Advertise on Bikeforums.net



User Tag List

Results 1 to 16 of 16
  1. #1
    la vache fantôme phantomcow2's Avatar
    Join Date
    Aug 2004
    Location
    NH
    Posts
    6,266
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Question about performance auto upgrades and fuel economy

    I see people modifying their 4th generation accords to gain more power. One of the most common and effective bolt-on ways to increase power is replacing the intake manifold, plenum, and throttle body. Specifically, they change their stock F22A1 configuration with the manifold/plenum/throttle body with an H23. Supposedly this manifold allows for greater airflow, and the throttle body is of a larger diameter anyways, furthering the benefit.
    People are always lauding their new setups, how this provides +10HP and really makes a difference in "the high end."

    I don't drive in "the high end,"; my rpms are generally almost always below 3000!
    My interest isn't so much in power (though every once in a while it's nice to have fun with it) as much as enhancing reliability and fuel economy. Would these enhancements do anything to improve fuel economy? I would think that the the less-restrictive design of these new components would reduce the effort necessary to breathe, requiring less fuel to be burned to maintain a given speed. Of course if this is true, it could be negated by a driver anxious to realize performance gains . But just suppose said driver had good self control, would any benefit in fuel economy be realized?
    C://dos
    C://dos.run
    run.dos.run

  2. #2
    gmt Grumpy McTrumpy's Avatar
    Join Date
    Sep 2008
    Location
    Binghamton, NY
    Posts
    11,904
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I increased the MPG of my truck by using a more open air intake. It should work, as long as you have a light foot.

    (not by very much though)

  3. #3
    J E R S E Y S B E S T Jerseysbest's Avatar
    Join Date
    Apr 2005
    Location
    DC
    Posts
    1,852
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    At this point in your car's life, its not worth it. Save the money for your next car (or bike)

  4. #4
    BikeForums Founder Joe_Gardner's Avatar
    Join Date
    Oct 1999
    Location
    Salt Lake City, Utah
    My Bikes
    Santa Cruze Superlight, Bianchi Pista, Klein Race
    Posts
    105
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    My TDI jetta is chipped. It accelerates much faster then previous, its now a fun car to drive. On road trips, it still gets 40mpg. Used to get 43 - 45 mpg, but the roof rack eats up 3 - 5mpg it seems.

    The chip box unit cost $350 or so, and was worth every penny. I have had it on for the last 50,000 miles, other then a bit of embarrassing black exhaust when really getting on the throttle, I really really like it.
    http://www.joe-gardner.com <-- my photo site.
    http://www.joe-and-heather.com <-- the wife an I.

  5. #5
    la vache fantôme phantomcow2's Avatar
    Join Date
    Aug 2004
    Location
    NH
    Posts
    6,266
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Jerseysbest View Post
    At this point in your car's life, its not worth it. Save the money for your next car (or bike)
    My car has very reliable has not had much money poured into it. If i can find these parts at a salvage yard, then it is worth it. My hope is to keep this car through grad school, so another 4-5 years.
    C://dos
    C://dos.run
    run.dos.run

  6. #6
    phony collective progress x136's Avatar
    Join Date
    Sep 2006
    Location
    San Hoosey
    My Bikes
    http://velospace.org/user/36663
    Posts
    2,958
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by phantomcow2 View Post
    My car has very reliable has not had much money poured into it. If i can find these parts at a salvage yard, then it is worth it. My hope is to keep this car through grad school, so another 4-5 years.
    If you're looking for longevity above all, your best bet is likely keeping it stock and maintained well.

  7. #7
    Senior Member
    Join Date
    Aug 2006
    Posts
    998
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm not sure about this model Accord, but I'm pretty sure that the MPG gain is going to be negligible at most. With the additional equipment that is being put on, that would likely far more exceed the 1-2 MPG difference that the benefits would entail.

    Finally, if the Accord is new, kiss your warranty goodbye if this is done. Also, it is difficult to sell a vehicle that has mods compared to completely stock, because of concerns about engine life.

    My take: If you want the added horsepower, go for it, but make sure to know that you will be taking a big dent in the vehicle's resale, and affecting engine life in an unknown way.

  8. #8
    Junior Member truskool's Avatar
    Join Date
    Sep 2008
    Location
    FL
    My Bikes
    miyata
    Posts
    11
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    this will not have a big effect on your MPG, simply allowing the intake side to breathe more efficiently is half the battle, now you need to open up the exhaust side as well. yes the intakes are somewhat restictive on your car but that doesnt mean that the exhaust is not. the money that you are going to spend will just end up hurting you if your looking to save money on gas. unless your looking for the extra HP as well, this mod is pretty pointless. to keep that accord running to its full potential stock, keep a clean filter in there, maintain oil changes keep proper air in your tires etc. dont get me wrong though, the H22 has tons of potential if modded right

  9. #9
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by phantomcow2 View Post
    I don't drive in "the high end,"; my rpms are generally almost always below 3000!
    My interest isn't so much in power (though every once in a while it's nice to have fun with it) as much as enhancing reliability and fuel economy. Would these enhancements do anything to improve fuel economy? I would think that the the less-restrictive design of these new components would reduce the effort necessary to breathe, requiring less fuel to be burned to maintain a given speed. Of course if this is true, it could be negated by a driver anxious to realize performance gains . But just suppose said driver had good self control, would any benefit in fuel economy be realized?
    No, you need to consider a car as a tuned pump with specific optimized frequencies and RPMs like an organ. By opening up the intake with larger tubing, you raise the resonance frequency where maximum VE occurs. This raises the peak-torque RPM, which also increases peak-HP ratings. However, this has an effect of lowering low-RPM torque, causing the car to accelerate slower in the low end. Drivers end up having to use the higher-revs for decent acceleration, or use larger throttle-openings in the low-end; both of which have a detrimental effect on gas-mileage.

