| Nascar Heat Facts : | ||
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You've read all the "quick-fix guides". You've read all the canonical texts on car physics. Now you sit behind the wheel of your favorite racing simulator staring at the chassis setup screen. OK, so where do you start? What should you do first? After that, then what? Maybe you just use the default setups that come with the simulator. But after hours, days or even weeks of tweaking on the chassis, you're still a half second off the pace of the leaders and the chassis is just a different kind of junk than the junk it started as. Sound familiar? In this article, Blackhole Motorsports chassis pro Julian Data mentors "greenhorn" sim racer Timothy Bennett in the "ins and outs" of setting up a chassis from A to Z. Here, Julian not only shares his wealth of knowledge regarding car physics, but we get a chance to "peek" inside his head and witness his approach to setting up a chassis. We'll be using the Nascar Heat™ racing simulator by Hasbro Interactive. The track is the North Carolina Speedway. At just over a mile in length, speeds at the ends of the front and back stretches approach 170mph. You've got to break at both ends of the track, and the two corners are just different enough to cause many sim racers to scratch their heads. Timothy Bennett >> I'll run 30 laps tonight using Heat's Advanced setup as a starting place. What data do you look at/record after running your first 30 laps on a setup? What kind of data are looking at during the run? What mental notes are you taking during the run? Julian Data >> Here's what I look for:
Timothy Bennett >> Julian, here's the results of my first 30 lap run in Hardcore mode. What do you think? Lap Times (sec)
1/4 Run - The car feels tight all through the turn. Having a hard time getting it to stick on the bottom of track. Have to let off the gas early to avoid braking hard, which locks the brakes and causes the rear to kick out. Also, can't get into the throttle too soon as the car doesn't want to turn while exiting the turn. All four corners are still green. 1/2 Run - Feathering the gas exiting the corners to keep from hitting the wall. The wear indicator for all four corners seems to have turned a lighter shade of green. End of Run - In the latter half of the run, the car "loosened" up a bit. It became easier to get into the turn and keep the car on the bottom of the track. Also, I didn't have to feather the gas, but could drive off the bottom of the corner real well.
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. My Thoughts: Looking at the lap times, I know that I need to trim at least 1/2 second off. So that's my goal. The car is a handful the first 10 laps or so. It's really tight, and it doesn't loosened up until about lap 25. I can't drive hard into the corners, because braking hard is dangerous — it moves you from a tight condition to a very loose condition almost instantaneously. I feel like if I could drive a little harder into the corners (or drive out of the corner a little sooner), I could improve my times. I definitely would like the car to stick on the bottom of the track. The lap times didn't really drop off too much at the end of the run, and the tire temps (with the exception of the RF) were mostly stable throughout the run. I didn't really expect that. What do you see? What's our first move? Maybe a sway bar adjustment to help loosen it through the whole turn? Julian Data >> The RF is heavily loaded by looking at the tire temps. The setup really falls after the 30 lap mark, a known trend since you are close to half tank. Need to balance the tire temps a bit more. First adjustment: Increase the Rear ARB, increase Rear Weigh.t It's going to be a bit free in the middle of the corner for the first 30 laps and it will most likely get looser these laps. Timothy Bennett >> Increasing the RARB makes sense... that will loosen me up through the turn. I stiffened the rear sway bar one tick to 0.600". By moving weight to rear, I assuming you want to heat up the rear tires. OK... so how much weight? I decided to move about 18 lb. from the front to rear. Here's the results. Lap Times (sec)
1/4 Run - Braking can create a loose condition at the entrance to Turn 1. Pumping the brakes seems to help. Also, I had to be careful not to get back on the gas too soon. Definitely easy does it in the corners. We have definitely loosened the car up through the corners. Driving hard into the corners creates a potentially dangerous situation. Tire wear indicator show all four corners are still green. 1/2 Run - Really loose into Turn 1 at the beginning of this part of the run (laps 8-11). By the end of this part of the run (lap 15), the setup has stabilized somewhat, and I'm able to keep the lap times more consistent. Tire wear indicator on all four corners still showing green. End of Run - Tire Wear
