What do you think of your strut bar?

[Mikepage]

Ok

[Vracer111]

Originally Posted by husker741

Which kind do you have and was it worth it? Does it really stiffen up the front too much? I already have RCE Yellows and I'll track it rarely, but I'm interested in spending a little for a strut bar if it helps. I just don't want the ride greatly effected because I heard it does make it stiffer.

I have the Grimmspeed and before that another brands single piece bar (with tubing having a thinner sidewall), and the Grimmspeed is probably the most worthwhile mod with a stock suspension besides solid aluminum steering rack bushings. The ride is noticeably affected...for the better. It does not make the ride stiffer, quite the opposite - it gets rid of much of the jarring and chassis crashing from seams, bumps, and dips and smooths out the ride. It may require just a tad more initial steering input to rotate the car, but it does not introduce understeer in cornering - the chassis is much more settled and planted through the corners; actually feeling more responsive and neutral handling than stock.

Grimmspeed bar combined with solid aluminum steering rack bushings is such a great setup that going back to stock would be a disappointment. You can just go full bore in a corner and it will be more precise and controlled than before, none of that little bit of chassis hesitation on initial turn in or slightly squirreliness nature of the chassis throughout the turn. It makes the handling sharper, the steering absolutely linear, and whole car much more toss-able at the same time.

That is my experience driving my FR-S with the Grimmspeed bar and TIC steering rack bushings with the stock Michelin's on much lighter and slightly wider wheels (17lbs, 7.5" width) and the traction/stability turned off almost 100% of the time. If you keep or increase the stock unsprung weight you will not see as good results...unsprung weight is everything on ride quality of a stock suspension setup - always reduce it whenever you can.

[GrimmSpeed]

Holy crap, you guys are seriously a kick ass bunch of guys. I can tell you right now that all of your positive feedback keeps our team going when times get rough and we need to keep pushing forward. Thank you for the constant reminder that the time and effort are absolutely worth it!

Justin Grimm

[Mikepage]

Thank you for the review Vracer111.

I just placed on order an the Whiteline rack and pinion bushing

[boredom.is.me]

Originally Posted by Mikepage

I just placed on order an the Whiteline rack and pinion bushing

I got the Energy Suspension steering rack bushings for $15. And yes they get the job done.

[GrimmSpeed]

Originally Posted by wu_dot_com

now according to Grimmspeed's data, the total deflections between the strut towers are .017". a typical bolt hole tolerance in aerospace manufacturing setting is .010". thus if the two hinge were manufacture under those condition, the tolerance stack up between the two hinge hole will be at .020", which is greater than the total allowable deflection. Therefore, the strut bar will not work in this condition because load transfer cannot occur unless the strut bar is properly loaded under compression. on the other hand, if they drill the hinge hole to .005" tolerance, the total stack up will be at .010" and the maximum rigidity improvement will be less than .007" assuming zero deflection. On the other hand, a wielded design will not have such tolerance stack up issue.

Another problem with the hinge design is that over time, the loading and unloading cycle due to vehicle operation will elongate the hinge hole. Thus eventually a hinge design will be less and less effective as the unit age.

PS. keep in mind that .017" Grimmspeed data is only applicable under their specific test condition. it does not mean that if the hinge hole were manufacture to .010" tolerance wont have a positive improvement during real life operation of your car. this number is only being use for reference only. in addition, the .010" tolerance refference above is a statistical tolerancing average of both positional and diametral tolerance.

This is a solid analysis. To be fair to the multi-piece braces as a general design concept, the tolerance stacking is only really applicable in a brace where the design and hardware don't allow you to rigidly secure each joint. Now, I don't believe that any of the available 'hinged' designs can provide that sort of rigidity, but it's certainly possible. We had a few concepts that would have demonstrated that, but they were cost prohibitive and offered no real advantage. Ok, so they looked pretty cool, but that was about it.

The reason that I wanted to mention that is because some critiques of our bar accuse the slotted mounting holes of having the same design flaw. My response to that is in two parts. The first is that 12ftlbs, through the stock fasteners, provides more than enough clamping force to keep the car in place, no matter how long those slots are. The length of the slot is of no concern in that regard. The second part is that the slots are necessary to be able to place the bar down onto the studs. The studs on each side don't protrude from a coincident plane, so un-slotted holes would make installation nearly impossible. You can set our bar down on a flat table to see the difference in angle.