    If you want improved gas-mileage, you must do the opposite of those upgrades. Lower the torque-peak into the ranges you use most by decreasing intake-running diameter and increasing its length. You'll end up with lower peak-HP figures, but will have more torque down low where you operate most of the time. You'll be able to drive with lower throttle openings for the same acceleration and speed, and get better gas-mileage.

    The basic idea is to reduce the amount of air entering the engine. Similar to V8 engines that cut off 2 or 4 of their cylinders at high-way cruising speeds to increase gas-mileage. Anything you can do to reduce the air-flow through the engine will increase gas-mileage. It's the inverse of the axiom that everyone knows, to make more power, you use more gas. So to use less gas, make less power.
    Last edited by DannoXYZ; 01-11-09 at 11:41 PM.

  10. #10
    Senior Member mustang1's Avatar
    Join Date
    Jul 2006
    Location
    London, UK
    My Bikes
    2006 Allez, 2012 Mares
    Posts
    2,680
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Increasing breathing space reduces torque at lower end but increase power at top end. If you are not a regular top end driver, this will reduce overall driveability of your car. I'd agine Honda thought this thru so probably best to leave as is. Spend the money on a new accessory for your bike if you have a brnong desire to part with $350.

    Edit: I just read what danno wrote: that's what I was saying but danno said it a lot better.
    Last edited by mustang1; 01-12-09 at 12:56 AM.

  11. #11
    Bike ≠ Car ≠ Ped. BarracksSi's Avatar
    Join Date
    Jul 2007
    Location
    Washington, DC
    My Bikes
    Some bikes. Hell, they're all the same, ain't they?
    Posts
    13,857
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    In brief: more power = more fuel burned. More airflow = more fuel burned.

    Honda -- heck, most carmakers these days -- have their engines very well-tuned for their purpose. Like Danno illustrated, any modification means that you're going to compromise, lessening one performance aspect while improving another (hopefully, anyway).

    When I was tossing around the idea of swapping a K24 into my Civic, I kept toying with the numbers to decide which transmission to use, whether I keep my EP3's stock 5-speed, get a 6-speed from an RSX-S or ITR, or use the TSX's that Honda put on that K24. I ended up deciding that the TSX ratios were the best for that motor, putting the engine right back in the powerband with each full-throttle upshift and not forcing it to short-shift like the RSX or ITR trannies would, or dropping it below the powerband like my stock 5-speed would.

    Anyway, I still haven't heavily modified my car's engine or done a swap. The money I've spent on bikes and gear would've gone towards a nice K20A longblock, though......

  12. #12
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I once saw a Porsche 911 with a 3-cylinder Geo Metro engine laid flat in the back. Not sure of why he did it, perhaps as a design, engineering and fabrication exercise. Certainly got much, much better gas-mileage than the original flat-6.

    For innovative auto-mods, I always like to check out The 24hrs of LeMons.

  13. #13
    blithering idiot jhota's Avatar
    Join Date
    Feb 2004
    Location
    beautiful coastal South Carolina
    My Bikes
    1991 Trek 930, 2005 Bianchi Eros, 2006 Nashbar "X," IRO Rob Roy
    Posts
    1,263
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    i know some folks prepping a rustbucket for this year's LeMons series.

    oh, and changing the intake won't help fuel economy. like Danno said.

    an exhaust header might, though. but not enough to justify the expense.

  14. #14
    Bike ≠ Car ≠ Ped. BarracksSi's Avatar
    Join Date
    Jul 2007
    Location
    Washington, DC
    My Bikes
    Some bikes. Hell, they're all the same, ain't they?
    Posts
    13,857
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I've known some drivers who turboed their Hondas and ended up with better gas mileage.

    It wasn't because of the turbo adding efficiency, though. It was because they drove more gingerly so that they wouldn't spool up the turbo and draw attention to themselves.

  15. #15
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    A turbo actually presents an intake-restriction and limits air-flow through the engine at steady-state highway speeds. This results in less power produced and better gas-mileage under those conditions than a non-turbo car.

    If you compare the maximum-output of the turbo'ed motor, say... 250bhp, versus a non-turbo car of same power, like a 5.0L V8, you'd get significantly better gas-mileage AND have the power when you need it... heh, heh...

    A tri-Y 4-2-1 exhaust-header will help low-end performance and gas-mileage. A 4-1 header will be good for high-end HP, but will result in poor low-end performance and low gas-mileage.
    Last edited by DannoXYZ; 01-12-09 at 03:27 PM.

  16. #16
    Bike ≠ Car ≠ Ped. BarracksSi's Avatar
    Join Date
    Jul 2007
    Location
    Washington, DC
    My Bikes
    Some bikes. Hell, they're all the same, ain't they?
    Posts
    13,857
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Hmm... maybe I should go turbo after all... It might be easier and cheaper than a swap. However, it doesn't have that instant-on response that's so good for balancing the car mid-corner.

    (see, this is why I never settled on what to do with the motor...)

    I have to say, I liked manipulating the gas pedal and "playing" the whirring turbo sound on a diesel Ford Transit van that we rented to drive to Austria. What a crap motor it was, though.

    The DC5-R Integra motor came with a 4-2-1 header, but it wasn't known for low-end grunt; think it might've been chosen to help instead?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •