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.
This week’s bulging Tech Mailbag has been split into two parts. Part 2 to follow tomorrow.
Why do the new F1 single turbo engines sound worse than all other turbo race engines? I found the sound the single turbo Honda Indy engine much more pleasant. I heard the single turbo Renault at the 1979 Spanish GP and found the sound very distinctive, especially the turbo lag.
Phil D., Victoria, BC, Canada
MP: As someone who’s been in love with the sound of racing engines since I was a little kid, I must admit I love how Formula 1 has drawn so much attention to the importance of sound and motor sport. I tell people all the time that racing is built on three pillars: speed, looks, and sound. You can knock down one of those pillars and get by, but with F1 losing on sound and looks in 2014, no wonder diehard fans are in an uproar. The new F1 turbos just aren’t that angry, nor do they need to be with so much energy recovery power making up the total output feeding the rear wheels.
F1 turbos in the 1980s revved lower but sounded awesome, so you don’t need a high-pitched whine to generate quality sounds. The big differentiator was sheer violence taking place in the combustion chambers back then; you heard and felt the power when they went by at 11,000 rpms, and the brutality of the experience—akin to a rocket launch—was unforgettable. Somehow, more than 25 years after F1’s last turbo era fell silent, they’ve managed to conjure up a new formula with engines that sound like they are being fed veggie burgers instead of raw meat.
Take a listen to the in-car audio from Simon Pagenaud’s twin-turbo Honda Indy car engine from last month—other than using a good recorder to capture the sounds, I did nothing to alter or amplify what it captured. It sounds gutteral, nasty, and what I think most people would want to hear from such a car. Then listen to Lewis Hamilton’s precise, aseptic Mercedes turbo from last weekend. Hopefully F1 will follow IndyCar’s suit.
I really love your new mailbag column. Very informative. My question concerns the effect of fuel loads on lap times. This is often talked about during a Formula 1 broadcast as they describe how the car gets faster as it burns off more fuel but I never hear about it on an IndyCar broadcast. Is it a case of IndyCar being heavier causing the weight of the fuel to matter less or is it more a case of the F1 cars being so much more precise and knife-edged?
Randy Holbrook, Resaca, GA
MP: Fair point, Randy. For whatever reason, it isn’t discussed much in IndyCar, but it should be. Indy cars are heavier, and do carry less fuel, but those factors don’t diminish the fact that drivers experience balance changes as fuel burns off and the car gets lighter.
Here’s my question: let’s assume you are the race engineer on an IndyCar, and you are facing the first Friday morning practice on a street circuit, so the track is green with virtually no grip. As the weekend goes on, rubber gets laid down, the grip levels go up, etc. [ABOVE Helio Castroneves and Ed Carpenter at Long Beach, 2013. LAT Photo] How do you, as the engineer, adjust the car for the increasing grip levels in terms of springs, bars, aero and shocks? How do you guess what the optimum set up is for race day when the track is probably in its best condition but now you have a full load of fuel?
Richard
Flower Mound, Texas
MP: Richard, history is a pretty good guide, and for first time visits to a track, a lot of the initial work centers on determining grip levels throughout the course (after getting the basics like ride height and cambers dialed in). It’s never consistent from corner to corner, so with the car in the setup window, teams will often make longer runs to monitor and capture tire wear data. On top of what they learn in practice, they’re also running a lot of computer simulations in the background, which removes a lot of the guesswork on suspension and aero settings. Sim is also happening before the event to provide a fairly decent (and possibly dead accurate) starting point. Basically, there isn’t as much guesswork as one might suspect.
Is this near correct? The current cost of a DW12 is about $350,000 and with spares for a year another $150.000, and the engine lease is $650,000. so the actual cost per car is $1,150,000. Is this near what you know as the actual costs? Would it be fair to suggest that a chassis could be produced (one off) for $500,000?
Here are 10 PRODUCTION engines including the car with price. http://www.automobilemag.com/features/news/top-10-cheapest-500-hp-cars-205027/. A Hendrick or Roush engine producing 800+ HP are priced from $45,000 to $80,000. There are many modified production engines available for less than $100,000.
