Driving Impressions: Lower Stress Bar

[Kirk]

I don't have any solid driving impressions of this change yet, which I posted about over here:

http://986forum.com/forums/performance-technical-chat/12915-diy-rear-suspension-brace.html#post114410

At least there are no creaking or noise issues and the car feels solid and performs fine. I had it up to 112 mph this morning, no problems.

Franco, you're right that just a thicker plate would probably accomplish the same purpose, if not even better. You could also use solid flat bars instead of round to do the same thing and with less fabrication work. I'll have to take another look at the plate to see how much work would be involved with making a new one, but I imagine it's going to be a lot tougher than these lower stress bars. I know there are a couple air scoops that re-direct air up to the transmission for cooling that are attached to this plate, so that would have to be part of the design too.

As for the eye bolts... well they use the same kind of design on most upper strut bars, so I imagine it's stiff, but there is no question that making the Ernie Bar with one solid piece of aluminum is stiffer yet. I used the eye bolts on the smaller stress bars just because that was necessary to fit them into the slot where they mount and they made installation MUCH easier.

By request, here's another picture of my assistant showing off the hardware while wearing something a little more silky...

Kirk

[blinkwatt]

Hey insite where are you putting the jack stands underneath the front of the car in these pics? Does it leave obvious indentations?

[djomlas]

Insite, thx for finding out about this mod.
I just got done drilling and installing a piece on my car, took it for a drive, and wow, you really can tell that there is some more support in the back, that its not as twirly around the corners anymore.

i love it when you can actually feel the mods that you install, and for the price you cant beat this, i actually had some random pipes and bars in the garage, and happened to be the right size, so free hehe.

thx again

[edevlin]

"since they have now over one year of experience racing the Cayman platform, i asked what they've found a need for and what they've installed on their car. in addition to a host of other stuff, Ernie mentioned a lower stress bar to me. "

I have put off getting one of these because I was going to make one, but have not gotten around to it, so I plan ordering one next week. In addition to the stress bar, what other things have you done to tune your suspension, thanks,

Ed

[HB.]

Topics like these are exactly why I love this place

[rick3000]

I agree $10 modifications are the best, because any $10 improvement is worth it, in comparison to a few hundred dollar modification.

So all you have to do is take a 1" or 3/8" round bar (or a 1" flat bar) and shave the ends flat then mount it under the plate?
Is that it?
Also, I don't understand what the two extra bars with eye bolts do. Could someone explain that.
And you could you do this in the front as well?

Thanks!

[blinkwatt]

Does someone here want to make a bunch for 986forum.com? I'd be willing to pay for your time & efforts,it'd kinda be like a group by thing. Mantis wants at least $150 for the bar shipped to my house,I'm sure someone here would be willing to make the same thing for less.

[insite]

blinkwatt -

the jack stands go under the boomerang plates that retain the sway bar. they don't leave any indentation. i'll take a pic tomorrow as i'll be doing some work.

a word of caution to the others: for street duty, a solid lower stress bar might be okay. if you go to the track, you'll definitely want something with heim jointed ends, otherwise you risk breaking the bar mid-corner, causing sudden camber loss and a certain spin.

[blinkwatt]

Originally Posted by insite

blinkwatt -

the jack stands go under the boomerang plates that retain the sway bar. they don't leave any indentation. i'll take a pic tomorrow as i'll be doing some work.

Thanks I'd appreciate it.

[rick3000]

Originally Posted by rick3000

So all you have to do is take a 1" or 3/8" round bar (or a 1" flat bar) and shave the ends flat then mount it under the plate?
Is that it?
Also, I don't understand what the two extra bars with eye bolts do. Could someone explain that.
And you could you do this in the front as well?

Could someone explain this to me.
Thanks!

[Kirk]

Originally Posted by rick3000

So all you have to do is take a 1" or 3/8" round bar (or a 1" flat bar) and shave the ends flat then mount it under the plate?
Is that it?
Also, I don't understand what the two extra bars with eye bolts do. Could someone explain that.
And you could you do this in the front as well?

Thanks!

Yes, that's pretty much it, or just order it from Mantis.

