Question on handling... anecdotal evidence accepted

[jvanzyl]

So here's the question - if you add a whole bunch of bracing to your car, can you set your coilovers to a softer setting? And retain decent handling? Are the two values linked in anyway?

I'd like to ride out bumps a bit better, but don't want to go softer on the coils...

[lamcote]

How do you define decent "handling"? If you mean you value fast responses to steering input (eg like a kart) above all else then you probably need the dampers stiff regardless, if you mean nicely balanced and controllable at/over the limit of grip you probably would benefit from stiffening the chassis and softening the dampers. Maybe it's really a combination of both of these and the trick is finding the ideal compromise?

Just my view.

Personally I prefer the Lotus approach, softish springs and firm dampers. I'm not sure what the torsional stiffness of an Elan is, but they seemed to handle nicely with this approach.

Also don't forget that any spring has quite a narrow range of critical damping according to; it's spring rate, the suspension design and the weight of the car. Given that coilovers can have a range of different spring rates fitted, I suspect the full range of damping available isn't really appropriate for use with any single spring rate. For example, if you are using the softest springs available, I personally would only be using the softer end of the damper settings.

[MR TWO]

So here's the question -
Q1) if you add a whole bunch of bracing to your car, can you set your coilovers to a softer setting?
Q2) And retain decent handling? Are the two values linked in anyway?

Q3)I'd like to ride out bumps a bit better, but don't want to go softer on the coils...

A1) There are loads of settings, 32 on my BC's. I have a fair amount of bracing, though no rear swaybar.
A2)These things are no doubt linked, but much depends on your preferences and your tyres.  You will get a much better explanation from someone other than me.. I guess Matt will be able to explain it all.
A3) Once I got my car to drive the way I liked, the ride was harder/ harsher than ideal -though completely doable.  Anyhow I bought great seats which solved the problem

See you tomorrow

[silversprint]

Bracing doesn't really affect ride comfort. Cornering maybe but only a few select  pieces.

You would be able to run softer springs if you have a shock with better valving that has a more digression curve. If you are running a shock like a BC that has linear pistons you will struggle trying to hold the car at corner entry and  dealing with a harsh ride. It's a compromise.

[jvanzyl]

Sooo... say you happen to install these:
 m https://page.auctions.yahoo.co.jp/jp/auction/b252803805 m

and you had tein mono sports, would that improve the over all ride on every day surfaces as well as improving the cars ability to hold "entry" into a corner?

[silversprint]

I don't think those braces do much of anything.

Good tires and suspension do all the work. The monosport should be decent however I haven't tested one yet since they are hard to get in the states.

[1979scotte]

I don't think those braces do much of anything.

Completely disagree.
Cant have enough bracing.
All the braces i have fitted have improved the car.
This may go against the majority but ive never been scared of doing that.

[silversprint]

Improved how? They are not going to magically make the ride softer. The strut tower braces and the lower from brace have a specific purpose mainly under cornering load but most of the other braces may have more of a placebo affect.

About 10 years ago we took a spyder with every single brace we could find. Took off each piece one at a time put the car through some track laps and roads use. Then we put each piece on individually and repeated. There was no noticeable difference in laptimes or ride.

[ChrisGB]

Improved how? They are not going to magically make the ride softer. The strut tower braces and the lower from brace have a specific purpose mainly under cornering load but most of the other braces may have more of a placebo affect.

Subjectively, reduced scuttle shake and improved ride over poor surfaces are the most obvious improvements. Anything that reduces flex in the shell gives the springs and dampers a more stable, better coupled platform to work from. Not all bracing is made equal either.

[1979scotte]

Improved how? They are not going to magically make the ride softer. The strut tower braces and the lower from brace have a specific purpose mainly under cornering load but most of the other braces may have more of a placebo affect.

About 10 years ago we took a spyder with every single brace we could find. Took off each piece one at a time put the car through some track laps and roads use. Then we put each piece on individually and repeated. There was no noticeable difference in laptimes or ride.

I know what it feels like with and without and feels better with front mid and rear braces.
The braces specified above i have never used.
As i said i am sure people will disagree.
How modified was the car you used?
Coilovers turbo etc etc?
Mine was 1zz turbo with coilovers.

[lamcote]

The strut tower braces and the lower from brace have a specific purpose mainly under cornering load

Can anyone explain what this specific purpose under cornering actually is?

[jvanzyl]

don't know what the purpose is, but I know what the effect is!
Strut brace removes under steer, steering is way sharper and the general rattle of the cabin etc was reduced. Going over bumps and holes became better and the car absorbed the impacts of the road via the shocks rather than the chassis.

[jonty]

It keeps the suspension consistent so it only moves as designed, if the brace is working well you'll get a more consistent feel to the handling as the suspension loads change (i.e in turn in or over bumps) since the wheels are not pointing in different directions as the chassis flexes

[silversprint]

Strut braces work because all the load on the suspension is focused on the shock tower. Under cornering load the shock tower can actually move from the stress. The strut brace keeps the towers in their fixed location. Triangulate braces like the stock rear brace work the best. A brace that just connects the two towers together without attaching to the chassis is effective.

[lamcote]

According to everything I have seen, the vast majority of cornering load is focused on the bottom link and the point at which it attaches to the chassis. The strut towers see relatively little sideways load, particularly due to the length of the strut. In addition, the sideways load is running in the same direction for both strut towers during cornering ie what cornering load there is pushing both the towers in the same direction for any given corner (not towards each other as people seem to imagine)! So a strut brace would just move with the towers if there is any movement. That is why I don't understand how connecting them together can make a huge difference to chassis stiffness in cornering. Maybe steering feel is improved though?

[shnazzle]

I installed both front and rear at different times without any expectations. Especially the rear, check my RR thread. I had no interest.

Just pop open the frunk and remove plastics and you tell me whether you think there's room for torsional stiffness improvements. It's a gaping hole!

The front brace stiffened the front up noticeably. Very noticeably.
So much so that I could do a blind test with someone and they'd know when it went in.

The catch; there has to be little  slack in the rest of the suspension for you to notice.
If you're on stock suspension with Toyo tyres I'd dare say you wouldn't notice due to the amount of force being absorbed by the tyre wall flex, suspension, and body flex.

As for the rear. Again,open the engine lid and have a look.
Subframe, anti-roll bar, x-brace, engine in between, firewall, rear crash bar, and the body....
Is adding a little piece of metal between the struts really going to help?
I didn't notice a thing. Not one. I removed the x-brace and left the strut brace. No change.
Maybe on Ohlin dampers on a track with an experienced track driver?... Dunno.

[lamcote]

The key point is torsional improvement IN CORNERING. As I say, the towers both move in the same direction under cornering so linking them together with a brace can have little to no impact. I would expect that the force differential, created during cornering, between the two towers is about equivalent to a fairly heavy man pushing on the side of the car. If the towers move in this scenario I'd be very surprised.
Steering feel may be improved but getting more rigidity to resist cornering forces I doubt very much.

[shnazzle]

I don't think both tower's would move in the same direction to be honest.
But as I have no data to back that up, I'll stick with bum-metrics  s:) s:)

[lamcote]

As for the rear.
Subframe, anti-roll bar, x-brace, engine in between, firewall, rear crash bar, and the body....
Is adding a little piece of metal between the struts really going to help?

You could say, as for the front.
Front subframe, front anti-roll bar (though no impact), no engine (but it's on flexible mounts so has no impact), front firewall, front crash bar, and the body....
Is adding a little piece of metal between the struts really going to help?

[lamcote]

They do though, the cornering force pushes both the tyre contact patches in the same direction in a corner, this force rotates the strut assemblies about the inboard lower mounting points which therefore pushes the strut towers in the opposite direction to the cornering force. Thus, in a left hand corner the cornering force pushes onto the both the tyres from the right, this force then tries to rotate both the struts together to the right around their respective bottom inboard mounts.

Understanding this is quite fundamental if you are looking to tune the chassis.

[shnazzle]

I don't know. I just know it works  s:) s:)

[lamcote]

Well I wish it didn't because I can't afford a strut brace at the moment, so I'll continue to convince myself I don't need one! And I'll thank you to humour me....

[shnazzle]

Haha! Well if it helps, you can have my rear brace haha

[lamcote]

Thanks for nothing!

[Carolyn]

My views on the subject.

If you look at expensive cars that offer models with both a conventional roof and a convertible, the cars with a roof go round a track quicker.  The convertibles also tend to be heavier as a result of extra chassis stiffening, built in by the manufacturer to compensate for the lack of stiffness supplied by a roof. This is true of such exotica as Lambo's and Astons.  If you imagine a series of rectangles going through the cross section of a car from front to rear, there is a tendency for the corners of the rectangle to 'lozenge' as sideways forces are applied.  This changes the distance between the corners of the rectangles, affecting the geometry of the suspension.
So bracing will improve your lap time.  Whether you prefer a stiff or flexible car is a matter of personal taste, but stiff cars go round stuff quicker.

I was a sceptic about under-bracing until I installed one.  The car is actually smoother and more pleasant over the rough stuff, as Scotte said.

The front struts have a lot less holding the towers straight than the back ones do, as Patrick (Shnazzle) points out.  I have TRD strut braces front and rear.  I've tried the car without the front brace and the difference is noticeable.  Haven't performed the same experiment with the rear one.  When I get the car back on the road, I'll give it a try.