Page 1 of 11 12345 ... LastLast
Results 1 to 15 of 151

Thread: M90 vs. M112 discussion

  1. #1
    Join Date
    Apr 2002
    Location
    Madison, Ohio
    Posts
    17,532

    M90 vs. M112 discussion

    I don't expect this to go the long route as there may not be a lot to say but I wanted to put this out there.

    After talking to Charles and from my own testing I have drawn a preliminary conclusion that the M90 may be a BETTER blower than the M112. I was perplexed after seeing the boost readings from the M112 cars I have been involved with and the boost readings from the MPX cars I've been dealing with.

    It has been my universal experience that the MPX will eventually outperform the 3.8L motor. If you run the rpms up high enough the MPX will start to creep boost showing a VE that is higher than the motor.

    On the M112 cars I've been seeing boost fall off at high rpm. Charles has confirmed to me that this is not news. The Cobra and Lightning guys have big problems with this when attempting to move large volumes of air and this is what led to the development of his 2-cycle blower case for the lightnings. The problem is that the rotors are enough longer that the case takes longer to fill. In order to fill the rotor cavity completely, port timing has to be dramatically increased. A stock M112 basically sucks compared to an MPX.

    So if you have an M112 you may have to get the thing ported just to keep up to an MPX and even then I have my doubts as Ricardo's blower already has an MPIII case on it. Charles said he has found that a stock case M112 will start to lose efficiency at as low as 14000rpm whereas the MPX has not shown to have this problem at almost 2x that speed making the MPX capable of more cfm than even a ported M112. The rotors simply require that much more time to fill due to their added length. Sometimes less is more....

    Who would have guessed? With the right pulley combination the MPX might be capable of more than we ever thought.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  2. #2
    Join Date
    Sep 2004
    Location
    Indy
    Posts
    5,621
    It all makes sense.

    Having said that, and with all of the success of the MPx, I would say the MPx's inlet port is good for that of an M90. Add two more inches of rotors and then what do you need? Larger than the MPx, I would say.

    Since Charles is already dealing with Lighting and/or Cobra guys, then one day an MP112 kit should come out. Gotta be in the makings.

  3. #3
    Join Date
    Nov 2004
    Location
    butler pa
    Posts
    1,926
    I always knew that I never was able to run the MPIII to the max due to belt slip. and now with the MPX and 10 rib setup I was able to spin it faster than I ever dreamed possibe. and it still was making power! I really can't wait till next year when i have a set of ported heads and a real cam. i do believe the boost pressure will drop a few pounds since it will actually make it into the cylinders. But It was good to know that the MPX was able to be pushed to 25 lbs of boost and still perform. after the heads and cam maybe i will try pushing it further, maybe 50%?
    https://www.youtube.com/watch?v=7bNS...e_gdata_player 10.070 video
    Best ET to date 10.070
    Best MPH to date 130.51
    best 60' to date 1.312
    MPX blower/ NO NITROUS!

  4. #4
    Join Date
    Aug 2004
    Location
    Long Island, NY 11793
    Posts
    5,112
    Geeez Kevin. You're just scary!


    Ira

  5. #5
    Join Date
    May 2002
    Location
    NYC
    Posts
    17,429
    Although not 3.8 specific the guys with supercharged 4.6 SOHC engines have yet to make over 400rwhp with the m90 as far as I know. They do however have 4.6 SOHC with over 400rwhp utilizing the m112 however. I bought an MPX from Charles to see if I can top both numbers. Currently getting things modified and buttoned up on that project. So at least from that standpoint well see where it goes. I also recall the GTP guys making more power with the m112 rotor swap as well but havent really researched it to much. SOmething to look into being they have been doing this swap for some years now
    Last edited by XxSlowpokexX; 11-03-2007 at 02:15 PM.
    They don't call me "SLOWPOKE" for nothin!
    http://www.sccoa.com/forums/garage_v...vehicle&id=110
    Quote Originally Posted by ricardoa1 View Post
    I love the filter. Its pimp. paper element and 10Mircron filtration, 12" long cause size matters.

  6. #6
    Join Date
    Apr 2002
    Location
    San Bernardino, CA
    Posts
    4,523
    yeah but look at the restriction of the mpiii case on a m112 hybred,

    the vee is not located at the end of rotors its 1 inch not two 1 inch towards middle of blower than it is on a m90.

    now why cant a m112 be ported like a mpiii and the vee will be in right location .
    I can mod a m112 to bolt directly to a sc lower manifold the snount will position pully way out front but I can shorten a snout and shaft or make a new one from scratch .
    its a pain but a m112 jag blower can be made to fit just as good as a m90

    yes flow drops at certain rpms in stock form so you fill in silencer ports smily face the inlet beyond the mpiii do vee work make a intake plenum no big deal,
    make a top to mount ic tubes , no big deal,
    shorten snout or make new one and shaft to locate pully in stock location no biggy .
    I look at Ricardo1s m112 and see many draw backs to its design the m90 case is too restrictive as vee is in wrong place bad outlet flow .
    if anyone wants a m112 made to fit a 3.8 i can do it
    id like to do one i sold my m112 to a friend who needed it so i dont have a blower to modifiy.

    any one has one ill convert port make all parts nessissaryI.E." intake plenum raised top " to mount it correctly for material cost only . id like to see what a real m112 ported to hell can do.

