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Strutbraces - Any point?

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Old 04 November 2004, 04:18 PM
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papascooby
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Default Strutbraces - Any point?

On an 04WRX

cheers
Old 04 November 2004, 04:23 PM
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Adam M
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always a point, look pretty and give you something to buy. If very rigid in construction they might actually make the front end feel more rigid, but the difference will probably be marginal unless you go for proper chassis strengthening.

That said i have cusco front and rear upper and lower strut braces.
Old 04 November 2004, 04:32 PM
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corradoboy
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The chassis on new-age Scoobys is very rigid (IIRC 200% more than classics) so the need for bracing is negligable unless you've already gone through other significant suspension mods. Spend the money on the rear droplinks and a good geometry set-up, and if you really want to stiffen it up, add some Prodrive/Eibach springs and Whiteline ARB's. Only after all that would I justify bracing.
Old 04 November 2004, 04:50 PM
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sKunk
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I put a front strut brace on my sti8 and it pretty much dialled out say 80-90% of understeer. No other front end mods, rear drop links on though.
Old 04 November 2004, 05:05 PM
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I put one on my 02 STI and it makes not one jot of 'noticable' difference. May be noticable when driven hard on a track but I reckon the cars rigid enough as it is. Certainly haven't noticed any difference personally.
Old 04 November 2004, 05:21 PM
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Edcase
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Originally Posted by papascooby
On an 04WRX

cheers
I built my 02 WRX almost completely modularly as I wanted to make sure I wasn't wasting time or money, particularly with the handling.

For the new age cars I would recommend the chassis modifications in the following order:

Eibach springs
Whiteline adjustable rear antiroll bar
Solid rear drop links
TSL Geometry
front strut brace
Lightweight 17inch wheels
quickrack
rear strut brace

Anybody who says the stut braces don't make a difference, either bought the wrong strut brace, or haven't tightened it properly. Even on the new cars it makes a huge difference.

The front will almost totally eliminate the final remnants of understeer remaining after you change the springs and rear ARB / links.

Be aware however it will make the steering slightly heavier (I personally think it feels too light anyway) and also may make the ABS kick in earlier over bumpy surfaces.

It will also marginally affect your ride quality, but hey, you aren't driving a Mercedes.

The rear brace is only really worth doing if you track the car. It helps stop the car from wanting to lift an inner rear wheel when taking sharp bends, and also makes it much much easier to make small adjustments to the attitude of the rear using the throttle (Ie lifting off and left-foot braking during the corner)

You will probably notice your tyres wearing a lot quicker tho, but again, the car is for driving, not wrapping up in cotton wool.
Old 04 November 2004, 06:02 PM
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sparkykev
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Don't forget to tell your insurance company, as with one fitted, a prang to one corner at the front could spread the damage across the car.
Old 04 November 2004, 07:42 PM
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I also heard the story of newage bodies being so stiff that a strut brace would do nothing - but I still bought one and still noticed the difference.
The change was very subtle - less understeer and less front roll/rapid weight transfer from side to side across rough roads.
This is on an 04 WRX wagon with std wheels and suspension. The brace was a Titanium STi model.

Nick
Old 04 November 2004, 08:45 PM
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Sprint Chief
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A word of note!

Adding a strut brace can cause the suspension geometry to change slightly. To be sure of understanding the effects you must have the complete alignment checked over - if you take it off again later, this applies to both when you add and take away the brace. Otherwise you can't be sure whether the effects you are experiencing are caused by the additional stiffness or the geometry change (which you could achieve without the brace!) Also all suspension components interact so the ideal setup with and without a brace might be different... very complex subject!
Old 04 November 2004, 09:05 PM
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Danny B
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There is an awful lot of mythology around this stuff that goes back to body-on-chassis beam-axled racers in the 20s - I'm not kidding. There are two effects that are important. Basically, the body structure is like a "fifth spring" between the front and rear suspension. If that spring is not stiff enough then the body relaxes out any redictribution of roll moment that the anti-roll bars were trying to make and so the car is unresponsive to handling balance tuning with springs and bars. However, once the body is "stiff enough" then making it stiffer offers no benefits. A good rule of thumb is that the torsional stiffness of the body (between suspension mount points) needs to be about ten times the roll stiffness of the stiffest suspension end (usually the front). If you chase the numbers through you end up with about 5-7 kNn/degree as the requirement for a body structure. Most modern monocoques comfortably exceed that and the Subaru with its bonded screens both ends does too. Somewhere I have a figure but can't recall it right now. Anything over 10 is good, 15-17 is current "state-of-the-art". So in that case, a strut brace does very little. The second effect is a bit more complicated. The body moves on the suspension but the wheel also moves on the tyre - the tyre is in many ways a "secondary" suspension system. That movement is partially controlled by the tyre and partially by the suspension damper and happens 10 to 15 times a second. The body is a flexible thing that has its own resonances and because of the shape of most cars at the front - they need a hole to put the engine in - it can get quite flexible in just about this frequency region. If the body goes flexible - goes into resonance - then the damper just moves with the body and can't contribute to the control of the tyre and in fact can do something bad called "mass loading" where the tyre is carrying not only itself but also part of the body _while it resonates_ (it's important to separate the static 'weight carrying' from dynamic things in your mind). In those cases, the strut brace can help because if it is a good design then it stiffens the front end usefully.

What all of the above means is that the effectiveness of a strut brace is strongly connected to the stiffness of your suspension. So for a Scoob that is fairly standard, the strut brace probably doesn't do a great deal, but as they get modified and stiffened the brace will contribute more to a well controlled feel over less-than-perfect surfaces.

The final point about strut braces relates to the emporor's new clothes - having bought a flash one, not many people will admit they can't really tell the difference.

Sorry for such a long answer but it isn't straightforward, especially when I'm denied my usual engineering shorthand of "Hz" and "modal damping" and so on...
That was from Prodrive handling guru Damian Harty
Old 04 November 2004, 09:27 PM
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Having fitted strut braces to several cars, including my currentdaily driver, top and bottom front and a rear top I can detect no change whatsoever. I agree with Adam that they look pretty but they also add weight so I conclude the money is better spent elsewhere.
Edcase: I am sure the mods you have listed will combine to make a marked difference to the handling. My own list in priority is Whiteline Rear ARB, Whiteline Anti Lift Kit and Eibach Springs. The springs were probably unnecessary. The geometry needs setting/checking with any significant mod.

Anybody who says the stut braces don't make a difference, either bought the wrong strut brace, or haven't tightened it properly. Even on the new cars it makes a huge difference
Tightened in or out and how much because you are altering the geometry as Sprint Chief has indicated?

The front will almost totally eliminate the final remnants of understeer remaining after you change the springs and rear ARB / links.
Be aware however it will make the steering slightly heavier (I personally think it feels too light anyway) and also may make the ABS kick in earlier over bumpy surfaces.
How can a front strut brace eliminate understeer, make the steering heavier or have an effect on ABS. Are you not confusing this with other mods that had that effect. eg Fitting the anti-lift kit makes the steering heavier and changing springs can affect the adhesion of tyres to the road surface.

The rear brace is only really worth doing if you track the car. It helps stop the car from wanting to lift an inner rear wheel when taking sharp bends, and also makes it much much easier to make small adjustments to the attitude of the rear using the throttle (Ie lifting off and left-foot braking during the corner)
I thought I had a good understanding of suspension and geometry but I cannot imagine how any rear strut brace could possibly stop an inside rear wheel from lifting but I am happy to be enlightened.
Old 04 November 2004, 09:35 PM
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DuncanG
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Call me a cynic but I wonder if the people who swear that strut braces reduce understeer are the same people who swear that fitting an ALK actually reduces lift.
Old 07 November 2004, 11:46 AM
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Good point Duncan. There are quite a few people who, having spent money, benefit more than others from the placebo effect.
BTW I think the ALK makes the steering heavier as the castor angle is altered.
Old 07 November 2004, 12:08 PM
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davyboy
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People spend money on mods - Regardless of any difference it has made, you have to justify your purchase....so you come on SN and tell everyone!

When I had my WRX I went to TSL and got Eibachs, geometry, brakes lines and brake pads....oh and a gear ****.

I never noticed one bit of difference with the car, and this was at a time when I was doing track days and going to the ring....wait a min.....my hand got cold on the **** on cold mornings.

Most of us do not drive their cars hard enough to notice any difference......but you have to say you have on SN to justify your purchase.
Old 07 November 2004, 12:09 PM
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Why do Subaru fit front strut braces as standard on the latest JDM STI's if they dont contribute to the handling Perhaps it just helps sell cars ??

