Here are some dyno plots of the KYB and the Koni I found over at Miata.net. Is anyone versed in reading these plots and could advise on spring rates that would match well with them?

KYB GR2 (Excel-G)


Koni STR.T

 

Links not working.

 

Not sure, I can see them. Anyone else? Try Ctrl + F5 perhaps and see if they work

 

They work for me. The koni looks mega soft. The GR2 looks like it might be able to handle up to like 400 pound rates, maybe.

 

That was a crap plot of the Koni's, here's a better one of the rears that goes up to higher velocities (STR.T's have been referenced as being the same as Koni Sport's on Full soft). Still look low on matching spring rates?

 

On the volvo forums the ghetto way to get stiffer sways was to just run two of them. Under your rules would running two stock sways be considered modifying oem?

 

I wouldn't test my luck with going with a KYB or Koni. The first gen Integra I raced got popped for Tokicos and a stock front sway bar. 110 crank horsepower of fury on Tokicos got 2 penalty laps.

With Chump you need to get it good enough. It's not going to be a Xida or anything, but you can potentially do some real damage with a self re-valved shock and eBay sleeves and springs. You might need to burn a few weekends shaking down the car and finding the right balance so that you don't take laps for non-stock sway bars.

 

Are spring rubbers allowed? They work. Keep both sways and work on the spring rate balance between front and rear.

Slamming into the bump stops will upset the car. I would almost say to leave them long and shorten the springs so that the transition happens early. If it works correctly, the stops will have room to compress somewhat gradually. I thought I read once that the factory stops start at around 350 lbs/in under compression and go up from there as they get squeezed. Remember that the factory designed the car to contact them under hard cornering.

 

Haha that would be something to work out! I don't think that would fly as a no cost mod since it's not necessarily to OEM spec, that is unless the Miata got into some radioactive goo at the plant in Japan-land and sprouted some extra sways bar arms : )

 

We will definitely need a few weekends shaking down the car, luckily we have Putnam Park, Waterford Hills, Gingerman, and Gratten Raceway close by!

 

I think those would be a value add, at least $10 per rubber. Will read into them though as they may be a good way to increase spring rate while retaining ride height at a desired level. Have you driven with these first hand?

That's good thought on the stops, either shorten them and go soft or keep them lengthy and use them to effectively increase the spring rates. Regardless, an abrupt change in spring rate is never a nice feeling at threshold grip...

 

Well the miata was made in Hiroshima, there's got to still be some hot pockets from little boy.

 

FrankenMiata - Handling with a Hacksaw > MotoIQ - Automotive Tech, Project Cars, Performance & Motorsports

 

Neat rule.

When you cut a spring, you raise the rate by the percentage of the cut. Which is not very much.

What if you did something more radical, like cut the spring in half to double it's rate, but then spacer it to put the ride height back up where you want it. Use modified bumpstops to set the up travel and limit straps to set the down travel. That would give you a racier ride height and higher rates.

For shock damping, I've drilled a drain hole at the top of a shock and drained the fluid. Replaced it with heavier fluid from motorcycle shops. Then put a rubber patch over the hole and secure it with a hose clamp. This was mentioned earlier...but I've actually done this. Worked fine.

For a stiffer front sway bar could you get away with using two stock swaybars, stacked like spoons? I've done that before attaching a lower bar with a whole bunch of hose clamps. You cut the last couple inches off to clear the links.

Kinda sounds like fun.

 

Instead of cutting the springs and adding a spacer, would placing solid materiel between the coils doing the same thing? Like an aluminium or hard wood? This would be less hassle and be non-permanent if you want to tune it a bit.

 

Yes, if you locked out half the coils. Spring rate is inversely proportional to the number of free coils.

But if they object to the spacers or blocks, you could also do it with half springs and just cut away the perch and weld it on higher. Pure mod, no extra parts.

 

Those guys did some great backyard engineering work, I've been referencing them a lot! Sure wish we had access to some of those shops or similar equipment, would make all this paper modifications sure go smoother.

 

Sounds like you have some good experience, have any pictures to share of your shock modifications or I would really enjoy seeing that double sway bar.

Raising the spring seat is a sweet and simple idea, no question it was a free mod

 

I'm reading and looking, it looks like you would have to go with a high durometer rubber to get any significant rate increase on your springs. Could certainly be an extremely handy tuning tool while testing at the track and maybe permanent use. Wonder why these aren't more common. Anyone used these on track or even around autocross or town?

Longacre Racing Online -- Tech Article "Spring Rubber Use"

 

Anyone ever used SACHS shocks? They're German if my research suits me but I don't see a lot of info on them. Parent company is ZF ZF Friedrichshafen AG | ZF Motorsports