Welcome to Marshall Pruett’s new Racing Tech Mailbag on RACER.com. If you have questions about the technical side of the sport for Pruett, who spent most of his life working as a mechanic and engineer in open-wheel and sports car racing, send them to PruettsTechMailbag@Racer.com. We can’t guarantee your letter will be published, but Marshall will always reply.
Q: With the ARX-04b unveiling, it’s another in what seems to be a trend of very tall, sharply contoured vertical fender pieces. The same can be seen on the Ligier and Toyota. These appear like they would produce much more drag than a more wedge shape, such as the Oak Morgan. What is the aerodynamic benefit of this blunt shape?
Andrew in Baltimore
MP: Andrew, I asked my man Nick Wirth, designer of the ARX-04b, to answer your question: “These fender shapes come as a direct result of the unfortunate legality holes above the front tires. We are all trying to minimize the effect of these holes and having them in curved surfaces promotes flow out of the hole which is bad for the flow down the rest of the car. Basically, the flat topped and rather unattractive shapes that prevail nowadays minimize the flow out of the hole, and therefore minimize the holes’ impact on the rest of the car.”
Q: Would it be feasible and safe for IndyCar to return to gasoline-powered engines? It seems to me that current fuel-cell technology would allow it. At the least, gasoline-powered engines would increase IndyCar’s commercial appeal. In addition, wouldn’t the engines develop more power if they ran on gasoline? That would increase the spectator appeal.
Steve, Aurora, Colo.
MP: The cooling benefits within the combustion chamber that come from using an alcohol-based fuel help with the lack of intercooling, but no, other than the marketing value that Chevy and Honda enjoy, there’s no reason for IndyCar to stick with E85. The caloric value of E85 ethanol is rather limited compared to gasoline.
Adjustments to fuel injector flow rates, compression ratios and engine mapping would be required, obviously. If IndyCar wanted to put more power to the ground, a return to methanol would do the trick in an instant: “We’d pick up 80 to 100 horses instantly on methanol and we’d reduce some of the knock issues,” said an engine-building friend from the paddock…
Q: I am a fan of sports car racing and feel that the WEC (and IMSA for that matter) have the widest variety of technology currently in racing, with more new cars and engines coming than I’ve seen in years. I hate the restrictions placed by F1 on engine design and fuel flow as a way of leveling competition.
That said, having read about the WEC’s new fuel restriction for LMP1 at Le Mans, I am perplexed. The WEC (similar to F1) is limiting the exact amount of fuel allowed to be used, but quantifying it per lap of Le Mans, rather than rate as they do in F1. That seems to me to be an extremely fine-grained measurement, possibly too fine. I am all for fuel economy and have no problems with a fuel limit like in years past, but this seems to me to take away a team’s strategic use of fuel over 24 hours. What other ways are available to accomplish this Balance of Performance and why choose this one?
On a separate note, after watching the St. Pete IndyCar race on TV and online, I saw they had a neat map showing the location of every car during any lap of the race. How accurate is this system and could it be used to prevent a situation like Alex Job Racing had at Sebring? Or would it be easier to just paint the car’s number on the roof so the camera can see it?
Jonathan Charles
MP: Hi Jonathan. IMSA actually has the same vehicle location mapping tool. The suggestion I made to IMSA after the Alex Job issue was to record the information via a DVR (or similar). Along with trackside TV and in-car footage, being able to rewind the map video to a specific timestamp and pick out the location of each car would be a great tool to use.
The ACO’s new fuel-limited formula also acts as a BoP tool, but it’s really about marketing. The ACO wants its factory P1 teams to make Le Mans relevant as a leader in emission reductions, fuel consumption reduction, etc. Considering the hundreds of millions of dollars being spent by each factory, I’d ask whether the money would be better spent on R&D projects to reduce road car emissions and consumption. The track-to-street benefits, in this case, are likely to be small. I’m not a fan of the formula.
Q: In this week’s column you described the functions of the steering wheel buttons. In that you mentioned that two buttons were for left and right weight jacking. Do these allow the driver to jack more weight to aid turn in or to help hold the car straight along the straights? Or is there some other purpose?
