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Marshall Pruett's Tech Mailbag for March 7

Marshall Pruett
Friday, 07 March 2014
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Can you explain how Helio failed post-race inspection at Texas Motor Speedway last year? It related to the height of the diffuser exit. Penske boss Tim Cindric denied getting any benefit from it, but No. 3 crushed the field in that race.
Chris R., Stroudsburg, Pa.

MP: Helio crushed the field because his car was better and he was a master of being patient and careful with his tires in IndyCar’s low-downforce package. The infraction didn’t provide an advantage. His diffuser was off by a few thousandths of an inch as a result of the jam nuts on one mounting rod being left loose, which ended up giving him a few extra pounds of downforce. After the race, I asked Honda if Helio’s Chevy-powered car, with its illegal diffuser height position, was the key to victory. They came back a few days later after running some simulations at that height and said it made almost no difference, and didn’t turn a losing car into a winner. That’s good enough for me.

Will a new manufacturer paired with Cosworth need to develop an aerokit for IndyCar? That'll cost them more $.
Greg, Belleville, N.J.

MP:To be competitive, yes, but there’s no requirement for any of the manufacturers to produce aero kits for their teams, nor do the teams have to buy them. With Chevy tasking Pratt & Miller to design their kit, and Honda using Wirth Research to do theirs, any manufacturer running the stock Dallara bodywork will be at a significant disadvantage.

With what looks like an engine shortage (again) at Indy this year, would it be possible to "grandfather in" last year’s motors? (If they haven't been melted down to make the "new and improved" 2014's. How serious is Cosworth, and does an auto manufacturer have to badge the engine, or could Boeing, Bombardier, Mack Truck, Lawn Boy?

MP: No shortage of engines whatsoever, Mike. Granted, both manufacturers have pushed getting their revised 2014 engines ready to the last minute due to the homologation cutoff date, but you’ll see a full fleet of cars – as many as teams need engines for – at every round, including the Indy 500.

Cosworth is serious enough to commission an engine design, and they could build it and enter it as a Cosworth if they wanted, but it wouldn’t make good business sense. They’d lose money with each lease, which makes signing a manufacturer – including the ones you mentioned – a better choice. I’ve yet to see any limitations placed on the kind of manufacturer eligibility for this, so go for it, Lawn Boy!

I think so much fan anger over P2/DP balance at Daytona really came purely from the Corvettes being overpowered, rather than anything with the Dinan or Ford packages compared to the P2s. From hearing Scot Elkins talk about engine testing since then, and Ford talk about the SIRs, it seems pretty clear to me that GM just wasn't reaching the mass airflow that would result in them dropping the HP expected. Does that seem to be the case, and one that will get the DPs all on the same page so they can match the P2s as a group?

Also, any thoughts on the Sebring test and how the two sets of cars will balance out in higher-downforce trim? From what I saw in split times, it looked like the AXR car was just plain fast on the second half of the track after being pretty even on the front half, which looks to me like something they figured out that other teams haven't rather than a BoP concern. Were the dive planes enough for the DP guys to feel they've balanced the cars, or are they looking for more?
Andrew, Baltimore MD

MP: Can’t say on reaching mass airflow. It could be the sizing of the turbos inlet cover/compressor preventing the Ford’s SIRs from feeding them enough volume. The AXR guys were the pace-setters and felt their Corvette DP needed more aero grip up front, so I’m guessing we’ll see them ask for bigger dive planes to be homologated.

That’s one thing to keep in mind: the bodies for each type of DP have to be homologated, so teams can’t go back to the trailer, weld up a set of giant aluminum dive planes, and try them during the next practice session.

I spoke with Elkins after the test and we both agreed that since AXR turned a bunch of laps at Sebring in November – the only DP team to do so – and they had Sebastien Bourdais on maximum attack, it was a perfect storm of speed and experience setting that lap time rather than the Corvette DPs outside the BoP window. Drop Seb’s time, and the mix looks pretty good among DPs and P2s.

With carbon brakes, similar downforce and more power, the restrictive rules for the P2 cars – and that’s based on the ACO more than IMSA – has them struggling to assert themselves. Skinny tires and less power (from what they once had) have made the current P2s far less exciting to watch. Having seen Marco Andretti go flat through Sebring’s Turn 1 in 2008 in an Acura P2, the recent regulations have simply neutered their ability to impress the eye or the stopwatch. Admittedly, watching Bourdais' bomb through Sebring’s Turn 1 at full power in November was pretty cool. Bottom line: more power good, less power bad.

I wanted ask you about Honda LMP program: are we seeing the dawning of the future for TUSCC and WEC merging P2 rules? I ask because they green-lit the Honda DP spec motor and now the ARX-04b project. It got me thinking maybe Honda is planning that TUSCC and WEC will use the same chassis (ACO spec) the difference will be motors. Am I way off or on to something? And one more question and it’s about IndyCar if Dallara is open to competition, so does that mean another company ala Swift can start selling chassis or is Dallara the exclusive supplier?
Kevin from NJ

MP: Kevin, Dallara is the exclusive supplier for IndyCar. If another manufacturer wanted to come in before the contract is up, it would have to be negotiated. With the nasty fight over spare parts prices in 2012, I’m not sure if any other manufacturers would want to consider getting involved before the next chassis is commissioned.

I would just like to ask about IndyCar aero kits and their progress. Could you give us an update?
Henry Moe

MP: Everything is on target for their debut in 2015, Henry. Look for Chevy and Honda to wait to test them in public until as late as possible.

Can you please explain where we are with anti-stall in IndyCar. It's been available since St. Pete 2012 and we are now two years down the line and yet it still isn't sorted yet. Wasn't this supposed to stop these silly FCY's and keep races green. With the addition of standing starts, isn't there a solid reason to have a fully operational anti-stall system. Very little has been said about anti-stall in the last two years so I'm hoping you can change that, Marshall.
Graeme Watson, Brentwood, Essex, UK

MP: Wish I had that kind of influence, Graeme… As I wrote in a previous question, anti-stall is now a mandatory item that must be activated. Whether it works every time it’s needed could be a topic to monitor this season.
Of the issues preventing anti-stall from working as desired, Indy cars idle lower than some of the cars where the anti-stall technology was developed, meaning the system has less time/revs to react when a stall was about to occur. Pit lane has also presented a few issues with anti-stall engaging when drivers bog down leaving the box. It’s still a work-in-progress, but with IndyCar requiring its use now, I assume the kinks will be worked out with help from all parties.

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