slick1851

http://farnorthracing.com/autocross_secrets3.html

slick1851

Bilstein

Bilstein makes amazing shocks - they are mechanically simple, parts are dirt cheap and readily available, and the innards of their street shocks and their full-race shocks are identical. Crack open a Bilstien street shock, and inside are the same parts as inside their NASCAR shocks. That means that there is a simple conversion process (involving welding a boss onto the shock body to fit a Shraeder valve into the gas chamber) to turn an off-the-shelf street Bilstein into a full-race, user-serviceable, user-revalvable NASCAR Bilstein.

(Oh, and don't turn up your nose at "NASCAR" - they are every bit as sophisticated in NASCAR as any high-dollar road racing series, and they have larger economies of scale so parts are cheaper. Any time you can raid a NASCAR parts bin, do so)

The hardest part of getting race shocks onto production based cars is fitment. Real Race Shocks mount with a standardized 1/2" heim joint, so that aside from body and shaft length, race shocks are all interchangeable. The OEMs, however, seem to change shock mounting methods and dimensions *****-nilly, so the trick for a production-based-car racer is finding somebody who makes a shock that fits. Bilstein, being a huge company (they are a division of Theissen-Krupp), makes a ton of fitments, so if you can get your hands on one - PRESTO! Convert it to a take-apart and you've got real racing shocks for a bargain price.

Bilstein's tech support was also easily the best I ever worked with. Bill Hindorff at Bilstein would design valvings for me to fit design curves, and he went way out of his way to teach me how to design my own shimstacks (partially, I suspect, so I'd stop bothering him to design me shimstacks). I got tons and tons and tons of help from Bill, way out of proportion to my importance, and the end result was me learning how to effectively tune shocks.

There is only one small problem with Bilsteins: no *****.

Bilstein does not really make adjustable shocks. They have a rebound adjuster (and they use it on the PSS9 series shocks) but it is really crappy and hard to tune - to the point of worthlessness. It's an on-off switch for the most part. That turns out to not really be a problem for those inclined to tune shocks by revalving, but the average customer wants a **** to fiddle with and so Bilsteins wound up being a hard sell. Those that bought them were universally ecstatic with their performance, but it was tough work getting anyone to buy them when they could buy a shiny quadruple-adjustable from some no-name brand.

And those people were invariably unhappy....

You can add a compression adjuster to a Bilstein, by buying Penske or Ohlins remote canisters, throwing away the Shraeder valve and the separator piston, and attaching the remote to the valve hole - that what my personal shocks were - but that's a lot of money to get more weight and little extra functionality. It just isn't needed.

mitchntx

iTrader: (14)

Exactly. Great post!

If you can give Bilstein your car's weight, corner weights, cross weights, spring rates, sway bar roll rates, they can valve them for your specific application.

How to make a real shock fit your car?


For the F-Car, this extension which screws onto the top of the shock shaft in place of the hiems adapts them to the F-Car's fitment issue.

http://www.daymotorsports.com/produc...OCK-EXTENSIONS


On the rear shocks, the bottom mount needs a pair of conical spacers like these so that the shock can articulate interence free. And use a quality grade 8 bolt for mounting.

http://www.daymotorsports.com/produc...APERED-SPACERS


The front lower requires a little fabrication. Weld these shock mounts to your lower A-Arm and you are good to go.

http://www.daymotorsports.com/product/25/SHOCK-MOUNTS


Then look at all the shock choices you have.

http://www.daymotorsports.com/shop/Shocks-%26-Springs


Also, don't turn your nose away because these are dirt track components. Dirt tracks all over the country run very sophisticated suspensions. So don't get caught up in the stereotype.

Sam Strano

iTrader: (41)

Might want to do a bit more digging into some things. Namely the source. Smart enough guy. But one who constantly got beat down. He's an autocrosser, or was--quit a number of years ago after winning one championship in a new, lightly contested class.

Some think I'm super arrogant and cocky, but I'm just upfront about things. So, being upfront: I've won more SCCA Championships in one year than the author of the link above won ever--and in the cars the folks on this site own too. There is indeed some good information in the link, also some dribble. The author at one point claimed my Camaro was prepped to 65% of the limit of the rules of the class I was racing in (a class he tried for a while, lost badly in, than ran from, claiming the rules were too limiting). Of course he never actually set up a Camaro. Later when the Mitsubishi Evo 8 came out, he proclaimed that nobody could make that car quicker than stock for autocrossing, it was that good out of the box. That's certainly not the case, never was... but in the years since an Evo modded beyond Stock category specs is hugely faster than stock version--often running as quick or quicker than modified C6 Z06's.

All I ask--consider the source.

Bilstein shocks are in and of themselves very nice... trouble is they aren't perfect for this car either. We all have preferences. Mine it toward useable adjustment in a proven package that bolts on, which is why I normally use a Koni when looking to make a car handle well. Some prefer to use other things and forgo adjustment for say a rod-ended mount. Ok. To each his own.