Username or Email Address
Do you already have an account?
Forgot your password?
  • Log in or Sign up

    VWVortex


    The Car Lounge
    Page 1 of 3 123 LastLast
    Results 1 to 25 of 71

    Thread: So 12.5:1 compression huh....

    1. Member nismo4life's Avatar
      Join Date
      Mar 14th, 2007
      Location
      CT
      Posts
      2,166
      Vehicles
      '06 Cooper S (#squaresidewallcrew), LS400 drift car
      03-28-2012 02:44 PM #1
      So forget about the 200hp, so the BRZ only runs 12:5.1 c/r? I don't think thats enough uphill passing power...




      hah, but on a serious note I am curious about something and I'm sure the throng of very smart TCLr's can help me out.

      Read the specs released not to long ago on the FA20 and was really surprised to find that its running a 12.5:1 c/r. Just off the top of my head I know the Honda J series runs 11:1, the F20C 11.7:1 and the K series varies between 9.5:1 to 11.5:1 so I was really surprised to find that Subaru put out a very high compression 4 banger, yet it seems to be lacking in power as opposed to other engines in that displacement range.

      Now just take this with a grain of salt because I know its comparing apples to oranges, but lets just for a minute compare the K20a2 to the FA20. Both 2 liters, both 86x86 bore and stroke, both 4 cylinders, 16v's, dohc, and variable valve timing. The FA20 however has 12 years of technology advancements over the K, which includes direct injection, and im sure other small things.

      When you take into consideration they make the same rated hp, and roughly the same rated tq at the crank, why does the 1.5 point higher c/r Subaru motor make the same as the K series? Does it really just come down to the intake/exhaust flow of the head design being less efficient? Much less aggresive cam lobe profiles? Another thing is the fuel economy. The RSX-S posted roughly the same numbers as the BRZ/FRS so does it just have to do with a boxer platform being less efficient in n/a trim versus an I configuration (though Porsche has clearly proven that not true with the GT3 engines) or is there other technical aspects that I'm missing?
      Quote Originally Posted by Ocean City PD View Post
      (ie....red light challenges, running over the hood of police cars etc.) Yes we watch youtube also....
      '09 Honda Ruckus

    2. Member sicksappeal's Avatar
      Join Date
      Apr 3rd, 2007
      Location
      North Jersey
      Posts
      543
      Vehicles
      '98 Cherokee Sport 5spd, '04 DBP R32
      03-28-2012 02:47 PM #2
      I think there are too many variables to accurately compare it to another 4 cylinder. Take gearing, for example..
      VRSociety #182

      Quote Originally Posted by vwlarry View Post
      The Car Lounge: Abandon common sense all ye who enter here.

    3. Member GRN6IX's Avatar
      Join Date
      Jan 2nd, 2003
      Location
      East Windsor, CT
      Posts
      4,011
      Vehicles
      2003 GTi VR6, 2006 Touareg V8
      03-28-2012 02:48 PM #3
      Isn't it direct injected?


    4. Member nismo4life's Avatar
      Join Date
      Mar 14th, 2007
      Location
      CT
      Posts
      2,166
      Vehicles
      '06 Cooper S (#squaresidewallcrew), LS400 drift car
      03-28-2012 02:56 PM #4
      [QUOTE=GRN6IX;76625306]Isn't it direct injected?

      Quote Originally Posted by Ocean City PD View Post
      (ie....red light challenges, running over the hood of police cars etc.) Yes we watch youtube also....
      '09 Honda Ruckus

    5. Member Omnilith's Avatar
      Join Date
      Jan 15th, 2010
      Location
      Bay Area, CA
      Posts
      1,394
      Vehicles
      2002 SVT Focus, 2000 Focus ZX3, 1966 Cortina, 1987 Dodge Charger, 1998 Tacoma, 1983 Plymouth Scamp
      03-28-2012 02:57 PM #5
      It is direct injected, which alters the compression rules greatly.

      Since you're only compressing air until the injection event occurs, pre-ignition is much less of an issue.

    6. Member nismo4life's Avatar
      Join Date
      Mar 14th, 2007
      Location
      CT
      Posts
      2,166
      Vehicles
      '06 Cooper S (#squaresidewallcrew), LS400 drift car
      03-28-2012 02:59 PM #6
      Quote Originally Posted by Omnilith View Post
      It is direct injected, which alters the compression rules greatly.

      Since you're only compressing air until the injection event occurs, pre-ignition is much less of an issue.
      So does that mean direct injected engines require a higher c/r to make the same power as opposed to a lower c/r with traditional fuel injection?
      Quote Originally Posted by Ocean City PD View Post
      (ie....red light challenges, running over the hood of police cars etc.) Yes we watch youtube also....
      '09 Honda Ruckus

    7. Member Omnilith's Avatar
      Join Date
      Jan 15th, 2010
      Location
      Bay Area, CA
      Posts
      1,394
      Vehicles
      2002 SVT Focus, 2000 Focus ZX3, 1966 Cortina, 1987 Dodge Charger, 1998 Tacoma, 1983 Plymouth Scamp
      03-28-2012 03:03 PM #7
      It doesn't mean a loss of efficiency, it just means that when you don't have to worry about your mixture detonating during compression that you can get away with high compression ratios, further improving efficiency.

      As to why this particular 2.0L "only" makes 200hp, I can't comment, but I'd assume it is tuned with a bit more low end torque, which is probably limiting peak power but improving overall drivability.

      Both the Mazda "Skyactiv" 2.0L and 2012 Focus DI 2.0 DI motor also run high compression... 12:1 in the states. They're obviously set up for fewer revs and a heavier torque bias than the Subrota motor.
      Last edited by Omnilith; 03-28-2012 at 03:06 PM.

    8. Member compy222's Avatar
      Join Date
      Apr 7th, 2005
      Location
      Pothole, MI
      Posts
      15,056
      Vehicles
      2003 Miata SE, 2003 Honda S2000, 2007 Honda Fit Sport
      03-28-2012 03:17 PM #8
      gearing is a big factor.

      the advances in technology primarily come in fuel maps, overall power for displacement/fuel used, better computer control of the ignition process, and more flexibility in determining timing advance.
      Quote Originally Posted by capsaicin View Post
      AP1 S2000? I can not in good conscience talk you out of that. May your slip angle be great and your bed not be the couch!

    9. Member Toaster29's Avatar
      Join Date
      Jan 19th, 2000
      Location
      Birmingham, Al
      Posts
      4,807
      Vehicles
      997TT, F80 M3
      03-28-2012 03:23 PM #9
      Compression is only one piece of the puzzle, as is DI. This engine makes 200 hp from 2L, but doesn't need as much rpm to do it. I don't know the torque figures off the top of my head, but I would put money on the FA being more tractable...not that the K20 isn't either. They are making more torque out of 2L with the FA (particularly down low), no need to rev as high, and better low rpm performance. People like to talk about 8k screamers, but then everybody bitches about the revs on the hwy, etc...so they all are getting displacement (or torque) boosts and dropping the rpm/lengthening the gearing.
      '07 997.1 TT 6MT: Arctic Silver / Sea Blue. AWE exhaust, PTF custom 93/E85, BBS CH-R in widebody fitment, 5.9 60-130 E85, platform record
      '15 F80 M3 6MT: Alpine White / Sakhir: Exec pkg, LEDs, carbon roof, Harman Kardon, black 19s, etc
      Past: 300 hp B5 A4, 500 hp Evo 8, 2 450 hp E92 335s, 520hp C6 Z06, and a 750 hp CBA GT-R

    10. Member someguy123's Avatar
      Join Date
      Sep 30th, 2005
      Posts
      16,010
      Vehicles
      Lexus Hybrid, '15 Panda Smart
      03-28-2012 03:26 PM #10
      It makes 100hp/L with no forced induction. All's good.