Tony Cossor, Australia
MP: Hi Tony, the weight jacker (ABOVE) is used to add or reduce diagonal load on the tires, and except for rare situations, the device is only used on ovals. Teams have their own preferences on where to place the weight jacker – on one of the four dampers – and its function is to add or reduce weight on the front or rear of the car to increase or decrease oversteer/understeer.
Q: You stated that F1 is currently limited to 15,000 RPM, and this is true, but due to the fuel flow limit they are unable to exceed 12-13K. Am I wrong in this assumption?
Gregory Speetzen
MP: You are 100 percent correct, Gregory. At least from what I’ve seen from the in-car feeds, 12,000 rpm is the average right now, same as IndyCar.
Q: I just wanted to say something right off the bat. As a current Mechanical Engineering student and all around car buff I find your Tech Mailbag to be quite possibly the greatest thing currently on the internet. (I sincerely mean that.) I love all the little technical details about racecars.
1. This whole fuel flow meter issue in Formula 1 seems needlessly complicated to me. Why can’t the FIA just determine a set amount of fuel for each track and teams can’t exceed that amount? I’m sure it would be easier to enforce. As a whole I don’t like the whole concept. I mean it’s not like Ferrari has fuel efficiency at the top of their road car priority list. I’m just saying racecars, especially F1 cars are supposed to be loud, fast and powerful.
2. I vaguely remember it being mentioned somewhere that there was a discussion about bringing DPs to Le Mans. Just wondering if there was any progress with that idea.
Chad W. Kennedy
MP: Kind of you to say, Chad. I spent my teens and 20s devouring every racing tech item I could find (still have most of the magazines and books I purchased back then, too). It’s an odd affliction, and one I’m glad to share with you and others.
As I mentioned to Jonathan above, the need to promote eco-friendly racing has superseded common sense in F1 and at Le Mans at the moment. We’ve basically gone from the hard-hitting NFL to non-contact flag football overnight, and that doesn’t sit well with me. I’m all for big technical challenges, but when the result is racing at less than maximum speed, I have to ask if the smartest decisions have been made by the rule makers.
On the DPs-to-Le Mans topic, I spoke with ACO tech boss Vincent Beaumesnil earlier this year and asked if anything had changed on that front and he said cars that do not conform to ACO regs will not be allowed to race, regardless of the recent relationship they’ve forged with the TUDOR Championship.
Q: So in years past, ACO and FIA prototypes had louvered fender extractors. At least on the front. In the past seasons they have moved to an open rectangle. I understand that one of the reasons use to be trying to keep an exploding tire contained. In my opinion, they also held down some of the rain spray giving less of an advantage to the drivers at the front.
What caused the change in the rules to abandon the louvers?
On a side note, the Delta wing almost runs open rears with a bumper flare behind. Was this a performance concession or is there a reason the rear of the car needs dramatically different aero?
David from St Louis.
MP: Hi David—the louvers had nothing to do with containing tire explosions—it was about extracting high pressure air from the wheel well and helping to accelerate low pressure air from the front underwing. The big louvers were abandoned to comply with the anti-blowover changes that were implemented, as well as the addition of the large engine cover fin.
The DeltaWing was designed in a proverbial vacuum, with few restrictions based on P1 or P2 rules. The ACO did want the rear tires vented, and the easiest way to do that was to leave that section open. Under the ownership of Don Panoz, the DeltaWing DCW13 coupe now has venting above its skinny front tires as well.
Q: I’ll ask a “what-if” question here… I remember in F1 back in 1993, teams were developing things like active suspension, anti-lock brakes, traction control and other exotic technologies for the time. I seem to remember hearing about anti-skid control, programmed gearboxes and even the ability to modify various parameters real-time from the pit wall during the race…
Now, my question is, where would racing be today if all of these emerging technologies back then were allowed to flourish freely? Would we even need drivers in the cars today?
