsars are one car I know off the top of my head which usually experience excellent improvements in steering reponse and corner stability.

Some cars come with the strut braces standard as well - but usually better engineered than just a bar which goes across to both towers. A form of triangulation would be far better than just a straight bar - alot of factory implimentations of front strut braces actually bolt to a strengthened area of the firewall.

I think they can work when properly designed and developed for the vehicle they're being used on.

 

[CMF_turbo march-rolling shell]

one of the cars i have driven with/without a strut brace was actually an n14 sss,.. with a whiteline bar fitted and then taken off, no difference, which bar did you have fitted on yom? that said i think the whiteline offering of a strut brace is pretty sad, if there is movement it would help it, but hardly a beefy upgrade, most whiteline bars are pretty small in diameter, something similar in design to an auto select or hks kansai brace for the 32/33/34 series of skylines would be good, there at least 75mm in width. i can think of a few cars that come standard with strut braces, ep82/ep91 starlets, r33 gtr /34gts/r, but that said, a strut brace is not all they use, there's also alot of undercar bracing aswell. some form of cross brace underneath the car would definately be beneficial i think, something that would tie both side of the car together, several are made for the mazda mx5 "butterfly braces" there sometimes called. a form of triangulation would be great, tomei strut braces link the firewall to the towers, none of which are made for the k11 however there's also braces that link the lower control arms to the front tow hooks that are made in japan for the k11... i'll c if i can get some pics....

 

[CMF_sodaniel]

One for you tech heads...

Cusco - a leading suspension, diff and chassis rigidity specialist in Japan has composed this video to show the effects of a strut tower bar on a standard car...

warning, need high speed net connection:

http://www.jdm-option.com/eng/pr_CUSCO/towerbar.html

 

[CMF_sodaniel]

And I agree with turbo, that whiteline make piss weak strut bars... small in diameter, weak pivot points, and overall not much better than eBay strut bars... but then again, it is a micra after all, you are not going to find much better...

 

[CMF_sodaniel]

It depends on what stage you install the strut brace... My old MX-5 for example, had a brown davis half cage, cusco sway bars, tein coilovers, cusco underbody triangle tie bar, diff brace etc... So when I put in the strut brace (which was an OKUYAMA Carbing 1 piece aluminium, work of art), I didn't feel a difference at all. However, other MX-5 members with who got the same brace as their first mod, swear by it.

With the micra, already had these **** stiff coilovers using 6kg f/r rates, so difference? Very little...

 

[CMF_turbo march-rolling shell]

very true. if you have stiff as coilovers to begin with, i doubt any front strut brace is going to give you much of a driving improvement. nismo make, or did make a decent size strut brace for the k11, gtrholic has one on his car, cusco also make an interesting design, a dodgy version of triangulation if you will. carbing make some great products, and as far as i'm aware, they still make braces for the k11

 

[CMF_turbo march-rolling shell]

here's that brace i was talking about
. whether its beneficial or not is a big ? but its an interesting design.

 

[CMF_sodaniel]

Wow that's interesting, what brand is that? The colour looks like Cusco.

 

[CMF_turbo march-rolling shell]

its some home-tuned item from japan, it might be cusco, but i think its more like someone trying to make it look cusco. from memory there about $400.

oh, been meaning to ask, are the rear rg's adjustable height also? how much adjustment do you have, ie: how low can you go?

 

[CMF_Nissanmania]

That Cusco demo is very informative and the cable-tie test is a good one to measure the decrease in chassis flex with a strut brace.

I feel that unless you are driving at the limit (this will rarely happen on the road and if you did you'd get a ticket!) you aren't going to feel the difference that a front strut brace makes. That doesn't mean it isn't helping, just it will be hard to feel. In any sort of competition your car is pushed way beyond what you would ever do on the road and that's where you will feel a big difference in steering response - even more so with stiffer springs as there is more response. An under body brace will help a little bit more to tie the front suspension down and minimise flex that would alter wheel alligment settings mid-corner.

I'd agree that given the little weight on the rear and the fact it's a beam axle there wont be much benefit in a rear strut brace. Bracing between the front and rear would be much better but harder to achieve.

I dont think extra bracing to the firewall would pay much dividends given (as already mentioned) the close proximity of the strut tower to the firewall. You'd have to be pulling some big-G's to feel the difference or doing some rally jumps - in which case you'd have a roll cage anyway.

 

[CMF_sodaniel]

Hey turbo...

To be honest, I haven't meddled with the setting at all since I got the car. However, the previous owner told me it was damper adjustable, and if you set the damper stiffer the car will also go lower... I have the spec sheet for it (which you can't get on RG website), if you want it I can scan it for you.

BTW, just had a quick squiz on the okuyama Carbing site... man those cages are very cool!

http://www.okuyama-go.to/products/carbing/nissan_01.html

 

[CMF_turbo march-rolling shell]

yeh, the jgtc ones are damper adjustable.. there still listed on there website, but.. they are apparently no longer in production, i tried ordering a set when we were in japan just before christmas, but, to no avail. i've bought a set of gabs in the meantime, before i find something serious.

 

[CMF_Yom]

turbo march-rolling shell WROTE:

"one of the cars i have driven with/without a strut brace was actually an n14 sss,.. with a whiteline bar fitted and then taken off, no difference, which bar did you have fitted on yom? >

T'Was a whiteline bar on an N15. Made a rather noticeable improvement in that the car felt more solid around corners and steering response appeared better. n14 is pretty much the same front end as n15. Who knows mabye that n15 had been in an accident.. Little things like that can have a huge effect on chassis stiffness.

Those blue bars there - I like the idea but they're not bolting to a structural part of the vehicle. Basically everything infront of the firewall in the k11 is a crumple zone (except where the wishbones bolt to the chassis - those protrusions there are constructed with high strength steel - the rest of it is only around the cabin shell. So I think they would do very little. What they might do is reduce the amount of crumpling which occurs in the front end in an accident - but then again depending on how strong they are they could actually spear through the firewall and cause even more damage And reducing the effectiveness of the front end's crumple characteristics would be terrible for saftey.. the body of the k11 is typical small car of the 90's - very weak. It needs the front end to crumple or it will just fold up and deform.

This is why new small cars are so heavy.. They've simply got more more meat in the structural areas of the passenger cabin.

 

[CMF_xsoarerx]

sorry to bring up an old topic but some things to add...

a mate made a good point a while ago, in terms of the top of strut tower braces, the best ones you can get are the cusco type ones with the thick steel construction.

if you think about the 99buck ebay specials people get, you have two thick steel mounting points either end and then a alloy lightweight member between them which would have a greater flex then the heavyer thick steel cusco ones.

thick tubing style

compaired to

obvously both cusco ones would be good but cheep ebay specials might not be internally reinforced like this one is or be using quality alloys like cusco...