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The SCCA "Sport" Time Trial classes require stock (OEM) or off-the-shelf standard lowering springs. no coilovers or sleeve kits or conversions permitted. While the OEM springs have been usable with tall bumpstops, i'd like to try the car out with some lowering springs. i tried to order mazdaspeed springs, but they are NLA. i am thinking the Swift or Progress or RB springs might all be viable alternatives due to the relatively high rates and modest lowering. Will be pairing with off the shelf bilstein HDs (B6), which feel a bit overvalved for OEM soft springs anyways.
guess my memory was not so good, you're better off trying to find a set of the MS springs it seems
Originally Posted by AlexCisneros
I had posted these in another thread and thought it may be useful to everyone. In this manner I can edit when new information is made available and keep it up front.
All have been converted to lb/in.
Stock RX8 6spd
F 155.61 lb/in
R 112.86 lb/in
Stock RX8 Automatic
F 144.21 lb/in
R 101.46 lb/in
Mazdaspeed Spring
F 280 lb/in
R 190.4 lb/in
Tein high tech
F 179 lb/in
R 129 lb/in
Tein S Tech
F 196 lb/in
R 140 lb/in
RS*R
F 181.44 lb/in
R 122.08 lb/in
Tanabe Sustec NF210 (Normal Feel)
F 162.4 lb/in
R 112 lb/in
Tanabe Sustec GF210
F 179.2 lb/in
R 145.6 lb/in
Auto Exe
F 212.8 lb/in
R 145.6 lb/in
Espelir
F 212.8 lb/in
R 151.2 lb/in
Racing Beat
F 187 lb/in (calculated 20% Stiffer than Stock)
R 136 lb/in (calculated 20% Stiffer than Stock)
H&R
F 194~203 lb/in (calculated 25%~30% Stiffer than Stock)
R 141~146 lb/in (calculated 25%~30% Stiffer than Stock)
Eibach
F 180-187 lb/in (calculated progressive rate 15%~20% Stiffer than Stock)
R 130-136 lb/in (calculated progressive rate 15%~20% Stiffer than Stock)
If you *really* need a set and can't find a set of the Mazdaspeed springs, I have a set of one of the TEIN springs. I can try to find part numbers somewhere. They're on a blown-*** set of Bilsteins and they lower the car a LOT so you'll be messing with bumpstops.
The Mazdaspeed springs were recently discontinued but i could seek "new old stock".
The Swifts are NLA according to touge factory.
Progress do not appear in their catelog anymore and may be NLA.
I had a friend (fantastic driver but has since moved to the dark side of C5Z06 in SCCA AS) who autocrossed his stx rx8 on the racing beats and said it was super impressive for just springs... and the lowering is very modest, so i might give them a try.
i had eiback prokit at one point on my white rx8 and they were decent but a bit low in height for the rates.
Last edited by hufflepuff; 09-23-2021 at 02:54 PM.
The Progress std springs weren’t that great any way205 lbs/in. front (3.6 kg/mm)
145 lbs/in. rear (2.5 kg/mm)
you can get a 3.8/2.7 set from Japan (Espelier?)
the main focus should be the rate and then quality, specific to the application.
Even if you can’t find a new set of MS springs, there might be a used set out there. Think the stiffest I’ve seen otherwise are Manzo @ ~230 lb/in front rate
What about OEM R3 springs? I've looked but I can't for the life of me find their spring rate. And I swear they sit a bit lower than the GT spring of the series 2. They are marked with the red / magenta dots on the springs from the factory if I'm not mistaken.
I don't think anyone ever checked or posted the rate, but I'd be surprised if it was different than the S1 Sport. Even the sway bar changes were minimal, and the Bilstein shocks were used on other models though the valving may be revised some. They're not lowered either. But hey, if you want to run a stock RX8 a lot of people swear they handle fine
This is the best I could do with the pictures I have on file. Same wheels just swapped between the cars.
unfortunately the second pic with the R3 in the rear has it on Mazdaspeed wheels, which are 18’s.
The reason I brought this up, the R3 springs are a different part number when compared to the 6 speed manual trims. I’ll see if I can measure their spring rate before installing them on my GT.
Then why do I see 3 part numbers? This is from a MY 2010 search, I'm reading this as:
F191-34-011C R3?
FF14-34-011A Sport
FF22-34-011A GT
If this isn't relevant to the overall conversation I can move this elsewhere. But I wanted to help with different spring options if it was helpful. I tracked my stock R3 for a few years on OEM springs and shocks. Yes it was just fine. My GT is a softer ride for sure when compared to the R3. And I don't feel it's just the shock that is different. But I could be wrong.. with the pandemic I don't have more than 1 car out of storage at a time.. and am lacking the space to really investigate this.
well again, these are just factory stock components that aren’t going to be better than aftermarket stiffer lowering springs with aftermarket shocks
my best estimation is
standard/normal tokico
sport tokico
tuned bilstein
but for starters, those parts numbers are all changed from the past, so I’m not entirely sure because I don’t recognize the designation ar the beginning of the number like the way it had been done previously, but this has all been discussed and covered in the past. If anything it’s a result of the RX8 being discontinued since 2011 and consolidating to fewer and fewer parts that are going to cross referenced onto models they never actually came on. A lot of S1 parts now have the later model designations on them.
so start with this thread, Ash is probably the most knowledgeable Mazda parts resources person on this forum
it wasn’t just shocks, but stiffer bars, but don’t underestimate how much shock valving can make a ride feel harsh. You can easily have 2x higher rates and it feel softer just with shock valving. Low speed bump in particular can make the road feel you big time.
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09-20-2021, 12:24 PM
, completely different car and suspension. Their RX8 rate is on soft side. The same as the Eibach kit, may even be re-branded. 
