Trackside testing Flatout and Rob L. There? anyone else who tracks?

I own a Ferrari but race a Porsche doing POC club racing. I can give you a partial answer based on my experience doing road racing not ovals. A car should be tuned using front and rear anti-roll bars. Ride height should be set with a four corner balance using four scales and then left alone. I don't believe in tuning using tire pressures. All race tires have an optimal pressure and once you find that keep it the same. Finding the optimal pressure for any tire takes a lot of effort and you don't want to throw a variable like suspension tuning into the mix or you'll never get your tires right. I don't run a wing so I can't comment on that. Yes, I often have to setup the car to stick in certain high speed turns knowing I'm giving up grip in other turns. That is, the rear may be stepping out in a long sweeper, I tighten the front sway bar to keep it planted but start to get understeer in low speed tight corners. You have to juggle the setup and sometimes adjust your line to compensate. There's no perfect setup for every track. That's part of the fun of it all. I keep a notebook out at the track and write down all changes and the result and then put it in a computer log. When I return to that track next time I have a base to start with. Once in a while I almost fool myself into thinking I know what I'm doing, but the roar of guys passing me will usually bring me back to reality.

 

Good attitude Drew, you'll get a lot out of your motorsport!....

....but with regard to tuning with your roll bars....try to tune the end that's giving you the problem as much as possible. If you have oversteer, tune the rear before going to the front roll bar, and vice versa. With the GT3 you have that luxury, shame the 360/355 C cars have to have different bars fitted.

With Ferrari, playing with ride height will reap great rewards BUT, I'll say it again B U T.... you MUST check/adjust camber and toe if you move your ride height significantly (+-3mm~), as Ferrari's typically have enormous amounts of bump steer and camber gain.

I agree about tyre pressure. Find the sweet spot and never vary by more than a lb or 2.

If you have a wing, tune it last. Maximise mechanical grip first. Springs is the biggest noticable change, but often impractical trackside for numerous reasons, so adjustable shocks are the way to go if you are a serious player.

Bottom line though, is that EVERYTHING you adjust WILL AFFECT something else!! So it's knowing how much to do, when and where, that is the Holy Grail of set up......

 

The most important thing in motor racing or high speed lapping is to maximize the traction offered by the four tires. This can be done in 2 ways:

1. By the driver in how they handle the machine.
2. By the driver / crew in how the machine is prepared for the track and conditions.

It is very easy to get lost when setting a car up because there is so many variables to consider. The advice I always give is to go out and buy a tire pyrometer. DON'T buy one of those point and shoot guns. To really understand tires you need to use a needle pyrometer as tire carcas temperature is critical to understanding the way the car is performing. In addition to this you want to keep detailed notes on as many variables as you can record. When taking your tire temps always start at the same wheel. Choose the one that does the most work at a particular track and then go to the tire that does the second most work, etc. When you collect enough data patterns will emerge and setting the car up will become easier and easier.

There is no magical formula to car setup and certainly no one individual change is the cure all. Find out what each change you are willing to make is supposed to do to the handling of the car. Also find out what the optimum tire temperature is for the tires you run. With this information you can chase one simple guideline for vehicle setup:

Assuming the tires are operating within their optimum temperature range, strive to ensure that they run at the same hot pressures and temperatures all around (certain exceptions apply but we are looking for uniformity here).

 

How serious do you want to get? Ideally, in my limited experience ... rent a track that is suited to whatever you are trying to test. Some tracks are very abrasive for tires, some are better for aero, some are better for handling, there are short and long ovals, etc. etc. Rent and share with other cars/teams who can conduct themselves professionally. Know what you are going to test and be prepared with necessary spares, tools, people. You must test in the disciplined manner Maranelloman suggests - and the driver must be able to be consistent over a large number of laps. Data should be recorded in detail, everything, weather, track temps, etc. Data acquisition IMO is the best way to go. To me, a 2 day test is better than one day, as it allows time for overnight reflection and debrief.

This, of course, is only for those determined to take all of the fun out of just going to the track and hanging it out.

 

"The 348/55 has solid non-adjustable bars. But tell me about how you tune with sawybars anyway. Do you soften an adjustable bar in the rear to correct (reduce) oversteer and stiffen the front for less "push" or what?"

I try to learn something everyday, so I will use Phil's advise and only adjust the sway bar at the end of the car that I'm trying to correct. So:
Rear bar, soften or move the drop link away from the bar to decrease oversteer, firm or move the drop link towards the bar to increase oversteer.
Front bar, soften or move the drop link away from the bar to decrease understeer, firm or move the drop link towards the bar to increase understeer.
When you soften or move the drop link away from the bar you are shifting weight onto that set of wheels which causes them to grip better.
That's my sway bars 101. It's hard to believe no one makes after market adjustable bars for the 348/355's. There's a ton of aftermarket stuff available for Porsches.

