(This article first appeared in the May 2007 issue of SportsCar magazine)

By Philip Royle

Just over a year ago we thought it was about time we built a RallyCross car. After all, RallyCross looked like a blast. With fast yet safe speeds on a dirt (or snow) playing ground with somewhat familiar autocross rules, what’s not to like? Once our minds were made up that this was a project we could sink our teeth into, we started shopping for a solid base car that would be up to the riggers of racing on the dirt. Our requirements were simple: the car needed to be powerful, somewhat lightweight and have a limited slip differential from the factory. We also decided early on that we wanted a front-drive car (this was very much an arbitrary decision on our part, so you’ll just have to go with it).

As it turns out, finding the car was easy. We chose a 2004 Nissan Sentra SE-R Spec V that, with the exception of a few squeaks and rattles, was in exceptional condition (and at the time was only two and a half years old).

The Spec V is powered by a 175 hp, 16v, 2.5L, four-cylinder motor, but thanks to the engine’s relatively large displacement, the motor produces a smooth 180 lb.-ft. of torque – 10 more ponies than the normal SE-R, and 49 more horses than the 1.8L Sentra.

For those looking to save money with the non-Spec V SE-R, it’s important to note that – at least with this model year – only the Spec V comes with the helical limited slip differential, and it’s the diff that plays a key roll in the Sentra being an ideal RallyCross car. With a peg leg powering the car on a loose surface, finding traction would be all but impossible.

Both the SE-R and Spec V come with a quicker steering ratio (15.8:1 vs. 17.48:1) than the standard Sentra, but oddly have a larger turning diameter.

The potential downside to the SE-R and Spec V models are the transmissions the cars came with. The V was only available with a 6-speed manual, meaning the gearing is a little close. While this is good for around-the-town grunt, it can limit you when racing on courses where the speeds hover around 60 mph – as is the case in autocross and many RallyCross events. However, not having to worry about tuning around an open differential makes dealing with a 6-speed tolerable. Also, this model SE-R is a must-avoid car as it was only available with a four-speed slush box. What was Nissan thinking?

The Amazing part of the Spec V is the price. Brand new, the V had a base price of $17,500, which was only $200 more than the SE-R. That $200 got you 17-inch wheels as opposed to 16s, the better tranny, and the V came with spring rates that were 15-percent stiffer up front and 16-percent stiffer in the rear than the SE-R.

An option our V wasn’t equipped with, which we would have liked, was the Brembo brake package. This package includes bling gold Brembo four-piston front calipers clamping 12-inch rotors, with rear rotor measuring 10.9 inches. The stock rotors on our model are 11-inch up front and 9.13-inch in the back. The calipers are also single piston all around. Our model also came equipped with ABS.

New, our little Spec V dinged the register at under $20,000. If you were shopping for a similar model right now, you could probably find a good example for between $11,000 and $13,000. Not exactly cheap, but racing isn’t cheap.

So it was just over a year ago that we obtained our V with the goal of hitting the dirt – this was about the time Southern California RallyCross events dried up. There were some events taking place six or seven hours north, but that was too much of a drive for us – we opted to wait for the events to come to us.

And here we are.

Today, Southern California is getting back into the swing of things with many RallyCross events slated for 2007, and that’s not to mention the Western States Championship that will take place in Jean, Nev., in September. It was time to dust of the V and go racing.

The plan is to build a competitive, highly modified RallyCross car. As the project progresses, we’re going to see what needs tweaking on the V and improve those areas. The first goal, however, was to see how the car would react in its bone stock configuration.

We loaded the car onto the trailer and towed the V north to Jean, which (as mentioned) is the future site of the Western States Championship. Since the goal is to compete at this event, this looked as good a place as any to baseline the car.

The dry lakebed in Jean is rough, but the surface breaks up quickly. What this means is that by the third run you quickly stop running a race line and start looking for available traction. This also means there’s a lot of dust flying around, and if you’re not careful (and the door seals aren’t sealing quite up to snuff) you can wind up with a lot of dirt entering the cockpit.

A good tip is to ignore the dirt as it flies around the cabin.

Since our Sentra was still sporting the stock Continental 215/45-17 ContiSportContact summer tires, traction wasn’t exactly plentiful; however, this didn’t mean the car was out of control. With ample mid-turn left foot breaking and some not-so-subtle yanking of the handbrake, the car would rotate nicely, and the differential would allow you to floor the gas and power out of the slide. With just enough angle through the turns a good rhythm could be had.

By the end of the event, it was obvious our vehicle choice was a good one. The car pulled hard in second and third gear, and the power was just enough that throttle modulation was necessary – once aggressive tires are added, however, this will probably not be the case. As for the stock tires, they did a fine job, but the surface was a little tough on them, leaving the front left tire with a nice bubble on the sidewall. While RallyCross isn’t an overly damaging sport, it’s not nearly as easy on street tires as autocross, so we recommend bringing a separate set of tires to race on.

The event results were promising. Out of 16 entrants, we finished third – and since we were beat by a rear-drive Toyota MR2 (sporting somewhat aggressive, yet still Stock legal, tires), that meant we were the fastest front-drive car. Our overall total was 9.11, with first place overall scoring an 8.85. Second place overall scored a 9.07 in the same MR2. Finishing fourth overall was a Dodge Neon ACR, with a 9.27.

Our plan now is to add a couple components to the Sentra while sticking to the Stock rules. That basically means we can bolt on snow tires. We’re also going to play with disabling the ABS, since that’s allowed by the rules, to see how different the driving experience is, and which suits our driving style best.

Ultimately, we’re going to prep the car for the front-wheel drive Prepared or Modified class, depending on how much power we think we’re going to need, and hopefully compete at the Western States Championship. Now that we have one event under our belts, we’re experienced, confident and boisterous. We’ve also left the event completely addicted to a new type of racing. Oh man, this is going to be a fun and dirty project.

RallyCross car prep

With no knowledge of how to set up a Stock-class car for RallyCross, we took our autocross knowledge, mixed it with a liberal amount of trackside advice and then hoped and prayed all went well.

As far as we were concerned, the most important thing was that the tires stay on the rims. Finding a consensus on what tire pressure to accomplish this, however, was difficult. The advice ran the gamut from the somewhat vague, “Run those pressures high,” to one competitor pumping his street tires to 50 psi. In autocross, 40 psi is a good starting point, so we decided to try that. We ended up filling the tires to 39 psi front and rear (39 psi was chosen because it was nearly 40, but not – don’t ask why). The tires never pulled off the rim, so from the looks of it, relatively small sidewall tires (215/45-17) can safely run at around 40 psi on a not-so-grippy dry lakebed without unseating. Had there been hard ruts, we may have bumped up the pressure another couple pounds, but at that point we could risk blowing the tire.

As it was, we did end up damaging a tire. With two of six runs remaining, the front driver’s side tire formed a bubble on the side, just below the tread. The bubble didn’t stop us from finishing the day, though, and the bubble got no worse (this being the advantage of towing to an event).

The final setup trick was taping down the handbrake button. Having watched many a rally, we knew the handbrake played a key role in making sure the car rotated nicely. Having no clue how the car would react on the dirt, we took some duct tape and liberally taped the button. This allowed for the handbrake to be used during the event without worrying about the handbrake not releasing.

As it turns out, this was an incredible idea, and it aided dramatically through a couple tight turns. Without the handbrake, our score would not have nearly been as low as it was.