So if a one off chassis costs $500,000 and an engine for it cost $100,000, and to make sure it’s safe we include an approved safety cell costing $100,000 we have a race car costing $800,000, and you’d own everything, and using “ingenuity” wouldn’t this add two things that MIGHT bring new fans…..a new look and a new sound to the race, (The only race that means anything or pays anything is the “500”…quick tell me who won Barber last year…took a minute didn’t it?). The series by contract is bound to the DW12 and engine packages till at least 2018…so separate the “500” from the series and let it do what ever they want.
If open wheel has a future…it certainly starts with a new formula…because if we are subjected to “spec” racing till 2018-2021, (except for the Danica Race [2005] the attendance at the Speedway, and TV audience has declined)…… the loyal fans will be gone and the kids today will be watching something else…bet on it.
Please defend the current state of affairs and formula, I’d love to be proven wrong.
Ted Wolfram
MP: I’m not much for defending or disproving theories. What you’re describing was called the Indy Racing League. Teams bought a chassis for just over $300K, engines that made about 700 hp for about $100K, rebuilds were in the $25-35K, tires were usually free from Firestone or Goodyear and…no one cared or watched.
Today’s professional racing series thrives (and survives) on two things: sponsors and manufacturers. Revert back to the IRL formula, and we may as well turn out the lights right now. The problems with TV ratings and popularity go far beyond the formula. If spec formula didn’t work, NASCAR would be sitting alongside IndyCar and the TUDOR Championship in the 0.2 Nielsen category.
Thank you for having this tech mailbag. I had been anticipating asking you about 3D Printing and it’s use in racing technology, specifically, but my questions range broadly on the topic, so I hope you can touch on the subject a bit. Is anyone with IndyCar or IMSA or other sanctioning body or manufacturer currently using this technology in racing (it seems some in F1 use it)? Would IndyCar allow it’s teams to design aero kits, mirror brackets, seats, et al, using this technology (has the idea even been broached)?
Thank you,
Pat, Colorado
MP: I just saw photos of the new Dallara IL15 Indy Lights car in the wind tunnel and the entire model was 3d printed. For those who’re accustomed to seeing wind tunnel models done in carbon fiber, it’s an interesting development, for sure. It’s become normal elsewhere, but not so much in our little world of North American road racing. There’s no reason for IndyCar or IMSA to prohibit the technology for rapid prototyping, but since it uses plastics/polymers to do the printing, the materials aren’t suitable for the rigors of competition. Once they find a way to use carbon and Kevlar, we might see this printing technology take off in our sport.
Reading about the new engine in the Porsche LMP1 (v4), there was a lot made of the inherent advantages of V4s. Why aren’t they used more often in racing and in production cars if there are do many advantages? Cost? Imagine two heads are more expensive than one. But as the owner of a high performance inline four, I can see where something smoother and lower might have advantages.
Ed Joras
MP: Porsche went with the V4 solely for packaging purposes. The new ACO P1 regulations call for ultimate efficiency in every area which led Porsche to build a racing engine that has zero relevance or similarity to anything it sells. It’s obviously shorter than Audi’s V6 and Toyota’s V8, which will improve the 919’s balance, and because of its V design, its level of rigidity will be much higher than an inline-4 and won’t require the extra bracing needed with I4s.
I have a few questions. The first questions are about IndyCar tires. In older races (CART late 90s give or take) I’ve watched on YouTube I recall mentions that outside tires on ovals were larger than the inside tires, and it seemed the rear tires were quite massive. [ABOVE Gil de Ferran at Twin-Ring Motegi, 1998 LAT photo]. Is there still a difference in the size of tires between outside and insides, and how do the tires compare to what they were 15 or so years ago?
My last question is about the aero kits for next year. Will there be an open roll-hoop? It seems to me this would remove drag and increase the speed on the cars, not to mention it would look better than the current bodywork. I thought the Formula E concept based on the current Dallara IndyCar looked pretty good!