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. Comments: Only minor improvements in lap times. Lap time consistency did improve, particularly at the end of the run. The tire temperatures on the rear picked up on average by about 10°. But is this enough? How even should the tire temperatures be? Getting the car slowed down going into Turn 1 without seeing the rear end out the passenger window is still a challenge. Must pump the brake. Julian Data >> Here's the reason why I wanted you to adjust the RARB and Rear Weight... during the first run you told me that the car had a hard time turning the turns — I am concentrating in the middle first. Now by no means are these adjustments final since you start playing with other areas, things will change. My goal for tire temperatures at this particular track range from 200-210º. The setup in it's present state isn't doing that right now. So let me surmise how the car is feeling now:
Here's what I want you to change:
Tire Wear: I don't like how fast the RIGHT sides are wearing. In order for the right sides to last longer, we need to soften rates, which I might add might drop the tire temperatures since there's less force onto them. We will start with the tire PSI first. Why do the tire pressures first? Here's why, tire pressures give the most influence in finding which direction to head. Remember a tire is basically part of the suspension as its sidewall flexes thus giving you another spring rate adjustment. So with that all said, let's drop the RIGHT side tire pressures by 2 psi as a starting point. I know this is a big drop but it will tell me, which way to go on feel and tire temps. From this point on, please start running the car up to 35 laps. (Ed. Since we're working on a race setup, Julian later suggested just running a full fuel run) Timothy Bennett >> Here are some additional comments I have concerning how the car feels:
I'll make the suggested adjustments and run a full fuel run. OK... I dropped the RR rebound to 200, decreased the grille tape by 5%, and reduced the right side tire pressures by 2 psi each. I then ran 69 laps. Here are the results: Lap Times (sec)
1/4 Run @ Lap 18 - What can I say... TIGHT. Tight entering the corner. Tight in the middle of the corner. Tight exiting the corner. Did I mention it the car feels tight through the corners? 1/2 Run @ Lap 36 - The car loosened up some during this part of the run — though I wouldn't categorize this setup as "loose", it just wasn't as tight as in the first part of the run. This part of the run produced my fastest laps, though I never broke 24 secs. It was easier to get into and off the corners. End of Run @ Lap 69 - Seems like in the last half of the run, the car picked up a tendancy to pull to the right down the backstretch. Also, the car was VERY VERY loose braking into Turn 1, particularly the last 10 laps of the run. At lap 61, the car broke loose under "light" braking entering Turn 1. I got completely sideways in the middle of the turn. I saved it and kept it out of the wall, but light pumping on the brake was absolutely necessary the last part of the run. Tire Wear
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. Comments: Lap times dropped dramatically (1/2 second on average), presumably due to the decrease in the right side tire pressures. The changes to the grille tape and RR shock rebound I believe did help with the "loose under braking" condition entering Turn 1. The condition did return with a vengeance the last 10 laps of the run. On lap 61, the car suddenly and without warning broke loose under "fairly light" braking. I got completely sideways through the middle of the corner, but managed to save it and keep it out of the wall. But by far, this setup was pretty tight all through the corner for the majority of the run. Julian, can you comment a little more on why the tire pressures give you information on which direction to head? Also, what are the different directions you're trying to determine? Julian Data >> What I am trying to do is fix the ailments you are having, and at the same time thinking of ways to make the car/tires last longer during the fuel run since this is a race setup. Here's my response to the 3rd test... OK, so we have added some time back to the laps. Is this bad or good? From a laptime standpoint, that's a big fat NEGATIVE! But what's a good thing about the last adjustments? Did you notice anything? ...Look at the wear... we have now decreased the wear in HALF! So what's the next step? Well, we need to get those laptimes back down and fix the problems with the setup. From the results, we can conclude the following:
What I see: The left side of the car isn't getting any heat in the tires as in the earlier runs. We lost 20° or so on the left sides. The right side tire temperatures show the RF still doing a lot of work and the RR not doing much, which shows that the setup is biased to the RF. Remember, I would like to see the tire temps balance out. Overall, the tire temps have dropped thus giving us great wear! Here it goes for the next round of adjustments:
Timothy Bennett >> I bumped the Front Sway Bar by one bar, and I bumped the Rear Sway Bar by two. Additionally, I dropped the RF spring 50 lbs. Finally, I dropped the RF and LR shock bump each by 50. I then ran a 70 lap run. Here's the results. Lap Times (sec)
