NASCAR Race Weekend Central

Tech Talk: Trent Owens Discusses Michigan Rules Package, About-Facing for Sonoma

A week off for the Cup series allowed Trent Owens, crew chief of Aric Almirola‘s No. 43 team in the NASCAR Sprint Cup Series, to spend a week at the beach and think about anything but racecars.

Regardless, he feels like the series rules package run at Michigan International Speedway was a step in the right direction and might actually be close to the end point as far as taking downforce off of the cars.

Now he’s in California getting ready for the first road course race of the season at Sonoma Raceway.

This week in Tech Talk, Owens, among other things, discusses lifting the car off of the ground to facilitate rolling the body from side-to-side in an effort to move weight during cornering. He also touches on the point of emphasis of saving the rear tires and maximizing drive off of the corners.

Mike Neff – You had an off weekend last week. What does the crew chief of the No. 43 do when he doesn’t have to go to the racetrack for the week?

Trent Owens – With our schedule it seems strange. It fell in the summertime when the kids were off school and all of that good stuff, so we went to the beach and had some downtime, which was needed. We tried to do something where we didn’t think about racecars for once. We’ve got a grueling schedule coming up through the summer and the end of the year. It is really a perfect weekend to get a break. Looking at next season, I think they took that away. It is kind of just a chance to reset and not think about racing and gear up for the next half.

Neff – How do you feel the rules package went over at Michigan?

Owens – I thought it was a great package for Michigan. I didn’t think it was a big swing as far as balance stuff. I thought it worked; I thought it was another step in the right direction. I think we have to be cautious when we start running the tracks with low grip, like Atlanta. Places like that I think we can take off too much downforce for those kind of tracks. At Michigan it was probably the perfect package.

Further down the road, if we start running that package more we may find tracks where they might have to give us a little downforce back. … I don’t know how much more you can take off. At some point you’re going to get to that point, and that might have been it. I think they did a good job with it just being bolt on pieces and there were no balance surprises for us.

Neff – You now head off to the West Coast and make right and left turns. With the cars the way they are now, basically sealed off to the ground, that won’t always work at a road course, you have to build in some body roll. Do you have to set up the cars a little bit off of the ground to account for that weight shift from left to right on the car?

Owens – You are exactly right, especially when we come out to Sonoma. If you compare the [Sonoma] race track to Watkins Glen they are two completely different tracks. Watkins Glen we can get a little bit lower and we can focus on the aero stuff. Sonoma is completely different, you have to do everything you can to save the rear tire wear, so your driver can get back to the throttle properly. To do that you have to induce some body roll. You’ll probably see some of the cars sitting on the pit road a little bit higher, as far as ground clearance, than you see at other race tracks just to give some forgiveness to the tires.

Neff – We often talk about getting the drive off of the corner at places like Martinsville and New Hampshire speedways. When you try to attack that you can do things like splitting the truck arms. You can’t really do that when you have to go left and right because it will really hurt making the right hand turns. What other things can you do to improve drive off besides playing with the truck arms?

Owens – There are a lot of things to be gained with air pressure settings and camber. We have rear ends where we can change camber and toe. There are a lot of things with rear toe and camber. Then you have your basic springs, a little stiffer or a little softer, you can make sweeps that way. With spring rubbers you can try different things too. There are a lot of different options we have in the rear and then there are the shocks in the front of the car as well. We can play with different settings to get some more rear weight on the car and see if that will help us. You talk about the truck arms. Most of the turns on a road course are right handers so we can investigate areas with that and possibly give up a little on the left hand turns.

Neff – Due to the fact, as you mentioned, you can camber the rear end, is there benefit to leaning both tires in at the top so that you have camber working on the rear of the car when you turn in both directions?

Owens – When you have higher speed turns we tend to lean towards more camber on the outside tire. As far as forward launch we tend to get more drive with less camber. If you are turning to the right, less camber in your right rear/inside tire typically gives you better drive off. You have to tune it not to lose too much turn, because camber does give you turn, but you have to compromise for the grip. It can get pretty tricky.

