expo1

Thinking about getting this suspension part for my 8, do they really work?

http://www.specr.com.sg/brace.html

Can I get any feedback from others that have put these type of braces on their 8's?

Thanks
:D

Fanman

Haven't seen this on an RX8 yet, but my friend had this on his S2000. Made it stiffer quite a bit, but he had to drill holes in his frame, and it added a bit of weight (like 20 lbs.). If you are autocrossing, or running on the track these would help. Otherwise I would go for the RB springs to finish off your suspension. Unless you want to do the MS shocks & springs.

expo1

I do plan to attend 3-4 track weekends next year, did two this year and loved it. I have a set of 245/40/18 that will only be used for track days also. My reasons for not getting the RB springs or Mazda Speed Shocks/Springs is that when not on the track I average about 400 miles a week and I like the current ride. I also do not wish to dismantle the whole suspension to install springs. I can handle the install of sub frame braces. I think the RB sways, Strut towers bars, 245/40’s + frame braces?? Would give me a good riding as well as a good track car.

goforwand

Do you know what class underbody suspension components move you to for autocross? Not that it may matter to you, but just curious.

(I was thinking of doing this mod as well)

expo1

Will not run in any competitions (at least not next year), I belong to a club that lets you drive at speed on tracks like Watkins Glen / Pocono. You can pretty much run any CAR with four wheels so long as it passes a tech inspection.

takahashi

Get the over engine strut bar first.

OEM have a very weak one in there at present. I will go with Autoexe over MazdaSpeed.

Love it. An extra 10kg worth while. I don't see any cons in this mod at all. But I will go for Front and rear strut first before the under braces.

expo1

I already have the MazdaSpeed Carbon Fiber front strut tower brace & the Mazdaspeed Rear Strut Tower brace.

takahashi

My mistake not to look at your sig

Yeah... why not. I am thinking of getting one in Hong Kong when I go there but 10kg is still too heavy to take on to the plane right?

Love to have it, I worry that it will scratch the lovely brace at places where it will normally scratch the base of my car.

bureau13

Everyone always says this, but I wonder...I can't see it allowing much strut movement without collapsing, and I certainly haven't heard of any collapsing, at least that weren't in a wreck.

jds

takahashi

The strut bar we have OEM is pretty weak. The bottom brace is worth while on the track IMO. Certainly you can tell the difference straight away with a 4 pt over the engine strut.

I love my 4 pt MazdaSpeed strut but US MS 2 pt strut is not as good as Autoexe 4 pt, unless you don't like red strut bars.

Under brace is good, to make it even stronger - we only have 3 bars there at present. MazdaSpeed have a "X" shape brace but I prefer Autoexe's shape.

RXE16T

Nothing like stiffening up the chassis...... consider these as a form of Viagra.... you may need it and you may not..... depends on your personal application.

bureau13

Don't anybody hold your breath because I'm slow as molasses with this stuff, but I'm trying to get a prototype of something in the Mazdaspeed style fabbed up to see how it works. I've been somewhat skeptical of the interest in such a product, but this thread is somewhat encouraging.

jds

Sputnik

This kind of bracing is the main item that Mazda added to the Miata chassis between the 2000 to the 2001 model years. If you get a chance, drive a '99/'00 and a '01-'04 Miata back to back to get a feel for the chassis. The two cars don't even need to have similar suspensions and whatnot to feel the difference in the chassis.

For those of you who read through the threads about how effective a strut tower brace could be, and what types are better, remember that triangles are optimal for strength, and when you can't do that, closing off the end of a "U" to make it into a square is the next best thing. Another thing to remember is to strengthen the weakest link, and focus your efforts where the forces and mass are greatest.

Taking that into consideration, look at the picture in the link that Expo1 posted at the beginning of this thread. On the left side of the picture, you can see the front brace. At that point, the tranny tunnel forms a "U" channel, and the brace squares it off to make it stiffer. There are two points of the front suspension that tie in right where the brace is mounted, so the brace strengthens the chassis right where there is stress under handling. And even in a car outfitted with a relatively lightweight rotary engine, the engine and tranny are a significant portion of the weight of the car, and so you should make sure to keep the chassis around this part of the car as stiff as possible. In some cars, this even helps with throttle response and the like. While that portion of the tranny tunnel is already strengthened a little by the firewall, this brace looks like it should be effective.

