ok guys i made a 2pt STB to fit my 383 HSR. now i kno the STB does nothing with stock worn strut mounts so im upgrading them now.

The J&M solid strut mounts will be here tmrw and before i get an alignment i want to get all this done so the alignment is correct so i dnt have to do it again.

im gona be upgrading it from a 2pt to a 3pt with maybe (supports for the 3pt part) the 2 pt is made from 1.5"x.095" wall DOM tubing, the mounting plates are 1/4" steel and drilled through the strut tower and fastened with 2 (on each plate) 3/8"x 1" grade 8 bolts with nylon lock nuts.

here is my design for the 3pt (see pic) i will def be adding the "blue" parts to the 3 pt. my question is... do i need or would the "yellow" supports be worth it? additional weight would be minimal. but would the yellow supports do anything? or not worth it?

mods im doing before this alignment are... and have already been completed are.

new KYB AGX adjustable struts
new ball joint (pass side)
J&M strut mounts
8pt roll bar.
i added 3/4" baer billet spacers to the front wheels to push them out (also i was upgrading to ARP longer wheel studs
in the rear i had to adjust the rear UMI spherical end panhard bar for the new 17x10.5" wheels with 315 rubber.
I also added offset UMI spherical rod ended LCAs
installed a jegster tunnel mount tq arm
reinforced front LCAs and LCA mounts
added 2pt brace and am now making it a 3pt... this is the last thing to do before the alignment.

car already had SFC, TDS wonderbar and poly everything last time i had an alignment.

so what do u think of the design? i will try to find some 1" tubing with a min thickness of .095" around here for the 3pt converson.

 

"A 2pt will make a difference and if you need more i say screw the 3pt and go for a 4pt. i wouldnt take the risk of cracking my windsheild." "no need for the 3pt over a 2 pt. sry guys..."

Just wondering what's made you reconsider?

JamesC

 

im still alittle skeptical of the 3pt attachment. i personally dont think the base of the windshield is strong enough as an attachment point without reinforcement. and now that my windshield has 2 large cracks in it from just sitting on jackstands in my driveway im alittle worried about attaching anything to the base of the windsheild structure.

its obivous the windshield structure needs to be reinforced so connecting it to the STB is a logical choice, i just need to work out the mount points. for the windshield to just crack from sittin on stands is disturbing (yes they were pretty level since i live on a hill and i had to take that into consideration.
lets just say that im making a 3pt... but it will prob ultimatly turn into a 4pt (or 5pt if u count each bar to the side pillars). i was really just wondering if the support bars (yellow bars) are necessary on the 3pt converson.

 

I had a similar problem on a 79 Z28, it had braces running from the upper arm shafts to the cowl and the flexing cracked the entire cowl right down the wiper tray. Not a pretty result. IMO if you want to run it to the cowl area it's best to reinforce it with a large bracket or some other piece of metal so you don't tear out the steel and cause water and rust issues. For this reason I'm only using the main bar on my edelbrock STB, going to fabricate my own diagonal braces for it, don't like how it's supposed to be bolted to the cowl.

 

It would be interesting to know how many windshields have cracked specifically because of an STB. There have been very few reports of breakage on TGO at least. Mine hasn't--though admittedly I'd don't push the car very hard, and perhaps that's the key. At any rate, good luck with your project.

Curious, I did a search using "STB cracked windshield" and only came up with four results on TGO (and there was no smoking gun on the net either, at least that I could find). The following, I thought, was interesting, but feel free to search for yourself:

https://www.thirdgen.org/forums/susp...rut-tower.html

Given the lack of substantial evidence, the breakage/STB issue seems, as one poster mentioned, "an urban legend."

JamesC

 

I'm having trouble imagining this. Where would the other two pts on a 4pt brace connect?

 

well it would actually be a 5pt brace. heres a pic that illustrates the 4th and 5th attachemment points (yellow lines) that would attach to the pillar corners where the fenders,firewall,windshield, strut tower all attach to. i figure thats on of the major structual points in the engine bay/frame. since all attach at that one point. it would add structual integrity to the STB.

this is just a quick illustration it wont look this ackward in real life lol. btw the points are numbered for the mentally challanged lol

 

I wouldn't attach 4 & 5 to the middle of the "blue" bars. That is just going to keep those bars from flexing outward when the goal is to keep the strut towers and front framework from moving.

