I tried this in several sections but got no responses. Got no conclusive responses from the dealers either. PM'd Jason Saini who autocrosses the R3 - got no response.

I recently replaced my 05 GT with a R3... Trying to understand what Mazda did with the suspension of this car:

Car and Driver indicated that the car has stiffer springs in addition to the shocks. Other sources state that only the shocks have been changed.

When I bought the car, the dealer indicated that both shocks and springs were changed and I was under the impression that the car had the same Prodrive developed suspension used on the PZ, UK edition (not sure what it was called over here).

Does any one know if the springs and sways are the same on the R3 as on the regular 09 (and if those are the same as 04-08) ??? If they are different - what are the specs?

I was thinking about upgrading the sway bars after trying out the car at Mosport or Mid Ohio but with the Canadian Dollar at par, so now might be the time to do it. I had RB sways on my 05 with an otherwise stock suspension but was thinking of going for adjustable bars this time around. The R3 seems to be quite a bit stiffer than the 05 and I am not sure the RB would work as well. I will thinking of going with adjustable sway bars from whiteline. I am using 17" wheels with 225 Hoosier Koni spec tires (not sure how the 17s would work with the gearing so I may got 18' but still not wider then 225' rubber). On the 05 alignment was -1.4 front and rear camber.

Recommendations / thoughts are welcome.

 

Progress Tech used an R3 to fit the Sport Springs so they will be the same. Also I have had customers order sways for their R3's and no complaints.

 

Are you saying PT took of the springs and determined that they are the same as those std on the 04-08?

Do you know if the sway bars are the same as well?

 

^ Now that you mention wheels, how do I choose wheel size for the gearing on the R3??? Sould I go 17 or 18?

 

^ I think it will depend on the track. Overall 18s will probably work better in more instances but I don't know what size tires you are using.

 

The redesigned rear suspension got different shocks and the spring perch is lower than the earlier models, which also then required a longer spring. So the spring itself changed, but somebody will need to configure it in a spring tester to determine of the rate changed. I doubt it changed much, if any.

 

Thanks.

Do you have any thoughts on changing the sway bar on a stock R3 suspension? Whiteline v Progress - progress is a pretty stiff bar, and at first I though it may be a bit much if Mazda already stiffened the springs.

 

The springs aren't that stiff regardless

 

Spring pearch is actually higher on the 09s. Has anyone confirmed that the spring is different, or is the lower mounting point just a little higher?

 

Yes my bad, rear went lower with the 04-08 Konis which means the rear perch is higher

but also because without measuring themdirectly it's all just a guess. I never sawanything that indicate a spring rate increase.

 

Gave it some more thought:

The whiteline sway bars are solid which adds weight without adding stiffness - is there a point to making them this way?
Progress may be too stiff - front softest setting is around the same as the racing beat. If I get the progress bar I may just keep the front on softest and stiffest on the rear.

I never had adjustable sway bars before, I know it does not take long to make adjustments but how many track goers actually play around with them from track to track?

After all of those reflections I may just go back to racing beat

 

Fail .....

 

Solid bars are stiffer than hollow bars with the same outside diameter. You may be confused by the fact that, all things being equal, a larger diameter hollow bar will be lighter than an equivalently stiff, smaller diameter solid bar.

I don't make sway bars for a living, but I imagine people go with solid bars either because they're easier / cheaper to manufacture and/or because of packaging constraints.

The question you should be asking yourself is: do you feel the need to change the car's handling balance from track to track or day to day? If yes, then adjustability is good. If not, maybe not.

 

Thanks for the response. I was doing some reading on sway bar design - hollow v. solid. I don't have a math / engineering background but from what I 'understand', the advantage of a hollow cross section is a significant weight reduction without significant loss of resistance to torsion. I also understand that there are numerous other factors that must be considered beside hollow v. solid.

I may just start with going back to racing beat sway bars and if I feel the need to play around with the sway bars get adjustable ones. I hope that I can get a different type of bushing for the racing beat sway at the urethane ones they supply get 'squeaky' and require frequent lubrication.

 

I'd like to know what the R3 spring rates are and how they compare to earlier models, or even the 09 GT and Sport models. Now, I have never driven a Sport or GT or any pre-09 RX-8, so I can't comment on those spring rates, but I feel the R3 rates are pretty high for a street car and can't imagine those earlier cars would be this stiff. I'd almost say the wheel rates are stiffer than a stock '02 s2000.

My s2000 on 900 lb/in springs is STIFF and the R3 isn't too far behind. If I had to guess, I would say the wheel rate of the R3 is about a third to a half of my s2000's wheel rates with 900 lb/in springs.

 

The 06 springs are soft as hell. You don't feel it so much on the street, but you definitely feel it on the track and autox

 

+1 My '06 Springs are definitely very soft.

To the OP, I can probably count on one hand the number of manufatcurers that make cars that come off the factory line with spring rates that are ideal for motorsport competition (autocross, road racing, etc). The firmness you're probably feeling in your R3's ride is probably due more to the valving of R3 bilstein shocks than the spring rates.

 

I know that the 06 (04-08) has soft springs, I am not sure how this got into the discussion. I know that the Bilstein's on the R3 can significantly contribute to the stiffness. My question was regarding the specs of the sway bars and the springs.

It seems that there is no clear answer on the springs but the consensus is that they are similar to the regular springs or a bit stiffer. I assume that the sway bars are the same as 04-08.

Any other suggestions / recommendations for changing the sway?

 

I don't like most FSB's out there b/c they're much stiffer than stock. On an RX-8 with a completely stock suspension (springs & shocks), they probably offer some improvement in handling, but if you ever upgrade to coilovers, they could be much too stiff.

Personally, I'd start with coilovers then move to swaybars. Otherwise, just run the car bone stock for a track event or two and then contemplate making changes.

 

I am not planning to change anything on the suspension other than the sway bars. Hence the thread about sway bars.

 

Then go with Bryce's (Race Roots) advice in post #2. Progress Technologies makes swaybars that many are happy with...

 

If you're going to make hypotheses without even having real data and facts (butt Dyno opinions don't count) you might as well be posting in that stupin Renesis oil tech thread

 

I just wanna know ... is it a direct swap from a 09 R3 suspension parts to a 04 - 08 Rx8? Someone mentioned that its different but I can't find that claim anymore...

I love the ride in the R3 and would like to replicate that in my 07 Rx8...I know there are changes but to me the shocks and sprigs combo has the most prominent effect...

Thanks!!!

 

The rear struts on the 09 are different. They would raise your car about 15mm.

 

FCK....thx S0l08!