Why the 2023 Acura Integra's Exhausts Are Shaped Like Curly Fries
If you were to find yourself beneath a new 2023 Acura Integra—or the mechanically related Honda Civic Si—we sure hope it's not because you were just run over. In that case, you might have more pressing things to worry about than the odd routing of the dual exhausts under the back bumper. But, hey, pretend you're on the ground, under an Acura or a Honda, wondering why there are pipes aft of the exhaust outlets shapes like curly fries. We were similarly curious (having put ourselves on the ground, under an Acura Integra, on purpose) and did some digging with Acura for answers.
What Does a Normal Exhaust Look Like?
Normally, exhaust piping follows relatively straightforward routes from the engine to wherever the gases are intended to exit—usually the car's rear end. This typically manifests as straight-as-possible piping leading from the headers, which collect gases from each of the engine's cylinders in individual pipes and merge them into one or two outlets that flow into a catalytic converter, to a series of resonators (for shaping or quieting the noise) and mufflers and, finally, the tailpipes.
There are a few bends here and there, mostly so the piping can clear things like the rear suspension, the fuel tank, or other obstacles, but conventional wisdom holds that they don't double back on themselves or otherwise make any unnecessary trips side-to-side.
How the Acura Integra's Exhaust Looks
The Integra's post-cat piping (aft of the catalytic converters) is a bit different. As we mentioned previously, this setup is nearly identical on the Honda Civic Si, which shares a platform, engine, transmission, and general layout with the new Integra. While the piping follows a relatively traditional central pathway rearward, toward the back of the Integra, via a small tunnel, upon reaching the rear axle area, it splits into a T-shape, with one pipe turning to the right and another to the left.
These two pipes bend slightly rearward and lead to small resonators, one per side, before taking a 120-ish-degree bend toward the vehicle centerline, followed by another (by which point the pipes are now flowing toward the front of the car), followed by another bend that points the piping back to the side of the car, and finally a gentler 60-ish-degree bend that spits the exhaust straight back, out from beneath the Integra's rear bumper. Why?
According to Honda, those squiggles in each exhaust outlet are, in fact, silencers. They serve essentially the same function as a muffler—Honda calls them "coiled-type silencers"—and their curious shape is highly intentional. While, like everything on a modern vehicle, their shape is somewhat influenced by the allowable space within the bumper and underbody area behind the rear axle, the specific pathway that piping takes plays a crucial role in the surprisingly guttural low-rpm sound the Integra and Civic Si make.
By snaking the exhaust piping into that circular route, Honda is lengthening the exhaust pathway, lowering the resonance frequency without using a traditional muffler . Honda engineers tell us that the design as first installed in the Si also emphasizes the 300Hz to 600Hz frequencies "to deliver a more aggressive sound." Skipping the muffler, Honda also was able to achieve that sound with a 27-percent increase in exhaust flow.
Good Vibes, Different Volumes
The old Honda Civic Si, you'll recall, featured a central-exit exhaust that spit gases from two tailpipes clustered at the center of the bumper. Compared to the new Si and its Integra sibling, it used two large mufflers in a somewhat unusual configuration: The same central post-cat piping flowed into a T-split, with each pipe flowing into the end of a transversely arranged muffler, one on each side of the car. Gases exited those mufflers about an inch from the inlets, reforming into a T before the piping exited the back of the car.
Doing some visual measurements—okay, by the seat of our pants here—the new, muffler-less exhaust setup has more piping. I.e., it's longer, mostly by replacing the old car's length of muffler with pipe, and then spinning that around into loops at each rear corner of the car. It's cool to see the progression of this concept by the engineers, as the new and old setups are clearly somewhat related, only the new version sounds much better, particularly at idle and lower engine speeds. And that's all things being equal, literally. The new and old Si, and by extension, the Integra, utilize the same turbocharged 1.5-liter I-4 engine, and the 11th-generation Civic's platform—again, shared with the Integra—is a modified version of the 10th-gen setup. We didn't note any untoward booming, either, despite the exhaust note being audible in both the Honda and Acura at highway speeds.
