More like mumbo jumbo at this point Paul. I guess I'll just have to get around to rigging it myself when I have time - maybe this winter!

Uh huh, uh huh, looks like a 6 pack job to me.

 

Where would put a brace in order to use the moment of inertia to its fullest extent . Up high away from the motor mounts or low close to the motor mounts .A better design would be to attach to the bellhouseing and link to the floor pan . Then people would say it will crack the floor pan . You can not win . Whos works best with what we have to work with at a low price . If any of the fender mounts with 6 bolts crack then so be it . At least the design tried to address the problem . Have any 6 bolt mounts ripped the fenders yet ? Use a spring to stop vibs or a pair of rubber bushings that do as well . What is the cost of the spring setup ? All designs will be flawed in someones mind, but they need to redesign and put out there product for a price that all can afford .Garfinkle can design a product that most will not find to be incorrect but the price will be out of sight and hard to install .

 

Where would put a brace in order to use the moment of inertia to its fullest extent . Up high away from the motor mounts or low close to the motor mounts .A better design would be to attach to the bellhouseing and link to the floor pan . Then people would say it will crack the floor pan . You can not win . Whos works best with what we have to work with at a low price . If any of the fender mounts with 6 bolts crack then so be it . At least the design tried to address the problem . Have any 6 bolt mounts ripped the fenders yet ? Use a spring to stop vibs or a pair of rubber bushings that do as well . What is the cost of the spring setup ? All designs will be flawed in someones mind, but they need to redesign and put out there product for a price that all can afford .Garfinkle can design a product that most will not find to be incorrect but the price will be out of sight and hard to install .

 

If'n I may interject. Apologies I just can't resist
Re: the TripleR brace sold by the RX-7 store. (shameless plug)
I have used this ETB for four *over* years now...continuously. I don't drag race but my car is "tracked" regularly (road courses) and driven HARD. My car literally has pretty much every modification one can make short of a single turbo. It makes reasonable power but is not a 500rwhp monster.
I do not not know of a performance based failure of this brace. And I'd hazard a guess over a hundred units of this ETB have been sold..right Phillip? Has it been researched and analyzed. Why yes it has. How do I know...because although a paper analysis may have been sufficient, in my learning days I played around with some FEA modeling and modeled the brace...many years ago when *I* developed that particular ETB. Now granted it is pretty much a direct rip off of the Knightsports brace (the inspiration) which has been on the market since probably the late 1990's but I still did the analysis anyway. So I am very confident the bar is designed sufficiently, and *when mounted correctly* will not lead to bending or cracking of the fender wall (at least not before something else breaks first) and will not over stress the LIM or UIM. I will note I have seen ONE failure at the UIM mounting point...FROM A SIDE IMPACT WITH A TIRE WALL. But a failure as a direct result of it's use. Nah. I'm not convinced...at all. Too many "positive" empirical datapoints.
Now there are 100 ways to skin a cat. One can over design and add 10 degrees of safety. But IMHO why 10 when 2 will do. Added weight and complexity, be it with the installation or the design, is all you will gain. The "Garfinkle brace," the brace designed by my fine friend in Texas , and that nifty drivers side brace (must get rid of the PS and AC to use that one though ), I'm sure are all equally effective. If price is your issue then go with the least expensive. Hypothesising this design vs that design and this failure mode vs that failure mode is pointless. I'm being a cynic, but these style of ETBs have been, and are in use in by the 100's in the US and who knows how many more in Japan. And this doesn't even include the same design principle as implemented on ETB's for the FC!
As I noted, sarcastically, above...this was debated Ad Nauseum last year with the same result. They work. The naysayers remained unconvinced or bitched about the "noise" and "vibration." Boo hoo....drive a Caddy
But I'm getting off topic.

The ETB's that look like they have a shock absorber instead of a solid rod...think again...it's not a shock. The GReddy, is it? Is merely a tube with a solid urethane bumpstop inside of it. It's as rigid as a solid rod with urethane or rubber pads between the fender bracket and the fender wall as in the TripleR ETB. Same principle, different application. So what do you want? As for a real gas shock, a la motorcycle steering damper...it's a possibility, and may cost you, but I refer back to overdesign for a simple problem...WHY? For the Bling Bling? Or for the performance?
Stepping off my soapbox to let the debate continue
Regards,
Crispy "Regan Rotary Racing" aka TripleR, Regan
- BS Mech Engr and MS Engr.
- 8 year USArmyReserve mechanic. (toot, toot)

 

 

Go Army!

 

haha, crispy's post ALONE needs to be a sticky!!!!

paul

 

Rotorsports racing made these mounts. They were 340 bucks with a core exchange. These are a brand new design. I have the first set of the duel urethane type. The older design was basically 1 very hard solid block of urethane. The disadvantage of the original type was you want some engine torque for various reasons and also a solid mount will allow for alot of vibration and noise to transmit into the cabin. The whole reason the motor torques over more is because the mounts are beyond thier threashhold. Instead of just putting a chair behind the door, why not just fix the latch? Thats my mentality at least. The whole point is replacing the parts that fail. The driveline of the FD was designed to twist a bit to tranfer torque to the rear wheels. I think you still want to allow a bit of engine torque. Too much and you cant even get the car in gear under high load rpms etc.

 

ZoomZoom,

I am thinking along the exact same lines as you. I am going to try to make my own like ISUposs did. Do you have any detailed pics of the Rotorsports mounts? I wish I knew what kind of urethane to use?

CrispyRX7,
I understand your point, you have not had any problems with your bar. I have heard of a few people with problems, but thats not the reason that I personally don't think it is a good idea. I just don't think it is the right solution to the problem.

I guess the real question is "If you have upgraded (erethane, or similar aftermarket) engine mounts, is there a need for the torque brace?" Yea it is a lot less $ and much easier to put in a torque brace then put in new motor mounts, but what is the right solution?
Again, just thinking outloud.

 

Just make your solid motor mounts out of steel.

 

WickedRX7,
Agree...solid motor mounst is another soln to the same problem. The drawbacks: higher cost and more difficult installation. Is it a "better" soln.? Depends on how you prioritize your needs and limitations. Building a ground up race car I would definitely consider solid motor mounts FWIW.
Regards,
Crispy

 

id never have solid mounts on the street. that would rattle the hell out of you.

paul

 

I do not have them in front of me but there is a picture on thier website. Also there is some info on the web about how to make your own mounts and what type of Urethane to use and basically a "how to" Do some searches on the subject and see what you come up with. From what i understand it cost one guy who made his own mounts around 10 bucks in material.

 

Now that we have discussed the braces thus far, why not siwtch the focus to the best preloading setup for our motors? I have my feed brace loading the drivers mount almost as much as I can..
What do u all suggest?

 

Here's a vote for the Garfinkle system:

http://us.autos1.yimg.com/img.autos..../indrvreng.jpg

http://www2.us.porsche.com/english/u...tung_foto1.jpg

-ch

 

Excellent question. I have the Border torque brace and always wondered that.

 

im surprised no one has tried or responded to the idea of putting something between the stock rubber mount and the steel safety strap around the mount. i used a piece of delron cut to fit in the gap between the strap and the rubber. total cost $5. time involved 10 minutes. appreciable reduction in motor movement with no noticable increase in vibration. im sure the bars reduce motor movement more but for the time and money invested this works great.