Welcome To V6Mustang.com!

We are the oldest and largest V6 Mustang forum on the internet. If you have any questions about your V6 Mustang or just want to connect with other V6 Mustang owners around the world, you have found the best place on the internet to do that.

Registering is free and easy! Hope to see you on the forums soon!

M112 Pulley Size Suggestions?

Discussion in 'Personal Projects and Builds' started by Black02v6, Dec 30, 2013.

  1. Black02v6

    Black02v6 Active Member

    Joined:
    Oct 3, 2006
    Messages:
    556
    Likes Received:
    0
    Trophy Points:
    26
    Location:
    Presque Isle, Maine
    Heres some quick background:

    SSM 4.3l Longrod stroker kit
    SSM 224/230 Cam
    Ported heads/Intake
    LS1 Valve Springs
    25% UDP
    Long Tube Headers
    X pipe with no cats
    ...
    Looking for some boost level suggestions. It's running about 5 psi on the gauge right now. Will also be running an AEM meth kit to lower intake temps. Need to make my order soon. Anybody have some input on how much boost I should make with certain pulley sizes?
    Thanks.
     
  2. bmckelvey

    bmckelvey FordV6Guy

    Joined:
    Feb 23, 2005
    Messages:
    84
    Likes Received:
    48
    Trophy Points:
    28
    Location:
    Madison, AL
    I have built a few 4.0 SOHC supercharged engines and run a few different types of superchargers. I have used 4 Eaton superchargers, one unit off the old T-Bird, a new MP90, an MP112 off a Lightning and right now I am installing a 2004 Mustang SVT Eaton on my 2007 V6. With your boost at only 5 lbs I guess you are running a stock 3.65" pulley (if it is a Mustang S/C) ? Did you change the crankshaft drive pulley on your V6 or are you running the stock V6 crank pulley? There are a lot of things that will impact the boost level you will get with any particular combination. What is your crank drive pulley diameter, what diameter drive pulley is on your M112 and what M112 do you have (new one, Lightning or Mustang ...)? What size is your MAF, Throttle body & intake tube. Are you running a 4.0 OHV or SOHC?
    With a Lightning M112 on my last 4.0 SOHC project (in a Ford Ranger) I was running 10 lbs of boost with the stock Lightning S/C pulley.
    Sorry for asking all the questions but any combination may have a significant impact on the amount of boost that your particular engine will make.
     
  3. Phil II

    Phil II Cone Destroyer Staff Member

    Joined:
    Sep 19, 2013
    Messages:
    1,442
    Likes Received:
    214
    Trophy Points:
    73
    Location:
    Columbia, South Carolina
    I have a similar setup to yours: 4.3, custom cam (228/238 .588/.605), and ported heads and lower with imrcs removed, and ported m112 (steggy VI). LTs x-pipe and cat-less exhaust with magnaflows. AEM water injection system with the big nozzle before the blower. I spray only water (meth would eat the teflon on the rotors and mess with the fuel trim).

    I use the 25% UDP and a billetflow hub with a 3.1" ring. Boost peaks at about 10 pounds, and is very responsive. I've considered putting on a smaller ring, but ultimately it seems best to drive the m112 well within its 60% efficiency zone. You can find the compressor map on Eaton's website. This permits more ignition timing without concern for toasting a valve.

    I'd give you a power number if I had one. It does make an incredible amount of torque.

    Verify your vacuum lines are setup correctly now before ordering a pulley. I only made 6 pounds of boost for maybe 2 months until I realized it was only partly right.
     
  4. bmckelvey

    bmckelvey FordV6Guy

    Joined:
    Feb 23, 2005
    Messages:
    84
    Likes Received:
    48
    Trophy Points:
    28
    Location:
    Madison, AL
    The 5 lbs of boost seems low to me as well. As Phil II has said, check for a leak in a hose, fitting, manifold or gasket, a small air leak will drop the boost. But with an air leak, you should also see a lower vacuum reading at idle unless your ECU is compensating. Here is a good link on 'youtube' if you have never tried to find a vacuum leak. The video is easier than me trying to type the "how to" :)
     
  5. bmckelvey

    bmckelvey FordV6Guy

    Joined:
    Feb 23, 2005
    Messages:
    84
    Likes Received:
    48
    Trophy Points:
    28
    Location:
    Madison, AL
    Here is the youtube link .....
     
  6. Phil II

    Phil II Cone Destroyer Staff Member

    Joined:
    Sep 19, 2013
    Messages:
    1,442
    Likes Received:
    214
    Trophy Points:
    73
    Location:
    Columbia, South Carolina
    I was thinking that you may not have the bypass valve actuator hooked up right. It's lower port needs to see vacuum and boost, just the same as the FRPS. I had mistakenly linked to the vacuum port on the elbow, which tended to hold open the bypass valve even during WOT. This robbed the low end torque but also kept temps down.
     
  7. bmckelvey

    bmckelvey FordV6Guy

    Joined:
    Feb 23, 2005
    Messages:
    84
    Likes Received:
    48
    Trophy Points:
    28
    Location:
    Madison, AL
    Did you get your boost issue resolved? My supercharger setup is up and running and I have been driving the car. I'm running the stock Mustang S/C pulley and the stock 4.0 SOHC crankshaft pulley and my boost gauge is reading just over 8 pounds. I did the math on putting an M112 from a 2004 SVT Mustang on a 4.0 SOHC V6 (4.6 to 4.0) and when you adjust the S/C RPM based on smaller crankshaft pulley (7.5 to 6.0 roughly), I should be making around 7.8 pounds of boost. Maybe my gauge is a little off or I am more in the sweet spot in the supercharger map or my intake and exhaust combination works a little better ... All I can say is my supercharged 4.0 is stronger and faster than most stock v8 Mustangs! But you know what the kick is ... just doing it yourself and having it start and run when you turn the key :)

    Anyway, ... I think you should be over 7 pounds as well.

    As far as the bypass valve, my install just has vacuum on the upper port and, I think, the lower port should be left open so there is no back pressure on the diaphragm. The bypass internal spring puts a lot of pressure on that bypass butterfly so it will stay closed under boost. As soon as you lift off the gas the manifold vacuum will snap the bypass valve open from the vacuum on the upper port. I've never connected anything to the lower port on my installs. But, maybe there are situations where that is required?
    Don't look at the Mickey Mouse flex tubing, I just put that on while I make a good air tube!! And, I will be cleaning up the wiring and hoses with split flex tubing .. maybe red to match the car ???
    ByPassValve.jpg