88RxTuner Posted October 4, 2008 Share Posted October 4, 2008 Just wanted to pop up a question about strut tower reinforcement. I was racing a couple guys through the desert last weekend (before I grenaded my trans) and hit a wash/ ditch/ pothole in the track pretty hard. Hard enough to dis-mount my tire and send it off into the beanpatch. Initial inspection off road, on an uneven, rutted desert trail, was that perhaps I bent a lower control arm, or a strut slightly. Left front wheel was cambered in at the top. Now, after new tires and a thorough inspection, I found that what happened was that the impact pushed the top of the strut tower (where the strut bolts onto the car) up, broke a couple welds, and deformed it nearly into contact with my hood.. thus reducing my wheel travel, and screwing up my alignment. Has this ever happened to anyone else?? Happened to me... Is there a GOOD solution for preventing this type of damage in the future (of course, without giving up off-road driving...) Im sure I could fabricate something that would work, but I'm looking for ideas from someone who's done it before... Thanks!! 88RxTuner Quote Link to comment Share on other sites More sharing options...
88RxTuner Posted February 13, 2009 Author Share Posted February 13, 2009 Bump... Nobody has any input on this? (fixed the problem, we're still in the re-assembly phase) I dont really want to do it again... Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 13, 2009 Share Posted February 13, 2009 This an EA82 then I take it? I did something similar with my EA81 wagon - 40 MPH, washboarded trail, etc. But in my case it bent the bottom of the strut like a bannana. The fix is to install a second shock - a mounting point will have to be fabbed to the control arm. Extra dampening will prevent it from slamming the wheel up too hard and fast and breaking stuff. Rguyver has done this to a couple different wheeling rigs after he discovered this propensity while jumping his EA81 hatch 20+ feet in the air GD Quote Link to comment Share on other sites More sharing options...
88RxTuner Posted February 13, 2009 Author Share Posted February 13, 2009 (edited) Ummm, yea, 1988 RX, EA82T, mostly stock suspension, some spacers on the rear coilovers to get the body up a little... Ummm, yea, happened directly after an airborne "incident"... lol Struts seem ok even to this day, after I repaired the strut tower damage all is good with alignment and camber, struts are not bent etc. Going to replace struts anyway, when I lift it this spring or summer (when warm weather and $$ come together) but I want to prevent this type of damage from happening again... Fabricating the new lower control arm shock mounts shouldnt be a problem.. but where do the upper mounts go? Onto the crossmember, and use really really short shocks? Or onto the strut tower and fab upper mounts into the tower as well? Thanks for the input... 88RxTuner EDIT: Out here in the desert, there is pavement and there is washboard trail... and I sure as hell aint gonna keep it on pavement, so I guess upgrading the suspension is the only alternative... 'Specially when the rallys come around here, OH, and the supertrucks that I just have to show off to... lol Edited February 13, 2009 by 88RxTuner Quote Link to comment Share on other sites More sharing options...
Txakura Posted February 13, 2009 Share Posted February 13, 2009 do you think a tower brace from strut to strut would help? granted it would not help in the case of massive air time impact, but i wonder if spreading the load across the two towers would help minimize lateral movement and provide an alternative stress path to spread the load over a wider area I've thought of making something out of .090" 7075-T6 and using 'tbd' tubing with NAS bolts in close tolerance holes to span the engine bay between the towers using the 3 strut mounting bolts I wonder if the same set up could be also used to run forward to the bumper mount bolts... in effect you'd have a three legged bracing system for the top of the towers providing some stability in two directions, all the brace loads would be in shear and tension it wouldn't keep you from shooting the strut through your hood, but it might prevent more mundane damage, like cracked welds and interesting alignment specs just an idea, not sure if it has any merit Quote Link to comment Share on other sites More sharing options...
subyrally Posted February 13, 2009 Share Posted February 13, 2009 there was someone a while back that was advertizing a plate that goes on top of the strut tower and acts to stiffen and reinforce the area. i think it had holes big enough that te nuts would still hold down the struts, but it was welded on to the tower all the way around, or something like that. if i can find it, ill post more accurate info. i think it was marketed toward rally car preperation Quote Link to comment Share on other sites More sharing options...
ivantruckman Posted February 13, 2009 Share Posted February 13, 2009 Subarus are not a high altitude vehicle Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted February 13, 2009 Share Posted February 13, 2009 Read this completely and then perform the mods and take lots of pictures. http://www.faberit.com.au/rxrally/Pics/RX_Docs/index.html Quote Link to comment Share on other sites More sharing options...