Chris (Phoenix, AZ)
Hi Chris—yes, tire stagger is still used, but the range of options has been narrowed with IndyCar having Firestone as a sole supplier. When Goodyear was in the series, it was common to have more options for stagger due to the competition between brands and the desire to create more separation between their respective teams. On the overhead air intake, I’d heard there was some debate on whether IndyCar would keep the current location (after saying it was open), so I spoke with my man Nick Wirth whose Wirth Research firm is responsible for Honda’s aero kit, and he says there are no requirements for where the turbos must be fed. Hopefully, that will lead Chevy and Honda to produce kits with low-line engine covers similar to what we had in CART and Champ Car.
This new mailbag is a great idea and terrific fun to read! Now that the new qualifying rules for Indy have been revealed, one of the issues that continue to be discussed is the lack of practice time for teams to work on race setup following qualifying. I’m not certain I agree that it is a huge issue, as a well planned agenda for the week before qualifying would surely include track time for race setup as well as qualifying setup. We always hear that teams must make significant changes between qual setup and race trim and that it takes some time to make those changes. Two questions: Up until this year, were there many teams only running in qual trim during the practice leading up to qualifying? Just what are the changes that have to be made between the two car configurations… suspension, ducting, etc?
Alan, Annapolis, MD
MP: Most teams, or at least the ones that want to win, spend the majority of their time leading up to qualifying working on race setups. Because the weather for the Indy 500 is always something that’s impossible to predict, teams go out and run in whatever conditions are offered each day and develop setups to suit those conditions. If Race Day is similar to one of the practice days, that setup will be used as the foundation of what’s raced. Some go as late as possible—well into Friday afternoon—before trying some low fuel/low downforce runs ahead of the traditional Saturday run for the pole. Teams get extra boost for qualifying, and that’s enabled on Friday for them to sample and develop setups around. The biggest changes between qualifying and race trim will come from aero settings, moving from scary-low to something that’s more manageable in traffic. You’ll have some suspension tweaks as well to ensure tires last a full stint. The most successful teams tend to treat qualifying as a nuisance—something that’s necessary, but takes away from preparing for the race.
Loved the first two editions of the tech mailbag. Keep up the good work. I thought I was going to have to ask how a differential worked, but you posted the EPIC video from Chevy. How much slower is a race setup compared to a qualifying setup? I’ve heard that at a track like Road America, teams will use less downforce in a race than they do in qualifying. Lower downforce would increase the straight line speed, making it easier to pass and harder to be passed. On the other hand, at Indy you might want more downforce in the race for stability in traffic. I would also expect drivers to have their cars ‘on edge’ for qualifying, but tame them a bit for the race.
Kyle in Raleigh, NC
MP: It really depends on the track, Kyle. Fastest race laps can rival the pole time at some tracks, which tells you either the setup difference between qualy and the race isn’t that great or, as often happens, teams find a bit more speed after qualy. To the scenarios you raise, it comes down to where speed is most important at a particular track. Take Monza. F1 teams focus on the straights, not the corners, because that’s where the passing happens or leads can be maintained. There are enough fast corners at Road America to keep teams from going silly-low on downforce, but they will push as far as they can. It’s no surprise that the better drivers are willing and able to hold onto a car that’s light on downforce in order to challenge for the win.
Here’s what I’ve never understood:
– Honda designs (or farms out) an aero kit for the Dallara-Hondas.
– Chevy designs (or farms out) an aero kit for the Dallara-Chevys.
– Except for nuances of the shape/dimensions of the engines, both of these aero kits have to fit on the exact same car. Aerodynamics is a pretty advanced science. So how much actual difference will we see from one kit to another? It would seem that once the respective engineers go to work, they will each independently come up with pretty much the same shapes. Which I expect to also be pretty much the same shape Dallara came up with.
So, by the time you festoon these cars with sponsor graphics, who the heck is going to be able to tell the difference from one to another? [ABOVE Eagle Aircraft practicing at Indy in 1982 IMS Photo]
(F1 cars all look different because the cars ARE different. But even built from the ground up, science has dictated that even they look pretty similar to each other.)
