NASCAR Race Weekend Central

Tech Talk: Center Turn, Brakes and Rear Camber with Trent Owens

The only trip to New Hampshire Motor Speedway for the Monster Energy NASCAR Cup Series in 2018 is coming this weekend. Teams will be trying to master the Magic Mile and break the stranglehold that the three dominant drivers of the year currently have over the sport. There are a handful of challenges facing the teams, and whoever handles them best will determine which car ends up in Victory Lane.

Trent Owens, crew chief for Chris Buescher, joins us this week to talk about the No. 1 challenge at Loudon: getting the car to turn in the center of the corner. He looks at how the ride height rule impacts that effort, whether drive off is as important as some make it and what the role of camber and caster is in turning at New Hampshire.

Mike Neff – Early in the race at Kentucky Speedway, it seemed like people were believing that new tires would make a difference. Late in the race, it didn’t seem that way. Was it a false sense that people got at the start of the race, but once the track rubbered up it really wasn’t that big of a deal?

Trent Owens – Yeah, it was really strange, thinking the tires were going to fall off. From practice it looked like there was going to be fall-off. I don’t know if it was a combination of going into the night, since we practiced during the day. Actually, the times started kind of maintaining. That is one mistake we did. Had we pitted earlier, kind of closer to the leader, and not run as long as we did, we might not have lost a lap in that first stage at all.

I think everybody was anticipating some fall-off. You saw guys hitting pit road, trying to split the stage right in half. The majority of intermediate tracks, where we do have fall-off, the fastest way to do the stage is to split it right in half. You saw a trend of that, some of the other cars running long just trying to save their night. It was interesting — towards the end of the race, with full darkness and cool temperatures, I think our lap times from lap 20 to lap 40 on tires were basically identical. Not a lot of fall-off.

Neff – How much did the handling of the car change when it went from dusk to full darkness?

Owens – For us, the handling of the car started off a little tight. We made a slight air pressure adjustment, and our car came around to be pretty neutral to almost free in the end. For us, I think the track freed up during the night. I think our front tires gained more grip than the back of the car, based on that balance. It was helpful for us.

Neff – We’re now headed to New Hampshire Motor Speedway, a very flat 1-mile track. We always hear that turning in the center of the corner is the key to winning there. What have you learned in the last couple of years with no-ride-height rule that helps make them turn in the center of the corner?

Owens – With the new ride-height rule, it has really helped us with attitude on short tracks. However, it has become too difficult sometimes when you can get the car too low and you don’t get as much response out of it. The car becomes less forgiving to work on, so to speak. Loudon is definitely one of the hardest tracks we visit to get the car to turn in the center, as you mentioned. One would think you would just free it up, but the minute you do that, you get really loose in. Then it is hard to get into the corner, especially under heavy braking.

It is definitely a tough balance. It is hard to keep the left side splitter sealed and keep the right rear corner up so you have a good attitude through the flat corners. The lower ride height has helped us achieve that a little easier, but as we lower the car, some other difficult challenges come into play.

Neff – Once you get the car turned, drive off of the corner is the ultimate ability that will set you up to be able to pass. Does having a car sitting so low all of the time make it more difficult to get the drive off of the corner?

Owens – I think the low ride-height rule has allowed teams to develop better setups a little bit easier. Potentially, a lot of the teams in the garage get a lot closer together. It has allowed all of the teams to develop good setups, and as each one gets more competitive it becomes way more difficult to pass. The best cars I’ve had at Loudon were cars that allowed the driver to come off of the turn and just turn under the car in front of him. If you wash out wide, it just kills your run and your momentum all of the way down those long straightaways. Definitely exit grip and exit turn, no different from center turn, is very, very important.

Neff – We saw some brake issues in Kentucky, since it is a mile-and-a-half that is pretty flat. Kind of like Martinsville, New Hampshire has some long straightaways going into some pretty flat corners. Is braking a high priority when you head there?

Owens – Yes, it always seems like this time of year we always see some kind of braking issues. As far as the intermediate tracks go, I think teams are trying to flirt with the safety factor and get the lightest weight stuff they can on the car. They may be experiencing some problems if their handling balance requires them to use a little more brake than they anticipated. Going into Loudon, we lean more to the short track type of braking packages. You can be a little more abusive, but it is really on the teams with how brave they’re going to be with their size of rotor and so forth, especially with how much heat it can hold.

