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"Most of the focus for the setup with this type of car is in getting it comfortable and preserving the tire--this also happens to be where the tire is working best."

 

Suspension Tuning with Mike Skeen, Jade Buford, Matt Romanowski, Dave Scott and Robert Metcalf

by Mike Skeen, Jade Buford, Matt Romanowski, Dave Scott and Robert Metcalf

 

With news of the Camaro 1LE Track Pack, it occurred to us that adjustable suspensions are increasingly available to track day participants.  But, how many HPDE participants have training or experience in suspension tuning?  We posed a hypothetical question to our team of professional driving coaches.  Here is the scenario:

You are asked to coach an experienced solo level track day driver (not necessarily a racer) with a new car.  Let's say he or she has just purchased the 2018 Camaro ZL1 1LE.  Here is a description of the car's suspension:  

“Adjustable suspension: The ZL1 1LE features racing-derived, lightweight Multimatic DSSV® (Dynamic Suspension Spool Valve) dampers front and rear for exceptional wheel and vehicle control. The front-end ride height is adjustable with the front dampers, which are used with all-new, adjustable camber plates. The rear stabilizer bar also offers three-way adjustability. All of the components are designed for quick changes at the track for optimal performance and a quick return to street settings when the track day ends.”

Camaro ZL1 1LE Track Pack

The driver has no experience with suspension set up, but understands it in theory. How would you go about teaching this driver the basics of suspension set up over the course of a weekend HPDE event?  Assume he is familiarized with the new car on track. Would the skills be specific to the particular track or would the knowledge be transferable to other tracks? If one weekend is not enough to accomplish this, how much training would be required for the driver to be able to do his/her own experimentation?  Would data logging help?  How would it be used?  Assuming there is a track support person to take tire temps in the hot pits, would those be useful? How would tire temps be used? 

 mike skeen400px

Mike Skeen, Professional Driver and Coach

Pirelli World Challenge,  IMSA WeatherTech SportsCar Championship, NASCAR Camping World Truck Series

http://www.mikeskeen.com/

In this scenario, the suspension adjustment is still fairly limited, but that is a good place to start for someone with limited experience.  Most of the focus for the setup with this type of car is in getting it comfortable and preserving the tire--this also happens to be where the tire is working best.  If you do not have the correct camber or toe, it's easy to wear out the shoulder of a tire on a fast, heavy car such as the Camaro.

It's rare that the primary focus in this situation would be on the setup, because at this level the driver would typically have more room for development than the car.  This is also something to consider in the process of tuning the setup--the driver has to be very consistent for best results.  That being said, we would start with a moderate run to warm up the car and stabilize temperatures (5-10 laps at most tracks).  Hot temperatures and pressures should be taken immediately after a quick in-lap, not after sitting in the paddock for several minutes.  Assuming the target pressure has been reached, the temperature spread here will give us a good idea of whether our camber and toe is close.  Short, 3-5 lap runs can be done after this to verify changes and their effects, but we don't need to fine tune before working on other areas of the car.

At this point, I would advise tuning with the adjustable rear sway bar and possibly ride height, based on driver feedback.  Again, we are focusing on making the car feel more comfortable in order to improve driver confidence.  These adjustments could be verified with data analysis if the driver is very consistent, but generally, feedback will suffice.  Be sure to go backwards on changes if there is a question--this will make up for changes in track conditions/tire life throughout the day.  Tire temperatures and pressures should be monitored throughout testing and if any significant changes are seen as the setup evolves, adjustments can be made accordingly.

These practices are certainly applicable to any race track and are only the very basics.  After trying all the different sway bar positions and possibly playing with toe/camber/ride height positions, the driver should develop a feeling for what to expect of each change.  This will make the process faster in the future as the driver will have a better idea of where to go to achieve the desired result without wasted adjustments.  There is really no reason an inexperienced driver (in terms of setup knowledge) can't do some trial and error experimentation as long as they are consistent and document the changes properly so that they know the result of every change and can go back to the baseline.  At the same time, a lot of drivers will go backwards with the setup because they are not consistent or disciplined enough to know what the result of their test was, so the performance could have gotten worse without them knowing.

 jade buford400px

Jade Buford, Professional Driver and Coach
Pirelli World Challenge, IMSA WeatherTech SportsCar Championship , Continental Tire SportsCar Challenge

http://www.jadebufordracing.com/

Hypothetically I would usually address any issues I feel with their car specifically on a track weekend on a case by case basis. For someone with little background in car setup trying to cover everything in a single weekend would just simply be too much information for one to process effectively. I would say it would take a couple dozen weekends at various tracks of actively tuning at all of them to really start to grasp all the scenarios and changes that can be made to a car's setup. But for example, If their car is understeering, I would help them learn to diagnose the different types of understeer and changes that can be made to help reduce the amount of understeer. I usually ask questions to help them learn to problem solve on their own. At what point in the corner is the car under steering? Initial turn in? Or once the car is loaded up and in its coast phase? Or on throttle tracking out? From there I would give a simple explanation that the dampers primarily affect the first few feet of weight transfer to any corner of the car. If the car is understeering on initial turn in, a simple damper change can be made to help this but if the car has already taken a set and the suspension is in its steady state going through the corner, a bar, spring, or ride height adjustment would be needed. 