If you attach braces 4 & 5 like I have the red lines drawn in, that would help to stiffen the upper fender rail/firewall mounting point.

In your pic, 4 & 5 also look to be at too sharp of an angle to the main STB bars to be able to provide much support. If you're going to do it that way, I would add a bar like I have in the second drawing below.

I will add that I'm no engineer/chassis builder, so this is just my opinion. If I'm way off, let me know and why.

 

as i stated the pic makes the lines look funny. i like the first pic u did tho... not sure how im gona do it yet but im actually fabbing it up as we speak. i wish vetruck or norm peterson would chime in. i wouldnt have to brace the 3pt like u have on the 2nd pic bc thats what the side short supports are for. the 3pt braces the strut towers from folding in on eachother (towards the firewall) on a angle... like folding paper for paper airplane wings. easiest way to explain it would that each strut tower on a hard corner will try to collapse and fold in on itself in the direction of the blue lines, as well as the 2pt bar. so when u install the 2pt brace it stops the inward folding but not the rearward folding/collapsing (as seen by the 3pt blue lines) im just trying to improve on an existing design thats all.

i do like ur first design as it seems to make some sense to me as well

 

As I said, I'm no suspension guru/engineer, and I agree some input from them would be useful as well. I was just tossing some ideas out there for you to correct what I saw as a possible flaw in the design you originally posted.

I agree on the direction of flex of the strut towers, and looking at your original idea, the bars going to 4 and 5 look to be at too shallow of an angle in relation to the strut towers and to the bars going from points 1 & 2 to point 3. It may just be the drawing, but to me it seems like your not providing any additional support to prevent the strut towers from moving backwards towards the firewall with the angle that the bars to 4 & 5 are at in relation to the strut towers.

Not sure I'm explaining my thoughts too well, hope you can follow my logic here.

If you REALLY want to prevent the strut towers from flexing rearward, it might be best to have the bars from 4 & 5 tie directly into points 1 & 2 on your tower plates. I'm just not sure about clearances and if the angle from the firewall pinch weld to the strut tower top is too low to get a good tie-in and also clear the hood. Something like below, although the green lines would probably be overkill. I tend to over-design things sometimes.

 

seems like the red lines would act like a full 12 pt cage would. with the front bars looping around the front strut towers and attaching to the front subframe. i wouldnt use the red ones in case i decide to use a full cage

the green lines seem to work for me... but i might have issues attaching to the pass side bc of the blower motor... very limited space over there. but i had the alignment done and it took 4hrs for all 4 wheels.

heres the updated pic of the 3pt brace. original tube is 1.5"x.095" Dom tubing, mounting plate is 1/4" thick. i slotted the bolt holes to allow adjustability before the alignment in case it was needed. here is the 3pt bars added and the support bars. tubing is 3/4" square tubing or .75"x.095. so its super light yet strong. its bolted to the windsheild support with 2 grade 9 bolts (3/8" x 1.5" with nylon locking nuts) not sure if i want to add bars to this like the green ones in your last pic.

now im gona reinforce the mounting point and paint it

 

Yeah, I was thinking the same thing about clearance with the blower motor. I swapped mine out for an old S10 motor and housing when I removed the AC equipment from my Camaro last winter and wasn't sure how close the stock stuff is. On mine I have plenty of room for a bar to mount there. Of course, I also reversed my hood so there are no hinges in the corners to cause clearance issues also.

Your bar looks great though. When you said you used square tubing I was a bit worried about how it would look with the round main bar, but I like it.

 

Heres some ideas for ya https://www.thirdgen.org/forums/susp...0-point-s.html

 

dont really have anything to add to the tread. but that is one clean looking engine bay.

 

yea ive looked at this but i never saw it on the car, i just saved a couple of random pics that ive had for a while. that thing is ridiculous esp it being in 4130 lol. seems that he designed it for 10 pts but the middle 2 bars that attach to the firewall from the center are not really in the right places. theres a reason the aftermarket 3pts go to the center of the windshield creating a triangle (super stiff). not to mention thats where the strut towers want to force themselves in a hard corner (inward and back at an angle). still sick work. wonder how much it helped lol.