 

There are different size anti roll bars available for 355 and 360 Challenge cars. I think 355 has choice front and rear, but 360 only has choice for front. Don't know for 348, might be the same as 355, not sure?

On the Porsche GT3, with its holes for the links, a good tip for fine tuning is to "split the change". There is no need to have the bars set to the same hole each side of the car. If you only want a small change, just move one side.

Also, with the GT3, if you find yourself running out of adjustment, a ride height change may work for you. eg, if the rear keeps stepping out on the high speed turns, and you're already fully soft on the bar, try lowering the rear only a few mm. They too suffer from geometry changes, but to a less extent. Still worth trying, especially in a one make series.

To correct low speed entry turn in, you can experiment with different compound brake pads if rules/costs prevent the fitting of a brake bias.

With regard to camber gain and bump steer components.... there is a NEED for camber gain, so to remove it is not good. Bump steer is the more of an enemy, and serious teams engineer all sorts of devices to try to control it.

On a 355/360, the lower they get the worse the geometry, so a road car on the track is not so bad, but a lowered race car gets ugly, but usually has less travel due to stiffer springs.

 

In So Cal the Ferrari guys are mostly polishers no trackers. Trackers are few and 99% of thoose are stock car trackers no mods. In fact I am the only guy I have seen on a track with a Ferrari who does Race group when available."

I used to belong to the So. Cal FOC. I went to the Virginia City Hillclimb nine times in the late 80's early 90's. In 2001 I called the FOC to try to get info to enter the Hillclimb again with my newly bought P car, and the president didn't know what I was talking about. That's when I decided the POC was the place for me. There are two guys with full race 360's doing our events. At our last racers clinic another guy came with two full race 360's, so it looks like there will be a Ferrari presence at our POC events for awhile.

 

A bit late to the discussion but here goes!

First off, when you say set up you must first determine what you goals are. In racing the goal is fairly simply (but the path there is fairly complex). In racing the main goal is to get the car to achieve the fastest lap time. PERIOD. In a nut shell you want the car perfectly balanced (no unwanted oversteer or understeer). Of course this is impossible so you spend time finding the best compromise that yields the fastest lap time.

At track days, the fastest lap time may not be your goal (it could be but might not be). It might be that you want to tame some unwanted trait like oversteer or understeer that may in fact make you slower but more comfortable in the car. It's rare at track days that people are doing serious set up changes to yield 0.20 seconds per lap (though there are a few).

The biggest limitation at most track days is that you have 20 (or 30 minute) sessions and cannot come in during a session to change something or evaluate it. Other than Trackmasters, here on the East Coast, I know of no one that has 1 hour sessions where you can effectively do real testing.

At most track days, when I had the 355 Challenge, I started with a baseline setting (usually provided by Ferrari of Washington's team manager). As Drew pointed out my first order of the day was to get the tires to operate within their maximum temperature range using a tire pyrometer (as Nuvo pointed out it has to be the pin type) and air gauge. Also make sure you get an expensive tire pyrometer that records the temps (so you don't waste time writing them down).

Once I get an even tire temp across the tire the next step is to evaluate how the car feels in certain corners (smooth transition, where is it loose, where does it push.....) .

There is no magic formula for what to start with. Your particular driving style will to some extent dictate what is important in setup as will the car you are driving.

In the 355 C my main concern was rotation at the apex on fast and medium fast corners. This was due to my driving style which uses braking in a straight line and early apexes.

On my Grand Am/HC car it's all about turn in (FWD). My main goal is good turn in and dialing out as much understeer as possible (which means setting the car up insanely loose at the rear).

Anyway, getting back to your original question, with the 355 C I usually worked with minimal changes such as tire pressures, sway bars, and if it was a track I visited frequently I would change springs between events and play with the shocks. I would fiddle a bit with camber and ride height as well.

Racing is a whole 'nother story. I am sure Rob L. can can back me up here as well, but I doubt he spends 1/10th the time on set up for his 355 as he does for his SRX7.

In prior years I fiddled with setups but didn't get serious until this past season when I was suddenly battling another racer at every track. We were dead even everywhere we went. The last six race weekends our fastest laps in qualifying and race were never more than 3/10's apart. I swapped out springs, changed camber, caster and toe settings, as well as ride height, sway bars and other items. Phill is absolutely correct about tackling the end of the car that is giving you the trouble, yet I see the exact opposite many times.