Having someone on hand to check tire temps and pressures is always useful and a lot of information can be gained from looking at how a tire is wearing. One can judge by the tire temperature if more camber is needed or if the car has too much camber and is giving up performance as a result. You usually want the tire to wear as evenly as possible but excessive wear on the outer edge of a tire is most common on street cars being tracked. Although, if the center of the tire is wearing faster, the tire pressure is probably too high and one would be able to learn this pretty quick if they have the pressure and temps from the tire. 

Data is a great tool. But I usually use it more to look at the driver than setup on the track day level. But it is very useful in pro racing. It's a great way to see how a change affects corner speeds and straight line speed and makes it easy to weigh the option of which direction one should take in setup. 

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Matt Romanowski, Professional Coach and Data Analyst

http://www.trailbrake.net/

Setting up a brand-new Camaro ZL1 would be a really fun day at the track. Assuming the car arrived at the track with a setup that was going to be in the ball park, I would suggest to the driver to work through a series of sweeps on all the major adjustments. The whole process is a bit iterative as one change can affect others, but the process of fine tuning and honing in on the perfect setup is part of the fun!

I would set a few things up to begin with. If we had some track support, I would take tire temps and pressures every time the car comes into pit lane.  Those temps and pressures would help us to dial in tire pressures and fine tune our camber settings as we evolve our setup. I think my first set of sweeps would be on the rear sway bar, trying to set the basic chassis balance. With only three adjustments, it would be pretty quick to dial that in to what the driver likes. Next, I would do shock rebound sweeps, followed by compression sweeps. These would get us in a good area of shock performance. Finally, I would work the front ride height to solve any oversteer or understeer problems.

Once all of this was done, I would then re-evaluate the camber and tire pressures, followed by tweaks to the shock settings and front ride height. This would all keep the car moving to finer changes and honing in on the perfect setup.

An important part of all this, regardless of what approach someone was to take, is to be systematic in your approach. I would build a test plan detailing the changes with what session they were going to be done, in the proper order, and have a track map and notebook ready for the driver to record their notes on how each change affected the car. Finally, I would use the data system throughout the test session to evaluate peak grip (lateral G), braking performance and traction (long G), speeds, lap time, and whatever other metrics were available.

 

Dave Scott

Dave Scott

Driving Coach and Former Professional Racer

http://www.racecoach.net/

It is wonderful to see so many cars coming from the factory now, street cars that are truly oriented towards track use.  The new Corvettes are great examples.  Some of the Porsches are.  And the Viper, which is now out of production, unfortunately.  To have the manufacturers back the car warranty wise for non-competitive track use is pretty cool.  So the example you gave is an excellent one.  A car that has some adjustability.  It’s a little different in the front and in the back.  In an HPDE environment, let’s say we get four sessions per day, it limits our amount of track time.  So the ability for the owner to feel changes we make and learn how to adjust his or her car is somewhat more limited than on a private day where you have eight hours of track time and you come and go as you please.  But you can still accomplish the same thing.  In no particular order here are some of the things that I would focus on to teach this driver about their new car, which they are not sure how to adjust. 

One of the things you mentioned was the ability to get tire temperatures and I am a big fan of a pro type pyrometer to get temperatures as the car is hot.  That information has helped me throughout the years with my own vehicles as well with racing and getting not only pressures right, but also things like camber.  One of the things I would do with the client would be to have a philosophical discussion before we got on the track of what a pyrometer does, what tire temperatures mean, and what things you need to look for.  If you see a temperature that is an anomaly, I would discuss what that tells you about how to get the car to be better and why this effects our ability to drive it easily and why it effects the car’s ability to handle properly.  

The other thing to discuss with them would be how different adjustments will make the car behave when they are pushing it.  Ride height is one of those in your scenario.  Sway bar is another one.  And the adjustability of camber and compression and rebound.  The next thing we would do is say we have two days, eight sessions.  Let’s say I have talked to the organizers and gotten permission to take the client out in their car with me driving in a different run group.  I would use one of those sessions to lay down a baseline lap as the car is when we took it to the track.  I would give the client my assessment of how it feels and suggestions for changes we might make.  Before we make those changes, I would have the client drive the car in their run group so they would have a true understanding of how the car feels on a track they know so that they have a mental baseline.  Then I would say let’s make some changes.  We are going to change one thing at a time.  Let’s say we are going to soften the rear sway bar.  I would take the client out, drive it, see how the car feels, and see what their perception of the feel is.  Then they would drive it.  Either they would recognize the change or they wouldn’t.  We would both agree on whether to keep the change or go back to where we were.  We would keep going on and make a change to the front end.  We would look at the tire temperatures and let’s say there was way too much temperature on the outside of the tread.  My recommendation is we add some more negative camber.  If we get better consistency of temperatures across the contact patch this would help tire wear and grip in the corners.  We make a change. I drive it and they drive it.  My approach would be to keep doing this and make sure that they were able to truly feel the difference each time, so that they could make mental notes of what we did and how this change made the car drive.  We would try to get the car to a place where they feel very comfortable in pushing the car.  They are not intimidated by it.  The car is not getting away from us.  They are not over-driving. 