Steve, Indianapolis
MP: Hi Steve, yes, absolutely. Your average street car has many of those same pieces of technology, but drivers are still required (although I wish I could use remote control to move many of them out of the way). Motor racing has always been filled with cutting-edge technology, no matter the decade or era, with drivers often asked to utilize technology that reduces the amount of direct inputs they once made without assistance. If there’s a gripe among older racing fans, it’s centered on driver aids taking away the pure essence of driving, but I rarely hear those complaints from the veteran drivers.
As for where the sport would be today if all of the cool F1 tech of the 1990s continued forward, I don’t think we’re far off. KERS wasn’t even a concept anyone was talking about from ’87-’93, but it’s here and highly advanced. DRS was never permitted, but it’s something teams would have implemented on their own if the rules had been open. F1 transmissions are technological marvels, the engines have been taken to a fairly insane place and I’d say only the suspension is somewhat conventional, but if active suspension does make a return, the systems Williams and McLaren put to such good use two decades ago would now look primitive.
Provided an increase in technology doesn’t flatten the talent curve between drivers, I’m all for whatever comes next.
Q: So we have finally seen a clean race from the merged sports car series, without the AMs, and yet again we saw the advantage was to the DP cars (and terrible TV coverage). We do need to see how things work at Laguna because when there was racing, Sebring did show some competitiveness between the prototypes. However, I don’t think that the rules (tires and fuel at the same time) and current BoP work to allow the P2s to have a reasonable chance at battling for the win given the American style of officiating (read, “deploying the safety car too much”) and the tracks they are running. The P2s are good on tires and the quick corners, where you don’t pass much, and the DPs have acceleration and top speed. What can they do with the BoP for a short term fix, because the tire/fuel rule will have to change for next year.
On the F1 front, the Bahrain race was the best of the season throughout, probably because of all the testing. Does it stand to reason that if more testing at tracks they race was allowed, we would see more races like that GP?
We also learned about the “split” turbo on the Mercedes engine and during the preseason that Ferrari is using a single ballistic shield. What other surprises do you think the engine manufacturers’ might have going on?
Daniel, Atlanta, GA
MP: IMSA addressed all of the performance deficits the DP had compared to its P2 counterpart, and then some. The P2 is, barring a slight bump in power, fixed to running full ACO specs, and those specs are rather unspectacular when compared to what P2 cars once turned for lap times. The DP has been freed, the P2s remain restricted, and we have a Prototype class where the free cars are now fast wherever they go. DP has returned to its WSC roots, albeit with closed tops, and the better WSCs were seriously quick. For IMSA to tip things towards the P2s, it will need to slow the DPs by taking power and downforce away.
On Bahrain, it’s actually the opposite that made the race so crazy. A general lack of mastery with the 2014 F1 cars has led to some unpredictable racing. The more teams learn about their cars and formula, the closer the racing will become.
I still want to see photos of Mercedes’ turbo arrangement. If it’s as described, Ilmor deserves a big pat on the back.
Q: Please explain how the current version of push-to-pass works. I know there are a limited number of boosts per race but in the past I seem to remember that each boost lasted only as long as you were accelerating. But I’ve also heard that each boost is time-based depending on the track (10 seconds, 12 seconds, etc.). Which is correct and which is better in your opinion?
Blake Fountain
MP: Rather than cut and paste the P2P section from the rulebook, I asked IndyCar VP of technology Will Phillips to provide a more relatable answer: “There are 10 pushes per race, and the time duration of the boost is based on the length of the longest straight. There are minimum thresholds that must be met for it to work, but fundamentally, you can arm it in the corner and once you’re hard on the throttle and those thresholds are met, you’ll get all the extra power. If you decide halfway down the straight you don’t want the extra power, you can back off the throttle, but you’ve committed to that full period of time whether you use the power or not. You cannot, essentially, lift off the throttle and save a few seconds of Push-to-Pass for later use.”
