The performance profile of the turbo four may have doomed it to being merely a footnote in Honda's illustrious history.

When the 2013 Acura RDX launches this spring, Honda will quietly close down a spur line of its Anna, OH, plant. Since 2006, it had been building the 2.3-liter four-cylinder engine used in the first-generation RDX there. These engines were unique, the company's first to be fitted with a turbocharger from the factory. But the redesigned 2013 RDX will be available only with a V6, and with no other application for the turbo four, Honda's most impressive performance engine will die an ignoble death.

The 2.3-liter turbo was a variation of the 2.4-liter four used in the Honda Accord and the Acura TSX. Rated at 240 horsepower, it was the 260 lb-ft of torque that made things special. Honda's traditional approach to engine design had favored high-revving, small displacement engines that made generous power thanks to variable valve timing technologies – but at the expense of torque output. So when Honda announced that it would be producing a turbocharged engine for the first time, it seemed to herald the next wave of Honda performance. Finally, some torque to match the howling VTEC power. But sadly, it was the performance profile of the turbo four that may have doomed it to being merely a footnote in Honda's illustrious history.

The RDX sold just over 15,000 units in 2011.

The RDX, one of the first compact luxury crossovers, was envisioned as a sporty model that would attract the sorts of drivers that might wish they owned a Porsche, but wouldn't find a true sports car practical. Alas, those buyers never materialized – the RDX sold just over 15,000 units in 2011.

"The buyers of two-row crossovers are not quite what they appeared to be," said Honda spokesman Chris Naughton.

Naughton told us that the knife-edged nature of the turbocharged engine, with its narrower powerband compared to the smooth V6, wasn't embraced by crossover buyers. The other factor that likely kept the RDX from being parked in more driveways was its fuel economy – only 19 miles per gallon combined – and a penchant for premium fuel. The RDX was initially offered with a five-speed automatic with paddle-shifters that Acura called "Sequential SportShift," as well as Acura's "Super Handling" all-wheel-drive system. The redesigned model has a six-speed automatic and a simpler, lighter-weight all-wheel-drive system like the one found on the Honda CR-V.

Hopes that the power-dense four-cylinder might find its way into other Honda products has also been dashed.

With the 2.3-liter turbo going out of production, hopes that the power-dense four-cylinder might find its way into other Honda products has also been dashed. Honda uses a similar 2.4-liter four, though naturally aspirated, in other models, including the forthcoming Acura ILX. We imagine the turbo four might have served as a decent base for building a performance version of the Accord or a lighter but still powerful TSX. Even a turbo-four-powered CR-V is something we could embrace, giving some character to that ubiquitous people mover.

Applications in even smaller Honda vehicles – yes, we're stupidly imagining Civics and Fits with grapefruit shooter exhausts – might be a stretch, but we wonder if Honda's first attempt at turbocharging ending this way won't have bad implications for the future? Just as seemingly every manufacturer on earth is offering turbocharged engines, even in entry-level cars like the Chevrolet Sonic, Honda has prematurely abandoned them. Then again, as Honda's Naughton said, "We now have that expertise."

Here's hoping Honda uses it, once again.


