Pfadt Racing has produced a line of suspension products that have taken the Corvette market by storm and have been very well received by everyone who uses them. We’d like to share some insight on our product development discipline, how we use our Roehrig Shock Dyno, and what it means to you.

Because of the success of many of our customers (winning at the track, and enjoying a great ride on the street) we often find ourselves as the center of attention. We’re glad the competition has noticed us!

The Roehrig Shock Dyno

In the lobby of our Salt Lake City facility sits our Roehrig Shock Dyno. We use our shock dyno on a daily basis to analyze competitive shocks, quality check our products, and to develop new products.

Here is a short video that shows us setting-up, running and displaying data from a Pfadt Sport Shock before it is packaged and sent to a customer.

An engine dyno tells you how much power an engine makes by measuring torque and speed. Comparatively a shock dyno tells you how much resistance a shock has by measuring force and velocity. Given the results of an engine dyno, it is pretty easy to conclude that “more is better.” Unfortunately, given the results of a shock dyno, having “more” is not necessarily better. It’s having the “right” amount that is important.

And there in lies the opportunity for controversy – what is the “right” amount of resistance? We feel that there are a lot of components in determining the correct valving including performance at the track, comfort on the street, and offering a useable range of damping to achieve those goals. At Pfadt Racing, it is our approach to offer customers a valving set-up that provides a firm ride without being harsh.

Understanding Shock Dyno Curves

We had a customer call us the other day with some good questions about shock dyno charts. He owns our Pfadt Adjustable Sport Shocks and is very satisfied with the ride quality and the performance he has at the track. Like many of our racers, he has seen improvements in his times as a result of installing our shocks. His question was over some mis-information he received regarding shock dyno charts.

Let’s look at the most common graph - the “Force vs. Absolute Velocity” Graph. The data below is generic and shown for the purpose of learning the basic vocabulary of a shock dyno graph.

Compression – the area of the graph above zero shows the shock in compression. Compression is when the shock is getting shorter and the wheel is traveling up.

Rebound - the area of the graph below zero shows the shock in rebound. Rebound is the shock getting longer and the wheel is moving down.

The X-Axis shows velocity – meaning the speed of the shock shaft. Slow shaft movement is on the left of the graph and fast shaft movement is on the right. One common misconception of Low Speed and High Speed is that it is referring to the speed of the car. In fact, in this discussion speed is actually the speed of the shock shaft. So low speed situations are body motions: brake dive, body roll, etc. High speed is road inputs: bumps, pot holes, rumble strips, etc. So conceivably you could be driving slowly and still be in the high speed region.

Hysteresis - is shown by the separation between the curves. In the graph above the hysteresis on the compression side at 8 in/sec is much greater then the hysteresis on the rebound side at 4 in/sec. Hysteresis is primarily due to seal drag and is a trade-off between longevity and performance. In general, a shock with extremely low hysteresis will generally need to be rebuilt each season with new seals and a shock with extremely high hysteresis will not need to be rebuilt, but will give up a little in seal-related performance.

Pfadt Sport Shocks vs. C6 Z06

The chart below shows a comparison of our Pfadt Sport Shock at a setting of 6 and the stock C6 Z06 shock. The Pfadt Shock is in green and the Z06 shock is in red.

First, notice the amount of damping at low speed (left side of the graph), which is the body movement of the car like steering and braking inputs. The Pfadt Shock has more damping in this range which provides a more composed ride.

At high speed damping, like pot holes (from about 4 and greater on the graph), notice that our shock has less compression damping. This is exactly the reason for the improved ride quality of our Sport Shocks versus the Z06 shocks. It’s what we describe as firm without being harsh.

Pfadt Coil Over

Below is a dyno curve that shows multiple settings of our Pfadt Coil Overs.

This chart shows many different damping settings. The range of adjustment is greater on the rebound side than on the compression side. You can see the linear nature of the adjustment (the spaces between the curves) so you get an effective, usable range of damping adjustment.

This gives you a large usable range of adjustment and the ability to tune the dampers to meet your needs.

We see the charts, now what?

Now the part that is black magic, voodoo, and hand waving… What do you do with these graphs?

Most people that get a shock dyno graph with their shocks file it away in a folder to never see the light of day again. The key to attaining practical information from a dyno chart is using it in conjunction with linear transducers while testing your car. Unless you can correlate your car to the chart, the chart is of little use at the track.

Professional race teams will use this data as a way of viewing and recording the behavior of a shock setup at a particular track. Then at future races at that track they can start where they left off, so to speak. They will also test each shock to make sure that it is matched; usually this means that both fronts and both rears act the same.