    11. Member nismo4life's Avatar
      Join Date
      Mar 14th, 2007
      Location
      CT
      Posts
      2,166
      Vehicles
      '06 Cooper S (#squaresidewallcrew), LS400 drift car
      03-28-2012 03:36 PM #11
      Quote Originally Posted by someguy123 View Post
      It makes 100hp/L with no forced induction. All's good.
      Not arguing that, just surprised its not somewhere in the 220-235 range with all the tech advancements over the decade.
      Quote Originally Posted by Ocean City PD View Post
      (ie....red light challenges, running over the hood of police cars etc.) Yes we watch youtube also....
      '09 Honda Ruckus

    12. Member compy222's Avatar
      Join Date
      Apr 7th, 2005
      Location
      Pothole, MI
      Posts
      15,056
      Vehicles
      2003 Miata SE, 2003 Honda S2000, 2007 Honda Fit Sport
      03-28-2012 03:45 PM #12
      Quote Originally Posted by Toaster29 View Post
      Compression is only one piece of the puzzle, as is DI. This engine makes 200 hp from 2L, but doesn't need as much rpm to do it. I don't know the torque figures off the top of my head, but I would put money on the FA being more tractable...not that the K20 isn't either. They are making more torque out of 2L with the FA (particularly down low), no need to rev as high, and better low rpm performance. People like to talk about 8k screamers, but then everybody bitches about the revs on the hwy, etc...so they all are getting displacement (or torque) boosts and dropping the rpm/lengthening the gearing.
      and by having a high revver on the highway you will burn more gas. greater injector duty and less overall efficiency. to roll at 73mph is 4k in the s2000. i simply can't do better than 25-27mpg in that scenario without cutting my revs/speed back.
      Quote Originally Posted by capsaicin View Post
      AP1 S2000? I can not in good conscience talk you out of that. May your slip angle be great and your bed not be the couch!

    13. Member boner's Avatar
      Join Date
      May 18th, 2002
      Location
      Ottawa
      Posts
      3,202
      Vehicles
      93 corrado vr6, 95 golf race car, 05 trailblazer, 06 BMW 325ixT
      03-28-2012 03:49 PM #13
      CR isn't everything. it could very well be that they've got some realllly small cams in there so that not a heck of alot of air can get in there thus needing less fuel thus becoming more fuel efficient.

      it's not that they couldn't make more power outta this package, it's that they chose not to.

    14. Member compy222's Avatar
      Join Date
      Apr 7th, 2005
      Location
      Pothole, MI
      Posts
      15,056
      Vehicles
      2003 Miata SE, 2003 Honda S2000, 2007 Honda Fit Sport
      03-28-2012 03:51 PM #14
      Quote Originally Posted by boner View Post
      CR isn't everything. it could very well be that they've got some realllly small cams in there so that not a heck of alot of air can get in there thus needing less fuel thus becoming more fuel efficient.

      it's not that they couldn't make more power outta this package, it's that they chose not to.
      this is probably also true. you'd probably really have to start looking into volumetric efficiency, flow rates, valve duration, etc. to really know what the motor is capable of.
      Quote Originally Posted by capsaicin View Post
      AP1 S2000? I can not in good conscience talk you out of that. May your slip angle be great and your bed not be the couch!

    15. Member
      Join Date
      Sep 24th, 2011
      Location
      Chino Hills
      Posts
      640
      Vehicles
      1997 MKIII GTI 2.Slow
      03-28-2012 04:23 PM #15
      Subaru's weigh more then cars they typically compare too. Plus AWD adds drag to the engine reving.

      Like my 97 120hp GTI that weighs 2500 pounds will kill a 2010 Civic SI 200hp in a 3200 pound car up the block a bit till it actually gets revving hard. I was playing this one guy in a commercial parking lot for a bit, and off the line I could always get 3-4 cars on him quick. He had access to lock the park where he had a small shop, and it was on the weekend.

