Trunks817

Hi All,

I bought a 2005 RX8 with a sunroof. Just wondering what are the best parts to reclaim the rigidity lost for the sunroof. I was thinking front and rear sway bars and endlinks but thinking this might be overkill. would strut tower braces help any?

Thanks in advance!

c0ldf1ame

iTrader: (5)

rx8 is already very rigid from factory, i don't think sunroof loses any torsional rigidity as much as just adding weight up-top. Sway bars don't really increase your chassis stiffness but will help with the body roll. If i were to do it again i don't think bracing is necessary, in fact a lot of autox-ers on this forum run without the factory front strut bar. Depending on your goals the mazdaspeed strut bar has a brake master cylinder brace that will help with braking feel

fuztupnz

iTrader: (4)

From what i've seen personally, and have read (I believe Eric Meyer has posted about the use of frame bracing) You'd have to have an super stiff suspension to really notice any flex out of the body. If you want to see the stiffness for yourself, put the car up on 3 jackstands. 2 behind the front tire at the jack points, an one in front of the one of the rear tires at a jack point. The car will sit almost flat with all 4 wheels in the air. The side without the jackstand only sags less than a half inch. If the chasis wasn't as stiff, the unsupported side would sag and cause the car to teeter.

I'm not saying the strut tower braces and chasis braces do nothing, I'm just saying you'd have to run a damn stiff suspension, and drive around or at 10/10ths to notice the difference. I think Team or one of the other nationals drivers has a post about running no front strut bar. Don't remember who exactly.

GeorgeH

iTrader: (2)

+1 to all of the above.

The RX-8 has fantastic chassis rigidity, new braces are the last thing you should spend money on. Not that they would make an imperceptible difference - you may indeed feel a difference - but they won't make the car appreciably faster on the street.

Of course, if your main objective is to reduce NVH, then by all means, brace away.

And, as stated above, sway bars have nothing to do with chassis rigidity. They do increase suspension stiffness, however, and will reduce body roll. Nothing wrong with that, lots of people use them.

laythor

i have the MS front brace and it sure do look pretty

I've always deferred to the track and auto-x guys and i've never heard one of them suggest the 8 isnt stiff enough stock.

GeorgeH

iTrader: (2)

Sure, I've been tempted by a three point front brace myself. They look sweet, and I like the idea of triangulation. Just don't tell me your car slaloms faster.

alnielsen

iTrader: (4)

When I put a strut tower brace in my RX7, you could notice the difference immediately. Not so with the RX8. They have two different types of suspension. In the RX8, I don't notice much difference with or without a front or rear brace. I have the MS front & rear brace bar. The reason I have the MS front bar is mainly for the looks and the brake master cylinder stop. The brace that comes with the car is more than sufficient.

GeorgeH

iTrader: (2)

Yup. I've removed my OEM brace as a weight savings measure and never looked back.

Trunks817

Thanks for the reassurance guys. I know for the saab they made an under triangle bar to help increase rigidity and it helped a ton for the people with Sun roofs.

How do the 8's fair against the S2000's in Autox?

KamiSpeed

If you're looking for some extra underbody rigidity I have a couple of beatrush items in stock, check out my thread
KamiSpeed RX-R Beatrush

TopGear8

iTrader: (3)

That's because it's a Saab


The S2000 is faster than an rx8 on a autox course. On Hoosiers or on street tires.

Trunks817

indeed about the saab! it's like another world of performance, I didn't realize a car could handle this well from the factory.

how much Cash does it take to handle close to an s2000?

GeorgeH

iTrader: (2)

The S2000 will be faster at an equivalent level of prep, and it's classed accordingly.

So, if you run Stock class, the RX-8 and S2000 are in different classes (CS and BS, I do believe), while if you run in ST (on street tires) the RX-8 is in STX and the S2000 is STR. So, no matter what you do to your RX-8, assuming the S2000 driver has done roughly the same things and has similar driving skills to your own, the S2000 will be faster.

Now, a fully prepped STX RX-8 vs. a stock S2000 on street tires, the RX-8 probably has more performance potential. But that's just a guess.

Moral of the story: Don't bother comparing the performance potential of your car to another car that is in a faster class. It normally will not end well. However, work on your driving skills and you can take glee in out-driving somebody in what should be a faster car - that's a happy ending.

fuztupnz

iTrader: (4)

/\ Well said George