I recently purchased an 83 E21. PO swapped in a 5 speed but otherwise everything looks to be stock. The seller mentioned cracks in the B pillar and said a front strut bar may help limit cracking at this delicate junction. Now three weeks in of reading, watching videos and talking to my motor-head friends I can't decide; are hinged/fixed strut support bars worth the money? Some say the firewall is close enough to the strut towers on this model to render them all but useless, some say hinged strut bars do little as they still allow the frame to flex vertically.
Going to make popcorn now, please discuss amongst yourselves.
I doubt any stress bars will help with B-pillar cracking..
Which gives me an idea...
Maybe someone should start selling B-pillar stress bars! Like adapted luggage racks
I'd bet a handy fabricator could whip up a reinforcing plate that required little to no interior mods. As for the strut bars, if I ever come across solid ones I'll make the purchase, I don't believe single bolt hinged bars to be effective. For our cars specifically the best way to tighten up the front is to make/buy an "Alpina" bar.
I felt the alpina bar the first time I closed the door and backed out of the driveway. It makes a big difference.
Most of the internet search results for "alpina bar" are for a bar, i like beer but it makes me sway. JC Whitney says they have "the best selection of Alpina Bars but they lie. Ebay may have one but it is blocked at work so I will try that one in 2 hours. Forum search of the E21 and E30 subs show no results, are you making this up? Is it like "headlight fluid" <jk> .
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AHHA! http://www.angelfire.com/de3/bimmertoyz/alpina.html
Never mind; email to http://www.angelfire.com/de3/bimmertoyz/alpina.html bounced, i guess they got rich and retired.
"Alpina Bar" is colloquial. It's a bar that ties the ends of the front frame rails together.
Supposedly this was an innovation to be found on Alpina's E21 conversions, hence the name.
Those I've seen are much simpler than strut-top bars and are bolted on by simply getting longer bolts for the front sway bar mounts.
The cars are prone to flex as evidenced by the crack at the B-pillar.
Most everyone whose installed either a front strut or "Alpina" bar claims to notice improvement, myself included.
In my case I installed a strut-bar to address perceived weaknesses thanks to a front end collision before I bought it.
Even in the process of getting the bar and mounts aligned during installation, I could see the distance between the pillars change in jacking the car.
That was all the evidence I needed.
HTH.
Last edited by pommeree; 08-18-2017 at 04:27 PM. Reason: clarification, grammar
Eric P.
Thanks for the clarification Pommeree and thank you all for your assistance. I think i found what I am looking for:
https://www.racetep.com/automaker/bm...brace-e21.html
Also, sorry for the crazy posts, first time posting on this forum and I am not really sure what i am doing.
Last edited by MurgleBurgle; 08-18-2017 at 04:29 PM.
Eric P.
I actually just found it cheaper from the Mfg., Ireland Engineering. 76.00 is chump change compared to what i was about to shell out for the Strut Bar, i will give you an update after i get it installed.
http://www.iemotorsport.com/bmw/E21-...n-steering/E21alpnabar.html <--no wonder! it is actually an "Alpnabar"
My personal feeling is that strut tower braces and the "alpina bar" are both non-sense/placebo effect. However, I'd love to see some data. Shouldn't be that hard really; put a torsional load on the chassis (or whatever member you suspect to be flexing), then install whatever brace, and re-test. I've never seen any such data (I suspect because it would be inconclusive at best), but I would like to.
If you are building a house and want a wall to not rack you put on a diagonal brace. A brace placed horizontally across either the top or the bottom would do nothing to prevent racking under a torque or shear load. The best way to prevent torsion or shear racking would be opposing diagonal braces, or cross bracing in the shape of an "X."
Videos of the factory suspension testing, note the "Thumbs up!"
http://www.youtube.com/watch?v=qLcphWHWjSI
http://www.youtube.com/watch?v=f_arRxPONBY
Reading the descriptions- Ireland Engineering bar is painted and TEP's bar is powdercoated. Maybe that's why it's more expensive.
Do both come with the necessary hardware (longer bolts and lock nuts)?
Max
Last edited by mxl556; 08-19-2017 at 12:53 PM.
Strut bars, both front and back, and Alpina bars all produce a noticeable improvements in handling. I installed each sequentially...their effects are real, not placebo.
'81 E21 320i / '90 E30 325i / '̶9̶2̶ ̶E̶3̶4̶ ̶5̶2̶5̶i̶t (sold) / '15 Toyota XW30 / '̶̶8̶0̶ ̶E̶2̶1̶ ̶3̶2̶0̶i̶A̶ (sold)
I purchased my Alpina style bar from Ireland and can confirm that it is painted and comes with hardware. It is mounted to the forward most swaybar mounting bolt location and fits perfectly; the welds are clean and overall it is nice piece.
A few caveats to be noted: The paint on the bar was less than stellar with some very thin spots where the steel was showing. I purchased some Rustoleum Industrial spray paint in gloss black and re-painted with several coats. Should be perfectly fine for my weekend car but if corrosion is a concern you may want to strongly consider the powdercoat option.
The hardware also leaves a bit to be desired. The bolts are grade 12.9 M10x55 allen head cap screws in black oxide finish and come with two washers. Given the application I thought it more appropriate to use a regular grade 8.8 hex head bolt in zinc finish so I purchased a couple of 60mm long bolts from my local Ace Hardware and installed with new BMW locking nuts. I am glad I purchased slightly longer bolts because there are only a few threads showing below the nut.
I cannot comment on the TEP option. Their web page shows the same exact picture as Ireland and does say it is powdercoated so it might be worth the up-charge to get a better finish.
MJ
The Alpina bar from what I have read about was made famous by the Alpina Race Teams that were very successful, like was said it helps stop nose twist in changing lanes and helps keep the front end flat going into too turns--improves handling --strut bars assist in same way otherwise the towers will be uneven in turns and so forth,,common sense. I have a Alpina bar installed and yes I like it and handling is improved over stock--none there.
Randy
Last edited by 320iAman; 08-20-2017 at 11:55 AM.
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