For higher-rpm duty, Honda and Acura lean on Active Sound Control—in essence, augmented engine noises and, in the Acura, some active sound cancellation via the audio speakers—to amplify good noises and tamp down on less desirable ones. The tuning of these setups are different in each car; the Honda notably amplifies the engine note, more so in its Sport drive mode. In the Acura, we're told that augmentation was turned way down, with the focus pivoted from outright sporty volume to shaping the noises already in play for a more refined effect.
Of course, the sounds made by the 2023 Integra or the Honda Civic Si are only small parts of both compact cars' appeal. The Si is clearly sportier than the Integra, with a firmer ride and louder augmented noises and no available automatic transmission (you'll get the best-shifting six-speed manual available this side of a Porsche and like it), while the Integra delivers most of the Si's athleticism with greater overall comfort, refinement, and richer features. Both are fun to drive, attractive small cars. And owners of either one can blow plenty of hot gas about how weird their exhausts are.
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acura integra Full OverviewProsVersatile hatchback form factorZippy and fuel-efficient engineUniquely positioned and priced within the segment ConsNot necessarily better with the manualUnimpressive at the test trackCan't escape comparison to the Honda CivicHaving now lived with and tested the new 2023 Acura Integra, we know it isn't a revival of the driver-focused, straightforward hatchback the internet commentariat yearns for. This may dismay Acura acolytes, and indeed we'd celebrate the arrival of such a car in our crossover-saturated market.But don't forsake the 2023 Acura Integra because it doesn't meet your preconceived expectations. Even though it feels similar—perhaps too similar—to the Honda Civic Si, Acura sufficiently elevated the Integra to the luxury realm. It's a genuine rival to its European competitors, with some uniquely distinctive attributes. If you read on and discover it's not the Integra you wish it would be, well, maybe you need to grow up—the Integra certainly has.How Quick? Not ParticularlyOne of those attributes—the one most crucial in this test—is its transmission. Automatics are prevalent among luxury subcompact cars, but choosing the Integra in A-Spec trim and adding the Technology package unlocks a no-cost option to swap the standard CVT for a six-speed manual gearbox. As in every Integra, it's joined to a 1.5-liter turbocharged I-4 that sends 200 hp and 192 lb-ft to the front wheels. In manual Integras, the power is regulated by a limited-slip differential.Pauses introduced by clutch and shifter actuation are factors in the Integra's 7.7-second 0-60-mph time. All of its two-pedal rivals do the sprint in less than 7.0 seconds. Likewise, the Integra crosses the quarter mile in 15.7 seconds at 91.0 mph, trailing many of its adversaries in both metrics. Even so, the engine feels strong for its size, delivering a torquey surge on-boost that's accentuated by little wastegate whistles. What's more, its fuel economy rating of 26/36 mpg city/highway tops many of the 2.0-liter mills common in the set.Manuals typically enhance involvement at the expense of outright acceleration, and the Integra's shifter justifies the trade-off. It moves between gates precisely and is weighted so it requires deliberation but not undue effort. Automatic downshift rev-matching is activated by default—don't worry, you can deactivate it, but don't knock it till you try it. The clutch is less tactile than the shifter; it's light and engages vaguely at the upper end of its stroke. In fact, it caught out a few of our drivers with unexpected wheelspin.Fun-ishThe turbocharged, lightweight, manual 2023 Acura Integra embodies buzzwords that set enthusiast hearts aflutter. In most situations it's entertaining, moving with poise and pep that evinces the great engineering in its architecture. But the Integra is not a particularly sporty car, as proven by its test results and how it feels when driven hard.A 60-0-mph braking distance of 123 feet is on the longer end in this category. Fade was generally a nonissue even under repeated heavy braking, but the pedal, soft at the top and requiring significant depression, doesn't seem tuned for dynamic driving. This setup disposes it to around-town use, as does the brake auto-hold function, which works flawlessly—not always the case in manual cars.The Integra's 0.87-g skidpad average is about what's expected for the class, but the Acura's figure-eight time of 27.2 seconds at 0.63 g average doesn't impress, considering its rivals run the lap in the 26-second range. Our test team was frustrated by meddling traction control, which never seems to truly turn off and prevents full power unless the steering wheel is straight. Such interference negates