Wouldn’t it be cheaper for the series simply to mandate that the word HONDA or CHEVROLET appears on a very prominent part of the car, the same place (and the size of the graphics) for all cars? Will we really see any difference? Isn’t this a really silly, contrived way to go about pretending we have more than one car in the series? Everyone knows we don’t …
When the new regs go into effect, will teams be allowed to run the Dallara bodywork if they think it’s faster? Or will the engine suppliers require that the teams run their aero kit? Will Dallara even continue to make those body parts for their IndyCars? This whole aero kit thing has always seemed to me more like a catchy phrase than a practical idea which will significantly help to market the sport. (Frankly, I’m still not convinced it’s ever going to happen.)
What’s up with this?
Thanks,
Dean
MP: Look for noticeable, albeit somewhat subtle differences. I can tell ORECA 03, Morgan and HPD ARX-03b P2 cars apart from 50 feet, and they look incredibly similar. Will you be able to do the same with Chevy and Honda Indy cars? I do believe so, based on what I’ve seen one of the firms do with highly controlled formulas and specs. To your wider point, it’s an area for manufacturers to further distinguish themselves, which isn’t bad, provided the costs aren’t too high. It puts more people to work, and that’s also a good thing.
Dallara will not produce an aero kit, meaning every car will look different next year. I’ll admit I’m not a huge fan of the aero kit concept, but it addresses a need, and that need to make sure IndyCar doesn’t race with a chassis that goes unchanged for almost a decade like it did with the previous generation of cars. My man Roger Griffiths, who recently left his post as Honda Performance Development’s technical director, offered the best quote I’ve received on this topic when we spoke at Mid-Ohio last year:
“You could argue, if we look at it from purely a commercial reason for promoting aero kits and attempting to brand the cars with our own bodies, if we’d actually be better off taking all the money that we invested into aero kits and buy a better TV package. Would we actually get more exposure from that? It’s something to think about, isn’t it?”
I’ve been following racing, in general, since about 1998, and I have been expanding my interests since I was in High School in 2004. I began watching the Indy 500 in 1999, F1 on-and-off again in the early to mid 2000s before getting into it at the beginning of 2009 with a growing interest in Sports Car racing. But one thing I had heard about, was J-Dampers. I believe they were first introduced in F1 some years ago, and I think they have mainly been banned (as far as I know). My understanding is that they are supposed to help absorb any oscillation of the front end, providing better road contact and front end stability while cornering. How do they work though and am I right in what they are supposed to do? I believe IndyCar is using a J-Damper? How is it implemented in that series and where is it in the suspension?
Thank You and Best Regards,
Matthew Smith
MP: The J-Damper, which is short for “Jounce Damper,” was conceived by Cambridge University as a tool to control tire contact patch variance and oscillation, as you describe. They’ve been allowed in IndyCar since the Dallara DW12 was introduced in 2012, and per the rules, the technology must be contained within the damper. In F1, the technology was introduced as a separate suspension component. They’re also referred to as “interters” due to the effect they produce to try and render tire oscillation inert, and that’s done by counteracting those forces through a scissor-like screw and weight system inside the body of the shock.
If you really want to delve into the minutia, my friend Sam Collins broke the story on J-Dampers in 2008. http://www.racecar-engineering.com/articles/f1/understanding-the-j-damper/
What type of effect does the ambient temperature have on fuel economy? Is it significant to mileage? I’m thinking specifically of how this might affect LMP1 cars at Le Mans and F1 cars in general. [ABOVE Audi R18 e-tron quattro, Le Mans 2013 LAT photo]
Ryan
In a general sense, Ryan, it has two effects. Thicker the air, the more downforce produced, the more power/fuel required to push through the air. The cooler and more concentrated the air, the more power that can be made.
Why hasn’t there been a camless engine in motorsport (or production cars)? Koenigsegg are the only manufacturer I know who claim to have a working camless engine. The performance benefits seem obvious, but what are the technical problems that stop it from happening? With the FIA and ACO targeting more efficient engines in F1 and Le Mans, surely a camless engine would be perfect for both. I can’t see why it would be difficult to achieve.
