So far two things have reigned supreme in the IZOD IndyCar Series' trips to Sao Paulo, Brazil – rain, and Will Power. Both have a perfect record on the 2.536-mile street course in the first two runnings. To boot, Power's won the last two races from ninth and 12th on the grid. While Power heads into yet another race as the odds-on favorite, here are some of the other major storylines heading into the fourth round of the 2012 season.

THE FOUR HOMETOWN HEROES – The passion of Brazilian fans for open-wheel racing has never been questioned, and the fever should intensify to a greater degree than normal with Rubens Barrichello's homecoming in joining the IndyCar field for this year's Sao Paulo Indy. It may not be solely Barrichello's doing, but it's surely no coincidence that in the first two races of the year, IndyCar's TV ratings in Brazil were up some 40 percent from the same time frame in 2011.

He's one of four Brazilian drivers in the field, along with Helio Castroneves, Tony Kanaan and the returning Ana Beatriz for Andretti Autosport with Conquest support. Raphael Matos and Vitor Meira, in this race the last two years, fall from the field. Meira has scored the only Brazilian podium in this race, two years ago for both his and A.J. Foyt Enterprises' last top-three finish - a race Matos finished fourth in, the best finish for the Dragon Racing team in its six years of existence.

RAIN IN THE JUNGLE – I'm not sure whether Creedence Clearwater Revival has a big following in Brazil, but two of its songs, “Who'll Stop the Rain?” and “Run Through the Jungle” could serve as the unofficial soundtracks of the history of this particular race.

It always seems to be sunny and perfect the week before IndyCar arrives, and at least decent and clear for practice and qualifying. But come race day, Sunday, the skies have opened and left the track basically drowning with puddles and standing water as much a part of the circuit as curbs and concrete barriers.

A red flag of nearly 40 minutes interrupted the first race after a brief drizzle turned to a Noah's Ark-style downpour and left everyone scrambling for cover. Once the rain stopped and the race resumed, at least it was finished on Sunday.

Not so last year. The race moved from late March to the end of April and into May, but the weather came with it. It took 40 minutes to run 14 laps on Sunday and, citing another similar drenching of the track, the remaining 1 hour, 20 minutes was run Monday morning. Drivers took cover under, among other things, umbrellas (ABOVE) and tents (shown off by James Hinchcliffe, LEFT).

True to form, intermittent showers are predicted from Friday through Sunday, each day offering at least a 60 percent chance of rain.

Rain as the great equalizer, though, would be a major benefit to the Lotus teams – who appear at a genuine straight line speed disadvantage to the Chevrolets on Hondas. Speaking of engines…

TURBOGATE – It only took three races before the engine war battle between Chevrolet and Honda intensified. Chevrolet is a perfect three-for-three in both poles and victories in 2012, and Honda has now asked whether its single turbocharger could be adjusted – on April 18, a change to a 0.74 A/R compressor cover for it was approved.

Unsurprisingly, Chevrolet/GM objected and filed an official protest, with the hearing scheduled for Thursday. Much as the Chevrolet engine changes and respective 10-spot grid penalties was the big off-track talking point of Long Beach, “turbogate” figures to fill that role this weekend in the last race before the month of May.

TRACK CHANGES – After wholesale changes made last year to combat a largely grip-less concrete front straight and other portions of the track in 2010, the NZR Consulting crew led by chief track architect Tony Cotman has made some less drastic tweaks for this year. The hope is that the weather allows for a dry race and a proper opportunity to utilize it.

LIVERY CHANGES – Two of the Brazilians, Kanaan and Castroneves, will have different liveries on their cars this weekend. Kanaan's No. 11 KV Racing Technology car will reprise its Itaipava colors of a year ago, while Castroneves will shift to the white, yellow and blue Penske Logistics paint scheme.

Dario Franchitti, who ran a red, yellow and blue Kellogg's livery last year, has joined the black and gold livery party with Lexar signage adorning his No. 10 Target Chip Ganassi Racing entry.

This may be the last race of 2012 with more than one black and gold car, as Oriol Servia will run his last race in the Lotus DRR car and its associated paint scheme before the team switches engines, likely reverts back to its Dreyer & Reinbold Racing name, and returns to running different liveries based on different primary sponsorships. Sebastien Bourdais' standout black and gold McAfee Dragon Racing livery should be closer to the front if it's wet throughout the weekend.

