i could from an engineering perspective go into long detail arguement..but i'm not going to get into a pissing contest here...while your link is correct you are missing a point...for purposes of their example and ease of general explanation of the physics involved with a strut tower brace they disregard the vertical forces...in our car specifically we have more compression and tension than normal due to the lower transverse member's ends being bent downward. Vertical forces play a major part in this!!

I wasn't saying ours [oem] is totally ineffective..but put up against an aftermarket brace it is...Now as far as a jointed vs. welded brace...i had originally thought a solid welded piece was the way to go...but then thinking..again...it seems as though you get more rigidity with a jointed...but there is a positive and negative with each...

jointed - when vertical forces are applied...you can sort of view this as twisting of the body...say your racing...80+mph....as you round a turn that has a grade the outer wheel upon entry into the corner will be positively affected by the incline...therefore pushing the outer corner of the car up...at this speed the force of speed + impact will be tremendous...while the springs and shocks will absorb most the car body will experience a slight bit of twist...without a strut tower bar this would cause the open area of the engine bay to succomb to compression...therefore in a sense giving a temporary negative camber to the wheels...a strut tower brace will eliminate the compression but add the joint between tower and brace you have the least amount of stress in the bar since that one side can move that slight bit upward...the problem[negative] on compression and tension you are pushing and pulling between the 2 towers...therefore your stressing the bolts holding the towers to the brace...

non-jointed [welded] - generally you will have no room for flex...you have a welded joint to tower and brace...welds only allow for so much movement...granted there's not going to be much..but the little there is you have to calculate the force involved...so yeh..physically you have a more rigid piece when 100% welded but those stress joints will be less likely to give in the above scenario, as well as others, and could result in adverse conditions...

and then yes..the added aesthetics...aftermarket = nice...OEM=blah!

not picking a fight...just don't assume i'm clueless about what i'm talking about...been doing this for quite sometime now...

 

no problem...it's all a learning exercise... analytical minds and mathematics can explain most anything...given enough time and research The vertical loads are much harder to conceptualize, but of course are there - how to compensate for them is the problem...and like you say, they can be enormous.

BTW I've put my cash down on the side of my favorite strut bars below...so I'm (aahemm solidly) in the solid strut camp (at least in the front heehee).

 

Good discussion and exchange guys. Enough dissent to build on knowledge without a pissing match... Well done! I am actually learning something on page 4 and didn't get digusted with the downward spiral of 'mine is bigger' crap which usually causes me to stop reading a thread before the bottom of page 1.

I mean it, well done!!

BTW - I now remember why I went into Chemistry instead of Engineering. :D

Craig

 

good choose man engineering is cool chemistry is to boring

 

guys i will get pic up of the rear this week end camra was f up the act weight is un know but i do know the greddy is lighter my 2 year old was playing with it b 4 iit went on

 

cool man i can't wait tell i see the pic of man your 2 year old son was playing with them cool it most be light

 

Hey Spin9
What are your thoughts that the cars firewall is a little on the weak side and some have said that they are concerned about a 4 point front brace putting too much stress on the windshield and possibily cracking it?
olddragger

 

Yea, that's a good point. Don't know exactly where all the forces on these things go, but the firewall area (actually a lip above the firewall) where many of these 4-pts attach seems like simple sheet metal, and you can push it with your hand and it gives ! Maybe the extra 2-pt on these braces only gives moral support LOL!

Anyway, that played into my decision to go with the Autoexe brace. It is the only 4-pt I've seen that doesn't use the firewall as a 'push point', but rather forms triangles with the sides of the engine bay and strut towers and then adds a third, bigger, 'bent triangle', using the firewall wall itself as one of the triangle sides bracing the whole frontend structure.

Then as icing on the cake, the rear brace truly looks like it braces, with a solid top to bottom 4-pt triangulated box between the towers. And this rear area was one of the chassis strength 'points of concern' that required the engineers to add that 'back-of-the-seats' brace to get the rear grip back to acceptable levels. So a bunch more help back there, even if not too pretty, could hopefully make major grip improvements in the rear.

Oh yea, almost forgot, AND I can still put on my sexy CF Engine Cover to boot! :D

 

Spin9K
Woo hoo! That sounds like a good front brace to use. Glad they thought of that. Good luck with it. Question about the back one. Would it help with the rear end getting a sqiurrelly during high speed hard braking or is that more of a stiffer springs/shocks issue. I only have the rb sway bars on and I really like the ride so I preferr NOT to go to stiffer springs etc(dont have the cash right now for the coilovers).Two turns at Road Atlanta require some hard braking (from 125 down to about 70) and I want to plant that rear end(no jokes please!?) a little more. Any hope? You seem to know your suspension.
Olddragger

 

Olddragger, thanks for the vote of confidence. However, I'm just researching and doing what I think makes sense to me from all I read and heard about over the winter, and my experience last year. I'll be smarter by years end (and poorer) that's for certain.

