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Bilstein HD... what are they set up for from the factory?

What spring rates are the HD's set up to control from the factory? Does anyone know for sure?

soooo.. they won't handle a 550/350 setup at all then.

oh well.. off to stewart dev. they go then.

from FAT CAT

Quote:

Originally Posted by FCM

90-97 Miata
# Bilstein R-pkg - original-equipment on the '93LE and '94-97 R-pkg, these are digressive, monotube shocks. Digressive means the forces decrease (or digress) at higher velocities. Digressive forces are important to prevent either rebound or compression forces from upsetting the chassis, either with too much compression (wheel jumps up over bumps) or too much rebound (wheel pulls down over bumps). The factory R-pkg shocks can be used with up to 450/350 lb/in springs as a budget race setup. A coarse revalve from Bilstein (usually only one or two internal shims changed) may be performed at a cost of ~$65 per shock. In the past (pre 2010) we offered revalve services on R-pkg/LE shocks but have discontinued this service due to the time/material needed to update the parts to current standards. See Bilstein HD for more information.
# Background: very strong low-speed rebound damping and very weak low-speed compression
# Usage: Best suited to smooth roads or stiffer springs. Users have paired with springs from 300/220 to 700/325 (Spec Miata rates). Our suggestion is in the range 400/300- 550/350. These truly come alive with an FCM revalve!
# Revalve/rebuild? Can be revalved by Bilstein to achieve your goals. We no longer offer services on R-pkg/93LE shocks due to volume of orders for custom coilover packages using new Bilstein HDs.
# Dyno graph:

# Bilstein HD, 90-97 Miata - aftermarket, German-made, intended for 90-97 Miatas, may be adapted to 99-05 via FCM mounts
# Background: soft low-speed rebound and compression, although rebound increases very quickly. very strong low-speed rebound damping and very weak low-speed compression
# Usage: The valving was designed in Germany for German roads (which are smoother than most in the United States). Best suited to smooth roads or stiffer springs, up to ~450 lb/in front, 350 lb/in rear
# Revalve/rebuild? Can accept a very low-mileage 90-97 Bilstein HD but prefer to start with brand-new. You achieve better performance and longevity if we revalve new HDs whether shock-only or as part of a complete coilover package. Revalve cost is $150 per shock and we shape the entire damping curve based on vehicle + passenger weights, driving style and your typical roads. Bilstein revalves are less refined than what we perform based on our modeling and detailed consulation process
# Dyno graph:

So what I'm gathering from that, is if I was racing on a smooth, fresh track most of the time the HD's would be "OK" for the time being but would come alive with a good revalve. So it says 350 rear, 450 front... would stretching it out to a 550 be terrible? Or driveable for a season on the track?

beats me. You'd probably be best to just valve them right off the bat for your spring rates.

I know what would be best, but I'm running otu of $ and time to get this car ready for knox mnt hill climb. So I'm just looking at alternatives right now.

If I've learned anything in my time as a Miata owner....don't cheap out on suspension.

lol.. why does everyone always assume I'm trying to "cheap out'... I want tog et the car running, on the road and ready for the hill climb. I'm basically asking if I can get away with one event with stock valving... will I REALLY notice that much difference?

They will be valved sometime within the next month and a half to 2 months.

Hopefully I can let you know what 550/300 feels like on OTS HD's before the end of the month if that gives you time. I have experience with them with 400/300 and I can tell you (without typing a page or getting technical) they just feel really soft when you want them to be stiff, and really stiff when you want them to be soft. Not as much control as there should be.

I'm sure you already know about their faults of too much rebound, too little compression though.

I don't think your car will blow up if you use 550/330 on them for one event though (but don't quote me on that!:giggle:).

It would be in your best interest to have them revalved as soon as you can to extract the most from your setup if you do plan on driving your car to the limit.