Results 1 to 5 of 5

Thread: Cam timing questions

  1. #1
    turbo addict
    Join Date
    Dec 2005
    Location
    Lincoln, Nebraska
    Posts
    2,626

    Cam timing questions

    Does anyone know what the effects would be on the powerband, idle, etc if you were to adjust only the intake cam timing? How about the exhaust? I've been trying for several days to find good info on it but am coming up empty handed.
    “If the people of the nation understood our banking and monetary system, I believe there would be a revolution before tomorrow morning.” -Henry Ford

  2. #2
    Buy my stuff!!!!!!!!!!! :O) Turbo Mopar Vendor turbovanman²'s Avatar
    Join Date
    Dec 2005
    Location
    Abbotsford, BC
    Posts
    44,167

    Re: Cam timing questions

    I know on my Olds Quad 4, I adjusted the cams, 4 deg advanced on the intake and 4 degs retarded on the exhuast and the powerband moved up and hit so much harder, it would smash into the limiter. The bottom end was affected a bit.
    The only way to really know is to hit the dyno and adjust them or go to the drag strip and mess around.
    1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
    1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
    2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
    2004 GSW TDI, 5 speed, fully loaded, modified.

    Aurora ignition wires for sale. Link to info

    Super60 roller cams or custom/billet cams. Link to info

  3. #3
    turbo addict
    Join Date
    Dec 2005
    Location
    Lincoln, Nebraska
    Posts
    2,626

    Re: Cam timing questions

    I agree with what you had found Simon. Thinking about this more advancing the intake and retarding the exhaust will have the same effect that a cam with more overlap would have on a single cam engine- raise the rpm powerband and likely lower the vacuum at idle.

    From reading on other boards it seems like the intake timing has a lot to do with the rpm the engine will do best at. Advancing lowers the rpm while retarding raises it. If the exhaust timing stays the same we have a situation like your Quad 4; increasing or decreasing overlap.

    Looks like I'll be doing some street tuning to get the A/F ratios where I want them for 20 psi. Then hiting the dyno and trying different cam timing; likely in 4* increments so there should be a noticeable change.
    “If the people of the nation understood our banking and monetary system, I believe there would be a revolution before tomorrow morning.” -Henry Ford

  4. #4
    Buy my stuff!!!!!!!!!!! :O) Turbo Mopar Vendor turbovanman²'s Avatar
    Join Date
    Dec 2005
    Location
    Abbotsford, BC
    Posts
    44,167

    Re: Cam timing questions

    Awesome, let us know what you find. I might try messing around later.
    1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
    1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
    2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
    2004 GSW TDI, 5 speed, fully loaded, modified.

    Aurora ignition wires for sale. Link to info

    Super60 roller cams or custom/billet cams. Link to info

  5. #5
    turbo addict
    Join Date
    Dec 2005
    Location
    Lincoln, Nebraska
    Posts
    2,626

    Re: Cam timing questions

    Sounds as though the intake timing plays a big part in where the powerband is, RPM wise. The exhaust cam timing is more of a global effect, raising or lowering power across the board. I'm far too excited to get to the dyno to see how things will turn out.
    “If the people of the nation understood our banking and monetary system, I believe there would be a revolution before tomorrow morning.” -Henry Ford

Tags for this Thread

Posting Permissions

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