The two extra bars with eye bolts help to further stiffen up the rear end. Take a look at all of the picture attachments, not just the ones with the pretty girl. There's a photo that shows how the two extra bars tie the rear of the car to the lower stress bar.

[rick3000]

Thanks!
My car will probably never see the track anytime soon, if ever. So I may just do my own custom rear stress bar for a few dollars, as a project and to give some minor handling improvement. I'll let you all know how it turns out, and maybe it would be possible to make a custom front bar as well.

[insite]

Originally Posted by blinkwatt

Thanks I'd appreciate it.

blink -

here's a pic of the jack stand point. if you have the GT3 or RS brake ducts, you have to remove them to use this point. if you have the standard ducts, you can leave them in place.

[blinkwatt]

Thanks insite. I was under the car this weekend and I was wondering if that was the spot you were referring to. I noticed that that piece of metal is VERY strong.

Thanks again for the picture.

[roadracer311]

So, I was thinking about doing this mod, and it occurred to me that aftermarket tie rods are probably everywhere. Turns out that they are.

You can buy threaded tubes of just about any length (reverse threaded on one end and forward on the other end), and heim joints here:
http://www.speedwaymotors.com/m/105_Rod-Ends-Heim-Joints-Sleeves.html

If you buy the good stuff, it looks like it would cost about $45 + shipping.

Now that I look at it again, I'm not sure they have the right combinations of shanks and holes in the heim joints. I'm going to spend more time on it later. I'm sure someone makes something that just screws together out of standard parts and fits.

[edevlin]

"You can buy threaded tubes of just about any length (reverse threaded on one end and forward on the other end), and heim joints here:
http://www.speedwaymotors.com/m/105...ts-Sleeves.html

If you buy the good stuff, it looks like it would cost about $45 + shipping."

Hey, that is a great site, does anyone know what size parts (tube and ends) we need to get for our cars?

Ed

[roadracer311]

Originally Posted by edevlin

Hey, that is a great site, does anyone know what size parts (tube and ends) we need to get for our cars?

Ed

From earlier posts, it sounds like the center to center measurement for the holes needs to be 22.25 inches and the bolts that hold the plate to the bottom of the car are 3/8" in diameter (roughly, since the original ones on the car are metric).

The web site says that the heim joints add 1.5 inches to each end of the rod, so it sounds like a 19" long rod + a total of 3 inches of heim joint would be 22" (the adjustability would take car of the last 1/4 inch.

Now there's the question of which diameter rod to use, which heim joints. And then, jam nuts will also be needed to keep the thing from adjusting itself after it's installed. The one dimension I don't know is how long the new bolts need to be (the ones that bolt the heim joint to the car).

Given the amount of time involved in figuring all of this out and then not knowing for sure it's going to fit I can see the value in the Canadian-sourced one. Then again... it's sort of fun to figure out.

[rick3000]

^
According what I have read, the bar can be 3/4" or 1" thick. The bar should be 24" long with 22 1/4" between the two 3/8" holes. The end 2" of each side should be shaved down until flat. What we do not know is the length of the 3/8" bolts.

[Kirk]

You are correct, either a 3/4" or 1" bar will fit. I bought both sizes of bar stock and went with the bigger 1" just because it would fit. I did have to take off one rear anti sway bar mount and the lower stress plate to fit the 1" bar though. It doesn't just slide up there without making some room first.

Honestly I can't recall what length of 3/8" bolts I used. I bought a couple different sizes. I think the 1" long bolts were just a hair too short with the 1" bar AND the other "Bristol bars" that I installed. So I'm pretty sure I used a 1.5" bolt that was too long, but the extra sticking up at the top doesn't hurt anything. I wouldn't lose any sleep over what length of bolts to use. You can pick them up for a couple bucks at any hardware store...

The length of 22 1/4" between holes is about what I measured too. I did make my bar about 25.5" long though, which may be why I had to remove some stuff to fit it. I was following the "longer is better" stigma though and so maxed out the bar for what would fit.

Kirk

[rick3000]

Thanks for the clarification. I would probably make it as short as possible so it has less of a chance of interfering with anything and adding unneeded weight.
Are there alread holes under the car for this sort of modification?
Do you pictures of where they are?
Thanks!