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If my back-of-the-napkin numbers are correct you will absolutely coil bind those springs before the shocks bottom. Coil bind a spring even once will usually destroy it. Go to the eibach website, figure out your part number and look at the stroke numbers. The stroke of the shock is known but you can also simply measure the shaft. Allowed roughly 20 mm for the bump stop to be compressed to block height. you need to do this before you install them in the car and certainly before you drive it. Again, if my rough math is correct you will need a minimum of 7" spring, ideally with either a ZRT (zero rate tender) or short helper spring in the 100 to 200 inch pound range.
That's good to hear! I know I won't be able to really test them out until I get on track but so far I am loving them. Did you end up upgrading to Xidas?
Yes i did. Purely because my street car came with them and it made sense to have the lighter shocks on the car i cared about being light. I was not shopping and from a performance standpoint i cannot tell the difference.
I've posted here a couple of times but yet to pull the trigger on anything. Just trying to get a lower ride while handling well and not be really jarring. I drive about 30 miles on the highway to and from work 2 -3 times a month. Car is mostly just a weekend fun toy will never race. Has anyone compared these to say the Goodwin spec Road Race FEALs?
Yes i did. Purely because my street car came with them and it made sense to have the lighter shocks on the car i cared about being light. I was not shopping and from a performance standpoint i cannot tell the difference.
Damn that's an impressive statement. Everyone talks about Xida's as if there is no comparison.
I have no personal experience with them, but after having just taken my first aggressive canyon drive since putting on the Whitener's, I am curious how much better it can get. I am blown away with how well the car handles now. I guess with the Xida's there is a lot of adjustability for different conditions and situations, but yea, the performance of these are amazing. And still comfortable enough for the street!
Can confirm, I've run whitener re-valve Billies and Gen II XIDAs on my race car. The car came with the bilsteins and that's what I ran the first ~year.
Honestly, I was a little disappointed when I first put the XIDAs on. They were/are better for sure, and the adjustability helps, but they weren't as much better than the whiteners then I was expecting. I was expecting to be absolutely blown away by the XIDAs, but they were only a marginal improvement in my eyes.
Now that said, I only use the bilsteins for ChampCar races...if I'm racing in NASA or SCCA the car absolutely has the XIDAs on it.
Similar set-up for both damper sets...PTE/ST6 type car, OEM sways ~1000/400 springs on both, 225 hoosiers, etc. etc.
If my back-of-the-napkin numbers are correct you will absolutely coil bind those springs before the shocks bottom. Coil bind a spring even once will usually destroy it. Go to the eibach website, figure out your part number and look at the stroke numbers. The stroke of the shock is known but you can also simply measure the shaft. Allowed roughly 20 mm for the bump stop to be compressed to block height. you need to do this before you install them in the car and certainly before you drive it. Again, if my rough math is correct you will need a minimum of 7" spring, ideally with either a ZRT (zero rate tender) or short helper spring in the 100 to 200 inch pound range.
My back of the napkin numbers say the springs concervativly have 3" of stroke travel and that with the static loads on the suspension they will be compressed 2". I am going to do some measurements on car once I have some time and see how much the bump stops compress sans springs, add 1" to that and then see where my ride height is at and if it is acceptable. Yes they will go loose under droop.
I do have some 8" 325lb springs on the way and am looking for a set of 9 or 10in ~200-225lbs springs to eventually put on these. These 8k/6k springs are just curiosities since they came with the threaded sleeves.
FWIW I run the shortened stroke bilstein shocks and I run 6 inch 550 springs and 350 rear springs. I have extended top hats on the front and rear and at no point ever do my springs get loose. There is 0 need for my setup to run tenders or helpers.
Yeah, you listed all the stroke lengths in a thread a few years ago. Just gonna make sure they are burried well into the bump stops before the spring is fully compressed and maybe add some droop limiters. It's a beater street car on 185 all seasons, so not worried too much about running into any major issues. If my measurments work out (which I have no idea, still learning, and I learn best by doing), I should have about 1.4" bump travel before being heavy into the bumpstops and 2.75" droop travel before the springs go slack. My daily has only ~2.5" of droop in the back due to some oddball shocks and that seems to be plenty for the street.
I need to get arround to measuring stock bump and droop travel one of these days since I haven't yet and haven't found good measurements online.
