Author Topic: Strut Tower Brace for M42 (Read 43653 times)

bmwman91 · « **Reply #30 on:** July 18, 2006, 02:00:42 PM »

I had a Racing Dynamics one. It fit 100% fine. It is very nice to have one with the swiveling ends...getting it on & off is a snap, well comapred to fixed ones. A little pricey at $230, but i though it was worth it. And all that stuff about it being real weak compared to the steel one is nonsense.

Yes, the steel one is gonna be stiffer, but the handling difference between no brace and the RD one is HUGE, while the handling difference between the RD and steel one is miniscule in comparison.

In my crash I hit a tree sideways at close to 60mph, and the RD brace saved the motor (it did not survive though). I have been informed that having a really stiff steel one in there would have probably led my passenger & I to suffer a lot more injury as it would prevent the chassis from doing its job...absorbing impact. The aluminum one crumpled a lot more than the steel one would have I am betting, and I only had whiplash for a few days. I guess after being in a big crash I put safety first now, and I would not use a steel one for that reason.

Gustave Stroes (Dr G) · « **Reply #31 on:** July 18, 2006, 03:21:23 PM »

Just to make sure I'm not being mis-quoted:

1. I do beleive that a stress bar is helpful, on the track and the street. All my cars have one.

2. Make sure to read the second page of my stress bar analysis:
http://e30m3performance.com/myths/Strutbar_Theory/strut_bar_comp.htm

3. The Motorsport racecars had a full cage tied into the strut towers, they did not need a strut brace for this reason.

4. I never said that the strut towers would deflect 0.5". That was just to give someone an idea of how camber change related to strut tower deflection. But I would not underestimate how much they can flex with sticky tires on a bumby track. That is the main reason for a stress bar in my opinion - proper and consistent camber control.

HTH,

Gustave

bullmand · « **Reply #32 on:** July 19, 2006, 10:29:35 AM »

It's not clear from the relevant posts above (to me anyway). Does a bar on the rear actually do anything? Just based on the relative wimpyness of the rear shock mounts and the size of the shock towers it doesn't seem like BMW expected that much stress back there.

e9nine · « **Reply #33 on:** July 19, 2006, 11:20:16 AM »

Worry not - they haven't discussed it above. The rear bar is another can of worms in the e30 suspension world. Interesting point to note is that some e30s have issues of the welds there separating. Rare - but it does happen.

asubimmer · « **Reply #34 on:** July 19, 2006, 12:49:00 PM »

Some people say they don't do a thing, others say that they do wonders.

I don't have one but I think they do work on e30's. I have driven them w/ and w/out and before and after.

This all boils down to $100, you really can't go wrong on a bar for $100. Even if it doesn't work it still would be nice to have. I would have one now but I have been holding out for a double bar.

e9nine · « **Reply #35 on:** July 19, 2006, 01:01:47 PM »

Quote from: asubimmer

Even if it doesn't work it still would be nice to have.

:confused: help me out here. How it would nice to have if it doesn't work? Or am I missing something?

asubimmer · « **Reply #36 on:** July 19, 2006, 01:08:24 PM »

like a cone filter, their advantages are questionable but they sound awsome. A strut bar will stiffen up the body from saging, I don't think anyone disagrees w/ that. The argument seems to be do they add better response and handling. Even if it doesn't increase handling it still helps reduce sag and looks awsome.

That is all.

bullmand · « **Reply #37 on:** July 19, 2006, 01:12:49 PM »

Thanks for the input. I'll probably get one anyway. It's not that heavy and it probably won't hurt anything.

M42boy · « **Reply #38 on:** July 19, 2006, 03:49:45 PM »

Quote from: Gustave Stroes (Dr G)

Just to make sure I'm not being mis-quoted:

1. I do beleive that a stress bar is helpful, on the track and the street. All my cars have one.

2. Make sure to read the second page of my stress bar analysis:
http://e30m3performance.com/myths/Strutbar_Theory/strut_bar_comp.htm

3. The Motorsport racecars had a full cage tied into the strut towers, they did not need a strut brace for this reason.

4. I never said that the strut towers would deflect 0.5". That was just to give someone an idea of how camber change related to strut tower deflection. But I would not underestimate how much they can flex with sticky tires on a bumby track. That is the main reason for a stress bar in my opinion - proper and consistent camber control.

