I did my own version of Elephant racings strut brace

Cyberdennis · 08:37 AM

I wanted to have some sort of strut brace in my car, but didn't want to loose all of the luggage compartment. I then saw Elephant racings "QuickChange" strut brace system and thought the concept was really nice.

I thought this could be done with some metal fabrication, some turnbuckles cut in the middle and extended, and this is the result:

Starting with:

And all the turnbuckles cut in half and extended with some pipes from work

tharbert · tharbert's Garage

Very nice work...

Flieger · Flieger's Garage

Good for you, but beware any wrath from Chuck.

Cyberdennis · 02-15-2011, 09:52 AM

Quote:

Originally Posted by Flieger

Good for you, but beware any wrath from Chuck.

Ooooooooooooh........

Kroggers · Kroggers's Garage

Nice work Dennis...

Wil Ferch · 11:06 AM

Gentle critique....there is not enough rear-ward bending resistance with the extended sheet metal piece which captures the rear mounting if the "X" cross braces.

Can be considerably improved if there is a horseshoe shaped piece that connects this horizontal-plane section also to the front shock tower bolt. Or...if the side-view "L" shape was maintained for its entire width, instead of the "L" being cut-down to result in the "flat-only" section we see at the back-side of the tower. It would be an improvement.... yet still be somewhat weak in the up-and-down bending direction. That aspect can be improved with some sort of vertical boxed component. Might need another "L" section maybe vertically-too. Best would be not to use an extended metal piece at all and try to triangulate on the flat horizontal plane directly to the shock tower bolt. That original bolt location on the tower itself, is stiff horizontally and vertically. Another thought is to bring the entire bolted section much closer to the shock tower, and not have it hanging in space inside the trunk area as it does now. I understand why it was done,....to gain bolting access....but it severely reduces its effectiveness.

Great looking and tidy workmanship.

Cyberdennis · 02-15-2011, 11:04 AM

Quote:

Originally Posted by Wil Ferch

Gentle critique....

I'm just happy i got it all together in the end

.
If i notice that somethings won't work (on my street/trackday car, not race car), I might try again with some new parts.
The second prototype won't take that long to make

.

Cyberdennis · 02-15-2011, 11:23 AM

A picture with better quality:

911pcars · 02-15-2011, 11:46 AM

Nice work. I concur as to what Wil said about the strut tower brackets.

The tubes look to be steel. If so, 5 tubes become weighty. If you get to V2, try tapered tubes and rod ends in aluminum.

Sherwood

Wil Ferch · 11:53 AM

I often wonder how effective ANY of this stuff is for a street car...as we have a whole lot of rubber in various places being compressed and extended....the torsion bar rubber bushes, the top shock mounts, etc, etc....before we need to start worrying about millimeter type deflection of the sheet metal.

That said.... a simple change that would increase bending resistance, and to avoid any welded fabrication of the pieces, would be to

1.) Move the mounting holes as much toward the shock tower as you can, to minimize the "overhang" into space...
2.) to use a pure "L" shape for the entire length ( width, as installed in the car) of the original bracket, and finally
3.)...to use another "L" shaped piece back-to-back against the original one...suitably bolted together in various places to avoid welding for the home mechanic....

Something like this, as an idea--->

The red line shows the extension of the original bracket to maintain the "L" shape for its entire length ( "width"..as installed in the car) and the yellow line is the starting view of the mirror-image "L" shape piece bolted-onto the backside of the original piece. The red holes suggest moving closer to the shock towers. This is only a first thought suggestion and can itself be improved.

Cyberdennis · 02-15-2011, 12:12 PM

A few more pictures with the tubes connected:

The torsion bar bushings are no longer rubber and I know there are more areas that affect the flex of the car, but you have to start somewhere...

The reason I used steel tubes is that i got the turnbuckles with left- and righthanded threads and quick connectors at a good price and just wanted to see if I could make something like Elephant racings quick connect system cheap and working in the same way. I love taking something made for a complete different area and use it for something on my car, in this case from the marine area

Thanks for all your suggestions but I will start the season with my setup and see what happens

RWebb · RWebb's Garage

do you have the # hours you put in? and the cost of the parts?

my guess is there will not be any "Chuck Wrath" since the costs to do this for nearly everyone else will be fairly high

Bullet Bob · 02-15-2011, 01:16 PM

Why is there a need to brace to the front of the trunk? Given the locations of the ball joints on the a-arms there isn't much load transmitted to the fronts of the a-arms during cornering. The only loads the fronts of the a-arms will really see is tension across the front of the car during braking.

aigel · aigel's Garage

Nice fabrication.

I would love to see someone put strain gauges on such a set up and see what load actually goes onto these bars. That should give us a better idea if they are worth the $ or in this case the time.

I have a straight brace on my 993 and had one on my SC but for sure don't know if it made a difference or not.

G

tobluforu · tobluforu's Garage

Quote:

Originally Posted by Bullet Bob

Why is there a need to brace to the front of the trunk? Given the locations of the ball joints on the a-arms there isn't much load transmitted to the fronts of the a-arms during cornering. The only loads the fronts of the a-arms will really see is tension across the front of the car during braking.

Here we go...

Bullet Bob · 02-15-2011, 03:24 PM

Quote:

Originally Posted by aigel

I have a straight brace on my 993 and had one on my SC but for sure don't know if it made a difference or not.

G

I have had several people tell me that the cross brace does make a difference that they can feel in a race environment and I believe the diagonal to the brake housing is important. I don't think the other diagonals to the front corners do anything at all except add a little crash protection. Those front A-arm mounts don't even see any torque loads from the torsion bars. I was on the fence but I did go ahead and add them to my race car I am building

RWebb · RWebb's Garage

I'd also love to see some strain gage data...

w/o that, the next step down is to think about what Porsche AG did on their production cars and race cars...

after that, you can rely on "clinical experience" - i.e. how the thing feels, esp. useful if a double blind test is done (but it won't be)...

signature65 · 02-15-2011, 04:03 PM

Great excution.......but and just a question.....

Shouldn't the mounting be directly on the strut towers since thats where the suspension is moving and where the stress will be?

I was always under the impression strut tower braces were designed to work off each strut to keep the suspension geometry the same under load.

Jeff Alton · 02-15-2011, 07:52 PM

Nice work, gusset the intersection of the "X" ??

KTL · 02-15-2011, 08:45 PM

Quote:

Originally Posted by Bullet Bob

Why is there a need to brace to the front of the trunk? Given the locations of the ball joints on the a-arms there isn't much load transmitted to the fronts of the a-arms during cornering. The only loads the fronts of the a-arms will really see is tension across the front of the car during braking.

Think about the big hole cut in the chassis that allows the fuel tank to have a place to live? I think the front suspension area of these old 911s needs to be stiffened up a good bit. Notice how they can lift a front wheel. Even the lowest, stiffest sprung dedicated race cars do.