It is one of the tracks where we use a lot of brakes. Any time that is the case, you can anticipate possibly some problems. I think problems might be because of the parts chosen rather than just parts failures.

Neff – Denny Hamlin‘s team was drilling holes in the front of the car to help cool the brakes on his car. That is obviously detrimental to his aerodynamics. Are you limited to the number of brake ducts you’re allowed, and would you put in more than you require so you had the chance to open them if the need arose?

Owens – Yes, we are limited on the amount of brake ducts we can run. Pretty much all of the tracks we run have specs on brake ducts. The air that goes to the brakes has to be pulled through the nose. If we run a fan, it has to be inline. We can’t just run a fan behind the nose to blow on the brakes. All of the air has to enter through the nose and through a duct. My best guess is, if they were drilling holes to get more airflow, they may not have had a screen type brake duct opening. They may have just had a set of small holes which resulted in them not having enough square inches, period, to get the air flowed through. By rule, we have an adequate amount of cooling available to us. It is just all about packaging — how you route it, how much air you’re allowing through the nose, how the teams try and control it.

Neff – At a mile track, are you required to run a right side window?

Owens – No, we do not run right side windows on the mile tracks at all.

Neff – Do you still run a duct over to that side for driver cooling?

Owens – We will run the double NACA required duct for driver cooling. We pretty much have a rule for everything we put on the car (laughs). Yes, we will run the double NACA. I do not believe that it is required when you don’t run a side window, but there is some aero gains by having a window duct on there.

Neff – Since Loudon is so flat, how much are you allowed to yaw the right rear out to get the corner of the spoiler in the air and keep that right side of the car planted to the ground?

Owens – Well, by tech rules, when we go through the rear steer has to be set at zero. They have controlled a lot of the static yaw. However, through compliances and geometry, you can still see .1 to .2 degrees of yaw in the body through the corner just off of forces. Anything more than that is good. We try and get all that we can. Any time that you can get that right rear out there and get the side force gains and the spoiler in the air it is nothing but speed.

Neff – With the front geometry, since the track is so flat, do you do much in the way of camber and caster in the front tires?

Owens – When you talk about caster and camber, we will usually unload with a pretty generous split in caster between left and right, more on the right side, to get the car to turn through the center. We’ll do a lot with camber, much more with camber than caster. Reading the tire wears and the tire temperatures that we stop and get from Goodyear during the practices. We really focus on the distribution wear of the tire. That is really where your long-run speed comes from, the distribution of wear on all four tires. We even have the ability to mess with rear cambers as well. Camber is definitely something that we pay a lot of attention to on a flat track. You need to run as much negative camber as you can in that right-front tire without feeling like you’re going to have failures.

Neff – You can play with rear camber? How does that work with a fixed rear axle tube?

Owens – The axle tube is fixed, but we are allowed to run a sleeve that slides over the snout. On that sleeve that slides over the snout you can get about a half of a degree of camber change in either direction without having to change the whole housing. We can also change the toe, in 50/1000 increments up to about a quarter of an inch.

Neff – What is your favorite place to eat when you go to Loudon since everybody is always about the food and the lobster up there?

Owens – When garage time allows for it, I like to drive over to a little town on the coast called Portsmouth. I eat at a place called Surf.

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About Mike Neff

Mike Neff
What is it that Mike Neff doesn’t do? The writer, radio contributor and racetrack announcer coordinates the site’s local short track coverage, hitting up Saturday Night Specials across the country while tracking the sport’s future racing stars. The writer for our signature Cup post-race column, Thinkin’ Out Loud (Mondays) also sits down with Cup crew chiefs to talk shop every Friday with Tech Talk. Mike announces several shows each year for the Good Guys Rod and Custom Association. He also pops up everywhere from PRN Pit Reporters and the Press Box with Alan Smothers to SIRIUS XM Radio. He has announced at tracks all over the Southeast, starting at Millbridge Speedway. He's also announced at East Lincoln Speedway, Concord Speedway, Tri-County Speedway, Caraway Speedway, and Charlotte Motor Speedway.