Anyone want to compare MAF readings?
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 5 of 5
Northstar Engines and System Technical Discussion Discussion, Anyone want to compare MAF readings? in Cadillac Engine Technical Discussion; Looking at the OBD2 reader I've got hooked up, shows a peak airflow of 236 g/s air from the MAF, ...
  1. #1
    naif is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 Seville STS, 2004 Deville DHS
    Join Date
    Mar 2011
    Location
    near Virginia Beach, VA
    Posts
    1,274

    Anyone want to compare MAF readings?

    Looking at the OBD2 reader I've got hooked up, shows a peak airflow of 236 g/s air from the MAF, working out to about ~80.4% volumetric efficiency at peak RPM (6300). Anyone? Induction system in good shape, reasonable shape, or needs a cleaning? (I've no issues or complaints, I'm just curious...)

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    75
    Posts
    46,018

    Re: Anyone want to compare MAF flowrates?

    The standard automotive airflow calculation uses a VE of 80% - most wonderful for a stock engine.

    I'm not going to post it all - Google "automobile engine airflow calculations" and do the math yourself.

    3 years ago I screwed around with a mechanically modified MAF - JET Performance - and got exactly nothing worthwhile. This was done over two 821 mile round trips from MD to FL and I actually lost a half mpg, set mixture codes, and introduced a low speed/off idle stumble.

    So..........In answer to your opine, your engine and intake system is just fine..............but go ahead and work out the formulae - you'll convince yourself that the MAF/throttlebody modification idea is pretty useless on these engines: they already have a cold air intake tract and panel filter which flows more air than a 279 c.i. engine can handle as-is.

    Aw, heck - here are the formulae..............

    CFM = CID X RPM X VE / 3456

    VE = 3456 X CFM / CID X RPM

    For a NA engine, use a VE of ~80%.

  4. #3
    naif is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 Seville STS, 2004 Deville DHS
    Join Date
    Mar 2011
    Location
    near Virginia Beach, VA
    Posts
    1,274
    Thread Starter

    Re: Anyone want to compare MAF readings?

    Huh? I'm not interested in modifying it, but it could perhaps be an early indicator of exhaust cam wear for the pre-2000 engines. The only way to get more suck (without a blower) is to get a tuned (variable length) intake along with finding space for a bigger crossover pipe (there is no space), and that's not happening

  5. #4
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    75
    Posts
    46,018

    Re: Anyone want to compare MAF readings?

    Quote Originally Posted by naif View Post
    get more suck (without a blower) is to get a tuned (variable length) intake
    Your engine already has a tuned intake manifold with 8 variable sized individual intake runners coming off the distribution log. Everything before the center lower distribution log is designed for maximum cold air flow.

    .........not saying you're looking at modifications - just that a few of us have been there, and there isn't a gain to be had from fooling with the intake. You would have to have some pretty severe intake manifold sludge buildup before there would be ANY performance losses there - but a clean air filter and throttlebody is of prime importance.

  6. #5
    naif is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 Seville STS, 2004 Deville DHS
    Join Date
    Mar 2011
    Location
    near Virginia Beach, VA
    Posts
    1,274
    Thread Starter

    Re: Anyone want to compare MAF readings?

    For anyone coming along, to go from g/s to CFM depends on air temperature (and humidity), but using 15C air is 1.225kg/m^3, going from g/s to CFM

    m^3/s = g/s / 1225
    m^3/min = m^3/s * 60
    CFM = m^3/minute * 35.31

    Oops! I did my calculation wrong. It's about 80.4% for 236g/s - displacement is 0.0045648 m^3 and max rpm 6300 not 6000

    ----------

    Variable as in changing length, the runners help but to get everything possible the size needs to change...

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting