Are human beings this ignorant? A strut brace rant.

[Grandavi]

Day 1 of Supra Ownership - I drove the car
Day 2 of Supra Ownership - I found the forums
Day 3 of Supra Ownership - I bought a strut bar from ebay (for 15.00)
Day 842 of Supra Ownership - After not putting the strut bar on at any point in time (the price scared me) I found that if I bolt it to the wall it makes an excellent rag holder in my garage. Never did get it on the car...

 

[antigram]

hmm time to turn on my laptimer and see wether it actually makes a difference on the vuchtschoot track. If i have the results i will let you guys know

 

[Greek]

Can someone explain in a nutshell why a strut brace is so useless? I kind of see why, since it connects the two towers and not really anything that is part of the suspension system.

 

[Dan_Gyoba]

LOL. Well, I'll admit to having a strut brace. It's even bolted onto the car. I wanted to do some testing to see if it made an ACTUAL measurable difference (As opposed to a placebo effect difference.) I got it second-hand for $5, so whatever.

I was unable to measure any difference in chassis deflection using the bar. Test as follows: Jack car up by 4 jack points, lower each rear corner in turn until the support comes clear of the jack point, measure the amount that each corner would "follow" the support. (About 8mm averaged between the two for my car at time of measurement.)

I was unable to measure any significant compression or expansion load on the bar during traction limited cornering. (I did get a ping on it over a pothole though.) Test designed as follows: A pair of stiff springs placed either side of one side mounting bolt to a rig on the left side brace support. Movement limited to 2mm in either direction, with hitting either limit closing a switch which would light an LED on the dashboard. (One for compression, a different one for expansion.)

I then removed that rig, and did a completely non-empirical seat-of-the pants test. I couldn't tell a difference, though it's true that my car is a hard top, and I've been told that it's a much larger effect for Targa cars.

Since then, I've simply never bothered removing it, since I don't think that I'm in a position where the couple lbs weight (Even if it is at the front, and above the center of gravity) is going to make a difference. I do, however, feel that this is the most significant impact that the strut bar will have on the car's handling.

@Greek: Nutshell version: With a double wishbone suspension, there is no load between the strut towers for a strut brace to "brace"

 

[te72]

I bought my Greddy to give girls something to lean on when bending over the engine bay.

At least someone has figured out a use for them... I've used them as a good place to perch from when working on top of the engine or in awkward places of the engine bay.

Could they theoretically (if build solid enough) provide any engine bay protection in the event of a side collision impact?

 

[bioskyline]

Could they theoretically (if build solid enough) provide any engine bay protection in the event of a side collision impact?

with the bolt thru design i dont see that being possible. once the metal starts to bend, the bar will twist and go with it. if it was a solid bar like the TRD bars, pics below then maybe.

 

[Dan_Gyoba]

Well, as soon as the side impact was enough to start to move the strut tower, then the bar will transfer some of that to the other side. Might make the difference between saving your engine or not, but for all practical intents and purposes, it'll double the damage to the chassis, and make sure that the fender on the other side is also unsalvageable.

 

[mk3_7m]

Can someone explain in a nutshell why a strut brace is so useless? I kind of see why, since it connects the two towers and not really anything that is part of the suspension system.

With a machpherson strut, lateral loads go primarily through the lower A-arms, but because there is a moment about the hub, there is a smaller reactionary force going through the strut itself. That force can make the strut towers flex, making a strut tower bar helpful.

With a double-wishbone setup, lateral loads go primarily through the lower A-arms, but again there is a moment about the hub. However, with a double-wishbone design, the reactionary force to cancel this moment comes from the upper A-arms and not the strut. The strut itself is free to handle vertical forces. Since a strut tower bar only is effective in stiffening the tower against lateral loads and since the upper A-arms don't mount to the tower, stb's do very very little in our cars.

Saw this post while ago.

But yeah in the end it's their cars let them do what they want to it.

I think I learnt something from Jejock. It's best not to invest time on teaching clueless people. (not saying that to you, the people in the facebook group who are being ignorent)

 

[destrux]

It's pointless. Let them think it makes a difference. They prolly came from hondas. The whole point of the strut brace is when there is a strut that is the upper load carrying point. We dont have that.

Yeah, you're probably right... the sad thing is that most hondas don't have struts either! All the civics from 88' to 01', all the integras, all accords... all double wishbone front and rear.

The best place to tie the shock towers into would be a roll cage, it would increase the bending resistance of the chassis. I've seen this done on a few road racing supras.

 

[Turbo Habanero]

Easy test in theory just take a piece of paper cut it in the shape of the shock tower bolt the Strut bar over the paper go for a couple corners come back take off the strut bar and look at the piece of paper.

