GrimmSpeed Strut Tower Brace - Review
 

I just want to share my experience with the Grimmspeed Strut Tower bar. This starts out as a bit of a story...


For quite a while now, I've been a critic when it came to strut tower bars. They always seemed more of a engine bay dress up part than an actual structural part to me. I even did quite a bit of research when was planning my BRZ suspension mods, and one of them was whether or not I should get a tower bar. Well, in the course of my research, I read an article in Car and Driver on a guy who runs a K&C Machine for lots of motorsports teams, and he was quoted as saying something along the lines of "...he has never seen an aftermarket strut bar provide a measurable handling difference."

After reading that, I was convinced that this part was unnecessary for my car unless I was just going for looks (The finish on the bar was, after all, very nice)

So then, one day a few months ago, I was cruising facebook, when I saw GrimmSpeed talking about their new strut bar they were putting into production. I took a look, and armed with this 'new information' on strut tower bar testing, I stated my position.

Of course, that prompted GrimmSpeed to reply and state their position, along with a challenge - If I didn't think the bar would provide any benefit, they would like me try it out for myself. So, I thought - "what do i have to lose?"

As it ended up, we had a local HPDE track weekend coming up, so we worked it out that I could test the bar there. So they shipped one out to me. Here are a few photos from when I opened it:

http://i4.photobucket.com/albums/y14...ps949b7aac.jpg

http://i4.photobucket.com/albums/y14...ps002616cf.jpg

It was packaged pretty well, with everything necessary for installation.

I won't detail the entire install process, mostly because it's so easy there almost is no process. Remove 4 nuts, install bar, replace 4 nuts kind of deal.

Here it is installed:

http://i4.photobucket.com/albums/y14...ps729cfd2d.jpg

http://i4.photobucket.com/albums/y14...ps06a1ac5b.png

http://i4.photobucket.com/albums/y14...ps25bf219b.png

The next few days I drove it around town, but didn't really push it too much - just normal DD stuff, so I really didn't notice any difference, but I figured I'd try to reserve judgement until I was at the track.

So this past weekend I had the opportunity to put in some track time at Brainerd International Raceway in Brainerd MN. I had several 20 minute sessions, so it was a perfect time to test with and without the bar.

I tested first without it, since my suspension had been upgraded since my last track day, and I wanted to isolate the impact, if any, of the new bar and not confuse it with new suspension. Once I put the bar on, I felt an immediate difference when cornering. The front end was just planted - hardly any play in the tight corners and switch back curves. Its hard to describe, but I was sold. As the weekend went on, I was able to run two days of Autox as well, and again, felt a clear improvement.

I think one of the easier situations to describe was loading the suspension when I weight shifted the car in the middle of a sweeping turn (Turn 2, if you know the track)

I let off the gas to initiate my turn, and once I had my line, went right back on the throttle 100%. When the bar was not on the car, I would get a bit of hesitation from the front end when I wanted to hold the line. Less confidence inspiring, I'd say. With the bar it was very easy to hold my line as well as get good feedback from my front tires. Everything seemed to flow just that much better.

One thing I did notice a bit of, which I expected, is an increased amount of under-steer POTENTIAL. When the car was weight shifted properly into a turn, everything went fine, but If was off a bit, the car would push more than normal. The amount and intensity definitely would be different on each car depending on specific mods, but on my setup (Tarmac 0 Coils, 245/40 Dunlop ZII's, -1.5 Front Camber, -2.5 Rear Camber) that was the result. I'm sure I could eliminate it with a stiffer rear sway.

Anyways - I am very pleased with the bar - and I ate my words. There is a noticeable improvement provided. I definitely recommend this for anyone who wants a bit more stability out of their car - for track use or otherwise.

And, just because - here are a few track pics!

http://i4.photobucket.com/albums/y14...psb8b29622.png

http://i4.photobucket.com/albums/y14...psaef4d650.png

http://i4.photobucket.com/albums/y14...psedb8a4e2.png

http://i4.photobucket.com/albums/y14...psb78568a7.png

Good post OP

Why is your rear camber higher than your front? Seems contrary to everything I've read about alignments on this car.

Nice write up..

Thanks for being willing to give the brace a fair chance and thanks for the write-up. Glad the brace is treating you well!

Matt Beenen
Engineering

Just finished a weekend AutoX event, where our Sunday track was FANTASTIC. One thing I learned about the car now, however is this: I under-steer quite a bit with the tower bar on in an AutoX situation. On the larger road course, it kept the back wheels in line and was very confident. However, in AutoX, i need more rotation of the rear to get around some tight corners. I just pushed so much.