the differential's benefit in on-limit driving.Out on the road, the Integra is willing to play up to a point. Its tidy size and weight let it flow between corners, but the verve it initially presents evaporates if you ask too much of it. Instead, the Integra becomes overwhelmed by understeer and imprecision. Truly sporty cars come across as a vivid conduit between driver and road—the new Integra doesn't.Our Civic DutyAt this point we'd be remiss to not mention how the 2023 Acura Integra compares to the Honda Civic Si. The chassis, powertrain, and amenities in these vehicles are largely identical, and perhaps unsurprisingly they drive very much alike. The shared shifter and clutch play a part in that. But our tests verify Honda's interpretation is the higher performer: It's quicker, stops better, and is grippier all around. Crucial to that are the optional summer tires equipped on every modern Si we've tested; all-seasons are standard on the Si and the only choice on the Integra.Much more important than the Si's fractional test-figure advantages, though, is the fact the Honda is sharper, louder, and more direct—simply put, more fun to drive. At the point where the Integra falters, the Si stays hungry for the road ahead. It's remarkable how two vehicles so similar in hardware, performance, and general feel end up with such different personalities.All Hail the HatchbackThis is not to suggest the Civic Si is necessarily better than the Integra. Aspects of the Acura make it more appealing than its platform counterpart, and—critically—cars in the luxury subcompact category.Its hatchback format is high on the list. With a conventional small sedan, there will come a time when you'll size up its trunk opening, contemplating how you'll get some rather large thing inside. There's little such issue with the Integra: Lift the rear enclosure and revel in the big cargo area, made bigger by folding the second row. This setup makes Integra living realistic for anyone who carries bulky items or lifestyle gear. Its tall lift-over height is only a slight hindrance.The luxury quotient is there, too. Adaptive dampers fitted on the Integra A-Spec bring a suitably smooth ride in Normal and Comfort modes and stiffen just so in Sport. Plush centers and firm, supportive bolsters make the front seats quite comfortable. Beyond a standard 10.3-inch digital gauge display, the 16-speaker audio system, wireless charger, and head-up display added by the Technology package qualify the Integra to run in today's luxury league.Likewise, the cabin's layout and quality of materials are suitable for an entry-level luxury car. Yet the interior's similarities to the Civic are obvious. Acura could have done more to avoid such comparisons, particularly by distinguishing touchpoints like the steering wheel, shift knob, or infotainment system layout. But given how nice the Civic's interior is to begin with, how the Integra builds on it is no bad thing.The same notion extends throughout the experience: that the Civic is its starting point bodes well for the Integra. If you recall, the Civic was a finalist in our 2022 MotorTrend Car of the Year contest, and we deemed it "one of the best vehicles on sale" in a comparison-test win. Most of the Civic's great things are present, if not enhanced, in its Integra transformation.The Nicer Version of a Nice CarAcura succeeded in creating a rival to starter cars from other luxury brands and offering a unique, practical vehicle to drivers who want something more upscale than a Honda. The Integra's pricing—slightly more than $30,000 to start and less than $40,000 in our fully loaded test car—undercuts the field by potentially many thousands of dollars to make it an undeniable value. It's luxury on the cheap that feels nowhere near cheap.Yet even with its vaunted manual transmission, the Integra isn't the hot hatchback seemingly everyone across the internet insists it must be. That might be you. If so, accept the fact the Integra of 2023 isn't exactly like the Integras of yore. Time and progress ran their course, and Acura built a car that represents what it is now. If that's not enough, don't despair: This entry in the Integra tale is only at its beginning, paralleled promisingly by the reemergence of the Type S performance badge.Looks good! More details?2023 Acura Integra A-Spec Specifications BASE PRICE $33,895 PRICE AS TESTED $37,395 VEHICLE LAYOUT Front-engine, FWD, 5-pass, 4-door hatchback ENGINE 1.5L Turbo direct-injected DOHC 16-valve I-4 POWER (SAE NET) 200 hp @ 6,000 rpm TORQUE (SAE NET) 192 lb-ft @ 1,800 rpm TRANSMISSION 6-speed manual CURB WEIGHT (F/R DIST) 3,040 lb (60/40%) WHEELBASE 107.7 in LENGTH x WIDTH x HEIGHT 185.8 x 72.0 x 55.5 in 0-60 MPH 7.7 sec QUARTER MILE 15.7 sec @ 91.0 mph BRAKING, 60-0 MPH 123 ft LATERAL ACCELERATION 0.87 g (avg) MT FIGURE EIGHT 27.2 sec @ 0.63 g (avg) EPA CITY/HWY/COMB FUEL ECON 26/36/30 mpg EPA RANGE, COMB 372 miles ON SALE Now Show All