Anyway, carry on, we love seeing good, informed discussion!

Matt Beenen
Engineering

[wu_dot_com]

Originally Posted by Mikepage

What is your job? You seem to have a good knowledge.

I work in the aerospace industry as a mechanical engineer. so my writing is not that good, but science stuff I do okay.

[Mikepage]

Edit from Matt : The first is that 12ftlbs, through the stock fasteners, provides more than enough clamping force to keep the car in place, no matter how long those slots are.

This is probably true also for all strut bar.

I don't think with this ftlbs of torque any holes will enlarge correct? And this enough to keep the bar in place like you say.

You seem to have created a good product Matt.

I just want to know if 3 pieces strut do the job too

[wu_dot_com]

Originally Posted by GrimmSpeed

This is a solid analysis. To be fair to the multi-piece braces as a general design concept, the tolerance stacking is only really applicable in a brace where the design and hardware don't allow you to rigidly secure each joint. Now, I don't believe that any of the available 'hinged' designs can provide that sort of rigidity, but it's certainly possible. We had a few concepts that would have demonstrated that, but they were cost prohibitive and offered no real advantage. Ok, so they looked pretty cool, but that was about it.

The reason that I wanted to mention that is because some critiques of our bar accuse the slotted mounting holes of having the same design flaw. My response to that is in two parts. The first is that 12ftlbs, through the stock fasteners, provides more than enough clamping force to keep the car in place, no matter how long those slots are. The length of the slot is of no concern in that regard. The second part is that the slots are necessary to be able to place the bar down onto the studs. The studs on each side don't protrude from a coincident plane, so un-slotted holes would make installation nearly impossible. You can set our bar down on a flat table to see the difference in angle.

Anyway, carry on, we love seeing good, informed discussion!

Matt Beenen
Engineering

to further add to Matt's point. the primary function for those bolt that those strut bars attach to are for clamping. force transfers can occur as long as sufficient surface contact exist (or 100% contact, no lift off) through adequate clamping. thus, the size and shape of the bolt hole is really irrelevant within reasons (as long as the bolt/nut can have enough surface area to applied clamping pressure on strut tower and strut bar, and the strut tower and strut bar interface surface is not expected to slide during operation). on the other hand, the size and shape of the hole would only matters if the bolt in question is design to carry shear load.

also the slot is absolutely necessary to guarantee fitment. the car engine is not consider as a rigid body. it is free to flex and deflect depending on the loading condition. thus the true position of the two mounting bolts can differ greatly, anywhere from .25" to .5" at times. in addition, the wielding processes of the strut bar also distort the true location of those mount holes. with all those factors combine together with a slanted surface, it is necessary to create a slotted hole.


The 12ftlb torque is really there to prevent fatigue damage to the bolt. It is determine based on the actual compressive stress properties of those materials of bolts, strut bars, strut towers combo. Since I never saw the actual calculations, I cannot tell you the exact tolerance that is associated with that 12ftlb. However one of two things will happen if you go over 12 ftlb. One is that the bolt will yield and stretch. The second if the strut bar / strut tower will deform. The likelihood of bolt stretch is more probable. In this case the separation of strut bar from strut tower can occur, thus the holes will elongate because bolt can slide in and out of the slot. in addition, the performance of the strut bar is null because of the additional slack that was generated which need to be taken up before the proper force transfer can take place. On the other hand, under torque will results in separation of strut bar from strut tower during operation. The same failure event will occur as an over torqueing the bolt.

[BlackyRose]

I think what a lot of us want to hear is how will our cars feel if we drive in large metropolitan cities (ones without elevation. curves, nice roads) with a lot of big roadways and highways. My commute to work has a few turns but nothing serious. Will I feel the difference on simple things like making a sharp fast right onto a new highway and traveling into and out of strip malls and subdivisions and what not. Its really hard for me to believe that stock tire and suspension guys would feel a difference unless they were driving in upstate georgia or north carolina, etc. I live in Florida where most of the roads are straight with some small oppurtunities to punch it on an entrance/exit ramp or into and out of some small highway curves

[Boxer486]

Originally Posted by Captain Snooze

My thoughts on my strut bar.
1 I was skeptical about it making any difference.
2 I was impressed with how much difference it did make to the feel of the front end.
3 I am not a good enough driver to tell if it makes any any difference to lap times. That is, I can't attribute any difference in my times to this bar.
4 For me it was a worthwhile addition, see point 2 above.