However, the Yamaguchi book says the proto RX-8 lost it's "tremendous rear wheel grip" when they cut the back end down from it's original 626 frame to the RX-8 size frame. They put in the Y frame behind the seats to restore the lost grip. Whether they did enough bracing or not, I don't know. What the cause of the loose rear end under braking, I'm not sure either. I have felt that as well doing the 115 to 75 brake thing before turning, and I do know you can never have too stiff a chassis though, so I'm hoping more stiffness in the back will improve the grip further.

I've also got adjustable front and rear sway bars, so I have another tool to work with, and I plan on stirring something like Kuhmo V710 race tires into the mix to up the ante a bit on overall grip and G-force capability. This track year will find the truth of my ideas.

 

No, I have it installed, you just need to screw it in, like any other strut bar.

 

Thanks spin k,
i guess this is another example of how useful this forum is to us. I too, will be testing on the track to see what works for me. Agreed, stiffer chassis is better on the track, just trying to keep my everyday ride as good as it is now. Test,Test. Our next track day has about 10+ 8's coming . All with various mods. Great time for comparisons. I'll keep you informed.
Olddragger

 

Ok, anyone... which companies exactly make a brace with the master cylinder support?

And OD, which brace did you get?

 

Hey Omicron,
It's been a while.
The front strut tower brace by mazdaspeed. I didn't get the rear one. Im not sold on it yet. Maybe as my driving gets better I will find the need.
Wish you could come to Road Atlanta with us but I know that would be a heck of a drive. Charles Hill will be there this time and he now has a bunch of sponsers.
ITs a gonna be FUN!
olddragger

 

rear photo ?

 

for the rear brace is it really necessary ...i would think that the body of the 8 would be stiff enough (granted their is always room for improvment). hehe but it's always inportant to match i guess.

i know on the FD3S you woudl notice an improvment by putting on a sturt brace in teh rear..but seeing how the RX-8 isn't a hatch back we have better structural rigidy in the rump. but i don't know too much about such things.....so please enlighten me:D

 

any pixs ?
im still leaning towards the ms rear bar, since i have the front installed its not right

 

tru.. i believe upgrading the stock is just for aesthetics... you wont FEEL the diference by going with a greddy or any other bar as a matter of fact...if you got the dough to blow then go!

 

Yeah, me too. So the 2 point MS bar has the master cylinder support, is that right?

I really wish I could! Why don't you guys make it "Road Colorado" instead? :D

 

Sorry to bring this back from the dead, but it was the only thread i could find about the Greddy strut bars.

I just picked mine up and man are they beautiful. I cant wait to get them installed, will post pics asap

 

from what I hear the auto-ex bars design is quite good, however, they are also very heavy compared to other bars, I believe I remember seeing someone say that the undercarriage support bars weighed like 50lbs a piece or something like that, can anyone coment on the weight of their strut bars.........are they heavy? they appear to by quite thick and look like they might be made out of steel? If thats the case I would like one thats made in aluminum, or carbon fiber

 

when i take the factory front one off, ill weight the 2 and let you know what i find out

 

Not true. I bought and installed the Mazdaspeed strut bar myself about a month ago. To this day I can still clearly feel how much of a difference it made to the handling, and this is the only mod I have on my 8 at the moment. It's not a feeling that just wore off overnight either, and it's not placebo. I can corner considerably harder than I did before without anything giving way because the entire front end feels like it's not leaning into the turn nearly as much as it did stock. And around wide curves, I can take them at higher speeds than before for the same reason. If you push the 8 hard enough, you'll feel the difference an aftermarket strut bar makes. For me, it primarily served as a confidence booster, as though the limits of the car had been safely extended.

The strut bar has sort of given me a taste of what the car would be like with aftermarket sways, shocks, and springs. If a strut bar upgrade already helps the car like the way I feel it, the RX-8 would indeed be one sick car with the full monty suspension stuff installed.

 

I don't feel like reading through all the pages, but I seached "bent strut tower) My brace is bent! so proof that the stock one is weak! unless its suppost to be slightly bent on the pass. side?

 

Pics?