Originally Posted by Cito

I have had the Progressive Track Springs on my RX8 now for about one month. During that time, I have used them on the street as well as for one event, an "autocross," at a local go-kart track.

THE CAR
2005 Mazda RX8 base model with Tokico D-spec shocks in back with adjustment cables and Koni yellows in front. That is really about it. I do have Whiteline front swaybar bushings and HKS single exhaust. The wheels are 5Zigen 17x9 +35 with 255/40/17 Dunlop Star Specs.

Distance from ground to center of wheelwell in inches (before/after):
LF: 27.375/26.25 RF: 27.25/26.25
LR: 26.375/26.5 RR: 26.25/26.5

So, on my car, the rear raised a bit and the front was nicely lowered. It looks better, but the pictures show that there is not as much lowering as one might expect. I think my stock rear springs were sagging, which is probably attributable to the tendency to carry heavy loads almost anywhere I drive for a long time. An interesting thought if going back to stock, maybe it would make sense to get new stock rear springs. As noted, my car has always been high riding. Even with these springs, the front looks higher than many cars in BS--part of that might be related to the shorter wheel and tire combination.

CAMBER (before/after):

LF: -1.3/-2.5 RF: -0.7/-2
LR: -1.5/-1.3 RR: -1.5/-1.5

These changes correlate well with the reduced ride height.

PHOTOS


STREET IMPRESSIONS
Positives: These springs have absolutely transformed the street handling for the better. The car is much less prone to understeer and it no longer has that obviously softly sprung feel. It feels similar to the stock S2000 I have driven and it rides better than the stock 350z I have driven--both on the street. As might be expected, the car is flatter through the corners. It is a little bit prone to oversteer, but only when I want it to be. I enjoy driving the car much more than I did before the change in springs.

Negatives: The ride is stiffer, and with this, my mild case of gynecomastia has become more noticeable. Thankfully, no black eyes or need for a bro, manziere,etc.yet. At any rate, the ride is definitely stiff, but this has been tuned to what I believe is a very acceptable level by adjusting the shocks to about 1.5 turns above full soft.

"TRACK" IMPRESSIONS
MaxQdata for the car with the tires and wheels (42), and with the tires, wheels, and springs (44) are attached. I posted the best runs (by lap) for each combination. Note that the best lap I had all day with the springs was my very first run. In looking at the lap times overall, the car was consistently faster with the springs. The 39.*** time before the springs was the outlier. With the springs, 39.*** laps were the norm. If I find time, I will compare the laps statistically.

Interestingly, my father ran faster times in the RX8 with the springs than he had in his prepared Mustang, which I was getting 37-second lap times in. I think this is a testament to how comfortable the car feels with the springs.

Positives
The car was immediately faster with the Track springs and it was SO fun to drive.

NeutralUnfortunately, the fun I was having really screwed up the lap times. One run I literally drifted through three of the corners dirttrack style. This is not the fault of the springs of course. Before the springs, even with the street tires, the problem was managing push and understeer. With the springs, the issue becomes managing speed and oversteer. There is no doubt in my mind that a better driver would be able to exploit the springs' potential very quickly. I need to play with the stiffness settings on the shocks to better balance the car especially in relation to use of street tires.

Negatives Really, I am not sure that there are any negative here. Even with my limitations as a driver, the springs consistently produced faster times. If you want a car that is benign and has no risk for spinning, then the springs might not be for you. Once you have tires and shocks, these springs are the way to go.

Well, that's it for now. The car is a better car with these springs. I would buy them for the street if the interest was in performance versus looks. I had never really considered using the RX8 for track days, but the change in the car with these springs has me thinking about doing it now.

Please note, I was not given the springs, I purchased them for $300. I was not paid for my thoughts or impressions.

Originally Posted by MilesJ

I hope not. I would like to get in on this group buy, where do I send my money?

Originally Posted by MilesJ

I hope not. I would like to get in on this group buy, where do I send my money?

Originally Posted by TeamRX8

Sign me up, but if the wait is too long I'd just as soon pay the regular price

I ran higher rates than this on the street and it wasn't bad, but it's a subjective subject.

Originally Posted by TeamRX8

Please remove me from the list, exit stage left .....

Originally Posted by Kafka

bump for yo!

My only worry is that will the spring rate be too much even for rx8 40th anniversary bilstein shocks? I am planning to get Bilstein HD with this combo...

Any light on the street comfortability of the track spring (I know you got the street one but its too low for my taste...I have to drive the car in the winter and too low = snow plow)

IMHO this will be as close as the Rx8 PZ set up (well even more than 60% more spring rate than the custom made Eibach spring Prodrive used)

Thanks!

Originally Posted by S0l08

Will these get built if we can't get 10 people on the group buy? Really doesn't look like it's going to happen. I'd pay full price if I could just buy them outright. Otherwise I will have to look into onother option.

Originally Posted by 2tone

wow, i let this slip my mind in the hopes i wouldn't want them still...ha ha. i'm definitely interested. i'm not sure how much life i have on my tein s's, and it's xmas time, so i'm not swimming in money right now!!

any idea on how much a non-group buy set would be? and like others have mentioned, if group buy never hits 10, can we still order these? i'm thinking in january i might be able to take the plunge.