Last edited by Mark_S; 07 November 2004 at 12:12 PM.
Old 07 November 2004, 12:23 PM
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[QUOTE=sKunk]I put a front strut brace on my sti8 and it pretty much dialled out say 80-90% of understeer. QUOTE]

mate, does your car have inner wings at all
Old 07 November 2004, 01:12 PM
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NotoriousREV
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Originally Posted by sKunk
I put a front strut brace on my sti8 and it pretty much dialled out say 80-90% of understeer. No other front end mods, rear drop links on though.
I think you'll find it was the rear drop links that helped reduce the understeer as the rear roll was reduced keeping some more weight on the front inside wheel.
Old 07 November 2004, 01:55 PM
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Rear drop links went on 2 weeks later.
Old 07 November 2004, 02:18 PM
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My understanding of this is that stiffening the front end (ie fitting a front strut brace) actually increases understeer!

Adding one (or upgrading to a thicker one) at the rear would reduce understeer!

All things being equal that is.

This is basic suspension geometry.

Correct me if I'm wrong?
Old 07 November 2004, 03:05 PM
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Jason: I think you meant to say ARB not strut brace.
Old 07 November 2004, 05:07 PM
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help with the cornering
Old 07 November 2004, 05:32 PM
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Edcase
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Originally Posted by harvey
Having fitted strut braces to several cars, including my current daily driver, top and bottom front and a rear top I can detect no change whatsoever.
So why did you bother fitting them again and again?

Originally Posted by harvey
Edcase: I am sure the mods you have listed will combine to make a marked difference to the handling. My own list in priority is Whiteline Rear ARB, Whiteline Anti Lift Kit and Eibach Springs. The springs were probably unnecessary. The geometry needs setting/checking with any significant mod.
The springs made the biggest single difference of every handling mod I did. Standard springs are IMHO one of the biggest weaknesses in the car. The Eibach springs not only reduce the centre of gravity they are also more progressive and so you get none of the DTM-style 'platipus' effect when cornering hard.

As you can see, the strut brace is several down on my list, I wouldn't reccommend doing it without stiffening / lowering your springs first, or doing the rear ARB / Links. But then, you can see that from my list...

Anti lift kit is not worth bothering with unless you are pushing out over 320bhp IMHO, and has a slight negative effect on the amount of dive under hard braking. I'd rather use a progressive throttle to control lift than compromise my braking.


Originally Posted by harvey
Tightened in or out and how much because you are altering the geometry as Sprint Chief has indicated?
Grow up it was a joke. And yes, of course you have to get the geometry reset when doing any major chassis mod, including springs and quickrack.

Originally Posted by harvey
How can a front strut brace eliminate understeer, make the steering heavier or have an effect on ABS. Are you not confusing this with other mods that had that effect. eg Fitting the anti-lift kit makes the steering heavier and changing springs can affect the adhesion of tyres to the road surface.
It makes the steering heavier because, when you turn the front wheels, they work against the torsional rigidity of the chassis. Try sitting in your car when its stationary and moving from lock to lock and see what I mean.

When you add speed and all the other forces it adds to the equation, if you suddenly stiffen that chassis, there is less flex when you turn the wheel, and so it feels stiffer. It's not a problem, I actually prefer it, I was just telling the guy what to expect...

It affects the abs because when you go over bumps with a stiffer front end, it can't dissapate the effect of the bumps so well, so it becomes skittish and so the ABS kicks in as it feels the tyres losing contact. Not an issue on track but definitely an issue when blasting over Exmoor as some of my previous passengers will attest.

Everyone who knows me will tell you how methodical I was about modding my car, and as a trackday fan, handling was my main goal and power was the very last thing I did (unlike most ) so don't give me the b0llocks about placebo effect either plz. I never got more than one mod fitted at a time and did at least one trackday between each mod.
Old 07 November 2004, 05:39 PM
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Originally Posted by davyboy
People spend money on mods - Regardless of any difference it has made, you have to justify your purchase....so you come on SN and tell everyone!

When I had my WRX I went to TSL and got Eibachs, geometry, brakes lines and brake pads....oh and a gear ****.

I never noticed one bit of difference with the car, and this was at a time when I was doing track days and going to the ring....wait a min.....my hand got cold on the **** on cold mornings.

Most of us do not drive their cars hard enough to notice any difference......but you have to say you have on SN to justify your purchase.
What a sad, narrow-minded attitude you have (something that seems to be a trend across a number of your posts I've noticed.)

Pads and lines are negligible without discs...and the standard 4-pots are useless anyway IMHO but to say you couldnt notice the difference between the suspension and geometry is ridiculous and you are just sowing seeds of doubt into new members yet to start modding.

(most) People come on here to share their experience and help others in the 'community', not to try and 'justify' their purchases!!!

I sold my scoob months ago but I still contribute.

Maybe you should stick to the Porsche forums with your attitude.