1/4 Run @ Lap 18 - Wow! The setup during this first part of the run was almost perfect! Not loose or tight in any part of the corners. The loose condition under braking is gone! I could put the car on the bottom of the track through the corner, and it didn't want to push or break loose exiting the corners. I turned two personal best laps during this part of the run! 1/2 Run @ Lap 36 - No major changes in the way the setup felt during this part of the run — still great! It might be wanting to pick up a push through the middle of the turn, particularly after the RF turned yellow on lap 29. Most likely it was the driver over-driving into the corner. As far as I am concerned, any lap >24 seconds was because the driver missed his marks. The car felt like it was capable of consistently running sub 24 second laps. End of Run @ Lap 69 - Setup tightened up a little during the last half of the run as the tires began to wear. After all four corners were yellow on the wear indicator, I noticed about 2/10 second per lap being scrubbed off. When the RF went orange on lap59, it was more difficult to turn consist lap times. I could feel the front sliding through the turns, and I had to make an adjustment in my driving style. Tire Wear
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. My comments: My first observation is that this setup feels really good! Wow! Not loose or tight anywhere in the corners. Only after about 50 laps does the car began to noticeably push. The loose condition under braking that has plagued me is practically gone! Tire wear is excellent. Lap times were definitely the best so far, including three personal best laps in the 23.7's!! Generally, lap times improved from 24.541 ± 0.725 to 24.186 ± 0.236 - an improvement of - 1/2 second per lap! Tire temperatures increased, particularly on the left side. However, tire wear didn't increase. That's got be good! Are the temperatues even enough around the corners? There was a general cooling of the tires during the last 1/2 of the run. Why is that? Seems like the tires would just continue to get hotter? Y]Julian Data >> Are we happy yet? A couple of observations about your run:
TB Tire temperatures increased, particularly on the left side. However, tire wear didn't increase. JD Amazing isn't it? : ) Traditionally, the right side tires take the most beating due to the bias of the chassis/suspension and the layout of an oval track, which promotes more wear and heat. Yet, the left sides usually wear very slow. If you balance the car properly - meaning, get all the tires working in unison - you will be able to not only run faster times but also for the long run! Think consistancy here. TB That's got be good! JD Yes, it usually is. So this is good! TB Are the temperatues even enough around the corners? JD The overall tire temperatures on all four tires is almost there to my liking. I still want to all four tires at the 200-205º (even 210º) range in which it seems to be the sweet spot at this track though it could be higher though could cause a great deal of tire wear rapidly thus giving you a short fast run per se. TB There was a general cooling of the tires during the last 1/2 of the run. Why is that? Seems like the tires would just continue to get hotter? JD This is usually the result when you have a soft suspension; you see as the fuel load lightens and the tires wear, they tend to not work as hard. We'll work on this to get more force onto those tires to keep them heated as this is work in progress. Adjustments: Since the first 50 laps were a success, I would like to work on the car at the last half stage of the full run. Now, think for a moment, since I am going to at this later stage, the setup could change a bit during those first 50 laps. Keep that in mind. So I am going to work on the middle and the entry of the corners. I usually brake the corners up into three sections: entry, middle/apex and exit. My first emphasis has always been the middle of a corner as I want the car to turn in the middle and then followed by entry and lastly, exit.
During this run, I am looking for the characteristics of the tire temps and how the car reacts during the run at the first quarter and last half. I am hoping to free up the car. I know that this will not be the last set of adjustments as I feel that the car will still be tight again at the later stages but should take longer to get to this condition. I just want to see where's this adjustment is going to direct me. BTW, are you hitting redline or does the over rev light come on? Timothy Bennett >> Lap Times (sec)
1/4 Run @ Lap 18 - When you warned me this setup would be looser, I was expecting a handful. My expectations was wrong. What was "loose" about the setup during this part of the run was that the slight push off the corner was gone. I liked the way this setup felt — better than the previous run. I could drive the car to the bottom of the turn, get on the throttle a little sooner, and really drive it off the corner. I like the "stiffness" of the chassis off the corner! 1/2 Run @ Lap 36 - Mostly the same as the first 1/4 of the run until the RF wear indicator turned yellow at lap 29. Then, it seemed like it picked up a slight push — just enough to keep me from breaking 24 second laps for a while... (More on that below.) End of Run @ Lap 69 - The last 1/2 of the run was really interesting as the chassis changed several times. The RR wear indicator turned yellow on lap 37 and the car got loose acting for a couple of laps. On lap 42, the right side tire indicators turned yellow and the car settled down somewhat, but lap times were a bit inconsistent. It was like it was in some kind of transition stage because around lap 50, the car really stiffened up and I turned some consistently quick laps (especially for 50 laps into the run!) In fact, on both lap 57 and 66, I turned laps in the 23.9's! At the end of the run, the car was still a pleasure to drive, even though the front began sliding through the corners just a tad the last few laps. Tire Wear
