Page 2 of 2 FirstFirst 12
Results 26 to 42 of 42

Thread: 3000rpm @ 70mph...what can be done to lower that first figure?

  1. #26
    Join Date
    Feb 2006
    Location
    Tim @ BMW of Dallas
    Posts
    1,889
    My Cars
    98 Z3 2.8
    My 3.46 diff in the roadster can be a bit exhausting on the freeway... Over 4k RPM @ 90mph. Sheesh. A 6-speed swap will happen one of these days.
    96 320i Touring
    98 Z3 2.8 Roadster
    01 PY M Coupe
    96 Z3 1.9 - DASC
    95 318ti Clubsport
    94 Miata M-Edition
    13 smart fortwo



  2. #27
    Join Date
    Aug 2011
    Location
    St. Charles, IL
    Posts
    129
    My Cars
    1997 BMW Z3
    Where do you get a diff?

    Paul

  3. #28
    Join Date
    Dec 2014
    Location
    San Francisco, CA
    Posts
    1,138
    My Cars
    2001 Z3 3.0 Coupe
    Quote Originally Posted by Watch Carefully View Post
    It's not an exhaust drone that bothers me--I probably should have described it differently--nor am I concerned about stressing the motor.
    Rather, I'm at the point (age 50, a veteran of 1000s of loud musical performances, although many with ear plugs) where a long highway drive is such a strain on my senses that my head hums and or my ears ring afterward, if I don't stuff them with cotton. Surprisingly, this practice sees me arrive at my destination feeling less worn out.
    Would some sound deadening perhaps better meet your goals?
    2001 Z3 3.0 Coupe--Sterling Gray/Sunroof Delete/5MT

  4. #29
    Join Date
    Apr 2011
    Location
    Redding Calif
    Posts
    4,131
    My Cars
    1999 Z3 2.5L 5sp
    Quote Originally Posted by ptimko View Post
    Where do you get a diff?

    Paul
    Junkyard, eBay, members of this forum... they're pretty common.

  5. #30
    Join Date
    Aug 2015
    Location
    Denver, CO
    Posts
    3,444
    My Cars
    1999 Z3M, 1999 2.8 Coupe
    Yeah, the guy I bought my 2.8 Coupe from found me a 3.46 in a couple days. 42k miles on it no less! It replaced the 4.10 that was in there, but he let me keep that too. I hear those are gold to the E30 M3 crowd, but right now it's just collecting dust in the garage.
    Nathan in Denver

    1999 M Roadster, VFE V3 S/C, Randy Forbes Reinforced, Hardtop, H&R/Bilstein, Apex PS-7, Supersprint
    1999 Z3 2.8 Coupe, Headers, 3.46, Manual Swap, H&R/Koni, M Geometry/Brakes, M54B30 Manifold, Style 42

  6. #31
    Join Date
    Nov 2005
    Location
    Finland
    Posts
    1,159
    My Cars
    Z3 Coupe individual
    Quote Originally Posted by Randy Forbes View Post
    While it's customary to think that 4th gear is 1:1 and 5th is an overdrive ratio, that's not the case with the 5-speed in the 2.8, 3.0 & 3.2 Z3/Ms; 5th gear is 1:1__or direct drive (so I'm still puzzled that most dyno operators insist on using 4th...).
    I dont know BMW 5 speed manual where fifth was not 1:1. Imho it always is and makes most sense like that. In most six speeds the fifth remains 1:1 and then 6 is over.

    Going to keep stock 3.15 rear end and add 6 speed some day.

    Problem with almost all noise insulation is weight. Cheap noise insulation usually is not made for cars and such will suck water into it over time and then it really starts to weight, and corrode metal, and start electric gremlins etc...
    Last edited by Remotion; 11-15-2017 at 07:04 PM.

    Z3 & E36 RamAir systems, send private message for more information.