Originally Posted by Captain Snooze

The front end doesn't "shake" as much. That's the best way I can describe it. It feel more solid. Thing is, before fitting the bar the way the front end behaved was normal, I had nothing to compare it to but the difference was immediately noticeable on the bumpy streets around home.
Important part coming up. There is no way I would want to have the car feeling like it did before fitting the bar. The difference in feeling is chalk and cheese but I can not say objectively what performance benefit there is.

Ditto. I got the Hotchkis and the difference is obvious versus stock. I won't be going back and will be tidying up the rear now. I've used bracing to good effect on older cars but was skeptical about this chassis w/ high tensile steel and a basic firewall brace stock. It is readily apparent and beneficial.

Originally Posted by akyp

Installed TRD front strut tower bar and door stabilisers. No difference whatsoever. Perhaps because I'm still on stock Michelins.

Tires don't matter, I'm stock atm as well. Either the TRD brace isn't sufficient or you might be less sensitive to the changes. Or the rest of us have placebo from lighter wallets.

I had contemplated the STI offerings since this is a DD and like the comfort/compliance idea of allowing for vertical compliance but stiffening up lateral loads. However, I want to preserve the integrity of my new chassis as much as possible and believe compliance is the job of the suspension, not the chassis. So for me, make the chassis as stiff as reasonable without going full brace whore and dial in the wheel rates for my driving conditions.

In ten years, I expect to have a much more well preserved chassis and a decade's worth of sharper turn-in and more planted feel which =

[Boxer486]

Originally Posted by BlackyRose

I think what a lot of us want to hear is how will our cars feel if we drive in large metropolitan cities (ones without elevation. curves, nice roads) with a lot of big roadways and highways. My commute to work has a few turns but nothing serious. Will I feel the difference on simple things like making a sharp fast right onto a new highway and traveling into and out of strip malls and subdivisions and what not. Its really hard for me to believe that stock tire and suspension guys would feel a difference unless they were driving in upstate georgia or north carolina, etc. I live in Florida where most of the roads are straight with some small oppurtunities to punch it on an entrance/exit ramp or into and out of some small highway curves

I noticed obvious benefit from doing 20mph around a cul-de-sac. Stock car.

Of course, if you buy a poorly designed bar, the benefits will be less apparent.

People need to stop buying hinged, non triangulated stuff to stop encouraging manufacturers cashing in on bad design.

[Mikepage]

Originally Posted by BlackyRose

I think what a lot of us want to hear is how will our cars feel if we drive in large metropolitan cities (ones without elevation. curves, nice roads) with a lot of big roadways and highways. My commute to work has a few turns but nothing serious. Will I feel the difference on simple things like making a sharp fast right onto a new highway and traveling into and out of strip malls and subdivisions and what not. Its really hard for me to believe that stock tire and suspension guys would feel a difference unless they were driving in upstate georgia or north carolina, etc. I live in Florida where most of the roads are straight with some small oppurtunities to punch it on an entrance/exit ramp or into and out of some small highway curves

Everything you do to rigidity the chassis will add a better driving sensation. I don't say it will be a big change, not like night and day but you will probably feel it.

It's as you wish, for me, I want to improve the driving feeling even if this car have the better feeling for a car into this range of price.

Am sure you will improve your daly driving sensation, you just need to ask to all users who bought the Grimmspeed strut.

It's all about details, each details are important

[Mikepage]

Originally Posted by Boxer486

I noticed obvious benefit from doing 20mph around a cul-de-sac. Stock car.

Of course, if you buy a poorly designed bar, the benefits will be less apparent.

People need to stop buying hinged, non triangulated stuff to stop encouraging manufacturers cashing in on bad design.

I don't think hinged strut bar can be a problem if a good manufacturers like Cusco and Whiteline do it the right way.

Look the video I posted from Cusco. Look until the end