Un-rev in gear?
Results 1 to 15 of 15

This is a discussion on Un-rev in gear? within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Start the car, let the revs drop (due to temperature increase) to about 1250-1500 (not tried higher/lower than this range), ...

  1. #1
    Registered User poly_poly-man's Avatar
    Join Date
    Feb 2010
    Location
    Rochester Institvte of Technorcery
    Posts
    1,223

    Un-rev in gear?

    Start the car, let the revs drop (due to temperature increase) to about 1250-1500 (not tried higher/lower than this range), with clutch down, pop it into 1st. The engine slows down by about 250rpm...

    ...why?
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

  2. Remove Advertisements
    ClubWRX.net
    Advertisements
     

  3. #2
    Registered User teflon_jones's Avatar
    Join Date
    Apr 2007
    Location
    8000' up in Colorado
    Posts
    6,754
    Because the transmission stops spinning so the engine has less load on it, which allows it to run with ease at lower RPMs.
    Scott
    Past Subies - '11 STI Limited stage 1+ and '04 STi stage 2+
    '13 Wrangler Rubicon - custom front bumper w/12k lb winch & off-road lights, skid plates, diff guards, etc.
    '04 Porsche 911 Turbo GT2 clone 600 HP/TQ
    '77 F-150 heavily modded for off-roading

  4. #3
    Registered User poly_poly-man's Avatar
    Join Date
    Feb 2010
    Location
    Rochester Institvte of Technorcery
    Posts
    1,223
    Quote Originally Posted by teflon_jones View Post
    Because the transmission stops spinning so the engine has less load on it, which allows it to run with ease at lower RPMs.
    ???

    It does not correspond with the pushing of the clutch (I've tried), it's directly right after I put it into gear. The reason it seems odd is because the engine is still just spinning the flywheel, right?
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

  5. #4
    Registered User
    Join Date
    May 2010
    Location
    Chicago, IL
    Posts
    56
    Quote Originally Posted by poly_poly-man View Post
    ???

    It does not correspond with the pushing of the clutch (I've tried), it's directly right after I put it into gear. The reason it seems odd is because the engine is still just spinning the flywheel, right?
    When you put it in gear, the clutch engages just a bit. Giving the engine just a little load, not enough to move the car but it is there. I saw this when you have the car up on jackstands, if you put it in gear, the wheels will start spinning slowly. That tells me that the clutch is still touching the flywheel a little bit.

  6. #5
    Registered User poly_poly-man's Avatar
    Join Date
    Feb 2010
    Location
    Rochester Institvte of Technorcery
    Posts
    1,223
    Quote Originally Posted by monchis View Post
    When you put it in gear, the clutch engages just a bit. Giving the engine just a little load, not enough to move the car but it is there. I saw this when you have the car up on jackstands, if you put it in gear, the wheels will start spinning slowly. That tells me that the clutch is still touching the flywheel a little bit.


    This seems like a terrible idea - if you sat there all day with the clutch all the way down and the engine on and in gear, the clutch would burn up?

    Why would they design this into the car? Does it mean that we have to adjust our clutches, or is it just supposed to do that?
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

  7. #6
    Registered User
    Join Date
    May 2010
    Location
    Chicago, IL
    Posts
    56
    No no, it's not nearly enough friction to heat up the clutch. It just touches the flywheel a little, by that I mean very little. It's just because they're so close to each other. Besides, who would sit all day with their car in gear and the clutch depressed?

  8. #7
    Registered User teflon_jones's Avatar
    Join Date
    Apr 2007
    Location
    8000' up in Colorado
    Posts
    6,754
    Quote Originally Posted by poly_poly-man View Post
    ???

    It does not correspond with the pushing of the clutch (I've tried), it's directly right after I put it into gear. The reason it seems odd is because the engine is still just spinning the flywheel, right?
    Sorry, I misread your first post. I thought you were saying before you put it in gear but after you pressed the clutch.
    Scott
    Past Subies - '11 STI Limited stage 1+ and '04 STi stage 2+
    '13 Wrangler Rubicon - custom front bumper w/12k lb winch & off-road lights, skid plates, diff guards, etc.
    '04 Porsche 911 Turbo GT2 clone 600 HP/TQ
    '77 F-150 heavily modded for off-roading

  9. #8
    Registered User poly_poly-man's Avatar
    Join Date
    Feb 2010
    Location
    Rochester Institvte of Technorcery
    Posts
    1,223
    so basically, they're designed to be separate, but it's pretty much tolerances that make them touch?
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

  10. #9
    Registered User
    Join Date
    May 2010
    Location
    Chicago, IL
    Posts
    56
    That is correct, that is why it goes down a few rpms when you put it in gear

  11. #10
    Banned
    Join Date
    Dec 2003
    Location
    Dallas, TX / Sterling, VA
    Posts
    6,629
    I Support ClubWRX
    You're not reading the gauge properly. The gauge starts at 500 rpm. Proper, warmed idle is going to be around 750-850 rpm

  12. #11
    Registered User poly_poly-man's Avatar
    Join Date
    Feb 2010
    Location
    Rochester Institvte of Technorcery
    Posts
    1,223
    Quote Originally Posted by brfatal View Post
    You're not reading the gauge properly. The gauge starts at 500 rpm. Proper, warmed idle is going to be around 750-850 rpm
    I know this. "I'm in a rush and it's cold out" idle is more like 1k at the least. Each tick is 250rpm. I've noticed pretty much every time, I can let it drop itself to 1250, then putting it in 1st drops it down to 1000 (same with 1500 down to 1250).
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

  13. #12
    Registered User
    Join Date
    May 2010
    Location
    Chicago, IL
    Posts
    56
    I'm sure she was talking about warmed up already. We're talking about cold idle.

  14. #13
    Registered User Monk_Knight's Avatar
    Join Date
    Aug 2010
    Location
    Colorado
    Posts
    538
    Quote Originally Posted by brfatal View Post
    You're not reading the gauge properly. The gauge starts at 500 rpm. Proper, warmed idle is going to be around 750-850 rpm
    Mine idles at 1500 right after starting, then drops to just over 1k, then when it's all warmed up idles right about 500.

  15. #14
    Registered User poly_poly-man's Avatar
    Join Date
    Feb 2010
    Location
    Rochester Institvte of Technorcery
    Posts
    1,223
    Quote Originally Posted by Monk_Knight View Post
    Mine idles at 1500 right after starting, then drops to just over 1k, then when it's all warmed up idles right about 500.
    nope, the first line is 500, the second it 750, where wrx's are supposed to idle. If it really were at 500, your car would be barely working.
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

  16. #15
    Registered User
    Join Date
    May 2010
    Location
    Chicago, IL
    Posts
    56
    Engines idle between 750 to 850 as stated before.

Posting Permissions

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