It's time to present the finalists for the inaugural MotorTrend Performance Vehicle of the Year. Yes, after running through our contenders—those rides that missed the cut for the final round of voting the PVOTY honors, we're introducing those that did make the finalist cut. One of these vehicles earned our Golden Calipers, having excelled in all six of our criteria (safety, value, advancement in design, engineering excellence, efficiency, and performance of intended function). The weighting of some of those criteria may differ slightly from our Car, Truck, and SUV of the Year competitions—after all, when outright performance is our focus, efficiency is perhaps graded on a curve—but every single one is considered when choosing our winner.Read on to meet the first four members of our finalist field—the rest will be unveiled tomorrow—to represent the cars that made it out of our initial round of voting following evaluations at Hyundai's Proving Ground outside of Los Angeles. The finalists then went on to road drives on Angeles Crest Highway and, later, grueling track tests at Willow Springs Raceway. Come back on Monday, February 14 to see which one emerged with the title!
The investment in automotive electrification has ramped up sharply in recent years, with new advances in battery chemistry, motor and controller technology, and charging infrastructure being announced almost weekly. We've generally spared our readers the chemistry lesson required to describe every new battery electrolyte formula to come along, but we've passed along the most novel, interesting, and promising of concepts that promise to advance electrification. Here are highlights from just the past two years.Maybe Pair Capacitors and Batteries?Chemical batteries are great at storing energy. They just can't do it extremely quickly. Capacitors can accept and release huge amounts of energy quickly but can't hold this energy for very long. Capacitors on cars aren't new—Mazda introduced its i-ELOOP energy recovery capacitor on the 2014 Mazda6 sedan. But in November 2019 we reported on a joint research effort by Lamborghini and the Massachusetts Institute of Technology, to triple the energy storage capacity of ultracapacitors, by replacing the porous activated carbon used in most capacitors with a new powder composed of metal-organic framework compounds comprising primarily of nickel, copper, and molecular carbon that effectively doubles the surface area inside the same volume/mass of powder, which is how it doubles the energy density. Research continues, and although ultracapacitors will likely never replace chemical batteries, this Lambo/MIT ultracapacitor could greatly reduce the mass of the energy-storage battery required, guaranteeing both nimble handling, ferocious acceleration, and track-worthy regenerative braking.Mine the SeafloorA perennial and legitimate argument against complete electrification is the question of ethical and environmentally sensitive sourcing of the various metals and other materials required. So in June 2020 we reported on the discovery of naturally occurring polymetallic nodules that line the Pacific Ocean's abyssal deep seafloor in the Clarion-Clipperton zone (lying roughly between Mexico and Hawaii). These potato-sized blobs are typically composed of 29.2 percent manganese, 1.3 percent nickel, 1.1 percent copper, and 0.2 percent cobalt. They form naturally and sit in the silt, where they can be fairly easily scraped up using a drag bucket of sorts. This area is recognized as the planet's largest known source of battery metals and is thought to be capable of supporting production of 280 million EVs. But the metals supply and mining industries are awaiting a green light from various organizations studying environmental impact on fisheries, etc.The State of the Solid-State BatterySolid-state batteries promise to solve myriad nasty battery problems: Liquid or gel electrolytes are flammable and can freeze, so they need costly warming, cooling, and safety monitoring. Additionally, fast charging can result in the formation of lithium metal spikes that can pierce the battery's permeable "separator," short-circuiting the cell. One downside of solid-state is that lithium formation on the anode causes the cell to physically expand, which must be accounted for in the pack design. In December 2020 we reported on California-based QuantumScape's promising new solid-state battery, which claimed to boost range by 80 percent and to function at temperatures ranging from -20 to 80 degrees C, all of which attracted a huge investment from the Volkswagen Group. In the months since, we've reported on Toyota's in-house solid-state battery program, which is likely to see production in hybrid vehicles first, and on Factorial Energy of Massachusetts inking a development deal with Hyundai-Kia, claiming its battery can boost range by 20-50 percent.Gallium-Nitride