92RS_Ttop... no way i was getting over the blower motor on mine. not to mention the bars going to the edges of the Apillars would hit my cowl on the ram air II hood so im scrapping the idea of those bars right now.

yea the square tubing was easy for me to get and cost me nothing. i tried a couple of metal shops around here and no one had a small DIA round tubing. the 3/4" square tube is really really light, not to mention easy as hell to weld and cut for the angles. this made it super clean and easy to fabricate.

i just cut out a peice of 1/8" mild steel, 1" wide and 6" long. drilled two 3/8" holes for the upper (3rd pt) at the firewall to sandwich the firewall for added strength. in the pic i posted before they were just drilled and bolted through the firewall, this will increase the strength. right now the parts have been painted with POR15 and im waiting for them to dry

thanks ellocojorge, tried hard to get it that way. removed ALOT of stuff

heres the STB in the paintbooth! haha AKA jam packed messy garage

 

How did the old 2pt brace work for you? I'm just wondering about the thickness. All the ones I've been able to find dimensions for are made from .120" wall tubing. Have you had any problems with the .095" wall? I plan on making my own and if I can get away with the thinner tubing it would save me some $$ and be easier on my little Craftsman MIG.

 

i have had no issues with it as of yet. not like i would be able to tell anyway since its under the hood and i cant see it flex. .095" tubing is not that shabby. im sure its more than adequate. i mean most of the car is made of 22 gauge steel lol. stock subframes are just spot welded thin sheetmetal.

from wat i can see on BMR and UMI websites they dont list the specs of the STB. BMR states that there tubing is 1.25". mine is 1.5". the tubing DIA also effects the strength of the STB including the thickness. i wouldnt go thinner than .095" if i were to make one. my bar weighs very little even with the 1.5" tubing and 1/4" mounting plates.

 

I know you won't be able to see it flex while driving. I was just wondering if it was showing any signs of stress(paint/welds cracking, twisting/bent, etc) when you took it off. Did it help with how the car handles?

I missed the difference in diameter between your bar and the others. If .095" will work I'd rather use that since I can get it easier than the .120".

 

when i did the 2pt STB i had done more than one mod. with the engine swap/complete hop up, i had seam welded most of the engine bay, i had fully TIG welded the upper strut towers, fixed LOTS of rust, reinforced the front LCAs, reinforced my SFC more, added a 8pt roll car and did some other rear frame upgrading. the car was so stiff it made a huge difference. but i can not vouch what the STB did alone. and when i upgraded it to the 3pt i had upgraded the strut tower bearing caps to solid J&M mounts, and added new adjustable struts, so i cant vouch for the increased performance from the 2 to 3pt converson.

i have to say that the front end has NO flex. its very tight, and im feeling more road vibrations when i upgraded to the 3pt STB, J&M mounts, and AGX struts. again to fully appreciate the 3pt i would have to push the car to beyond .92gs i would assume.

 

You sound like me when it comes to upgrades I can't just do one thing at a time either. Last winter was a V8 rebuild and swap, trans rebuild, swapped coil springs front and rear, swapped both sway bars, all new bushings/balljoints/end links, along with rust removal and painting the k-member and front control arms.

Where did you get the strut mounts? I want to replace mine and am considering going to a solid mount. How bad are the road vibrations?

 

got them directly from J&M. hotpart.com

they cost 217$ ended up being 233$ including shipping. shipping killed me bc it took a week to get here (NJ) from cali, the car was ready for like 3-4days before they got here. i had orded the struts from summit the same day and i had the summit stuff within 48hrs lol.

the only ones out are the J&M and the spohn ones. i like the J&M bc they are more adjustable. both have 1" raised bearing heights, both use solid bearings. and the J&M bearings are replaceable. the road vibrations has increased alittle bit, but that could be from the 3pt STB as well. im gona assume the mounts did increase vibrations but its not that bad at all as long as ur on a smooth road.

the handling increase was INSANE tho, combined with the new struts and STB, its a whole new animal

 

Thanks for the warning about the shipping, I'm in PA so it'll probably take almost as long. I do love Summit's shipping though(most stuff is here next day for me).

The price and smooth roads thing might be problems though. I'm not sure how the roads are there, but PA roads are pretty bad. Looks like something else I'll have to look into a little more before I decide. The research is never-ending!!

