K-PAX Racing's attempting to turn an off-the-line Volvo C30 into a world-beating race car in 60 days. Driver Robb Holland's going to give us weekly project updates. Part three: hooning the stock car, welding a cage. — Ed.
Welcome back. For those of you who used the Snowpocalypse as an excuse to take the week off from work, well played my friends, well played. Unfortunately with the clock ticking down towards our season opener at St. Pete, my guys at K-PAX Racing didn't have that luxury and braved the near 20 below temps we got here in Denver, to keep us on schedule.
Before we got hit with the arctic blast, the team made the decision to take the second C30 (still in stock trim) and head out to High Plains Raceway (HPR) for a day of hooning dedicated testing, before we had to tear it down as well.
The thought behind our little field trip was that our race car, when finished, will still share its basic DNA with the street car and none of us had ever run a C30 on track in anger before. So before we got too far into the build we wanted to get a feel for what we had to work with (both strengths and weakness) so we could come up with a solid game plan.
The main things we were looking at were the ability to completely disengage the electronic systems (TC, ABS, ect) and handling. Now I know you're going to say "Handling? Aren't you going to change shocks, springs, sway bars anyways and won't the handling be totally changed when you do?"
Yup to all of the above, though even with all of those changes the basic characteristics of the car will still remain. We might be able to minimize any problems we find or enhance the good traits, but only to a degree (given our limitations within the series rules) and knowing what we have prior to finalizing our plans is hugely critical.
So we made the trek out to HPR, which is a great 2.5 mile, 15 turn, club track just east of Denver. It's a perfect track for testing, with nice elevation changes, a good variety of corners, and a track surface that has good grip without eating up tires. That last part is a hugely important characteristic for a test track, as tires are one of the largest expenses for a pro race team over the season.
If you do your testing at a track that chews on tires, then it is entirely possible to go through 2 or 3 sets of tires every test day. At a cost well north of $1,500 a set for our Pirelli slicks, the tire bill for the season could well exceed $50,000 for just testing alone! Yeah, ouch! Even for a factory-supported team such as ours, that's some serious cheddar.
Project engineer Dax Raub jumped in the passenger seat so that he could also get a read on things and headed out with me for a few laps. First impressions? I am Mclovin' this car! With my job I get the opportunity to drive a pretty wide range of cars so I've gotten pretty good at getting up to speed fairly quickly in whatever car I'm in, however fairly quickly usually means a lap or two.
When I hit the track with the stock C30 I came out just behind a BMW Z4, and like all the rest of you hoons accomplished drivers out there, my ego instincts kicked in and I spent the next several laps chasing him down. When I came off track (after catching him of course) I realized that I was basically at full chat from turn one in the C30 and felt 100% comfortable pushing the car to it's limits right away. No quirks, no issues, no problem.
In fact, the only real trait I noticed in the C30, was a stock set up that was a bit on the soft side for the track, which I mainly put down to Volvo's design philosophy, placing the C30 more in Sport Touring category than hot hatch. For anyone who owns (or is thinking of owning) a C30, simply throwing set of stiffer bushings, springs and sway bars on would tighten things up quite nicely and put the C30's handling squarely in the mix with cars like the GTI and MAZDASPEED3, (who will also will be competing against us in the series).
But the most promising thing is, that the C30's 2.5L Inline 5-cylinder Turbo engine seems to have a more usable power band than either one of those cars, which I hope will make my job as a driver a bit easier.
With our track day done we returned to the shop to let the K-PAX Racing crew to get to tearing down the second car and to also see how Teague was coming with cage for the first car. One of the hallmarks of K-PAX Racing has always been the level of thought and detail that goes into their roll cages and as a driver I find that immensely comforting.
As safe as this sport has become over the past decade or so, it is still a very dangerous way to make a living. We'll reach speeds of 130mph on the front straight at the Long Beach GP with nothing but tire barriers and K-rail to stop our forward progress if things should go all pear shaped. Speed doesn't kill, but the sudden stop will get you every time.
Instead of sitting here trying to pass K-PAX's master cage builder Teague Oliver's knowledge off as my own, I though it would make more sense for you guys to get it straight from the horses mouth, as it were. So with that thought, here are some excerpts from my sit down with Teague.
On Cage Building Philosophy
"A roll cage serves two purposes. First and foremost, it serves to protect the driver and secondly it helps increase chassis rigidity. The C30 has the amazing structural rigidity that all Volvo's are known for, which is really helpful as it allows us to simplify the cage and keep the weight down and let the chassis share the workload."
"Our main goal here is to connect the energy between the front and rear suspension points. We try to take the energy from the rear and transfer it to the front and use it to load the front end to increase front grip, which is key in a front wheel drive car. Increasing chassis rigidity with the cage is vital for doing that, as a flexible chassis won't transfer that energy as effectively."
On MIG vs TIG
"Most shops will MIG weld the cage with mild steel tubing. We prefer to TIG weld our cages for several reasons. First is that TIG welding is much more precise and that leads to a much better structural weld than a MIG weld. TIG welding also allows us to use 4130 Cromoly tubing, which is a better, lighter alloy than the mild steel used in most cages but 4130 must be TIG welded.
In addition with MIG welding, most sanctioning bodies require you to use thicker walled tubing, which means that the cage will be heavier when compared to one that is TIG welded. The only real downsides to TIG welding are that, it takes a lot longer and you have to have someone who is a certified TIG welder to do it."
On Welds
"We work hard to get the cage as close to the roofline as possible for rigidity and driver clearance. However the closer you get to the structure of the car the harder it becomes to complete the weld. It is critical that every tube is completely welded 360 degrees. If the person constructing the cage only welds 90% of the way around then that last 10% becomes the weak link and the point most likely to fail in an impact. Never, ever, leave a joint anything but 100% welded. If you need to maximize space in the car for a tall driver and can't complete the weld, then plan on cutting a hole in the roof to gain access to complete the weld."
On Crush Boxes vs. Door Bars
"In the C30 we are using a crush box instead of the traditional NASCAR-style door bars as we designed the seating position in such a way as to get the driver as far back as possible for weight distribution. If we used door bars then we would need to run them through the B pillar, which takes a huge amount of time. With the crush box we can avoid doing that and we also gain the benefit of being able to easily replace the crush box in case of a minor intrusion into the driver compartment, while door bars would need to be cut out and replaced."
Note: A crush box is just what it sounds like, a box with a Kevlar skin and an aluminum honeycomb interior crush structure. They bolt on to the drivers' side cage and replace the need for door bars. Our crush boxes are designed by Pratt & Miller (of CTS-V Coupe fame) and are approved for use by SCCA Pro. One of the other things that works in our favor is that our crush boxes are interchangeable between both the S60 GT cars and the C30 TC cars meaning we can carry fewer spares in inventory.
And there you have it, straight from the man himself. Next week we head into the paint booth and also get to sit down with the Volvo C30's "Electrical Architect" (yes that is his real job title) to get our heads around what it's going to take to make the C30's ECU play nice once it's discovered that we've removed half it's playmates on the CAN-bus system.
Oh and if we're really good we might be able to talk him into turning up the boost a bit for us...
Robb Holland is a professional racecar driver with K-PAX Racing and 3Zero3 Motorsports. When he is not racing in World Challenge, Holland works as a performance driving instructor and owns a travel company that takes US clients over to Europe to drive the Nurburgring. You can follow him on his Facebook page.
Previously:
Photo Credit: K-PAX Racing