300lbs spring on 1 gen RX7 causing bottoming out over curbs

S

SteveW10

New member
After 1 weekend with new Tokico adj, the left front (mostly right turns oin my home track) is much weaker compared to my right front. And the right front does not seem as stiff as when installed. ( I am comparing on setting 5 from new and side to side). I had rubber bushings on the rod of both shocks and they showed that the shocks had bottomed on both sides.

My current set up:
Camber Caster Plate, coil overs
Springs
Front 300lb Rear 175lb
Stock front sway bar, no rear


I race in a spec class and the suspesion is to the max of the rules. I was competitve with the front pack with my set up, in fact I seem down on power for the straits (like the starts) but seem to have higher corner speed. Track is on the rough side and there are a couple of areas that it is faster to run the curbs (bump-bump).

So does any one run 300lb springs out there? Is the spring rate too soft for the bumps? I am pretty sure most guys in my class are running 350 or 375 springs.

Thanks
 
Hard to say conclusively, as you didn't mention ride height. Obviously, if you have only an inch of travel left, and your springs are soft......

Some cosiderations though-

- Tokikos aren't a great choice in the upper spring rates. Most folks say that 350 is the limit, others say 300....YMMV.

- Your strut camber plates...above or below the strut top? More travel available if mounted above the strut tower......

-Your ride height...consider that you might be too low for the track.
 
Good points.

I have heard that about the tokicos, but it sounds like most people run 350 or 375 springs with tokicos. In searching the board, I was not able to find anyone with 300lb springs. Staying with the stock struct tube, what is a better option than tokicos?

Camber plates are mounted below strut top. How can you mount them above? There is still 4" or so of travel Don't have number on my ride hieght, but visually I am hire than other car in the class (fender gap)
 
Hmmmm, thats a lot of travel. Mounting the plates on top can help gain a bit more, which means you can lower the front a bit and end up the same.

But the bottoming seems odd. What is your front sway bar? Size? Links? Attachment points?
 
Steve, what is your Spec class ? A location of anywhere is of no help.

Before buying heaver rate springs you could try a spring rubber in the left front which will increase the spring stifness. Your front bar may be weak which will alow the car to roll over. By adding a rear bar you will loosen the rear taking out some of the load/potential push to the left front
 
Go with min. 350lbs springs,300lbs springs to soft special in a ruff track and stock sway bar.Sway bar for fine adjustment anyway.

Pro it champ.
ARRC champ.
was it7
now ita
 
Does it bottom on the first bump or only subsequent bumps?

With 4" of travel and a 300# spring I believe that your shock is jacking down....too much rebound to return to ride height between bumps. Try setting "1" and see if the bottoming goes away. If it goes away, try 2, 3, 4 keep increasing until the bottoming comes back and back off one.

Initially I ran 350/175's on Tokico's, changed to 375/175's and finally 400/200's. I felt the 400/200's were all the Tokico's could handle.
 
I measured the travel and there just under 3".

I ordered Susko's book, I will mount my plates above the tower and go for 350/175 springs. Next race is this weekend, so it will be a long night Thursday and Friday....
 
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