So, if you get ANY tower brace, you might want to look into a stiffer rear sway if you AutoX. How big? I'm not sure yet - but probably only mildly bigger - something like the WRX stock ones I hear are bigger and bolt right on. I welcome any suggestions.

Sounds about right, depending on your setup. Obviously, others may experience this to a lesser, or potentially greater, degree. As with most things, your suspension system is about finding a balance. If you've got everything carefully dialed in and add a strut tower brace to the front end, you'll want to balance with adjustments in the rear.

Either way, thanks again for the awesome, detailed, honest feedback! Like I mentioned, results may vary based on how you've got the car setup (and what you prefer as a driver), but at the very least, this should quiet the "strut tower bars do nothing" crowd a bit.

Carry on!

Matt Beenen
Engineering

I am installing mine in 10 minutes!!! Great write up!!

Nice write-up. I ordered mine today and look forward to testing it out. I've had great experiences with GrimmSpeed products on my 2002 WRX and look forward to my first GS product for my BRZ!

Thanks for the review OP. I'm also on Tarmac 0's and have a GS bar and master cylinder brace on the way that I found in the classifieds here.

:thumbsup:

Was actually thinking of taking mine off, since I'm stock all around, and I did notice a fair degree of understeer after install too. Probably stick it back on later.

Yea this can add understeer no doubt. However, I think it can be offset by an alignment change too.

If not, then a stiffer rear sway.

More rear spring is also an option.

since you have no doubt, i would love to hear why. i have no idea how a strut tower bar would add understeer

Is everything else about your car's suspension stock?

Sure - stiffening up the front or rear will cause that end to become more prone to sliding - If you stiffen up the rear, it will cause more oversteer. Stiffen up the front (with springs, strut bars, sway bars) will cause more understeer (pushing).

Now, this bar caused understeer may only be noticeable to those with the car set pretty neutral in the first place. I would imagine on a 100% stock vehicle, the bar would only lessen some of the natural oversteer.

Now - I have Tarmac 0 coilovers, whiteline rear camber bushings, and of course wheels and tires - which should be relevant in the conversation sitting at 17x8 with Dunlop ZII's 245/40.

I also have my alignment set at -1.5 Front, -2.5 rear. I am going to flip that around for next season and see how it goes. Should help balance everything out just changing that.

Nice write up - is this C&D article online? I've used rear strut bars on a MR2 and to me it made a very noticeable difference (I wanted more oversteer for AutoX - exactly like what you needed) compared to without PROVIDED it was installed properly.

Sure is - right here:
http://www.caranddriver.com/features...g-it-tech-dept

i dont know if thats how it works. or at least its not a very inclusive description of grip. if that were the case, why would manufacturers spend millions trying to improve chassis rigidity when all it does is reduce grip? i get that messing with the front roll couple will change the nature of the car but a strut bar isnt going to change that. the bar was measured to reduce deflection by up to a couple hair thicknesses. i could see it maybe sharpening response but i still havent really heard an explanation as to how it effects understeer.

Well - i'm not going to lay out the physics on understeer and oversteer - that's what wikipedia is for. [ame="http://en.wikipedia.org/wiki/Understeer_and_oversteer"]Understeer and oversteer - Wikipedia, the free encyclopedia[/ame]

And Here's your explanation on how strut bars affect understeer, keeping in mind understeer is a direct effect of a stiff front end of the chassis:
http://lmgtfy.com/?q=How+does+a+stru...ect+understeer

With my current setup, which is VERY close to neutral or even a little biased to understeer as is(because I'd rather keep it safe on the road course), this bar increases the tendency to of my vehicle to understeer.

If you add this bar ONLY to any car, it will either increase the amount of understeer or decrease the amount of oversteer to that vehicle. The vehicle's current setup will dictate the outcome - so like I said, on the stock BRZ which is biased towards oversteer, there will likely not be any major change - because the car will just end up being more neutral.

But, if you already have stiffer suspension components, a camber adjustment, or larger sway bars - the outcome could be noticeable - which it is for me.

here are my suggestion: before you try to get all cute with that google search, you look at the results. in the first two link, it says a strut bar eliminates weight transfer which shows they dont know what they are talking about. in the second link they imply that flex reduces grip so a strut bar would increase front end grip. its not hard to come to the conclusion that that means less understeer. they later go on to say a rear strut bar reduces understeer so i think that kinda shows they dont know what they are talking about. the rest of the links are just a bunch of forums that are typically having the same conversation we are having and coming to all sorts of random conclusion.

you are trying to convince me that somehow a strut tower bar generates understeer. i have a suspicion that you have been avoiding giving me an explanation because you dont understand the topic at hand. if im wrong im sorry but i would love to hear your reasioning.