HTH,

Gustave

Thanks for clearing this up Gustave... Makes a lot more sense now. I totally agree.

john mason · « **Reply #39 on:** July 19, 2006, 09:28:46 PM »

Quote from: john mason

HI GUYS
Allow me to explain/clarify the front and rear tower bars i have designed,front is a twin tube of 1in. dia. running across with punch/flared sheet metal shear plate on the top , positioned extreme rear-highest point of engine compartment ,for all type plenum clearances there are 2 types of materials of choice steel or aircraft grade domestic aluminum alloy 6063 t6-511, the end platforms are of the open top 6in. dia. with a 3 5/8 dia inner hole which allows easy access for camber/ dampner adjustments the bar assy. is of the hinge-less 1 piece design without bolted tabs, this is very good for load carrying abilities but can be troublesome on the installation as there is very little margin of variance amongst elderly chassis. front stl5lb alum.3lb rear stl.41/2lb alum2lb design revised and - approved/blessed by gustav stroes-
the rear bar is of same materials but is unique in that ther are 6 1/4 dia.bolts
per side that attatch bar side skirts to wheelhouse transfering 1200 lb. of vertical loads each bolt 6x1200=7200lb shear. this bar is very easy to bolt on-no welding required - but recomended for racers, sold under the name jjmtools ebay = not made in china , does not have carbon fiber scotch tape

A seldom revealed fact in regards to domestic aircraft grade 6000 series weldable aluminum tube it is 1/3 the weight of steel and in a compression load situation it is 2x stronger than steel before yield point, is also by nature is non-corrosive and non-magnetic, so it seems if the strut bar is designed correctly - welded precisely and in compression it would be an advantageous choice for a lite=weight add on load bearing structure

nickmpower · « **Reply #40 on:** July 19, 2006, 09:49:47 PM »

so how much for the aluminum ones John?

M42boy · « **Reply #41 on:** July 19, 2006, 09:56:24 PM »

Quote from: asubimmer

dang man, you should have let me know you were in town. I was at Korman this weekend some.

Actually, I wasn't at Korman... But, do want to check out thier facility when I'm up that way. I think they know the older cars better or as well as anyone in the country. If I hit the lottery, I'll hire them to restore/build an E30 M3 for me. :rolleyes:

I was up at "the yard" and some guy up there was installing one on a E21 320i with an M20 conversion (super eta block with worked iS head).

kramerica5000 · « **Reply #42 on:** July 20, 2006, 08:54:08 PM »

Quote from: nickmpower

so how much for the aluminum ones John?

yeah . . . what's the "Forum Member price"

silverblades181 · « **Reply #43 on:** July 23, 2006, 02:59:00 PM »

Quote from: bmwman91

I had a Racing Dynamics one. It fit 100% fine. It is very nice to have one with the swiveling ends...getting it on & off is a snap, well comapred to fixed ones. A little pricey at $230, but i though it was worth it. And all that stuff about it being real weak compared to the steel one is nonsense.

Yes, the steel one is gonna be stiffer, but the handling difference between no brace and the RD one is HUGE, while the handling difference between the RD and steel one is miniscule in comparison.

I also have the Racing Dynamics strut bar. Aside from looking very good, it stiffened up the front of the car and I saw a huge difference in cornering at the track. It's also very light and I love the fact it's not fixed. My strut towers were of the smaller distance and the bar initially didn't fit. I ovalised the holes with a dremel and it fits perfectly now and it can be adjusted for the larger distance struts. A strut bar of any sort is a must have for anyone tracking/doing heavy cornering IMHO. I recommend the RD bar.

Berlin · « **Reply #44 on:** July 24, 2006, 03:26:54 AM »

Quote from: silverblades181

I also have the Racing Dynamics strut bar. Aside from looking very good, it stiffened up the front of the car and I saw a huge difference in cornering at the track. It's also very light and I love the fact it's not fixed. My strut towers were of the smaller distance and the bar initially didn't fit. I ovalised the holes with a dremel and it fits perfectly now and it can be adjusted for the larger distance struts. A strut bar of any sort is a must have for anyone tracking/doing heavy cornering IMHO. I recommend the RD bar.

ditto, my rd bar owns aswell