Has anyone actually tested these on a track? Any thoughts at all on what sort of spring rate adjustments would be on the cards to gain the greatest mechanical grip benefit from the improved bump characteristics? I'm thinking as a guesstimate that you could consider moving from an 800/500 combo (with sticky tires - say 245 Hoosier r80 or r100 slicks) to 700/400 or even less?

 

You're still going to need enough spring to deal with yaw motions without bottoming. You should certainly be able to go down in sway bar size though. The drop spindles only make the force due to geometry less in roll. I know that if I went to less spring I'd be bottoming the splitter in braking.

 

I contacted a vendor in the UK about custom abs rings.


Price would likely be about $100 a pair.

 

I have managed to get hold of a Volvo c70/s70 ABS ring and found it may work with a bit of messing about. It is a fraction smaller than the miata ring (81.4mm OD, 72mm ID), but is close enough that you might be able to bore it out to fit the Miata half shaft, and then shave 1mm or so off the underside of the sensor mounting to lower the sensor closer to the ring.

If this works, it may be a good low cost solution as the s70/c70 rings can be had for $10-$15, assuming you have the means to bore the ring out to fit.

I have a race meeting coming up and need to get the car ready, might have a chance to look at this a bit more closely in a month or so.

 

Thought on these for a street car? I notice considerable bump steer when I lowered my car to Emilio's recommended ride height for the dual purpose street car.

Has anyone used these enough yet to give an impression?

 

What tie rod ends are on the car?

 

Stock

 

I believe the "r package" tie rods though stock have additional length for some bump steer correction, which is why asmasm asks.

 

I figured, I know I have read that some models, I Was thinking a 93 LE? had longer rods ends to help with bump steer. When I said stock I meant what came on my 10AE. They are the originals actually. If changing the rods is all that is needed I will certainly do that, but if there is significant handling improvements to be had spending $1250 then I guess I will have to find some car money....

 

93LE and R Package tie rod ends are the same.

 

The LE/R tie rods help just a smidge to reduce bump steer. Do not expect a dramatic reduction.

 

I just got a report from a friend running these spindles that the Volvo rings works (on the street at least), when the sensor mount is modified.
The rings fit without modification (just some force), but that might be different depending on the source. The cost of aftermarket rings were about $8 each here.

But how well it works in a race we will see next weekend.

 

Function verified in race conditions as well.

 

 

Just meaning that the ABS did not freeze up as it did before, when it matters. Testing on the street is one thing, believing that it works during trail-braking on the inside of another racer is something different (and things are hotter, probably affecting magnetic stuff).

After one season of fiddling with bolt heads, ride heights, alignments etc, the end result is no more speed than before. He is still some tenths behind the leader.
If the drop would have been 15-20 mm it would have been much easier to live with and the optimization efforts could have been focused on fine tuning the performance instead of just making it work decently.
Our season is short and only race five weekends, and the local Guinea pig is just a two man team on a spare change budget. Meaning that that there might be an advantage to drop the car, but to find it you need to be able to find the last tenths of each setup, and that requires some dedication.

If you want to go deeper, make your own spindles, preferably with radial brake caliper mounts. Making custom ones would probably be cheaper than the time it takes to make these work in your favor.
The Toyota hubs is a big plus though. Wonder if the ND spindles can be modded to work (and how many ABS pules those have)?

This is just my analysis/ramblings from the sideline (I have not tested his car, I know he's much faster than me), but it has convinced me that keeping the stock "crap" is the way to go. The service intervals are known and the compromises works so much better that it should do in theory.

Edit: Just one note, we have a min ground clearance of 75mm, but unless you mod your fenders it's hard to go lower than that anyway. Those racing on smooth concrete lots might get away with lower heights though. I normally have to repaint my front upper fender structure every year due to scraping from one specific compression, so I know my limitations.

 

Just spotted this - thanks! Props to you sir.

Can you post pics of how the abs sensor mount was modified? Did you just shave plastic off the underside of the sensor mount to lower the rear sensor?

 

Any new updates on the drop spindles?