Ok I baught my car with one of those thin aluminum strut bars at the front and none in the back… I never thought that flimsy thing did much under alot of stress, and for the back theres nothing so Im gettin my someone to weld a couple for me that I designed, Gimme you Opinion on them, they either going to be welded out Steel or Stainless Steel.
The Mid sections are Going to be raised like most of them, i just didnt draw a side view of it.
Don’t you need measurements and stuff?
Measurements for what, This is just a rough sketch of what its going to look like, you know how the engine bay looks like, guestimate how its going to be. When its going to be actually made everything will have measurements.
what i’ve always though that would be a good idea, is you should make the joints where the actual bar meets the shock tower ends thicker, a lot thicker, and or reinforced more. having something so thin won’t do shit. and i always thought a solid tube would be more effective.
the designs looks good, there will definatly be no flex in those, although i do think the X braces are a bit much, and will just be added weight exspecially if made out of steel. Just the two bars running perpindicular is enough.
For the rear bar, what is the point in having it cave in near the center?, again just seems like added work. and the strut mont only has to holes in the rear 
The front bar will be much more difficult as you have to take the intake manifold, valve cover and hood clearance into consideration.
Good luck, and post pics when their done.
Well good luck with that, but I’m curious as to how you plan to preload the bar after it’s installed… just one of many questions that could be asked about this product.
BAS, sorry if this is a stupid question but what is preloading the bar? im guessing its adjusting the length of the bar so that the proper tourque is applyed to the strut towers in a neutral position?
it’s a very nice design.
the strut is meant to reinforce the lateral movement of the car, so that means all the forces will run along the length of the bar. having only 2 perpendicular bars to support the strut will defeat it’s purpose because those bars do not support any load acting across the length of the strut.
having a solid piece of metal acting as a strut will have the same amount of strength as a hollowed out bar of the same size. the force will just be distributed across the existing material. so maybe if you had all those cross members built within a hollowed out bar, you’d have something extremely solid.
and for the rear strut, its better to have the bar straight instead of caving in because it will reduce the strength of the bar when a load is applied.
Tension, torque is something different. you Want Tension. as well if your frame is old, ( which all S13/240’s are ), you can get some pretty good sag, the preload, when setup at an alignment shop will help to bring the frame back into shape… IF this is just a show pc. then fine… but take a look at some of the other tower bars that are multi element I think you;ll find that instead of going from tower to tower with that setup if you triangulated and went from tower to tower and from tower to firewall you’d have a much better ’ performance ’ product… as well in th rear tower to tower but also tower to rear floorpan , again triangulated and preloaded you’d have a much better product.
Yea I forgot to Say there going to be made out of tubing, not just straight metal…, I know about the 2 holes, I just cut and paste the original mount to make the rear one :P. Preload will not be adjustable in this case… You will have to know how much preload you want then Weld the Brace according… And if one really wanted to It would not be difficult to seperate the brace and add a adjusting bolts. I just dont want it because that would be a weak area in the brace and defeat the purpose of all those supports.
The cars in the shop for something else, when it comes out were going to make the brace… i post pics.
yea, what I meant was tension, I just couldnt think of the term at the time.
i am currently making a triangulated rear bar that will tie onto the floor and towers like you said, but it will not have any adjustment. Will this be a problem? other triangulated bars such as the cusco dont have any adjustment.?
Will having the car lifted off the ground so there is no force on the towers, and makings the bar to size so that there is some tension between towers be sufficient? or will i need to have any tension at all? the towers will be in a neutral position, and when the car is lowered will stop the towers from angling towards each other, so will it not be doing its purpose?
Thanks in advance for the help.
this thread is showing once again the difference between technically correct and significant… the chances that you’d notice the difference between a brace with or without tension is slim to none in even the most agressive driving
if someone is serious about it, just run two turnbuckles in parallel where there’s most room, and in the back only the straight bar in a triangulated setup would need one, even a single low grade 14mm or 9/16 thread will have enough strength to hold the typical ric^H^H^Hdriver
Doing the job as well as you can. to the best of your knowledge, ( plus other peoples knowledge), and ability the first time around is never ’ not significant’…
You would promote doing things to less then ‘best product possible’ quality because of what you perceive as being ’ good enough for someone else '. why?
Actually in agressive driving… its noticeable. Do you think competition race cars use things like this?
I did a 1 min search to show a bit of a comparison, look at the top one and the bottom one. There is definitely a difference between the two.
http://www.thepartsbin.com/sitemap/nissan~strut_bar~parts.html
I get what your saying… for day to day driving, but for example, on the track it will make a difference.
Sideways… Thats what your doing when you raise it, put the bars then lower it. It will have compression. But since the car isnt brand new and the towers will be bent a bit from having all that weight on them from all those years, you can turn the bolts to add a bit more compression to straighten them. There is almost never tension on the rod unless, your car hits some hard bumps/ or experiences some intense driving conditions. The weight of the car and how the wheels act with/without load on them will affect the tension/compression on the Rod.
Check this out… it should explain some things.
http://e30m3performance.com/myths/Strutbar_Theory/strut_bar_theory.htm
well there is a matter of cost/time and the increasing precision required to do more complex designs…
and that brings up the other issue, whoever designs the bar when it’s not adjustable has to be working on a young chassis that hasn’t had the crap beat out of it so it’s more or less factory perfect measurements… anyone doing it on a 15yr old car will of course be off a bit and adjustability is nice to have even just for fitment regardless of the preloading ability
anyway back to the topic, if he wants to make and sell bars with the bells and whistles he won’t have a chance to compete with the chinese cusco/greddy knockoffs
and bas you know there’s tradeoffs in stiffness, you don’t eliminate the force you just move it around, when you concentrate it to a few points in a race car you can control it better provided your suspension and tires can deal with it… most street cars don’t have nearly the strength/stiffness/grip to be able to handle that kind of stress and it’s actually better to have the body twist and deform to absorb some of it, which is something a racecar with a cage doesn’t do
Yes but as you know the strut towers (F & R) and in particular the front unibody forks on a 240 are wet noodle soft. This is why I suggested a triangulated strut tower brace front and rear… and yes forces move to the rest of the body and will effect greatly the next 'weakest point ’ but the overall gain in suspension/steering control is of greater benefit. Ideally you want to do a full slate of frame foaming and seam sealing to remove some other key ‘soft spots’.
If he’s got the means and time and he’s just doing it for himself then making the best part possible is not going to cost him anything more then he wants to spend on it and no more time then he wants to put into it.
My final thoughts on this; if your doing this for show more then go, then get it cut and polished and your done…
If your doing this for performance then go back and do a redesign, ( simplify as well), to incorporate some form of triangulation and some form of pre-loading/micro adjustment. Be aware that once you start to frame stiffen you should do the rest of the body as well to rebalance & reduce the stress loads on the rest of the frame.