Q: I’m mostly an IndyCar guy but the other day I watched a video of an F1 pit stop. How in the heck are they changing those tires so quickly? I couldn’t tell what the technology is that’s allowing them to what appears to be simply pulling off a wheel and putting another on in no time flat. When did they change from the traditional tires/wheels like we still see in IndyCar?
Steve, Eden Prairie, MN
MP: F1 teams have been doing quick stops for quite a while now, and with no refueling, it’s all about tire-changing. Everything about the wheels, wheel guns, sockets, wheel nuts and jacks have been optimized for speed, and with three people per tire, compared to one in IndyCar, it’s a case of extra resources making the changes go so quickly.
Q: The caution is out! Then car after car piled in to the wreck at Long Beach. That seemed senseless and, if you added some Benny Hill music, somewhat comical… but only because nobody was hurt. Well nobody except a few owner’s wallets. NASCAR pushes a button and the lights are turned on at the tracks. What if Indy Car pushed a button and engaged the pit speed limiters on all of the cars? I’m not intricately familiar with how the limiter works and if it engine brakes the cars the idea is useless. However if it simply prevents them from going faster than they’re going until they drop gears and get down to the limit I could see that as being a way to possibly avoid an incident like the one we saw on Sunday.
Ryan
MP: I had a conversation with Ryan Hunter-Reay about this topic today. Indy cars have an onboard caution system that can be triggered from race control, but there’s no elevated warning function, per se. I wouldn’t want anyone to remotely control the performance of the cars, but I would like to see a holy-crap-slow-down-there’s-something-bad-around-the-next-corner type alert flashing in the face of every driver. If you watch the violence of the hits James Hinchcliffe took from two cars, well after the Turn 4 wreck happened (at the end of the video below), it’s clear something about the severity of what was waiting around the corner wasn’t received by Takuma Sato and Jack Hawksworth before they battered the back of Hinch’s car. It also doesn’t help that one of the corner workers was waving a green flag (down the track) after the crash took place (see pic above). I’d love to see IndyCar devise a “panic button” system they can use to reduce the carnage the next time a crash like this takes place.
Q: So, we have seen three TUSCC races and the BoP between DPs and P2s has been “interesting” (this is all my opinion, of course). At Daytona and Long Beach, the P2s might as well have been in their own class, because they had no chance of catching the DPs. And the podiums were all DP. At Sebring, the ESM HPD probably would have won the race without that final caution period, and ended up second.
If nothing changes, I would think you could safely predict the following likely winners:
Places where DPs are Prohibitive Favorites (80/20): Importance of top speed or point-and-shoot nature of circuits. Detroit, Indy, Road America, VIR, COTA.
A P2 Might win (50/50): Long race and/or high speed sweeping corners. I still only rate this 50/50 because a late yellow could hand the race to a DP (see Sebring). Laguna Seca, Watkins Glen, Mosport, PLM.
So at the end of the year, you are looking at 9-10 DP wins and 2-3 P2s. First off, does IMSA see this? And, do they care? I suppose I could understand if they did not make any changes at Laguna, because you want to see how the cars react to that track as its difference from the three they raced on before.
Second, if this happens and you are Honda or ORECA or Dome or anyone else developing a P2 coupe, are you going to put any effort not developing the package to run in IMSA if the car’s prospects are so bleak.
Third, if you are Ed Brown, are you feeling any sense of betrayal? If I were Ed Brown, and the cars are asked to run Detroit in the same configuration as they ran Long Beach, I would seriously consider coming up with a creative excuse to pull out of Detroit, Indy and Road America (he has to race at the Glen and PLM). But If I am Ed Brown, I have to be wondering what else is going to get IMSA’s attention?
FULL DISCLOSURE: My employer is now a title sponsor of a P-car. Which is a source of some personal conflict because I am a long time LMP guy.
But at least we are BACK IN RACING, DAMMIT, and we moved a few million marketing dollars out of GOLF! That’s a good thing, right? And I may be able to get to more than a one race! And they may be making cool team shirts that we can wear to work on casual day! And some us may be able to go to the races at Road America or Belle Isle or Indy and not have to take a day off.
I would feel a lot better if the P2s had a future in North America, though. It’s very troubling.