The other thing about sway bars is that they should be used as a fine tunning mechanism and not as a major set up change. Some may not agree with this but I really think you need to get the set up pretty darn close to optimal then fine tune with the sway bars.

The most important things I learned this season is that a) the stop watch does not lie, b) that fastest car doesn't always feel the fastest or the most comfortable, c) a set up early in the race can be great but turn into a bad set up 15 laps later and d) proper seating position is worth a half second, over a long race.

b) was my biggest hinderance. Case in point at Summit Point raceway there is a fast downhill increasing radius right hander (taken at about 110 in the Acura and about 120 in the 355 C). All season I was losing time in this corner to my championship rival. I noticed that he would turn in later but get very loose at corner entry. For those who know the corner, it's called the "chute" and any screw up on this corner will wrap your car up like a tin foil ball (kind of like the kink at Road Atlanta......you don't come away from that corner with a cracked bumper).

I finally started turning in very late which was against everything my driving style entailed. The car did indeed become very loose a required minor corrections nearly everytime. One, I wasn't at all comfortable with this at the start and two, I was convinced that I was loosing time doing this. However, after taking segment times I was quicker with the late turn in and the oversteer.

So, in closing, a lot of factors come into play in determing the right course of action to start the setup process. Once you have some data to work with you then make best estimate guesses at each track of where to start on setup taking into account weather and other track conditions.

I have yet to run across a track where I specifically set the car up for one specific corner, but tracks like Lime Rock and Summit Point have sections of track and corners that are all very important. At Summit Point it's all about getting through the "carosel" section which leads through 5 corners to the crucial last corner, which leads down the 3000 foot main straight.

At VIR it's all about the uphill esses and being able to get through them without lifting.

Hope this helps to add to what others posted.

Regards,

Jon P. Kofod
www.flatoutracing.net

 

If you use a "decent" wing, made for your chosen model, it will have adjustment designed into it that will preclude stall/excessive drag as an available setting.

The factory 355C wing and the Michelotto Year 2000 GT wing or even the current 360 GT wing that I use are all such examples.

If you buy a ricer version or make your own from a donor car....good luck!

If you want a big rear wing (bigger than a 355C), you absolutely MUST do something about front downforce, and probably horsepower too!!

 

Excellent thread. Billybob, I feel your pain, we all do.

Lot’s of good info here too.

A few years ago I attended the SCCA Runoffs at Mid Ohio. One evening there was a seminar hosted in a tent in the competition paddock titled something like “How To Make Your Car Faster”.

It was a 40’ x 40’ tent, I arrived about 10 minutes early, and it was standing room only. There must have been well over 100 drivers and crew there. Not hard to believe the popularity of a free seminar on this subject. There were three speakers, one a chassis designer/ manufacturer, one data engineer, one damper company representative (self-admittedly not an engineer, but very technically savvy).

Everyone attending is looking for that magic bullet or formula for successful chassis set-up. Anticipation in the air… finally, salvation. But not tonight.

The organizer and speakers were all well intentioned, and promoted their individual products and services well, but it wasn’t the answer the attendees wanted to hear. It was yet another affirmation that dialing in a racecar is hard work. The agitation began within fifteen minutes. After 40 minutes I was able to grab a seat on a bench. After an hour, there were only 30 people under the tent. By the time Q & A started, only eight.

As with other tasks or goals in life, there are many methods to discover a proper racecar set-up. Some better than others even though quite a variety will work. Basically it comes down to the time it takes to find a solution and being confident that you know why you were successful.

Carroll Smith’s books will tell you to first do your homework in the shop that will save time at the track (when time is most expensive). Like determining what the effect of raising the front suspension two turns of the spring collar does to actual ride height, rake, camber and toe. How much ½ turn of the tie rod affects toe. How rake changes affect wings angles. On pre-Modena Ferrari’s, what various thickness shims do to camber and rear toe.

For tires one starts with the manufacturer’s rep (though often not close to where you’ll end up, but you’ve got to start somewhere). (And on this subject, you can gather some basic data yourself like measuring the tire’s spring rate at given pressure and camber angle on a rig in the shop and one scale pad.)

At the track with an unknown car, or an unknown track (assume a formula car or proper GT with adjustable everything), start with establishing if the tires are working or not, then go for springs, then ARBs, then dampers, finally aero. Look for grip first and set up for the fastest corner (frequently not the one leading to the longest straight, it’s because it take longer to accelerate from say 95 to 100 mph, than it does from 45 to 50 mph; this is where you kill the competition.) When you run out of practice session time, you kill the end of the car with more grip to go for balance so the driver can survive for an hour.