I think maybe it's time I set something else as my homepage as this place is becoming a less and less attractive place to spend what little free time I had.

Sad to say.
Old 07 November 2004, 07:57 PM
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Originally Posted by harvey
Jason: I think you meant to say ARB not strut brace.
Yep sorry!

However isn't the effect the same?

Jason
Old 07 November 2004, 09:02 PM
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Edcase
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Originally Posted by jasonius
Yep sorry!

However isn't the effect the same?

Jason
No the ARB performs a very different role (excuse the pun ) to a strut brace.

The anti-roll bar links both wheels on the same axle to the chassis.

Essentially, the ends of the bar are connected to the suspension while the center of the bar is connected to the body of the car (usually using a combo of bushes and links ('drop links').

Because the anti-roll bar is attached to both wheels, body roll is only possible if the ARB is allowed to twist, so the bar's torsional stiffness determines its ability to reduce body roll. So fitting a stiffer ARB results in less movement and rebound by the opposite ends of the suspension, which results in less body roll, which loads the rear wheels more unevenly and provides slightly less grip at the rear than previous.

Althought that sounds bad, the front end should then resists less in proportion, leaving the front wheels more evenly loaded, therefore more available front end grip, therefore less oversteer.

The strut brace on the other hand, you're simply adding the fourth side to the 'open box' created by the subframe and the two suspension pillars. Regardless of what others on here seem to think, without 'closing' that box, the car will flex when you corner because the suspension pillars will be moving relative to each other as there's no direct physical link between them.

So with the strut brace you are simply reinforcing the shell and increasing its rigidity against torsional flex, as opposed to body roll.
Old 07 November 2004, 09:25 PM
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davyboy
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Originally Posted by Edcase
What a sad, narrow-minded attitude you have (something that seems to be a trend across a number of your posts I've noticed.)

Pads and lines are negligible without discs...and the standard 4-pots are useless anyway IMHO but to say you couldnt notice the difference between the suspension and geometry is ridiculous and you are just sowing seeds of doubt into new members yet to start modding.

(most) People come on here to share their experience and help others in the 'community', not to try and 'justify' their purchases!!!

I sold my scoob months ago but I still contribute.

Maybe you should stick to the Porsche forums with your attitude.

I think maybe it's time I set something else as my homepage as this place is becoming a less and less attractive place to spend what little free time I had.

Sad to say.
Listen, the Impreza as a road car is fine as it is. I tried to improve it.....peer pressure form here if you will.....and I didn't notice any difference. Am I really sowing the seeds of doubt? Or just sharing my experiences.......

I will help where I can, what I won't do is wear rose tinted glasses and say that every few hundred quid I have spent on a car has made a world of difference.

Don't read my posts and you can stay in your own utopia.

All the best
Old 07 November 2004, 09:28 PM
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Gutmann pug
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If a strut brace reduced understeer by 80% as suggested I would have one tomorrow but to be honest I would be amazed. Im pretty sure it would have been part of the PPP or some such kit if it made that much difference.
Old 07 November 2004, 09:38 PM
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Edcase
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Originally Posted by davyboy
Don't read my posts and you can stay in your own utopia.

All the best
I don't need to read your posts, I've been there, done it, and reaped the benefits.

http://bbs.scoobynet.co.uk/showthread.php?t=318113

Got bored of it, moved on.

I'm not one of these people who threw good money after bad trying to get that extra bhp. My car reached a point where, being a WRX and without the 6spd transmission and front LSD etc it would have been mad to push it any further. But every mod was considered, researched, tested and only then purchased and fitted.

And then taken on quite literally almost every track in the UK and regular trips over exmoor and dartmoor when visiting family.

My point is that the suspension and geometry changes the handling to the extent a full decat changes the engine...it's almost impossible not to notice the difference.

Gutmann - I totally agree, strut brace on its own would not really help, needs to be added after springs - they are the most important, followed by rear arb.
Old 07 November 2004, 09:54 PM
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davyboy
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You had a nice car, but would you not have been better off getting a STi in the first place?

Out of the crate it would have been faster? In terms of cross country and lap times?

I have been having a MSN chat with a scooby owning mate of mine, and we both blame Scoobynet for getting mods.........so it's got to be a good thing that people are objective?

Dave
Old 07 November 2004, 09:59 PM
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Undoubtedly but my budget initially wouldn't stretch that far, plus I got the last of the bugeyes so I figured the money I saved I could gradually mod it up to and beyond an sti.

And yeah, its totally scoobynets fault...I was initially getting PPP and suspension and keeping my lovely warranty


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