  7. #32
    Join Date
    Oct 2012
    Location
    Louisville, KY
    Posts
    4,503
    My Cars
    1997 BMW Z3 1.9L 5MT
    Quote Originally Posted by Remotion View Post
    ... Problem with almost all noise insulation is weight. Cheap noise insulation usually is not made for cars and such will suck water into it over time... and corrode metal, and start electric gremlins etc...
    Yes, cars should only use Dynamat-type insulation, which is a sheet of lead backed with sticky butyl. It is expensive, heavy, difficult to install even in the easy places, and mainly designed for sound originating inside the car (trunk sound systems). And it does nothing for the sound coming through a Z3 roadster's thin canvas top and minimal window sealing.
    Last edited by Vintage42; 11-15-2017 at 07:33 PM.
    BMW MOA 696, BMW CCA 1405

  8. #33
    Join Date
    Dec 2014
    Location
    San Francisco, CA
    Posts
    1,138
    My Cars
    2001 Z3 3.0 Coupe
    I agree that this is the wrong car if you're looking for a quiet highway cruiser.

    However....the OP looks to have a hardtop in his avatar image, so I was suggesting sound deadening with the possibility that it would bring the noise to a more reasonable level even though there are trade offs.

    OP....what tires are you running? They might be a big source of noise as well.
    2001 Z3 3.0 Coupe--Sterling Gray/Sunroof Delete/5MT

  9. #34
    Join Date
    May 2002
    Location
    SW Florida
    Posts
    12,681
    My Cars
    99-01 M Cpe & Rdts, X5M
    Quote Originally Posted by Remotion View Post
    I dont know BMW 5 speed manual where fifth was not 1:1. Imho it always is and makes most sense like that. In most six speeds the fifth remains 1:1 and then 6 is over.

    Going to keep stock 3.15 rear end and add 6 speed some day.

    Problem with almost all noise insulation is weight. Cheap noise insulation usually is not made for cars and such will suck water into it over time and then it really starts to weight, and corrode metal, and start electric gremlins etc...
    Numerous other manufacturers ADD a fifth (5th) ratio to an existing design to accomplish an overdriven final drive ratio.

    My in depth experience with BMWs__really taking them apart__began with a '99 M Rdstr, but I have spent some five decades (>50 yrs) playing with cars from just about everywhere, so while BMWs subcontractors may have started with a clean sheet of paper for their gearboxes, not all manufacturers do the same. I stand by my original statement.

  10. #35
    Join Date
    Feb 2016
    Location
    tempe, az
    Posts
    2,692
    My Cars
    1998 Z3M, 2006 330i
    Quote Originally Posted by Remotion View Post

    Problem with almost all noise insulation is weight. Cheap noise insulation usually is not made for cars and such will suck water into it over time and then it really starts to weight, and corrode metal, and start electric gremlins etc...
    I live in AZ where we are spoiled. We have no water issues. Still, I think cheap insulation would work well inside the car, where there shouldn't be any water. It's probably not as good as dynamat, but it's cheap, almost no weight to it, and very easy to install. As an experiment, cut a piece to fit the well behind the seats where the top lays down. Drive the car. You will hear an immediate difference.

  11. #36
    Join Date
    Jul 2016
    Location
    Vanderbijlpark, ZA
    Posts
    246
    My Cars
    '99 Z3 2.8 Roadster
    Quote Originally Posted by BimmerBreaker View Post
    Just realized OP asked how to lower the first figure. Never said second figure had to be the same

    Try 60mph and your cruising rpm will go down too
    How DARE you beat me to it?
    1999 BMW Z3 2.8 Roadster - show project
    1970 VW 411L Auto - show/restoration project (sold)
    1982 BMW 518i E12/8 - stolen
    1987 Mazda 323 1.5 SL - daily driver, backup show car

  12. #37
    Join Date
    Feb 2017
    Location
    Suburbadelphia, PA
    Posts
    458
    My Cars
    1997 Z3 2.8 Roadster
    Quote Originally Posted by kornfeld View Post
    I agree that this is the wrong car if you're looking for a quiet highway cruiser.

    However....the OP looks to have a hardtop in his avatar image, so I was suggesting sound deadening with the possibility that it would bring the noise to a more reasonable level even though there are trade offs.

    OP....what tires are you running? They might be a big source of noise as well.
    Summer are staggered 17s with 225/45 and 245/40. Winter are stock 16s with 225s, I believe.

    I do have the hardtop, which helps, but it is rarely on the car. I will try some simple insulation, and maybe my decibel meter app will indicate some improvement.
    Cheers,
    Brad

  13. #38
    Join Date
    Dec 2014
    Location
    San Francisco, CA
    Posts
    1,138
    My Cars
    2001 Z3 3.0 Coupe
    Quote Originally Posted by Watch Carefully View Post
    Summer are staggered 17s with 225/45 and 245/40. Winter are stock 16s with 225s, I believe.