Ride height/ rake changes are great for many cars, especially for production based chassis with crappy camber curves that take hours to change springs or ARBs. As stated by Phil, 348/355 is sensitive to 3mm (within reasonable race ride heights, got to get that CG low too).

Back to tires; remember that pressure changes and camber changes will change the spring rate of the tire. The suspension actually has two springs placed in series (neglecting the fact that the chassis itself is a spring too). Many race tires test around 1000 lb/in or much more. Call Competition Tire East with the part number of Goodyear slick you race on and ask for its spring rate; they’ll give it to you.

BTW, I totally agree with the driver’s influence on finding a fast set up (Jon gives a great example).

I do disagree with a couple here in this thread that there’s no magic formula. There is, but it takes hard work to get there, and the formula only supplies about 60% of the answer, the rest comes down to experience, preparation, timing and luck. Even in F1.

Investing in data acquisition equipment and interpretation skills will save an incredible amount of time and cash, especially when you consider just the cost of a set of tires. A kick @ss data system will cost $15,000. A great one, almost just as useful, may only be half that. A data system and the knowledge to use it justify its cost in tire savings alone, not to mention track rental, crew, aggravation factor, etc. Even $3,000 gets you so much further that intuition and guessing alone (I’ve been there). I’ll never go racing without data acquisition again. (Don’t forget to put your name and contact information on the lap time beacon. )

Even if you can’t justify the time and effort to measure the spring rate of your tires, the moment of inertia of your car in roll, pitch and yaw, plot suspension geometry (software is quite affordable now), a simple data system measuring lateral acceleration, steering wheel position, throttle position and wheel speeds will benefit you not only with set up changes, but driver coaching too (and might save an engine or two).

Magic numbers do exist for specific tires regardless of chassis. This is one reason Ferrari’s been so successful: their relationship with Bridgestone (co-dependent BTW).

And this is why that seminar at the Runoffs evacuated so quickly: the realization that this shizzle is hard work in order to win and know why you’re winning.

Best regards,

Rob

 

This is some good advice, Really!

 

So, are you all aware that 355C comes with no Datalogging, but 360C comes with a basic but usable Magnetti Marelli System as std equip??

The Marelli is not set up to use steering/brake or shox position sensors, but you can still do 90% of the learning as long as you get a professional to put some data into your car for you to compare your own against.

Most amateur drivers try to go faster by going faster. They usually end up in the wall if not trained early enough.

The biggest common difference an experienced professional has, is being able to go AS fast for LONGER in the lap. He (or she!) brakes less and later, steers less, and gets on the throttle more and earlier and stays on it for longer. He also has the physical fitness and mental capacity to be able to devote his concentration to driving and strategy and not just hanging on and praying to get round the next bend!

 

Don't buy a Stack.

That said, there are many great affordable systems. Invest a little more in a system that can be expanded if you think you may get addicted to the data (as all techno geeks do once you've played with the systems).

One of my affordable, reliable, user friendly favorites systems is AIM.

You need enough memory in the system to gather data for whatever your race length is (an hour?) with sampling rates that will provide valid data for lateral acceleration (sometimes built into the logger), steering wheel posiion (any car with stability control like the Corvette already has this sensor), throttle position (again, all production cars have this now), and wheel speeds, at least one front and one rear. If you're racing something built in the last few years, see if it has a CAN data bus for communications and you can tap into that data stream with an adapter from the data system manufacturer (which is how the 360 Challenge Marelli system works).

Price out an AIM system with those sensors and I bet it'll be less than $4000, maybe half that.

Buy a book on the subject, there are a couple good ones. My favorite is still be out of print: Data Power by Buddy Fey.

One I've not read is Competition Car Data Logging by Simon McBeath. I found that one on Amazon http://www.amazon.com/exec/obidos/tg/detail/-/1859606539/qid=1105023161/sr=1-2/ref=sr_1_2/002-0273097-6246407?v=glance&s=books


Best regards,

Rob

 

Actually contrary to conventional wisdom I always started out (at a new track) with maximum downforce, with the exception of Pocono long course (use 2 of the 3 NASCAR corners).

If you are doing everything correctly I would gather that you would tune the wing along with specific suspension set ups. In my case most tracks were high downforce tracks so that's where I started with the wing and then after getting the right suspension setup I would take some wing out to see what happens.

Remember I wasn't racing the 355 C so I wasn't going to those lenghts to use the wing in conjunction with set up changes to get a faster lap time.

In regards to the "noodles" comment I think Steve Early was referring to the extensive number of miles on that chassis (which was replaced with a brand new tub before Rob bought it).

Regards,

Jon

 

I saw that too. I'm glad I own one already.