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. My comments: You must be prophetic! It was amazing to see the car change during the part of the run you wanted to focus on! The average lap time during the first 1/3 of the run dropped slightly, though a little more consistent. The average lap time during the middle 1/3 of the run again dropped slightly. But, the average lap time during the last 1/3 of the run dropped by 0.265 seconds! That dropped the average lap time over the course of the entire run by 1/10th of a second! All that and virtually the same tire wear... who are you? The thing I noticed most about the tire temperatures was how they didn't cool off at the end of the run. I guess that explains that good grip I was getting the 1/3 of the run that helped me turn those quick laps. Good job! Maxing out RPM's at about 7200-7500. Julian Data >> Just remember where we start working on area, you might lose in another.. I this case, the first half. 1/2 run: Where did the push occur? In, middle or out? 69 laps and on: Wow! You were running some pretty quick times at the end of the run! The car's characeristics at the end of the run was due to the wear of the tires. So basically with the RF worn more than the RR, the was unpredictable and when the RR tire worn even as the RF, the stablized. Observations:
My Goal for this run: I am trying to get the car a just tad more freer at the latter stages of the run and also change the rate of wear for the RF. This is going to be a big set of adjustments. I hope we'll get that tenth back with these set of adjustments and better tire wear, if not, there's more adjusting. Also, tell me during the run the grooves that the car is comfortable or wants to be in. Don't change your driving style! Let the car tell you. I am thinking at half tank that the car wants to be a 1/2 or 1 car width up on the track. Setup Adjustments:
Timothy Bennett >> Lap Times (sec)
1/4 Run @ Lap 18 - Unlike any previous version of this setup, this one is capable of running 23.6's and 23.7's — fairly consistently. The car cornered extremely well during this part of the run. I could make it stick anywhere, which enabled me to get on the throttle much sooner in the turn. This is key to turning 6's and 7's — keeping the speeds up in the corners. At those speeds, the inside temperature on the RF would spike to ~230°F exiting the corner. I tried not to turn too many of those kinds of laps for fear of smoking the RF. Instead, I tried to turn consistent 9's. For all my worry and concern, we ended up having slightly better wear than the previous run. 1/2 Run @ Lap 36 - More of the same as the first 1/4 of the run. Setup not changing much. End of Run @ Lap 69 - The chassis was definitely more stable the last 1/2 of this run than in the previous run, which I think is what you were trying to accomplish. The 15 laps of transition as the corners all turn yellow was pretty stable. As the run wore on, the car definitely wanted to run a slightly higher line as it became tougher to keep lap times quick at the bottom of the corner. Late in the run, the car picked up our familiar slightly loose condition under braking. Nothing dangerous, but our average slowed 1/10th of a second during the last 10 laps. If you want to run hard, and aren't concerned about the RF temps, I still pulled a 23.8 on lap 64 just to see if it was still capable! Tire Wear
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. My comments: The inside temperature on the RF really threw me loopy. It was constantly 215-220 F, and if I pushed it, would spike to ~230 F on the corner exit. I kept out of the throttle in order not to wear it out, but we ended up getting better wear than the previous run. I could have average less than I did. The thing I didn't catch until I after the run was the fact that the middle and outer temperatures on the RF were consistently 200-210 F. The average temperature across the tire was less than the spiking of the inside temp led me to believe. Maybe we can make a camber adjustment and smear that inside spike across the whole RF? Overall the tire temps were cooler than the previous run. Lap times improved! The first 2/3 of the run, I averaged in the 23.9's. The average for the whole run improved by 6/10th to 24.017 +/- 0.141 secs. The setup really keeps the speeds through the corners. You can get on the throttle quick and really drive it out of the corner. I had many personal best laps with this setup, including a best 23.606 in one of the aborted runs! It takes a lap better than 23.728 to get on my BLAP board. What would I change? The rev light never comes on, so maybe a gear change to get a little more speed. Still need some more heat in the LF and maybe a tad more in the LR. Camber adjustment to even up the temps across the tires, too. That'll get more of the tire gripping. The car really feels neutral through the corners mostly. Julian Data >> The last set of adjustments were indeed set for the last half of the run. I see at the chart the right sides go orange from 60 laps and up, what are the condition of the left sides during these laps? Summary: I noticed that you said that the car moved up a bit in the turns and I am going to try to fix this for this round of adjustments. I am also going to try to get more heat back into the tire. Adjustments:
Here is the setup with all the changes.. Timothy Bennett >> Lap Times (sec)
1/4 Run @ Lap 18 - Unlike any previous version of this setup, this one is capable of running 23.6's and 23.7's — fairly consistently. The car cornered extremely well during this part of the run. I could make it stick anywhere, which enabled me to get on the throttle much sooner in the turn. This is key to turning 6's and 7's — keeping the speeds up in the corners. At those speeds, the inside temperature on the RF would spike to ~230°F exiting the corner. I tried not to turn too many of those kinds of laps for fear of smoking the RF. Instead, I tried to turn consistent 9's. For all my worry and concern, we ended up having slightly better wear than the previous run. 1/2 Run @ Lap 36 - More of the same as the first 1/4 of the run. Setup not changing much. End of Run @ Lap 69 - The chassis was definitely more stable the last 1/2 of this run than in the previous run, which I think is what you were trying to accomplish. The 15 laps of transition as the corners all turn yellow was pretty stable. As the run wore on, the car definitely wanted to run a slightly higher line as it became tougher to keep lap times quick at the bottom of the corner. Late in the run, the car picked up our familiar slightly loose condition under braking. Nothing dangerous, but our average slowed 1/10th of a second during the last 10 laps. If you want to run hard, and aren't concerned about the RF temps, I still pulled a 23.8 on lap 64 just to see if it was still capable! Tire Wear
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. My comments: This setup was a bit faster and a bit looser than any previous run. During the first 2/3 of the run I shaved off about a full second off my best lap time and my average lap time from the previous run. Now averaging in the upper 23.8's during the first 2/3 of the run. Shaved about 1/2 second of my average lap time during the last 1/3 the run as well. For the entire run, we are now averaging less than 24 seconds at 23.944 +/- 0.214 secs. Consistency, however, suffered a bit during this run. Standard deviation was larger by about 1/2 second. The car got looser as the run wore on. While I had many really fast laps, I also had few where I was dirt trackin' it through Turns 1 and 2. It was considerably loose braking entering Turn 1. Tire temps were up all around the car, especially on the left side where it +10F during the first 1/2 of the run. By the end of the run, the tire temps were about the same as the previous run. Tire wear increased somewhat -- I suppose that is in direct relation to the improved lap times. Julian Data >> Setup Adjustments: (time to start taming this setup!)
PS: I know I am going to be working on the left sides more! :) Timothy Bennett >> Lap Times (sec)
1/4 Run @ Lap 18 - A little tight while the tires are still cold, but still fast out of the box. No real complaints about the setup. Feels good through the turns. Just a tick loose under braking. I found a good line that I could turn consistent quick laps. On the bottom of the track through Turns 1 and 2, and about a 1/2 lane off the bottom through Turns 3 and 4. Off the throttle a tad sooner than when I naturally want to. Runs consistent 23.7's and keeps the tire temps reasonable. Very steady. 1/2 Run @ Lap 36 - Still really quick. Seemed to tighten up a tad during the first part of this segment. Car wanted to run about a 1/2 lane higher. Then, during the transition when the RF tire wear indicator showed yellow and the RR tire wear indicator still showed light green, the car got really loose entering the corners. Braking compounded the problem. After the transition period, the car settled back down. Pretty stable except during that transition time. End of Run @ Lap 69 - The really quick laps vanished during the last half of the run as the tires wore, though the car was really consistent. Could run consisent 23.9's. The setup felt mostly fine. A little loose during RF/RR transition periods, but much better than the Run #7. The car definitely wanted to run a higher line the last part of this run. Lap times were faster on the higher line than when I tried forcing the car to the bottom of the track. Tire Wear
Tire Temperatures (°F)
Note: All tire temperature readings were taken at about the 1/3 distance mark of the backstretch. My comments: This setup, while not significantly faster than Run #7, was definitely capable of turning more consistently fast laps. The extreme bad nasty laps at the beginning and end of the run disappeared. BLAPs were not quite as fast, but close.
Tire wear was pratically the same. In fact, long term wear seemed to slightly improve. I guess that accounts for the more consistent lap times during the last 1/3 of the run. Tire temperatures were significantly lower, but seemed to hold fairly steady through the duration of the run (except maybe the LF). |
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