pinchers

iTrader: (1)

Going on a track day soon and want to get either a lower H brace or a upper strut brace for the car, what would would be the best one to get so that handling is better.

172sport

iTrader: (6)

Its doubtful you would notice any difference with either. Assuming you havnt rose jointed all your suspension that is.

911

Totally agree with 172.
Spend the money on brakes or tyres.

The stock rubber suspension joints will deflect far more than the chassis members for a given cornering load. Yopu need to remove that flexibility first before the strut braces will add anything, and I'm dubious about the top mount braces personally, but believe in the bottom front ones by Whiteline

projectsubaru

H brace

cusco kid

sorry guys i dont agree with you at all.having built many rally cars tarmac and forest i have to say that strut braces work .when you have the subaru inner wing types you need the forth part to brace the box[_] the other part is the xmember,you now have a fully stressed unit.subaru body shell aint the strongest in the world and need all the help they can get .even with seam welding i still use braces front and rear .remember your handling will only be as good as body flexing allows thats why manufactures fit them for a purpose not for show the btm brace works well also i have them fitted to all my subarus 5 in total geo

Tidgy

think what there saying cusco, is that the strutbrace on its own isn't much good cos other parts will just flex more in responce

911

That is where I am coming from. The excellentWhiteline lower brace (I've had mine for 4 years now) triangulates the front chassis legs to the lower bulkhead via the lower wishbone front mountings of the front subframe. It is a snug fit.

That will of course add stiffness so limiting flex.

I feel with a road tyre shod car on track the cornering forces will compress the very compliant rubber bushes maybe (say) 2 or 3 mm.
Without the brace that flex will be incresed but not by much I think.

I doubt the brace will add much to controlling the geometry under such conditions

If the tyres are slicks the cornering forces will be much higher. The grip on slicks is amazing to experience, and controlling the geometry is more critical (and very desirable)

Maybe the trick is to change the wishbone front bushes to poly bushes when you fit a brace?

cusco kid

no thats not the point at all what i am saying is that the strut brace is the brace between the strut tops that will stop flexing its the 4th part of the box m8 [_] with suspension compression the inner wings will flex esp /with pillow ball top mounts fitted with normal complience mounts they will flex before loading up the inner wings,which will move or deflect the strut brace stops that.

cusco kid

50% of suspension is done through the tyre sidewall(deflection) before the suspension does its job, the higher the sidewall the more compliant the tyre is the more comfortable the ride the lower the side wall the harsher the ride less complience the more the suspension has to work when you use slicks the suspension has to work harder to cope with the extra loads put on it which in turn stresses the bodyshell tamac body shells dont last as long as forest shells due to extra loadings, tarmac is aggressive to the shell and i have built many rally car shells geo

911

Mmmmm.
Not sure about the Sti top brace! Been racing without mine for years and have gone faster year on year, but i use Whiteline stuff!

Besttop mount strut design I've seen is the stock EVO V one which bolts to the bulkhead and top mounts nicely triangulates the top.

172sport

iTrader: (6)

Dont get your point, to make a square box strong you need to triangulate it.
As per the evo strut brace for example.

cusco kid

inner wings are two sides lower xmember third side strut brace forth side of the box like a box section its easy think about it ,on a car chassis rail you have a three sided section the floor pan makes the forth part of the box section STRENGTH IS NOW COMPLETED geo

911

My criticism of the 'STI' type top brace (and most others) is the top of the square is 'secured' by just 2 long M6 bolts.
The bolts if slack act purely as pivots, hinge points even, offering little rigidity and allowing the square to deflect into a parallelogram.
Do the said bolt very tight and the rigidity inctreases possibly so the cross bar flexes now into a banana shap under load, esp with cross ply slicks like mine.

It would be great to triangulate the front but the engine is in the way...

A full multipoint cage extended to the suspension towers front and back and adding huge increases in torsional rigidity will get you there!

Porsche approached this issue to their front end using a large 'X' member across the front 'boot' space but there is only a fuel tank there to hinder.

Interesting discussion! Pity we are not in a pub with a lot of knapkins to draw on!

172sport

iTrader: (6)

This is what i put in my old pug gti rally car, no strut brace reqd. LOL

911

And another 50 bhp to accellerate it!

172sport

iTrader: (6)

LOL, its now fitted with a 230bhp mi16 motor............

911

That should do nicely.
Most 205 hillclimbers are at that level in about 600Kg?

500

A 'better' design of a Subaru strut brace perhaps?

Sorry for the lack of brace in the pic, but it is all I have to hand.

911

Agree, but find the project thread on Zen's new TA car and look at the brace on that!