    16. Member DubNMiatafan's Avatar
      Join Date
      Feb 13th, 2009
      Location
      Chicago, IL
      Posts
      3,027
      Vehicles
      1994 Corolla, 1990 Miata
      03-28-2012 04:56 PM #16
      Quote Originally Posted by Spatzle View Post
      Subaru's weigh more then cars they typically compare too. Plus AWD adds drag to the engine reving.

      Like my 97 120hp GTI that weighs 2500 pounds will kill a 2010 Civic SI 200hp in a 3200 pound car up the block a bit till it actually gets revving hard. I was playing this one guy in a commercial parking lot for a bit, and off the line I could always get 3-4 cars on him quick. He had access to lock the park where he had a small shop, and it was on the weekend.
      This is the 2nd person I've encountered on here that thinks the BRZ is AWD.
      ♪ Let's just drive, I wanna see what the wind does to your hair ♪

    17. Member SchnellFowVay's Avatar
      Join Date
      May 20th, 2001
      Location
      Las Vegas, NV
      Posts
      11,413
      Vehicles
      Bent M
      03-28-2012 05:01 PM #17
      Quote Originally Posted by nismo4life View Post
      Not arguing that, just surprised its not somewhere in the 220-235 range with all the tech advancements over the decade.
      NOOOOOOOooo.

      Don't suggest such a blasphemous thing.

      I have been tarred and feathered in numerous threads for suggesting such a thing (I even brought up the K20 comparison).

      Repeat after me:

      "The BRZ/FR-S is perfect in every way . . . questioning its specifications or comparing it to other cars on the market is a sign of disloyalty to the BRZ/FR-S . . . it was made to handle, not to accelarate . . . 0-60 in 7.2 seconds is fast enough for me, no questions asked . . . [rinse, and repeat]."
      I TCL.

    18. Member
      Join Date
      May 10th, 2006
      Location
      Vancouver/Melbourne
      Posts
      1,254
      Vehicles
      2011 Tiguan Highline, 2012 Mazda CX5 2.0i, 2008 Audi S3 3Dr Manual
      03-28-2012 05:03 PM #18
      Quote Originally Posted by Spatzle View Post
      Subaru's weigh more then cars they typically compare too. Plus AWD adds drag to the engine reving.

      Like my 97 120hp GTI that weighs 2500 pounds will kill a 2010 Civic SI 200hp in a 3200 pound car up the block a bit till it actually gets revving hard. I was playing this one guy in a commercial parking lot for a bit, and off the line I could always get 3-4 cars on him quick. He had access to lock the park where he had a small shop, and it was on the weekend.
      Your GTI will not be able to beat a 1998 Civic DX, let alone a Civic Si. You VW fan boys are more delusional than the VTEC crew of the 2000s.

    19. Member SchnellFowVay's Avatar
      Join Date
      May 20th, 2001
      Location
      Las Vegas, NV
      Posts
      11,413
      Vehicles
      Bent M
      03-28-2012 05:05 PM #19
      In all seriousness, though, comparing HP to HP is kind of innappropriate here.

      Since HP = (TQ x RPM) / 5252, making the same horsepower at lower RPM's means that the car is making more torque at lower RPMs than the K20.

      So this begs the question, again, why can't the car make more torque at higher RPMs and put out a bit more peak horsepower? The the torch and pitchfork crew will be after me if I bring that up again.
      I TCL.

    20. Member
      Join Date
      May 10th, 2006
      Location
      Vancouver/Melbourne
      Posts
      1,254
      Vehicles
      2011 Tiguan Highline, 2012 Mazda CX5 2.0i, 2008 Audi S3 3Dr Manual
      03-28-2012 05:05 PM #20
      Quote Originally Posted by SchnellFowVay View Post
      NOOOOOOOooo.