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • 165 Comments
      P54
      • 2 Years Ago
      Who informs the journalists? Honda's first street turbo car, the City, came in 1982 and in the late 80's they also made the V6 Legend with turbo. The 1982 CX 500 was the first motorcycle with turbo and Honda first in FI, only a 2 cyl. to prove that Honda could master the most difficult turbo application. Back in 1982 coming stock from the factory with 160+HP per liter was way ahead. Check out who did most wins in the 80's when Honda dominated with their up to 1500 HP, 1.5L V6 Turbo engine. Honda have lots of experience with turbo. For street use turbo cars have more problems than non turbo cars, maybe one reason Honda stay away from turbo for street use. Even though a turbo can get decent EPA numbers, it is when you step on the pedal and use the boost you are going to suffer for having turbo. Honda still have turbo diesel engines. For use in the RDX I think most owners will much rather have the silky smooth Honda V6 than the 4 cyl turbo. More power and better FE, why complain? The "character" of a turbo might be good for a while, however the smoothness of the V6 will be appreciated in the long run.
        Gubbins
        • 2 Years Ago
        @P54
        Legend V6 turbo? Not in this market---
          P54
          • 2 Years Ago
          @Gubbins
          In Japanese market Honda in 1989 introduced the "Wing Turbo" Legend with a 2.0L V6 engine.
      GVIrish
      • 2 Years Ago
      I beg to differ. The best 4-cylinder engine Honda made was the K20. It could easily push around 240 hp with light mods and could get over 300 hp if you were willing to upgrade the internals. It has a broad spread of power and was relatively light. Or you could make the argument that the F20C was the best engine they ever made considering that the only naturally aspirated engines that beat its specific output are in Ferraris. The K23T by comparison is nothing remarkable as turbo 4 cylinders go. Don't get me wrong, I would've loved to see it in other Hondas but it simply wasn't that impressive compared to the output of other turbo 4's. The real shame is that the high revving K20 series of engines is dead and we're stuck with the undersquare and boring K24.
        Fonin
        • 2 Years Ago
        @GVIrish
        "It could easily push around 240 hp with light mods and could get over 300 hp if you were willing to upgrade the internals." that ruins the whole post, the point is that this was all factory. any engine can make more power if you are willing to throw money at it.
          GVIrish
          • 2 Years Ago
          @Fonin
          My point was that the K20 has room to make significant increases in power for relatively little money, as compared to say, the K24A7 which makes the same power, more torque, but has very little potential. True, any engine can make more power if you throw money at it. But when it comes to naturally aspirated 4-cylinder engines that made 100 hp/L, the K20 (the 200 hp variants) is in a class of one when it comes to potential. Granted, the F20C and F22C had even higher specific output so from the factory so stock for stock, those were the best n/a 4-bangers ever made.
          NightFlight
          • 2 Years Ago
          @Fonin
          I think the point he was just trying to make is how mod friendly the K20 was. People with 8th Gen Sis were making 200WHP with some inexpensive bolt ons.
        NightFlight
        • 2 Years Ago
        @GVIrish
        I'll x2 everything you just said but my vote for the best engine in stock form would go to the F20/F22. It was absolutely brilliant. I would have loved to have seen the K23 make it into the 9th Gen Si. Maybe then it wouldn't be the laughing stock of the segment. It would have been far more fuel efficient in a non-AWD, lighter weight and more aerodynamic vehicle with a manual transmission. What we have now is a Civrolla XRSi, and it is a complete joke and bore to drive.
        H. Simmy
        • 2 Years Ago
        @GVIrish
        K20, F20C, K23T, B-Series, and H-Series engines are great and all has soul. Unfortunately Honda doesn't have one anymore, and therefore killed it off. We are now stuck with the basic K24 in every car that can bore everybody to death.
        rem
        • 2 Years Ago
        @GVIrish
        Well, what he probably meant was best performance engine still in production. Perhaps he should have said 'last' performance engine still in production....
        Jorsher
        • 2 Years Ago
        @GVIrish
        B18C5 in my CRX and F22C in my S2000. I think the F20C is a "cooler" engine, but the F22C made more sense for driving around the city. Also the AP2 has other improvements. Boring new stuff Honda
      NightFlight
      • 2 Years Ago
      FYI, this wasn't Honda's first turbocharged engine. The City Turbo was their first way back in the early 1980's.
        sqparadox
        • 2 Years Ago
        @NightFlight
        Come on Autoblog! The stupid mistakes in the writing here just seem to get worse and worse. Do some research; this is just pathetic. http://lmgtfy.com/?q=honda+turbo+wiki Check your facts! It's called being a good writer!
      Pinhead
      • 2 Years Ago
      FYI, VTEC doesn't come 'at the expense of torque'. It actually increases torque compared to other normally aspirated engines of similar power and displacement (ever drive an old school 4 banger with a hot cam?). Of course, a forced induction engine of the same displacement will have way more torque, especially the new breed of direct injection motors.
        Fonin
        • 2 Years Ago
        @Pinhead