    I do have the hardtop, which helps, but it is rarely on the car. I will try some simple insulation, and maybe my decibel meter app will indicate some improvement.
    Cheers,
    Brad

    I meant specifically which brand and model of tire....some tires are known for being very loud while cruising, while others aren't.
    2001 Z3 3.0 Coupe--Sterling Gray/Sunroof Delete/5MT

  14. #39
    Join Date
    Nov 2005
    Location
    Finland
    Posts
    1,159
    My Cars
    Z3 Coupe individual
    Quote Originally Posted by Randy Forbes View Post
    Numerous other manufacturers ADD a fifth (5th) ratio to an existing design to accomplish an overdriven final drive ratio.

    My in depth experience with BMWs__really taking them apart__began with a '99 M Rdstr, but I have spent some five decades (>50 yrs) playing with cars from just about everywhere, so while BMWs subcontractors may have started with a clean sheet of paper for their gearboxes, not all manufacturers do the same. I stand by my original statement.
    And I stay by mine because I stated BMW only. :P

    Z3 & E36 RamAir systems, send private message for more information.

  15. #40
    Join Date
    Aug 2015
    Location
    Denver, CO
    Posts
    3,444
    My Cars
    1999 Z3M, 1999 2.8 Coupe
    Quote Originally Posted by kornfeld View Post
    I meant specifically which brand and model of tire....some tires are known for being very loud while cruising, while others aren't.

    I've found mostly everything from Continental to be pretty darn quiet. I say "mostly" because haven't tried every model, but every one I've tried so far has been quiet. DW on my Roadster, ControlContact Sport on my Coupe. The latter are are A/S tires though...Coupe will get DW next spring if I can ever decide on a set of summer wheels.
    Last edited by s8ilver; 11-20-2017 at 03:14 PM.
    Nathan in Denver

    1999 M Roadster, VFE V3 S/C, Randy Forbes Reinforced, Hardtop, H&R/Bilstein, Apex PS-7, Supersprint
    1999 Z3 2.8 Coupe, Headers, 3.46, Manual Swap, H&R/Koni, M Geometry/Brakes, M54B30 Manifold, Style 42

  16. #41
    Join Date
    Dec 2007
    Location
    Great Dismal Swamp
    Posts
    16,026
    My Cars
    E36/7 E36/8x2 E46 F25
    The 310Z was the first box BMW used that was 1:1 5th. Previous five speed boxes, going all the way back the the last of the 2002 era, were 4 speeds (4th 1:1) with an o/d-ish 5th grafted into the back of the case.


    /.randy

  17. #42
    Join Date
    Nov 2004
    Location
    San Antonio
    Posts
    6,031
    My Cars
    Z3M Coupe & Roadster
    Quote Originally Posted by Tim95M3 View Post
    My 3.46 diff in the roadster can be a bit exhausting on the freeway... Over 4k RPM @ 90mph. Sheesh. A 6-speed swap will happen one of these days.
    6 speed was nice on the way home but we were in the wrong car

    Sent from my LG-LS997 using Tapatalk

Page 2 of 2 FirstFirst 12

Similar Threads

  1. What can be done to stiffen the chasis?
    By subspd in forum Convertible Questions
    Replies: 1
    Last Post: 09-05-2010, 04:00 PM
  2. 92 automatic tranny? what can be done to make it stronger?
    By jerseykat1 in forum 1991 - 1999 (E36)
    Replies: 9
    Last Post: 04-19-2010, 08:24 PM
  3. m42 engine and what can be done to it??
    By kokoman in forum 1991 - 1999 (E36)
    Replies: 28
    Last Post: 01-10-2008, 07:08 AM
  4. Brakes...what can be done to improve feeling and fade resistance?
    By fer2367 in forum 2002 - 2008 Z4 (E85, E86)
    Replies: 5
    Last Post: 12-14-2006, 06:52 PM
  5. What can be done to make a 2000 528i faster?
    By utgrad in forum 1988 - 1996 (E34)
    Replies: 5
    Last Post: 10-24-2004, 01:42 AM

Bookmarks

Posting Permissions

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