      Don't suggest such a blasphemous thing.

      I have been tarred and feathered in numerous threads for suggesting such a thing (I even brought up the K20 comparison).

      Repeat after me:

      "The BRZ/FR-S is perfect in every way . . . questioning its specifications or comparing it to other cars on the market is a sign of disloyalty to the BRZ/FR-S . . . it was made to handle, not to accelarate . . . 0-60 in 7.2 seconds is fast enough for me, no questions asked . . . [rinse, and repeat]."
      Get back to us after you quote the hp/torque ratings for the K20 and the F20c (S2000). The Subaru has better power to weight ratio than a Lotus Elise for crying out loud.

      Did you manage to fit a GPS in your car that knows wtf you live yet?

    21. Member Klim18's Avatar
      Join Date
      Nov 12th, 2008
      Location
      Chicago
      Posts
      1,319
      Vehicles
      09 VW Gti
      03-28-2012 05:06 PM #21
      Why are so many people commenting on the gear ratios, I am pretty sure when they were developing these motors they had them hooked up directly to the dynometer.

    22. Member SchnellFowVay's Avatar
      Join Date
      May 20th, 2001
      Location
      Las Vegas, NV
      Posts
      11,413
      Vehicles
      Bent M
      03-28-2012 05:07 PM #22
      Quote Originally Posted by too_slow View Post
      Get back to us after you quote the hp/torque ratings for the K20 and the F20c (S2000). The Subaru has better power to weight ratio than a Lotus Elise for crying out loud.
      Why so angry? I know all of this. That's my whole point.

      The car is close to a Lotus Elise in power-weight, yet it goes 0-60 in 7.2 seconds, uses economy tires, and has nearly 15 years of technology on the S2000.
      I TCL.

    23. Member SchnellFowVay's Avatar
      Join Date
      May 20th, 2001
      Location
      Las Vegas, NV
      Posts
      11,413
      Vehicles
      Bent M
      03-28-2012 05:08 PM #23
      Quote Originally Posted by Klim18 View Post
      Why are so many people commenting on the gear ratios, I am pretty sure when they were developing these motors they had them hooked up directly to the dynometer.
      This, too. Gear Ratios are completely irrelevant to engine power .

      They are relevant to accelaration numbers, but not to engine power.
      I TCL.

    24. 03-28-2012 05:14 PM #24
      I hate to beat the dead horse, but this car really is good despite a "slow" 0-60 and "only" 200hp. It's not perfect by any stretch, but nothing is. It could really use more oomph to please the boyracer/magazine cowboy set, but it's still a very fun car to drive. You can run the car hard without getting into trouble with the law. You can let your calm, responsible side rule by not getting involved in doing freeway pulls with the flat-billed, DC-shoed, dumped-and-chipped-GTI-driving brosephs because you'd lose anyways and you know it. You can fling it through corners pushing the car as hard as you want and get away from those brosephs where it really matters.

      The car really is about balance. Things are as they should be in all areas. It's better than the numbers. I'll be interested to see what a turbo version drives like if it comes out. I don't think adding more than another 30hp and 40-50lb/ft to this car is going to enhance the driving experience. If anything I worry it'll detract from what the car is.

      And yes, I've driven it - Probably more than most of the magazine editors, definitely more than most of those posting about it.

    25. Member Omnilith's Avatar
      Join Date
      Jan 15th, 2010
      Location
      Bay Area, CA
      Posts
      1,394
      Vehicles
      2002 SVT Focus, 2000 Focus ZX3, 1966 Cortina, 1987 Dodge Charger, 1998 Tacoma, 1983 Plymouth Scamp
      03-28-2012 05:17 PM #25
      I can't wait to drive one.

      On paper, a 7.2 second 0-60 sprint is disappointing, but everything I've owned is or was as slow as that yet a total blast to drive, so....

    Page 1 of 3 123 LastLast

    Posting Permissions

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