Nicky Gray
It’s a pretty cool concept, isn’t it, Nicky? It’s still in its infancy, but provided it becomes widely accepted, I could see rule makers allowing it in F1, IndyCar, sports cars, etc. With so many series disallowing new ideas, it’s more a case of writing the rules to permit camless engines than anything else.
Last year, the Honda IndyCars had several header issues but they were apparently unrelated. 1) Can you shed a light on what these problems were? 2) Does Honda’s switch to a twin-turbo affect the likelihood of more occurrences? 3) Is any part of the exhaust – or intake for that matter – open for the teams, or do the manufacturers provide/mandate identical systems?
Corey
Honda told me they tried a thinner (and lighter) material and it was a bit too far in that direction (at least two Honda suffered header collapses at the season opener in Sebring). The move to twin turbos won’t increase or decrease the chance of failure—it’s about materials and design, not the quantity of turbos. The intake and exhaust are spec components (intake feeding the turbos is designed by Chevy and Honda and made by Dallara, headers are designed by each and made/sold by their chosen vendor).
Just daydreaming about days gone by when innovation, ingenuity, and Indy went hand in hand. If you could go back and work on just one Indy car from each of the last 5 decades (60s, 70s, 80s, 90s, 00’s), what 5 would they be and from a technical perspective, why? Thanks!
Darrick in Indy
MP: Don’t worry, Darrick, I daydream about stuff like this all the time. The 1960s, as Alex Gabbard’s amazing book chronicles (http://www.amazon.com/INDYs-Wildest-Decade-Alex-Gabbard/dp/1884089712), was the wildest decade for Indy car designs. Turbocharging came into play, all-wheel-drive systems, twin engines, etc. For the Sixties, it would be the Lotus 56, aka, the Turbine car. Pure madness on wheels. I would have loved to been there at Phoenix in 1971 when Dan Gurney affixed his first flap to the rear wing on Bobby Unser’s Olsonite Eagle. It spanned 1979-1981, so I’ll take the Yellow Submarine, aka the Chaparral 2K, as my Eighties option. I worked on both IRL and CART Indy cars in the 1990s, but never the pushrod Penske PC23-Merecedes that crushed the field at Indy…imagine being part of that history-making effort. By the 2000s, the Reynards and Lolas were just evolutions of the cars produced in the late 1990s I worked on or was around, so I’d go with the curvy Panoz DP01 Champ Car of 2007.
I’ve noticed that depending on how high or low a driver sits in the DW12, quite a bit of flat “headrest” area may be exposed above the driver’s helmet. On a car with so few adjustment options, doesn’t this disparity in seating styles have a noticeable aerodynamic affect, especially on big tracks like Indy or Fontana and for drivers who have traditionally sat very low in the cockpit?
Travis, Valmeyer, IL
MP: It sure does, although windscreens can help deflect air over the more exposed helmets to minimize the problem. 1982 F1 champ Keke Rosberg was big on trying to duck down out of the airstream (drivers were far more exposed back then), and claimed he’d see an extra 50 rpms by lowering his head on the straights.
When Indycar came out with its original engine specs that could use a 6-cylinder or 4-cylinder, I was disappointed that no 4-bangers got involved. Would an inline-4 not have better aerodynamically than a V6 and would a 4-cylinder boxer engine not provide a lower center of gravity than the V6? Just wondering…and I guess my dream of Subaru getting involved in the series is over.
Zack, Atlanta, GA
MP: You’re correct on both points, Zack, although a boxer engine, despite its lower center of gravity, would likely interfere with the Dallara DW12’s underwing, limiting downforce. An I4 would also be an interesting choice, if it were still allowed. As I mentioned in an earlier question, additional support bracing would be needed between the bellhousing and tub to compensate for the I4’s lack of structural rigidity, but it could offer an improvement in internal airflow, which Chevy and Honda have been working to improve with their exhaust and turbo layouts. With the narrow I4 design in the back of the car and only one exhaust system/turbo layout on one side, I’d imagine the cleaner air flow through the car would be an advantage.
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