If there was stress the paper would get ruined correct?

 

[Carlos A]

this might sound like a dumb question
but I recently bought an 87 supra and I was wondering if I could put a strut bar without having to gut the interior
I don't care for the performance effect of it I got it free with the car. so u guess you can i'm going just for looks

 

[ghostmkiiiturbo]

Not sure why you would need to gut the interior. I'm assuming this for the rear struts. You would at the least have to take off the interior plastic caps over the rear struts to install it. Like someone said in this thread bolt it to a wall in your garage would make a sweet towel bar.

Since your new to the supra.. I'll let you in on a secret. Most Supra owners aren't into the rice factor on any level.

 

[Grandavi]

Supra's have struts?

 

[mjsn1]

Toyota already puts strut bars on their cars if they need it, mostly front wheel drive cars, i know that my brothers 2009 Camry and my previous 2003 Camry has them, so if the MK3 was to gain from the bars i think that Toyota would have installed them.

Anyway, i still have it on my car, i just like to hold on to it when im working on the engine.

 

[ghostmkiiiturbo]

Supra's have struts?

lol you got me. I read the word "strut" so many times in this thread tonight.

-0wned-

 

[Grandavi]

Confuses me a little, because I don't consider our suspension a Strut suspension. I believe the MK1 Supra had struts, but I don't think its accurate to say that about the MK2/3/4 suspension.

For some reason, saying that a Supra has struts just seems odd. Most retailers will call our shocks struts. I was fairly certain (not 100% sure) that strut bars are useful in Hondas... but as for Supras... they do nothing. I refer to my shock towers as shock towers, not strut housings...

I have never found a simple answer mind you...

 

[Wildfire007]

I've never really understood the difference between a strut and a shock. Maybe that makes me sound like a car noob, but I thought our cars had struts so if they don't have struts then I obvious don't know the difference lol.

 

[Nick M]

Even senior members were swearing by them.

No comment on the brace, but.... In general, that isn't saying anything. And it is common on internet forums.

 

[Grandavi]

To me, a strut is a cartridge. And typically they are in lightweight FWD vehicles, although the definition is loose enough to include a lot of different suspension systems.

MK3's are pretty beefy so I don't think "strut bars" do much if anything for the car other than there are some nice ones that add a bit of bling.

I think if our cars flexed I would notice it when disassembling my 25 year old interior... and there were no signs of body flex laterally... Even the targa off flex is over rated... I thought I had an issue with that, but it was my wheels... not the car. (a lot of people overlook the maintenance requirement of a retorquing the subframe bolts. I think the cycle is every 5 years?)

 

[Dan_Gyoba]

The Mk1 and Mk2 both had McPherson strut suspensions. The Mk3 and Mk4 have double wishbone suspensions.

http://www.toyotaracing.com/trd/parts_catalog/chasis_suspension/suspension_types.html

Strut suspensions are lighter weight and much cheaper to manufacture, but have larger limitations on camber adjustment and adaptability. They feature only one "A" frame at the bottom, with the shock absorber itself forming the upper mount for the steering knuckle, or for rear wheels, the wheel axle. Because the top mount is to the body, and not a subframe, as with our cars, the top mount point is subjected to stresses from cornering which can cause the top mount point to deflect from it's nominal position. In this case, a strut bar will help reduce or eliminate that deflection, and thus assist in handling characteristics keeping the tires flat on the ground.

The double wishbone front suspension of the A7 and A8 chassis precludes the necessity for such a piece, making it a purely appearance item. In this case, all of the stresses stay within the subframe, and none are transmitted to the shock tower mounts, so the brace does nothing. Well, it COULD do something in the event of a collision, like compromise the car's crumple zones or the like.

Targa flex is real, and measureable. It is mostly in the floor between the doors. The door hinges and latch take up the stresses on the sides, so the interior panels won't show signs. You might in the door sills though.

As to the the difference between a strut and a shock, it's really that difference between suspension types, however, many people call our front shocks "struts" because of the mounting pattern. Because struts have to carry lateral load, they need a more secure mount to the car body, and they typically have a large flange on the top to do that. Bottom mounts are typically 2 or more bolts along a vertical flange. Old school shocks used to have open eyeholes, and a single bolt at top and bottom to mount, allowing the shock to rotate as it needed. This is what we get at the bottom, but we get that typical "strut" mount at the top. Another typical difference is that shocks had nothing to do with the mounting of the springs. Because with a strut, the absorber IS the top mount, the springs had to be mounted to them, and the spring mounts would be on the absorber casing. This is the case for the A7 chassis, which is another reason why many people call it a strut. Most traditional shock absorbers did not have the spring mounts on them