        yes, VTECs purpose is to give 2 cam profiles essentially. one cam a low speed set of lobes, is used to promote low-end torque and qualify emissions. iirc the vtec change over for the 2.4 from the element/crv (2003) switched at 2300 rpm, where as the b series it was much higher. we used to build B-series motors back in the late 90s/early 00s, granted it was also a non-emissions regulated state.
      merlot
      • 2 Years Ago
      I wonder how many people here commenting actually drove an RDX? I find it puzzling the article says the powerband was "narrow". The engine had very little turbo lag, and moved the RDX to 60 in under 7 seconds. It was the fastest SUV in it's class at the time. The SH-AWD system was a gem. It definitely had some athletic moves. Having said that, yes, the fuel economy sucked (we averaged between 19-21mpg in ours) and the 5 speed auto was boring, although it did hold redline in manual mode). It's a shame Acura didn't but that drivetrain in a TSX; that would have been a sweet car.
        graphikzking
        • 2 Years Ago
        @merlot
        Then it would have only gotten about 22-24mpg in the tsx. BOttom line - it wasn't efficient. Forget about the power band - that was fine. The engine just stunk. Toyota Rav4 V6 was a MUCH better engine. More mpg, no premium fuel, no turbo things to potentially fix down the line. Just like Honda hybrids - honda turbo 4 stunk. The Ford Turbo4 (ecoboost) in the explorer is rated at 20city/28hwy. So again - same rough hp, torque and engine size. The Explorer is larger - yet it's rated 20-30% better efficiency.
      jinuhyung
      • 2 Years Ago
      I looked at the RDX for my wife and while it was a nice vehicle, it was too buzzy. I guess the inherent nature of a 4-cylinder motor hauling a relatively heavy crossover. The SportShift transmission was a joke and hadn't changed since my ownership of a 5th gen Prelude's SportShift transmission; albeit one more gear. Mediocre MPG and the flimsy rear seat folding mechanism didn't win us over, either. I've always hoped that Honda/Acura would use this motor in a Civic or similar.
      Master Austin
      • 2 Years Ago
      I will agree with previous posters, the 2.3L Turbo didn't particularly get good fuel mileage overall. Its as if every other article written over it critisized it for poor fuel economy and slow performance. It really didn't offer anything better than a normal V6 could, so essentially it became pointless. I'm sure the 3.5L V6 will do a much better job.
        Gorgenapper
        • 2 Years Ago
        @Master Austin
        Right engine. Wrong car. If it had been put in something like a Civic Si and the weight kept down to 2800~lbs, the fuel efficiency would have been much better.
        Gorgenapper
        • 2 Years Ago
        @Master Austin
        Okay, here we go... Acura RDX 1st gen... 3,968 lbs (!). When the 2.3L turbo is off boost, it behaves like a 2.3L engine. I think any 2.3L engine would be straining pretty hard off boost with nearly four thousand lbs to lug around (not including driver, passengers, cargo). It would be even worse if the RDX had been 4WD. So what do RDX owners do? They tap into the boost, either part throttle or flooring it. Turbo spools, Air/Fuel Ratio changes to run rich in order to prevent knock, bye bye fuel economy. Even so, I would say that 240hp is still not enough to efficiently move this fat pig of a CUV around... which leads to more lead foot syndrome, which leads to more boost usage, and lower fuel economy.
      Paul S
      • 2 Years Ago
      While a decent engine, putting it into a 3800 lb SUV was not the best choice. As noted above, the RDX got dismal fuel economy.
        Fonin
        • 2 Years Ago
        @Paul S
        yes it did. i was hoping to see a new s2k with a variant of this engine, or maybe a new Integra/RSX. they could always drop it into the TSX to replace the v6 there and shed some weight, would be nice to have for the wagon!
          • 2 Years Ago
          @Fonin
          [blocked]
      jonnybimmer
      • 2 Years Ago
      Update the K23 a bit (add direct injection?) and make it somehow fit in a TSX w/SH-AWD. I think I remember that the motor is supposed to be too tall or have some swap issue preventing Honda fans from dropping them into their cars (tranny issues or probably too pricey for the performance?) but if you can do it and if you can keep the price low enough, say just a bit below a similarly prepped A4, then it'd be a pretty decent competitor.
      CarCrazy24
      • 2 Years Ago
      This was a good idea in theory...problem was, it wasn't particularly fast and it got pretty poor fuel economy. The new RDX deserved an updated four cylinder turbo instead of the boring V6
        ClementZ
        • 2 Years Ago
        @CarCrazy24
        Wasn't particularly fast, yes. But it was really nimble. An improved I4 turbo wouldn't have helped anything. Honda thought a performance CUV would sell well, and it didn't. How the hell would making another performance CUV suddenly improve sales? The main complaint with the last RDX was lack of refinement and poor fuel economy. A new turbo I4 would only improve one of these issues (FE), but a V6 would improve both. And Honda's right. The new RDX is selling pretty darn well with its "boring" V6.
      Avinash Machado
      • 2 Years Ago
      So disappointing.
      rem
      • 2 Years Ago
      "Honda's traditional approach to engine design had favored high-revving, small displacement engines that made generous power thanks to variable valve timing technologies – but at the expense of torque output" Of course, those are all gone now too. As is there very short lived and ill fated attempt to use hybrid drivetrain's for performance. Long live the sohc v6?
    • Load More Comments