Semiconductor Chips to Speed ChargingIf the long Chipocalypse, currently still crippling auto sales as we write this, has any silver lining, it might be that as the industry tools up to produce more chips, some of that new production can be dedicated to gallium-nitride, rather than silicon-based chips. This semiconductor material, which enabled the first white LED lights and powered Blu-ray disc readers, is able to simultaneously withstand higher voltages and present a smaller resistance to electric current flow relative to either the silicon (Si) or silicon carbide (SiC) materials. Lower resistance means less heat buildup, which can allow smaller devices to deliver greater power flow and faster switching, which in the case of an EV's onboard power inverter can equate to faster charging and/or greater range. Our July 2021 coverage of Texas Instruments and Odyssey Semiconductors GaN chips noted that engineering samples were to be available in late 2021, which should mean production might commence after a few years of development."Cylinder-Deactivation" for Electric MotorsIt's hard to believe, but the same concept that boosts fuel economy of a piston engine by shutting several cylinders down and making the functioning cylinders work harder can be applied to electric motors, as well. Tula Technologies, the folks who pioneered the Dynamic Fuel Management system in use on more than a million GM trucks and SUVs, has introduced Dynamic Motor Drive. During certain high-speed light-load conditions, where electric motors are not quite as efficient, DMD pulses brief bursts of higher torque to meet the steady-state need, which conserves energy by reducing heat buildup in the rotor core and the power inverter. The power savings are minimal on mainstream permanent-magnet and AC-induction type motors, but they're significant on the cheapest synchronous reluctance motors, which are only used in industrial applications today. The technology promises to eliminate some of the noise and "torque-ripple" vibration that currently disqualifies these motors from EV use. It could also make them more efficient than AC induction and sidestep supply-chain worries inherent in permanent-magnet motors.Lower Cost Via Simplified ManufacturingThis tech story ran in conjunction with our 2022 Lucid Air Car of the Year coverage, describing the nascent Tesla Model S fighter's many innovations aimed at efficient, lower-cost manufacturing. The battery pack, for example, consists of two injection moldings. One incorporates the sides, top, and all power-delivery busbars, and the other includes the cooling plate. Because this only needs to contact the ends of each cylindrical cell, dramatically less heat-conducting glue is needed than in the radially cooled Tesla packs. The Lucid packs can be robotically assembled in a dark plant. The motor's hairpin-style square-section winding consists of just 24 individual wires that are woven for ease of assembly into the stator and the need for only 24 solder connections. And extreme downsizing of the power inverter, final drive units, and more yield impressive weight savings that pay off in cost and range improvements.Lithium-Sulfur Triple ThreatSilicon Valley battery-tech company Lyten came out of stealth in September and revealed a battery chemistry boasting triple the traditional lithium-ion batteries' energy storage per pound. That's because a sulfur atom can host two lithium ions, while a typical NMC-oxide cathode can only manage 0.5-0.7 ions. But during charging, those lithium ions sometimes bring sulfur atoms along with them when they migrate to the other electrode, and this depletes the battery. Lyten's secret is to cage each sulfur atom in one of the millions of tiny boxes afforded by their proprietary 3-D graphene sheets. And because carbon is more conductive than sulfur, power flows better than in previous lithium-sulfur batteries. The company says it has demonstrated 1,400 charge/discharge cycles (sufficient for EV use) and that it plans to select a factory site in Q1 of 2022 to support incorporation of LytCells for use in vehicles by the 2025 or 2026 model year. 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The team is targeting an energy density about one-third that of mono-tasking dead-weight lithium-ion. Still, studies indicate that replacing roughly 70 percent of the interior and exterior panels and 60 percent of the body structure of a Tesla Model S (85 kWh) or BMW i3 with SBC, should lower mass by 26 and 19 percent with range dropping by 36 and 17 percent, respectively. Alternatively, doubling the thickness and mass of these SBC panels to bring the cars back to mass parity should boost range by 20 percent in the Tesla and 70 percent in the BMW (while adding foot room). Cost estimates for this brand-new technology are not yet available.Lead image: Mina De La O/Getty Images
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