Neff – On a course like Sonoma, where you are turning right and left, do you end up tilting the left side rear tire in instead of out like you would on an oval?

Owens – You are righ. Both left side tires are tipped in because we are going left and right. You have to have some amount of negative camber in both sides. Typically we’ll have a lot more in the left side tires than the right side tires. You have a certain amount of left-handers so you tend to give up a little bit in those corners to get your right-handers all better.

Neff – This is probably a driver preference thing but when you go to the road courses, especially Sonoma, do you use a little faster steering box than you do on ovals because of the increased, low speed turns.

Owens – Yeah we use a 6-to-1 box where typically on an intermediate track we’d use a 12-to-1. It definitely helps the driver to have quick steering. The corners can be so slow out here at [Sonoma] and can be tight so they have to crank a lot of wheel to it fast. The speed up steering definitely helps that.

Neff – We hear them talk about it quite a bit on TV. What is it about the gear boxes on these cars that allows them to be shifted without using the clutch when you’re at speed? Is it how the gears mesh together or is it just the internal workings of the transmission?

Owens – I believe it is how the gears are cut. I’m not an engine guy or drivetrain guy by any means so I probably can’t tell you exact details. The way the gears are cut you can just pit it right into gear. They still have to be careful not to over rev the engines, or miss a shift. It still can happen but as long as the driver does a quick shift it goes right in. I think, for years now, we’ve run without any problems in that area. They still use the clutch to get off of pit road and things like that but when they’re on the track no clutch is needed.

Neff – When it comes to gear ratios, as you step up from first to fourth, are you pretty tied in based on rules or do you get to choose where your RPMs differ from gear to gear?

Owens – NASCAR gives us a range we can work within for first, second and third. Fourth has to be one-to-one. At least for third and second, if a driver doesn’t feel like he isn’t carrying a gear long enough or if he wants to stay in a certain gear through a certain section and not change into another gear, we have a small window of opportunity to try and increase or decrease RPM. Over the years, they’ve been coming out here for so long, they have kind of a handle on things and NASCAR has narrowed down the gear ratio rule. It used to be totally open but they have narrowed it down over time. We’ve got about 10 points to work with to fine tune things we find in practice. We are allowed one transmission change on the weekend and we are welcome to change ratios at that time.

Neff – NASCAR really frowns on guys running out of gas on the course during practice because it hinders everyone’s efforts. These races generally come down to some kind of fuel mileage. Are you able to calculate your fuel mileage and the amount of pickup you have without running the car all of the way out of fuel or do you need to bleed it dry once to know what you’re picking up?

Owens – We have two pumps in our cell. One is a little higher off of the bottom than the other. When the first pump hiccups we know we have a certain distance until it is completely out. With the new fuel systems and fuel cells it isn’t like what it was in the past. I think everyone is pretty confident what it actually picks up for fuel. They have the rules so tight I’m pretty sure everyone is straight up on what it can take. Really running a car out of gas, if that happens in practice I believe it is a mistake. I don’t think anyone is trying purposely to understand what the cars are going to pick up. With the EFI system and all of that stuff we get a readout of exactly how much fuel is used during the practice session.

We have a lot better tools than we had in the past but you are right, a lot of these road course races are run backwards. When you are good to the end on fuel, whether it is green or yellow, people will start pitting in hopes of getting a caution and jumping to the front of the field. Road racing always puts fuel on our mind, but the tools are a lot better these days, I don’t think you have to run it out of fuel in practice.

Neff – You’ve known this race was on the schedule for this weekend for some time. Have you already laid out what lap(s) you want to pit on barring unforeseen circumstances on Sunday?

Owens – In a roundabout way. We can tune our map to the EFI, if we aren’t getting the mileage we think we are. Based on past history we know what mileage we should get. We obviously have to check in practice to see if reality matches the virtual world. I haven’t done a lot of studying. The laps are pretty straight forward. You can run x amount of laps on a tank of fuel. You just start subtracting from there. We had a good race out hear last year. I’m looking forward to it. Aric spent some time at the Ford simulator getting some practice laps in.

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