I'm going to install a 31mm Smarty before Sunday morning one way or another.

Your pics and tips will certainly help me out.

Check out this classic thread.

Anti-Sway Bars

31mm is freakin huge. What are your rear spring rates? I can guarantee you will have to open the through the body holes up, considering my 22mm Tarett bar barely fit

Running 150# rears and stock front t-bars.
Rear stock bar next.

Hole for bar is 1 3/8 ". I have no stock bar so a hole is a hole.

Post a picture, please.

I suggest you try some browsing in the archives. There's a bunch of valuable information there.

-Lawrence

This install is Brad's creation for ultimate adjustabilty.
I do as I am told.

If 31mm is to big, we'll drop a size.
I just learned that the Smart bars all have the same diameter ends. This allows interchanging bars without re-drilling the mount holes or using different backing plates. It just slides in and out quickly.

Very cool,

31?!! holy crap! wasn't the stock one like 14mm? or 17mm?

early 911 = 13mm
914 = 15mm

Check the Bird site. Tech article with pics.

--DD

The tech article on the bird board has it!! Used it to install mine many moons ago!


M

Got off work a little early today and decided to get LARGE.

Went over to McMark's for a look at a tub with sway mounts. Thanks for the peek-a-boo!

Got home at about 5:00 and went for it. I'm working on 4.5 hours sleep mind you.

I finished assembling the drop link assymblies around 9:30 in the house.

Here's the pics

Check out this package.

gas tank out

oh yes

yes, yes

Hey, buddies! Those are some big arms.

My drops.

Tomorrow I finish.

I'll tell you about the ride with the BIG BAR.

Where's the pics of you bending over and drilling and figuring out all the difficult parts? You're making it look like a magic of TV project...

Damn, that is one SPIFFY setup!!! very cool dude!

Honestly, this was very easy. Smart Racing Products provides a step by step install manual.

They even include a hole centering/marking tool.

The hardest part has been getting that blasted fuel tank out.

Nobody likes a 91 octane headrush while siphoning fuel.

Any patient mechanic can do this one.

31mm is EXTREMELY large. I forget my physics, but that's probably about 20X the stiffness of stock.I think you'll need rear springs on the order of 500# or more to balance that out. I'm guessing you're going to find out bigger is not always better. Even adjusted at fully soft you won't be able to get close to the stiffness of say a 23mm bar.

Hopefully you lowered the bar in the car from where the stock bar sits. Otherwise you're very likely to have an unfriendly surprise when you try and re-install the fuel tank (tank will hit the bar).

Good Luck
Demick

The ratio of the stiffness is the ratio of the diameter raised to the fourth(!) power.

so (31/15)^4 = 18.

18 Times as stiff. Wow! Would that even be noticeable?

Andrew

I believe the SRP bar is hollow, so it is not as stiff as you guys are thinking.

That's good, but even if it only has walls 3mm thick...

( 31^4 - 25^4 ) / 15^4 == 10.xx So it would still be ten times as stiff as stock, even with tubing walls that were only 3mm in diameter.

--DD

Ouch! Math

I'm just a caveman...

What I do know is that it is stiffer than: nothing, stock bar, wood, plastic, rolled cardboard, rope, etc.

Watch the car dancin' at Marina on Sunday.

I hope the fuel tank fits back in without too much:smash:

True, the Smarty bar is hollow BTW.

I want to change to front fuel hoses while I can. How long should the hoses be to allow moving the tank around withou kinking the lines?

Here's the bar in it's new home.

So it would be equivalent to about a 27mm solid bar if the walls are 3mm.

Of course, the car doesn't even have a bar now. How is the handling now? I imagine it will understeer alot more. Hopefully it oversteers now and you'll end up closer to neutral.


That setup looks super cool by the way. I'd like to know how it works once you get the setup finalized.


Andrew

If the hoses are long enough that you are not cursing and throwing things then they are too long and will kink. If they are so short that you have to move the tank three times, cut up your hands on the tin, hit your forehead on the torsion-bar adjuster, break a flashlight, and work yourself into a frenzied tantrum they are just the right length.

-Ben M.

ps - I put a brass 90 degree elbow in the middle of mine to stop them from kinking. Worked great and allows slightly longer hoses that are easier to work with. I'm a slow learner but I eventually catch on.

I'm going out there to finish the install right now.

I've got 18" fuel lines ready to go.