HEAVY HEARTS FOR BRISCOES – Thoughts go out to Will Power's teammate Ryan Briscoe and his family, as his wife Nicole's grandfather passed away last week. Briscoe's start to 2012 has been underwhelming from a results standpoint despite his strong qualifying pace, but he ran strongly here last year, scoring a podium finish.

RESULT-HUNTING – Takuma Sato's near-miss both in this race last year and last race at Long Beach, when he was spun on the final lap while running third, means he's the only driver in the field not to have seen a checkered flag this year. While he's due a result just for having the worst luck in the first three races, some others who could desperately use a big result emerging from Brazil include…

• Justin Wilson. A strategic mishap demoted him from a potential podium, if not win possibility, at Long Beach. That's in the past. If the Dale Coyne Racing team has the car near the leading pace, Wilson can do the rest, and it appears their street course setup is ahead of their permanent road course setup. Forgetting the Chevrolet penalties at Long Beach, Wilson still qualified behind only Dario Franchitti and Josef Newgarden of the Hondas, and ahead of eventual runner-up Simon Pagenaud, who's been off to a torrid start so far in 2012.

• Dario Franchitti. We're this low in a preview and just now getting to the champion? Franchitti benefited from the Chevrolet grid penalties at Long Beach to start on pole, but persistent mechanical issues blighted his restarts and contact with Briscoe required a front wing change that cost him even more time. It seems crazy to say a mere top-10 would be a victory for him, but he and the Target Chip Ganassi Racing team can't afford to lose even more ground than they already have.

• Marco Andretti. Would you believe that through three races, Andretti is one of only four Honda and Chevrolet drivers (James Jakes, Josef Newgarden, Ed Carpenter) without a top-10 finish this season?

After dropping back at St. Pete, his impressive charge at Barber went for naught as his tires fell off in his final stint. Of course, he could count himself thankful for even still being able to race in Brazil, after his accident with Graham Rahal in Long Beach. Andretti's best finish this year (11th) matches Jakes and Newgarden, and with no disrespect to those two, Andretti should be finishing comfortably ahead of them, especially compared to his full-season Andretti Autosport teammates James Hinchcliffe and Ryan Hunter-Reay.

• Josef Newgarden. His “needing a result” isn't necessarily as crucial as the others mentioned above. Still, a quiet, consistent race where he gathers laps and stays out of trouble would be a welcome tonic after his first-lap departure at Long Beach. While I wrote last week that I loved his passing attempt at Turn 1, his getting home in one piece and clean will keep the Sarah Fisher Hartman Racing team on task for Indianapolis, where they will have more time to continue the learning and maturation process. A steady top-15, if not borderline top-10, would be a good result for him on a track he's never seen before.

BIA'S SECOND CHANCE – Given her best opportunity in an IndyCar after a relatively anonymous year and a half sojourn with Dreyer & Reinbold Racing, Ana Beatriz enters Brazil in the first of two starts with Andretti Autosport with some of the spotlight on her, naturally, as one of the locals.

While she'll get some attention, she'll still probably trail her three countrymen in media scrutiny. Also, expectations should be lower given she's only had one day's testing in the DW12, so she has a great opportunity to punch above her weight and prove herself worthy of further starts either with Andretti or another team going forward.

Essentially there's nothing to lose for “Bia,” and with the right mindset in place, she could surprise. She has shown sporadic moments of brilliance in IndyCar – qualifying 10th at Sonoma last year for example – and more frequently in her two-year Firestone Indy Lights career.

THE TOUGHEST PIT ASSIGNMENT OF THE YEAR – Spare a thought for NBC Sports Network's Kevin Lee, who has the unenviable task of trying to follow all 26 drivers, teams and associated storylines as the sole on-site pit reporter for Brazil. It's something the broadcast network employed the last two years and will do for a third time this year.

Lee handled it with aplomb last year on his debut after Jack Arute did so in 2010, and the task was made especially difficult given the rain delays and the constant quest to make sure all on-air time was filled without dead air. Booth commentators Bob Jenkins, Wally Dallenbach Jr., Jon Beekhuis and Robin Miller have the comfortable confines of a cozy Indianapolis studio to broadcast from.

• The IZOD IndyCar Series Itaipava Sao Paulo Indy 300 presented by Nestle airs on NBC Sports Network live Sunday at 11 a.m. Eastern.