Thanks for the input!

 

my shipping also got delayed for some reason for a day, i guess its bc of what was going on with haiti. at 217$ its a steal, then u think about it, much stronger than stock, no rubber bushing like stock, more adjustment. not to mention improved handling, raises strut mounting point for lowered cars (helps the struts work in there range more) so they dont wear out fast. a set of new STOCK mounts will run u 120$ cheapest... so for another 100$ u can have all the benefits of the J&M mount.

well the roads in NJ arent any better then PA lol. if anything they are worse.i live near NYC, like 15min from manhattan.

drives like a dream on the highway, most decent roads feel fine. i drive over some BAD roads in newark to get to work so thats where it kills me i guess. not as bad as u would think.

 

Have you gone over any train tracks? I have to cross 2 sets to and from work every day.

I was looking at the KYB mounts on Summit, but it doesn't say if they have the rubber bushing in the middle or if they are solid. I'm not planning on lowering the car, even though I know it will help with handling. If I lower it at all I'll get stuck going in and out of my garage and up the hill out of where I live.

 

the KYB mounts are stock replacement. same as the ones u have, just new. the rubber is harder than the worn stock ones but it will still flex a bunch and will get progressively worse as the car is driven. Vetruck had a post that said something like...

stock strut worn mounts 100% flex
stock strut worn mounts with 3pt STB 90% flex
new strut stock mounts 75% flex
new strut stock mounts with STB 65% flex
J&M/spohn strut mounts 10% flex
J&M/spohn strut mounts with STB 0% flex.

yes i drive over 2 every day. i also work in the same lot as a truck yard, and a constrution/ metal works area, which means the roads havent been paved in 20yrs and have potholes that eat hondas. manely bc only trucks travel down the road and is the "back" way. basically the road is entirely holes/divits/cranks. its kinda like driving in a vibrator lol.

i would upgrade them if your gona do them (which u should if there still stock) u will get more outa that mod then doing the KYB mounts and STB which will cost more than the mounts alone.

 

I musta missed that post by vetruck, but then I haven't read all of his stuff either. I know what you mean by vibrator-roads, I live in an old coal town and work near old steel mills. The roads here aren't any better. Nice to know I won't rattle the car apart driving to work every day in the summer.

I'll be making my own STB for the car eventually and I will replace the stock strut mounts when I do. The ones on the car have about 106k on them now assuming the are the originals. I have a spare one or two, I'll have to look at them and see if I can just weld in a piece of 3/16" or 1/4" plate and make my own solid mounts. While those J&M mounts won't blow my entire budget for winter upgrades, if I can make my own that's $230 that can be spent on something else. Plus I enjoy fabbing my own parts and being able to say "I made that."

 

i can not weld in a peice of steel. it doesnt workt hat way. the stock mount has a "bearing" but it sits in a rubber bushing. this is what flexes. the mount still has to swivel... hence why the stock mount has the bearing for when the wheel turns but theres no solid connection that the bearing sits in (stock has rubber). this is why the aftermarkets are worth it.

you will no be able to fab ur own strut mounts. otherwise ppl would be doing that. your best bet would be to fab other things. like rear LCAs, panhard bar, wonder bar, STB etc. not something like a strut mount.

even if u replace the stock worn mount with a new STOCK mount ull still have 75% flex.... so whats the point then really. and u wont gain the benefits of the STB u make or the good struts u put on the car.

 

I didn't think about the bearing in the middle and that the top of the strut would turn with the wheels. I figured the body of the strut rotated around the shaft.

With that in mind, I was thinking of removing the rubber completely from the mount. The center bearing is just held to the rubber by about 8 rivets around its perimeter. I have a spare one laying around, I'm gonna take it apart and see how its made. I think if I can reuse that center bearing I might be ok. If not, I will have wasted a couple hours, some scrap steel, and some MIG gas & wire.

 

no the strut shaft shouldnt move. evertime it twists i freak out and think im ruining it lol.

youve got a good point. maybe ill tear mine apart for SHlTS and GIGGLES lol. eh. still tho some added benefits would be lost, the stocks dont incorporate high strength solid bearings like QA1s etc and then theres the 1" of extra ride height. but that could be solved with spacers under the strut mount