Txakura Posted February 13, 2009 Share Posted February 13, 2009 (edited) Read this completely and then perform the mods and take lots of pictures. http://www.faberit.com.au/rxrally/Pics/RX_Docs/index.html jpg 33-37 would seem to validate the idea that stability can be achieved with a strut brace, that is a very interesting web find it shows that the body must be reinforced with doublers in the area of the strut tower and the inner fender to keep the car from distorting under heavy loads that is exactly what our desert flyer needs, and he seems to have the technology to do it - outstanding documentation, very good find makes me want to try it to see what it does on regular pavement! Edited February 14, 2009 by Txakura afterthought Quote Link to comment Share on other sites More sharing options...
coxy Posted February 15, 2009 Share Posted February 15, 2009 Having rallied for years here in australia and built different cars for others, I would stitch weld and plate the towers for what you are doing. When making a strut brace use a plate to cover the whole upper section do not just make Tag type mountings,as well I would triangulate the brace by also running from both towers bach toward the centre of the firewall not just across between the towers. Have also done similar stuff between rear towers as appropriate on some cars but with the triangulation dropping to the centre of the floor,dont forget to put reinforcing plate where you mount to the floor or firewall. Additional to this if for competition use you have the option or requirement for a Roll cage what we normally do when we fit up a multi point mounting Roll Cage is run the cage through to the towers as well if you have a cage fitted. Generally only use 2.4mm(12 gauge from memory) for plating with additional 5mm(3/16") smaller plates for cage tubing to mount to over the 2.4mm reinforcement already fitted.If possible any reinforcement plates should take the form of something that spreads the loads over both horizontal and vertical planes for optimum strength. Special stage rallying here sometimes takes the form of round Australia epic bashes,Look up the Redex Trials and an interesting Character by the name of "Gelignite Jack" we test our stuff pretty hard at times. Quote Link to comment Share on other sites More sharing options...
Txakura Posted February 15, 2009 Share Posted February 15, 2009 good stuff coxy, I had wondered if triangulating the strut braces might be a good idea to limit movement fore and aft, had even thought of a plate on the firewall to attach the struts to... chasing stress points can get kind of interesting I had also thought of a rear brace, but never thought to mount it to the floor, that's a great idea i'm glad you put some hard numbers in too, the material thickness had me puzzled as I haven't worked in steel or in gauges I wasn't sure what to use... I had been leaning towards .080" as the minimum doubler thickness and whatever that translated to in steel 'gauges' if I've offended anyone by semi-hijacking this thread... well, sorry. this is something I've been interested in for handling improvement and the door seemed open regards all, and 'g'day' to coxy Quote Link to comment Share on other sites More sharing options...
Txakura Posted February 15, 2009 Share Posted February 15, 2009 2.4 mm = .094", 12 gauge non galvanized like coxy said is slightly heavier at .104" so .080" is a little too thin, i'll have to get some scrap and see if i can work with 12 does sheet steel come in different hardnesses? what's automotive? I'm only familiar with aircraft aluminum and steel (301 cres, 1/4. and 1/2 hard) mmm I have some scrap titanium Quote Link to comment Share on other sites More sharing options...
88RxTuner Posted February 18, 2009 Author Share Posted February 18, 2009 Nope... Not offended at all, by all means your 'hijack' seems to have provided some more useful information that I may be able to take advantage of... Thanks for all the input, I too have thought of triangulating the strut towers to the center of the firewall, using the top of the struts as point A and a fabbed mounting plate where the spare tire used to be as point B, but never thought to connect both to each other and then to the firewall to provide 2 directions of support... Thanks again for the input, and by all means.. if it keeps it coming, someone else has my express permission to 'hijack'!! LOL 88RxTuner Quote Link to comment Share on other sites More sharing options...
Txakura Posted February 19, 2009 Share Posted February 19, 2009 I'll tell you what, when I make some templates and try to decipher the clues from that rally manual, I'll pass on the info here or in a new thread - at any rate i'll drop you a pm as a heads up that I have something to look at. first one to snap their car in half wins! Quote Link to comment Share on other sites More sharing options...
coxy Posted February 22, 2009 Share Posted February 22, 2009 A couple of extra pointers when fabricating stuff like this,always try to fit any bracing gussets on anything you fabricate along the neutral axis,this means for instance on a section of tubular metal along the Centre line of the tube ,easy to work out for any metal shape if you imagine bending a piece of metal the outer part of a bend will stretch and the inner will compress but along the Centre line the length of the metal will not alter this is the place to put any gusset plates for additional strength if required. On top of this if you need to fabricate a mounting for anything always try to put it into double sheer,basically take an engine steady bar as an example with a through bolt the bolt needs to go through an upper and lower plate so it is supported on both sides rather than just one side with the steady bar sandwiched in between what this does is stops the load twisting a single mounting and eventually breaking it. This is why all the best lower control arm mountings have the lower control arm sandwiched between the sides of the cross member rather than mounted on the end of a through bolt and held on with a nut and washer,it is possible to modify the later style with an additional plate that mounts where the washer sits and is bolted on to the cross member a little further on turning a single sheer mounting into the much better double sheer style Quote Link to comment Share on other sites More sharing options...
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