What do we do with these graphs? We use these graphs to test for consistency during shock building, so that the first shock built and the 300th shock built act the same.

We also use these graphs to test new valve designs, adjusting mechanisms and seal designs. Through track testing we can determine a shock setting that is fast and then look at the shock and linear transducer data to determine what characteristics of the shock damping are the cause. Once we isolate the valving that works best, we can build it into our product. Part of our development includes calculations to get close to optimal, but there is just no replacement for on-car testing.

Possibly the best data we can offer is a comparison of our shocks to stock damping data.

Broken into the four quadrants of a dyno graph, we compare our damping range (our Sport Shocks offer 16 damping positions) to stock.

Thanks for reading. Keep in mind that for every person who looks at a shock graph you can have a different opinion of what it means. It’s easy to dig up an odd-looking graph, slap a “Brand P” title on it, and claim it means something.

As our reputation proves, our passion is developing products that you love to drive.

With race season well under way, we’re all testing the limits of our race cars and of course our driving! Seat time is the only cure for better driving, but in conjunction with that, our engineers have been busy working on cures for your race car.

We’re very proud to formally launch our Pfadt Solid Spherical Bearing kit. Polyurethane bushings are a huge improvement over factory rubber, but solid mounts are the ultimate in eliminating friction and deflection in your control arms.

The factory bushing deflection leads to unwanted toe and camber changes in both the front and rear as well as steering sluggishness. We’ve been running these on our race car for two seasons now and we can run less camber (because we don’t have to account for the deflection), we get more consistent tire wear, and the steering is crisp and responsive.

Our kit replaces all 18 bushings with beautiful 6061 T6 aluminum sleeves, anodized Pfadt orange and laser etched with our logo and part numbers. The bearings are held in place with military grade Loctite 638 and retaining clips - they are actually easier to install then polyurethane bushings.

It takes about 108 individual bits to make one 18-piece kit. We do most of the work for you, so all you need to do is the install. Made and assembled in the USA, this kit is is the right solution for your control arms.

For additional information, please call Pfadt Racing at 888-972-2464.

East coast SCCA autocrosser Dave O’Malley has been having a successful season in 2008 running Pfadt suspension products. He has run our Pfadt front sway bar on his Z06 since last season but this year he paired it with a set of our new shocks. Dave wrote me a quick message to give me an update on his season…

Aaron,
I forgot to ask on the phone earlier… Do you have any logo vinyl?
I’d like to put some on my car as the shocks / front sway have been getting plenty of attention at the National events I’ve entered recently. I was thinking across the hood or something like that… I feel like it would help you guys out in shock sales as the car has been scary fast (posting times competitive with previous national SS national champs… ) and many are quite surprised when they see that the car isn’t on remote res. Penske’s or Koni 2812’s.
Dave

Our Pfadt Inverted Shocks and SCCA Super Stock specific front swaybar are proving to be a package that is impossible to beat given any budget.

Joe Gaudette is currently campaigning one of the first sets of Pfadt Sport Shocks to find their way into the highly competitive SCCA T1 Class. Joe races on the East Coast where the competition is stiff and many of the competitors are running triple and four-way adjustable shocks that are outside the budget of many racers.

When Joe found out about the adjustable Sport Shocks he was very excited to give them a try. After a terrible accident last season, he rebuilt the car and finally headed out for the first race of the season, a national race at New Hampshire International Speedway. The weekend was wet but Joe was able to qualify 4^th in class and then take home the 1^st place trophy!

“It is our first National win! First race of the year, first race since the wreck and first race on Pfadt shocks!! ..the shocks felt great. I wasn’t able to really fiddle with them that much because it was wet all weekend but I think the ability to soften the rear for the rain race was a huge help. Thanks for a great shock!” wrote an ecstatic Joe after his win.

We are very excited that Joe was able to run the first set of Pfadt Sport Shocks in T1 and immediately start winning races! Joe took home his first ever national win in the first national race of the season and has lead his region’s SCCA T1 points race ever since!

Congratulations Joe! We’re looking forward to you taking the T1 Championship home this year and setting the new standard for T1 shocks. You’re making us proud!

The Pfadt Adjustable Sport Shock is perfect for autocrossers and street enthusiasts!In terms of features, these shocks give up nothing to the competitive shocks on the market! These shocks set the new standard for an adjustable sport shock. They are great as a stock shock replacement and a hardcore track shock and everything in between.

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