I would also focus on two other things.  It’s easy to set a car up for me.  But my driving style may or may not be similar to the client’s.  I make this point early on.  I’m going to make suggestions, but we are going back and forth, you driving and me driving, to see if it suits your driving style.  It’s important to have a track note book.  We talk about variability of settings, where we started, tire pressures, camber, sway bar stiffness, compression, rebound, everything you can adjust and what changes we make and our perception of how the car feels and the reality of how adjustments made changes in tire temperatures.  We would track every iteration of that.  We would come up with the ability to self-coach and the ability to have baseline settings that work for each track they go to and each type of weather condition.  It’s a lot of work, but a new car that has a lot of adjustability is complicated. 

People will HPDE a car and then put on a better suspension with twenty clicks of compression and eighteen of rebound and they are lost.  There are so many permutations and combinations, they spent ten grand on a suspension and there are so many choices and they don’t know how to do it so they put everything in the middle and hope for the best.  That is often where people will hire me.  I have this suspension and I have no idea how to do it.  So we will go through the combinations so that the client feels the changes and can make their own decision about what’s going to work for them.  

 

metcalfracing4

Robert Metcalf

Driving Coach and Engineer

http://metcalfracing.com/live_pages/home.php

The first thing you need is to understand what the various parameters of set up do.  For example, everybody is familiar with the concept of camber, but you ask somebody how should you set the camber on your car and they are going to give you a deer in the headlights look.  What you are trying to do with that particular parameter is to generate a little bit of what I call camber thrust.  If you can imagine this example, take a pencil with a rubber eraser on the end, put the eraser end down on your desk and incline it a little bit and then pull the eraser along on top of the desk while the pencil is at some angle and it’s going to slide relatively smoothly.  Now reverse the direction it travels so that the eraser is leading the pencil and try to push that eraser along the desk and all of a sudden it gets a lot tougher to do.  Well the same thing happens with a tire when you’re cornering.  If you have that tire leaned into the turn so that the car is pushing outward on that cambered tire then, like that rubber eraser, it’s going to be harder to push.  That increases your cornering force.  If you put too much negative camber into the suspension in order to generate that camber thrust, it’s going to overheat the inside edge of the tire and you are going to wind up with blisters on the inside of the tire and it’s going to come apart.  So, you’ve got to balance that and you need to put in as much camber thrust as you can generate without overheating the inside edge of the tire.  Tire temperatures are very good at showing that.  I usually set the camber dynamically at a race track by measuring the tire temperatures when the car comes in.  I generally try to put just enough camber in it to generate about 10 to 15 degrees more inside edge temperature than it has outside edge temperature.  That’s really about all you can do when you’re running a tire hard and you’re up around 200 degrees.   If you run those tires at 220 or 230 you’re going to start having trouble with them.  So you’ve got to understand that parameter. 

By checking tire temps you can also determine what the static pressure in the tire needs to be.  You can tell if it is crowned a little bit because it’s going to be hotter in the center, which, again, you don’t want.  You try to adjust the pressure in the tire by your tire temperatures.  So you need to understand those variables and then there are other things that are more transient.  For example, you have a car like the Camaro that has dynamic shocks on it, double adjustable shocks, and you’ve got a situation where the car wants to oversteer just as soon as you turn on the wheel.  What you’ve got in that situation is when the weight transfer happens, you turn the wheel, the car rolls over on the outside and all of a sudden it unloads that inside rear tire.  If you’ve got double adjustable shocks on it, you can go in there and soften the rear rebound on the rear shocks and that keeps that inside rear tire from unloading when the weight transfer happens.  You do that on a car that has that oversteer problem and it’s going to cure the oversteer.  So again, it’s knowing what all those various adjustments and parameters on the car do.  So the first step in learning how to set up a car is to know what the effects of all the changes are. 

Once you have a grasp on that then you can do some laps, come in, talk to your engineer or your coach and say it’s doing this and its doing that and its doing something else and if you add all three of those things up it kind of sounds like we need to play with the bump in the front shocks or the stiffness of the front springs or something of that nature.  It’s usually a consensus between the driver and the coach or the engineer in terms of coming up with what is actually going to make you faster.  The first prerequisite is knowledge of what all those adjustments do. 

Another technique that I’ve used on a driver before, especially when he gets pretty good, just so he will know what it feels like when it happens at some point in his career, you can do something like take one shock and go to full soft on rebound and not tell him about it.  If he’s got a radio he’s going to go about a half lap and he’s going to get on the radio to you and say, hey, this thing is all over the place, what’s going on?  When I do something like that I’ll explain that I did that so when that happens, when he has a hose on a shock break or he loses pressure in the shock, now he knows what it feels like.  You can do the same thing by disconnecting the sway bar or taking out all of the caster in the front suspension and sending him out.  That’s one of the best ways to teach a driver to identify a problem when he is out on the track.  

 

Bottomline:  Make one change at a time, take tire temps and make notations about everything, epecially what feels comfortable to you (Editor).  Thanks coaches!

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