I am trying to put together a shopping list and am stuck on the shocks. This is for an NA.
Which of the following will fit on an NA? I already have NB tophats so it would be great to be able to use those for this build. My understanding is that the B8 is for a lowered car. This is a track car that runs on Hoosiers, I was thinking 450-550 rate springs for the front and 300-350 rate springs for the rear. I have read through the first and last several hundred posts in this thread and have not found the solution.
NB Shortened shaft bilstein shocks are what you want. That's what I use on my NA running 550/350 springs. Also look into extended front and rear tophats.
NB Shortened shaft bilstein shocks are what you want. That's what I use on my NA running 550/350 springs. Also look into extended front and rear tophats.
Got it, thank you for the help. NB shortened shaft being the NB B8 shocks, correct? Why not go with the NA B6 shocks and not have to worry about the extended tophats?
Updating this for anyone searching the thread in the future...
From 5XRacing:
Hi Jesse, thanks for reaching out. This is an easy one, the NA Bilstein HD (B6) shocks are the way to go for a track car, and our Coilover shock mount system will pull the NB top hats into the equation for you. This is how our Spec Miata coilovers are set up and the parts they consist of. This can be your guide as to what's needed to set up your own DIY coilovers, or I can put together a special product on the site that includes all of these components and allows you to choose your own spring rates in the meantime:
qty 2 of 24-014885 Bilstein HD Front shocks
qty 2 of 24-014892 Bilstein HD rear shocks
qty 2 of 6" 700 in/lb Front Eibach race springs
qty 2 of 7" 325 in/lb Eibach race springs
qty 1 of 5X Racing coilover sleeve and perch kit
qty 1 of genuine Fat Cat Motorsports shock mount kit
qty 4 of OEM 1999-2005 NB Miata shock hats
We've never had spring bind issues with the 6" in front and 7" in the rear, and believe me, if there's gonna be an issue with it, Spec Miata racers would have figured it out in the last 20-years we've been using this setup! No point to add another inch worth of spring if you don't need it, and that'll also reduce your ability to lower to a certain extent too, as that extra inch will be an inch less you can lower than with the 6".
If my back-of-the-napkin numbers are correct you will absolutely coil bind those springs before the shocks bottom. Coil bind a spring even once will usually destroy it. Go to the eibach website, figure out your part number and look at the stroke numbers. The stroke of the shock is known but you can also simply measure the shaft. Allowed roughly 20 mm for the bump stop to be compressed to block height. you need to do this before you install them in the car and certainly before you drive it. Again, if my rough math is correct you will need a minimum of 7" spring, ideally with either a ZRT (zero rate tender) or short helper spring in the 100 to 200 inch pound range.
I have had some 4" springs on my personal cars for 5 years and they are not close to binding.
I have had some 4" springs on my personal cars for 5 years and they are not close to binding.
The white stuff in the picture is clay:
Not sure what kind of shock that is, but spring appears to be a Hyperco. 4" 600# Hyperco which has a total stroke of about 61mm, about 90% of which is useful. So ~55mm. No spring manufacture will recommend using 100% of stroke.
Also assuming a 35mm bump stop block height of about 20mm. OEM rear is 131mm stroke. Bilsteins around 126mm. So rough math would be 55m spring stroke for a shock stroke of 106mm.
The reason they don't coil bind is because your car is very light, you run it very low and have no effective droop travel. Your springs are not doing anything when dropped much past static ride height.
While you may be happy with that level of functionality, it's not something I would recommend nor promulgate.
Final list check, please let me know if you see anything wrong. This setup is going on an NA, I already have NB tophats so those are not on the list. The car runs on Hoosiers for track days and rarely sees street miles.
Also, NA B6 (HD) Bilsteins can be purchased new from aj-usa on ebay for $400 shipped for the whole set. Just use the "make an offer" button and tell him you're getting the whole set.
Why are you going with NA bilstein shocks? 650 seems like a lot of spring on stock valving.
I am basically doing the build that the spec miata guys run. The NA HDs are heavily damped and some of the SM guys run even heavier springs than 650/350. I have not seen anything other than anecdotal evidence from anyone, so I just listened to what some SM guys told me. I am open to suggestions though.
05-09-2020, 12:19 PM
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