Page 2 of 2 FirstFirst 12
Results 26 to 37 of 37

Thread: 850i downpipes

  1. #26
    Join Date
    Sep 2018
    Location
    Belgium
    Posts
    307
    My Cars
    1990 850i and 1970 2800C
    i routed the fuel return lines above the cam cover... and didn't reinstall the 2 lifting lugs. Now all bolts from the inlet manifolds are reachable with straight 1/4" extensions , no swivel magic needed ….one can even see them all ! Installed the manifolds ( new gaskests and liquid gasket sealer ) in 1 hour ! Only the 2 x 2 nuts were the cast horizontal connections are in the manifolds needed a grinded down socket and a wobble extension, but one has a clear view on those....and can start the nut with a finger . This was fun comparing to demount it with the oem return line in the way . I'm sure i can demount it now in 1/2 hour . No more fear for those manifolds !

    Had to end the evening job as i damaged 1 O ring mounting the injectors in the fuel rail ... and i have no spare. Tomorrow to the shop....

    With a bit of luck car is running again tomorrow.

  2. #27
    Join Date
    Sep 2018
    Location
    Belgium
    Posts
    307
    My Cars
    1990 850i and 1970 2800C
    i finally did a dyno again ... ( had to prep the E9 for a rally next week ) .
    Again same results , but we filmed the boost gauge straight to have a exact measure.
    We don't have the "bug" , i have seen the throttles going 90° open and stay there. ( visual with a stick on the throttle taped)

    At 4876 rpm we have max 416 HP at 0.3 bar boost . After that it stays "flat" till 6000 rpm , but boost go's higher to 0.4 bar .
    At 4585 rpm we have 616 NM

    Boost gauge is connected on the manifold ( T on the FPR hose) , so after throttle .

    I'm running now crankshaft dia 155 mm , charger 52.5 mm , so x 2.95 … just below max revs for the Raptor V ( would be x 3)

    Is this ignition related ? from 4876 rpm till 6000 he get's 0.1 bar more boost but doesn't do anything with it … HP stays "flat"....

  3. #28
    Join Date
    Jun 2008
    Location
    SF Bay Area
    Posts
    3,774
    My Cars
    Supercharged 850ci
    Its very strange to me, if boost is going up and AFR stays 11 to 12.5 range the HP has to rise makes no sense that it doesn't.
    Only way it would stay flat if injectors are maxed out and AFR goes lean...

  4. #29
    Join Date
    Sep 2018
    Location
    Belgium
    Posts
    307
    My Cars
    1990 850i and 1970 2800C
    no Ed , AFR stays 11...12.5 , injectors are 300 cc ( 30 lb) , new fuel pump unit / new filters , 98 octane fuel.
    Perhaps timing ? and why should it take advance away ? any sensor (we have no knock sensor) that can do that ? mapping ?

  5. #30
    Join Date
    Jun 2008
    Location
    SF Bay Area
    Posts
    3,774
    My Cars
    Supercharged 850ci
    Quote Originally Posted by Belgiumbarry View Post
    no Ed , AFR stays 11...12.5 , injectors are 300 cc ( 30 lb) , new fuel pump unit / new filters , 98 octane fuel.
    Perhaps timing ? and why should it take advance away ? any sensor (we have no knock sensor) that can do that ? mapping ?
    I don't understand why that's happening, no timing should not change(timing can be monitored on dino), what spark plugs do you have?

    What about compression? Have you done the test??

  6. #31
    Join Date
    Sep 2018
    Location
    Belgium
    Posts
    307
    My Cars
    1990 850i and 1970 2800C
    NGK BKR6EK ( 2288) ( also new plugs.... )

  7. #32
    Join Date
    Jun 2008
    Location
    SF Bay Area
    Posts
    3,774
    My Cars
    Supercharged 850ci
    Quote Originally Posted by Belgiumbarry View Post
    NGK BKR6EK ( 2288) ( also new plugs.... )
    Honestly there is no reason why you should have power drop like that, I would suspect compression at this point. Do a test.

  8. #33
    Join Date
    Sep 2018
    Location
    Belgium
    Posts
    307
    My Cars
    1990 850i and 1970 2800C
    can it be OK up to 4700 rpm and drop power above, due compression ? here are the curves from yesterday : (values x 0.75 as we only drive 3 sets rolls instead of the 4 )

    BMW 850i - downpipes - NM.pdfBMW 850i - downpipes - PK.pdf

  9. #34
    Join Date
    Sep 2008
    Location
    Santa Barbara
    Posts
    3,462
    My Cars
    91 Dinan860 & 91 850 6sp
    cam timing is off
    '91 Dinan 860 Stage III (new 6L engine)
    '91 Dinan 850 TT stage III (brand new engine) 21st Century Tech meets 18th Century Dinan...
    '91 850i 6sp (mint) (sold)
    '90 Dinan 750iL TT stage III (Guido - The Beast)
    '94 850 CSi The Detroit Auto Show car (restored to factory perfect) (sold)
    '96 850Ci, The George Carlin car
    ''73 3.0 csi, '08 535i, '03 X5 4.6is
    ...and a few other non BMW cars

  10. #35
    Join Date
    Sep 2018
    Location
    Belgium
    Posts
    307
    My Cars
    1990 850i and 1970 2800C
    i timed the cams a few weeks ago cartoonz..... they are spot on.

    https://www.bimmerforums.com/forum/s...ith-water-leak
    Last edited by Belgiumbarry; 02-09-2019 at 03:24 AM.

  11. #36
    Join Date
    Oct 2016
    Location
    Shoreview MN
    Posts
    977
    My Cars
    Had a 1991 BMW 850
    A thought, Boost pressure could be going up but if the heads are the bottleneck HP will remain flat because the air is just backing up. Of course you would need to pull the heads and flow test them and then port and polish etc to see any potential gains.

  12. #37
    Join Date
    Jun 2008
    Location
    SF Bay Area
    Posts
    3,774
    My Cars
    Supercharged 850ci
    Quote Originally Posted by rjjablo View Post
    A thought, Boost pressure could be going up but if the heads are the bottleneck HP will remain flat because the air is just backing up. Of course you would need to pull the heads and flow test them and then port and polish etc to see any potential gains.
    With FI heads usually are not the problem, I am getting around 500 WHP at 11psi.
    Like I said, do the compression test and report back, it's very simple to do.

Page 2 of 2 FirstFirst 12

Similar Threads

  1. E36 M3 Cabrio vs 850i
    By NotConvicted in forum Kill Stories
    Replies: 6
    Last Post: 01-13-2003, 06:13 PM
  2. Will 850i rims fit on an E36 M3?
    By NoSoup4U in forum Tire & Wheel Forum sponsored by The Tire Rack
    Replies: 4
    Last Post: 01-09-2003, 08:48 PM
  3. WTB: 98 M3 downpipe!!!
    By okiedokie in forum BMW Parts Wanted
    Replies: 5
    Last Post: 08-25-2002, 12:06 AM
  4. Looking for an 850i/ci 6-speed
    By artherd in forum BMW Parts For Sale
    Replies: 10
    Last Post: 04-30-2002, 09:28 PM
  5. 850i custom cabrio on Autotrader.com
    By Libra in forum General BMW and Automotive Discussion sponsored by Intercity Lines
    Replies: 5
    Last Post: 04-29-2002, 12:42 PM

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
  •