I'll be on " My Vineyard Lap " in no time. ( 2 hours ).

Report to follow.

Stock torsion bars. This bar will work fine. I never intended to keep him on the 150's. Most people running 27mm bars have 21 or 22 torsions and seem to do just fine. This 31 combined with stock bars will work perfect.


B

2 schools of thought come to mind for a streetable setup:

soft springs/torsion bars and stiff swaybars
or
stiff springs/torsion bars and soft swaybars


the 1st one seems easier to make changes to as long as the swaybars are adjustable and is what it looks like Trekkor is doing

My prediction is that the car will do a lot more plowing than dancing on Sunday. You'll need to add a lot of roll stiffness in the rear to balance it out.

Demick

I'm at a loss for words

I'm in fantasy land. Is that a little tear drop?
Nope a little drool drop.

This set-up is FANTASTIC. PERFECT.

I promise you all, this is not the same car I bought just a few short months ago.

I would of posted sooner, but I kept getting lost out there.

Heres a few more shots for you DIY'ers

set-up

fuel lines

whooo-wat?

hope you put hose clamps on too

I love the math.. but it is for engineers. The determining factor that NO engineer can give me details on is the TIRES. I come from the soft spring big bar school. I want adjustability in the bar. It is very difficult to swap out torsion bars at the track..very easy to adjust a bar. In the case of a full blown coil over F+R car.. I would run a smaller bar and adjust with spring rates. Factory Porsche GT3RSR's and GT3cup cars come with little tiny sway bars... we adjust with spring rates and fine tune with sway bars/shocks. Trekkor now has a ton of adjustability with Koni's and big bar.

This setup isnt for everyone and I dont recommend trying it. :finger2:


B

why the Smart bar vs. Tarret or Racer's Groups?

Tarret is cheapest the TRG then Smart...

Action shot.

Massive improvments. Yes, stiffer rear springs and rear bar are in order. Compared to before, this bar is AWESOME!!!

Here's the before shot from 4-25-04.
I will install 200# rear springs to help balance the car.

Demick, was that you drivin' on 280 sat early eve?
I was towing to Marina heading south. ( I waved )

i don't think so, sir ....


after talking to you today, it seems the car needs some serious spring in the rear to balanced out.
you got piggy understeer today, couldn't set the bar on full soft (cause brake lines are in the way), but even with full soft, now that you have sticky tires, you'll have to step up on the rear spring rate considerably to be able to actually USE your sway bar. a rear sway bar will help offset some ...

problem is, if you go too stiff in the front (sway bar wise) you'll have to go REALLY stiff in the back to get it balanced, which is good for road racing, but will make the car very *jumpy* on a AX course ...

anywho, i suggest, get the rear bar, then pump up your rear spring rate until the front bar is actually useable.

you made a big leap with those sticky tires and *monster* front bar, now you neeed to balance the car right.

then, you need to learn how to drive!
Andy

j/k of course. hey you beat me by 1 sec. today!

This little piggy went to market...

Massive understeer. This is a new feeling. I couldn't kick the rear around for the life of me. All said, the car still handles it best ever.

Dropping 3 psi off the front tires helped me shave off 5 seconds from first run. Koni's on full firm rear and half on front.

I wonder what rear spring rate would be best for me along with the stock rear bar? 200, 250 more?

I want to get more adjustment out of this front bar. I'll resolve the brake issues soon.

I don't mind a stiff street ride, as I don't run this car much on the street anyway. I just put fuel in it since Reno! ( 5-16 )
The roads in Napa are nice and smooth unlike the Bay Area highways

BTW- we all got 9 timed runs plus fun runs with 20 second waiting between runs until my legs and arms BURNED.

Marina good.

Just reviewing this old thread.

Bottom line is this: I was running the falkens at WAY to low a pressure.
Maybe 35psi. No good.
39 front 41 rear is perfect.
Koni's full firm in front, full soft in rear.

I ran this set-up all year and just made improvments in my driving.

BTW, I'm still on the 150# rear springs and keep moving the SRP bar towards a stiffer setting.

This bar is the heart of my suspension.

KT

QUOTE (trekkor @ Jan 22 2005, 10:12 PM)

This bar is the heart of my suspension.

told you so!

Andy

Nine months later...

200# rear springs and stickier tires.

I've learned to drive better, too.

Two TTOD's and several top fives at the PCA a/x's

Sure, this is the most expensive bar on the market.
It will never disappoint you.


KT