Ed Joras
MP: I have a commentary piece coming on this exact topic. IMSA chose to carry P2s and DPs forward in its new championship, and while the series runs under a Balance of Performance construct, making sure both types of cars land in Victory Lane is vital to the companies that manufacture those cars. This viewpoint has nothing to do with the racing, and everything about ensuring the financial health of the Oaks, Coyotes, Orecas, Rileys, etc. If P2s were cleaning up, I’d be saying the same thing about DPs needing to win. The last thing the series needs is for a bunch of owners to find themselves with uncompetitive cars that have no resale value.
Q: May sound dumb but do the current IndyCars use traction control?
Chad Frankenfield
MP: Thankfully, no, Indy cars currently run without traction control and, as a result, we get some tasty oversteer to enjoy (ABOVE). Using a spec ECU from McLaren definitely helps police the topic. TC briefly appeared in the early 1990s and again towards the transition when CART became Champ Car. TC was even permitted by the rulebook in some of the instances where it was used…
Q: Back from 2 days at Long Beach, talk about fantastic attendance and a fantastic show on Sunday! I wanted to ask about the qualifying times on Saturday though, and see if you could elaborate on a few things. I attended qualifying in 2012 and was impressed with Ryan Briscoe’s time of 68.6089 sec. For only having the new engines a few weeks, I think most would argue that was a solid time. Knowing that Honda and Chevy are always developing their engines (not to mention the teams are more knowledgeable about the chassis and how to tweak it), I expected 2013 would be faster and sure enough Dario blew me away with his qualifier of 67.2379 sec. However this year I was a little surprised to see Bourdais’ 67:791 sec as the top time overall (2nd round). I was expecting low 67s or maybe even very high 66s. I know the weather this year was similar to that in 2012 (High temp at Long Beach airport was 66 this year, 64 in 2012). I also know it was quite a bit warmer in 2013 (High was 81)
I know air density is a function of temperature and that hotter temperatures yield lower air density and subsequently should result in less drag on the car. On the flip side, it’s always been my understanding that a hotter track results in less grip. Anyway, I was wondering if you could elaborate on what role temperature plays on qualifying times at a course like Long Beach. Also, is it possible that Firestone’s reds were of a harder compound than last year, thus resulting in less grip and marginally slower times? The pavement around town has obviously aged since last year as well, could that have factored in?
Dan Leins, Gilbert, AZ
MP: Some great points and observations, Dan. Of the drivers I spoke to who made the Top 12, and some who missed out, many had a tough time nailing their setups on reds. What worked over the bumps in St. Pete didn’t necessarily translate as much as expected in the LBC. But the biggest change, which accounts for about a half-second difference, is the alteration to Turn 5 where the rumble strips prevented drivers from cutting the corner to the same degree in 2013. The 2014 engines definitely have more power, but putting that power to the ground was more of a challenge this year, which also kept the pole time from being lowered.
Q: What is the crash durability of the Dallara IndyCar? I know that the tub is a one-piece carbon fiber piece, but what about the attached components that get wrecked during an accident? Do the attachment points get rebuilt or as they screwed directly into the chassis? In passenger automobiles, generally once the frame is bent in a major impact, they can be bent back to factory specifications but it seems that the strength of the chassis is compromised. I’m wondering if this is the same for racecars, i.e. do they have a limit as to the number of times they’re rebuilt and is there a point where the entire chassis is wrecked beyond repair?
Jonathan Kim, Los Angeles, CA
MP: So far, the DW12 has been a robust car that has taken more punishment from round to round than any other open-wheel chassis I can recall. On the tub itself, the suspension pickup points are bolted in place to metal bulkheads instead of to the carbon fiber/honeycomb material.
For carbon tubs, reuse really depends on where the damage is done. If it’s done in a structural location where high loads are fed, you can expect a cosmetic repair and the tub to be used as part of a show car. If it’s something like a puncture through a wall or another location where torsional rigidity and safety isn’t compromised, it will be fixed and return to service.
Comments