In the same picture, you see the rear brace on the right. Again, this brace squares off the "U" of the tranny tunnel, and ties in a couple of suspension mounting points. Also, note that this sits right under the fuel tank, which also carries a bit of weight when full. So this brace should also be effective.

And while you are adding some weight to the car, you are adding it below the center of gravity, and near the center of the car, so it's not too bad. But make sure that you aren't losing any ground clearance that you need (some of this type sticks down a bit, and will grind, especially when you've already lowered the ride of the car). I can tell you from personal experience that adding even over 100 lbs of effectively placed bracing to a 3000 lb uniframe car is well worth it. And don't forget, a stiffer chassis not only improves handling, but also improves ride and road noise. A stiffer suspension rides much better on a stiffer chassis. In some cars, I have ridden in cars with stiffer suspensions with stiffer chassis that rode better than stock versions of the same car, but that will of course differ between cars and setup.

---jps

expo1

Nice post JPS, looks like I know what Santa will be lugging down the Chimney.

nhk

Hope this picture help

GeorgeH

iTrader: (2)

The stiffening Mazda did on the '01 Miatas was not intended to increase the overall stiffness of the structure (i.e., bump the modal frequencies up a few hertz), but rather to reduce NVH. It was a perception thing - make the car feel stiffer to the driver. And yes, it worked - there is a difference you can feel. So, as you state, those changes are very analogous to those people are attempting to do here in their RX-8s.

However, it's important to point out that the '01+ Miatas never were competitive against the '99-00s in autocross or showroom stock road racing. The reason? They are too heavy.

I think we need to keep the benefits of aftermarket braces in perspective. Most aftermarket braces reduce NVH, but do little to improve the overall structural stiffness of the car - i.e., reduce the amount of bend or twist between the front and rear subframes. I am very skeptical that an RX-8 with 100 lbs of aftermarket braces would be faster around a track than a stock car, assuming no other changes. Unlike the early Miatas, RX-8s are very stiff from the factory, and I would be very skeptical of any aftermarket claims of improved performance due to bracing. Improved NVH, sure, but not performance.

Still, reducing NVH is an admirable goal. And I do agree with your comments about chassis braces making stiffer suspension more palatable. I've experienced that first hand in Miatas. So, if the braces make somebody more comfortable adding the MS suspension, well then the result may indeed be better lap times at the local track. But I'd bet good money that in the hands of a accomplished and dedicated driver, the car would be even faster with the braces out, even if the stiffer suspension rattle the interior bits more than we might like.

Rotary Titus

just wondering... how hard is it to fabricate something like this yourself? Does one simply weld together regular steel and powder coat them? From the Autoexe one it looks like it attaches to holes already in the chassis?

bureau13

Is the Autoexe piece made of steel? I'm pretty sure the Mazdaspeed braces are aluminum.

jds

RotorManiac

Go for the Mazdaspeed with no second thoughts. Autoexe is 11kg, too much. Cortc said the Ms are about 3-4kg max

takahashi

Do you think the "X" shape is stronger than the Autoexe design. 10kg is nothing, esp if it is under the centre of gravity. Better to loose 10kg above the centre of gravity, ie. myself

I know MazdaSpeed is good and I like most thing about it but just having the "X" shape .... I am not 100% sure it is what I want.

I don't mind having steel, since the bottom of the car tends to scratch high kerbs and stuff....

see the pic of Autoexe,.... look at the catalyst! It have the same scratch marks as it is on my cat.

zaku

I did intall the full set of autoexe under braces and tower strut bars. They looks great. I think they really "tighten up" the chasis, but it bring more noise when the road conditon is bad. The steering response is sharp, especially when I'm driving on winding hills. The under braces do decrease ground clearance about 10-15mm. The scratch on them may be unavoidable if you have to park your car in parking tower or steep underground parking lot.

takahashi

10-15mm... what happen when you lower the car by 20mm too!!

Hmm... let's consider again. :o

insup503

so do these underbraces require additional drilling into the frame or does it bolt onto holes that are already present? and where can you get the front and rear strut bars from autoexe?

takahashi

insup..

short answer is no. It simply use the same holes as present in the car for Autoexe.

I have 2 sources in Japan and HK... Japan wise is superautobac shop (you need a contact there) or Autoexe shop. Japanparts.com can do it for you. For HK, GT sport distribute Autoexe products now.

RotorManiac

Hehe, it seems that ground clearance is a common worldwide problem:D
Thats why this product is not in my future plans.
Is it possible for someone to put them on only for the track, or is installatiton a pain?