Try it and let me know. :)

im not doubting your experiences. what im questioning is the way you state your opinion as fact when its based on zero quantitative data and half opinions you tried to spoon feed me was the opposite of what you were trying to prove. suggesting things like offsetting a strut bar with a sway bar is probably not an appropriate solution. and i imagine that with all your mods, its just the nature of the car youve built. cars that are stable at a road course typically deal with significant understeer in an auto x setting strut bar or not.

Well - I don't care anymore - I don't want to spend time trying to explain it.
However, what I know for fact is - Tower bar went on, car as currently setup understeers.

To fix, i'm going to re-align and if that doesn't work, i'll get a thicker rear sway.

Fwiw all his complaints in his last post you had included in your posts from the beggining (set up may vary, can be changed multiple ways, neutral track setup understeers in autox)

i learned the value of a solid front bar when i put a non-adjustable 3 point on my other car. huge difference. i believe a strut bar only induces initial understeer because your driving style maybe be use to feeling the front flex at the beginning of the turn. throughout the turn you should notice increased grip and response because both tires are being planted much firmer and equally then before the rigidity upgrade. my 2c

Installed mine last weekend and took it for a spirited drive througha little local Canyon network and it was a big change but enough to know that when I was pusing it the front was a lot more locked in.

Really like the product, wish I could get more grimmspeed products for my 86.

for those with stock suspension on the FR-S, did the bar make the car feel more neutral?

^^^^

In for this also. I am staying all stock and dont track or autox my car. Thoughts??

I would skip it then. It will only provide benefit in mid to extreme driving situations - Otherwise it's just a $150+ bar for dress up.

I do track the car occationally, so the car being more neutral in terms of handling is not a bad thing.

Installed mine lastnight. Love, love, love the feel.

Same coils as you gopher but different alignment settings. -2 all around. No particularly glaring signs of understeer but the car is certainly less "tossable" due to the reduced body roll.

Granted, our setups are different. I'm sitting with -2 camber all around with 265/35 Michelin PSS. Car hooks like crazy. I love it.

Perfect word IMHO - "tossable"

good lord on the tires lol. Fatties :)
Yea - when my car wakes up for the year in March, or you know, July with our weather here in Fargo - I'll have it realigned.

I put my stock wheels and tires on a few weeks before I put the car away, and I will say it felt more light on it's feet than with my 17x8 245's. But, meh.

That sounds like my kind of setup! Thanks for your feedback!

In my sti, I have equal amounts of fun on 225/45 'street tires', 255/40 RS-3 and 225/45 R-Compound slicks. I think that they each have their procs and cons. The sharpness and resolution that the narrower tires offer is awesome and the car is certainly more 'tossable. On the stickier 255's, it's just big, fat, dumb grip with less 'sharpness'. The slicks, of course, are a whole different ballgame and I find them to actually be less fun.

Any pics?

Matt Beenen
Engineering

I actually posted a short review in my build thread. Not sure if you guys caught the tag or not.

:thumbsup:

http://www.ft86club.com/forums/showp...&postcount=114

Do you need to drop one of the shocks to install this, or is there enough slop or a slotted holes on the bar?

Cheers


Edit - I see that you don't need to drop the shock. PM'd.

No need. The install takes minutes.

I'm pretty bad about catching tags and mentions so I had not seen that yet. Thank you very much for the review, I couldn't agree more!

Chase
Engineering

I thought I'd resurrect this thread for fun and a couple of questions.

1) How much does this weigh (don't see it on the mnfr web site)

2) I've read it's important to get the front wheels off the ground before installing a strut tower brace, this appears to bolt on without and since there's no adjustment I guess it wouldn't matter if the front end's off the ground anyway. Does that make it less effective than another type like the Tanabe that has some adjustment and suggests unloading the front suspension first?

It's maybe 8lbs? Its so long it was hard to gauge when I held it.

In my experience, there's no reason to lift the front of the car to preload it. I figure you'd want to bolt it to the car with normal load on the towers anyways.

There's a reason they made a solid bar instead of a adjustable bar through all their testing...