  7. #7
    Join Date
    Apr 2002
    Location
    Madison, Ohio
    Posts
    17,532
    Well, it all comes back to how much do you want to spend to make something work? People didn't like spending $3000+ on an AR, but if you want to build an M112 kit that is a viable performance option for people then you have to make it less expensive than a good working M90. Sure someone can build one or two M112 kits and have good enough success with them but what about everyone else?

    I think people are overlooking what's already here. Gee, I'm sounding like Kevin.

    Well, I bought an MPX myself and will be using it on my own car soon enough. Another interesting thing is that I already knew that an MPX will put out over 400 deg outlet temps at 20psi, but what what I am also learning is that with the proper equipment the temps aren't that big of a problem. Today on the track I ran 23psi all the way down and with a double IC and alcohol injection ACT's never climbed above 90 deg. Of course it's 55 deg here today but my point is that there are ways to fairly easily overcome the heat problem.

    Before anyone jumps off saying "ya but since the M112 is bigger it has to be better" you have to look at the physics involved. Charles had to go to a 2 cycle design to move enough air to make the M112 work at the CFM levels needed to make the power the Lightning guys were looking for. With even an MPX sized inlet the M112 still can't move enough air to fill the rotors. I saw that on Ricardo's car and when I mentioned that to Charles he said he already knew that would happen. I didn't know or expect that to happen.

    I think a lot of the gains seen from going to an M112 blower have been due to a less than MPX quality M90 being compared to it. Another big problem with the M112 (which I have already witnessed) is it's ability to make absolutely monstrous boost at low rpm. Those who know will tell you that making too much boost at low rpm is what kills these motors. If we could trade some higher rpm power for some low end torque we would go faster and break less parts. This is why I feel that the M112 may not be the answer for our cars and I haven't seen anything to suggest that an MPX can't do everything that an M112 can do and its a whole lot simpler.

    I now have a couple of dyno charts where we can see just what an MPX does compared to say a ported 94 blower, for example. I'll post them later today but it would be pretty easy to see how someone could compare an M112 to one of the ported 94 blowers and say "wow, look at that." We already have that with the MPX.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  8. #8
    Join Date
    May 2003
    Location
    Omaha, Nebraska
    Posts
    6,157
    Quote Originally Posted by XR7 Dave View Post
    I don't expect this to go the long route as there may not be a lot to say but I wanted to put this out there.

    After talking to Charles and from my own testing I have drawn a preliminary conclusion that the M90 may be a BETTER blower than the M112. I was perplexed after seeing the boost readings from the M112 cars I have been involved with and the boost readings from the MPX cars I've been dealing with.

    It has been my universal experience that the MPX will eventually outperform the 3.8L motor. If you run the rpms up high enough the MPX will start to creep boost showing a VE that is higher than the motor.

    On the M112 cars I've been seeing boost fall off at high rpm. Charles has confirmed to me that this is not news. The Cobra and Lightning guys have big problems with this when attempting to move large volumes of air and this is what led to the development of his 2-cycle blower case for the lightnings. The problem is that the rotors are enough longer that the case takes longer to fill. In order to fill the rotor cavity completely, port timing has to be dramatically increased. A stock M112 basically sucks compared to an MPX.

    So if you have an M112 you may have to get the thing ported just to keep up to an MPX and even then I have my doubts as Ricardo's blower already has an MPIII case on it. Charles said he has found that a stock case M112 will start to lose efficiency at as low as 14000rpm whereas the MPX has not shown to have this problem at almost 2x that speed making the MPX capable of more cfm than even a ported M112. The rotors simply require that much more time to fill due to their added length. Sometimes less is more....

    Who would have guessed? With the right pulley combination the MPX might be capable of more than we ever thought.
    Hard to figure where the thread was intended to go Dave. No one offers at this time M112 blower conversion. Ricardo talked about it but has not done much with it as he is working on his own. Ive done 2 conversions of Jaguar blowers but have no plans to do any more at this time. My blower is stock with no porting and I have considered sending it out to have it ported to the extreme and probably will in the near future. Doesnt do me any good to add a lot to the discussion here as I still have a EEC which is limiting my performace to replace,which apparantly no one has. Since the M112 is not an option at the moment it seems to be more of a discussion to show how good the MPX is as the present option for big HP. The M112 is a great blower but since Paul never finished solving the problems with it. Only a couple of us are currently working on solving the problems. So there is no real comparrision of the two blowers. A extreme ported M112 matched against the extreme ported M90 would be more a apples to apples comparision. If ricardo modifys his outlet to open it up to at a minimum the size of the stock M112 his will be closer to an apple to apple comparission and hes only overdriven 15% not 25%. Its a good discussion one way or the other but what happens if we over drive a M112 MPX hybred 25%. Regardless A extreme ported M112 I believe will match MPX and more but untill you have a working one to compare the two its doesnt mean much other than a good discussion

    Ken

  9. #9
    Join Date
    May 2002
    Location
    NYC
    Posts
    17,429
    I had a typo in my post..The SOHC 4.6 guys have exceeded 400rwhp where as the m90 equiped ones have not.

    We need to see where it all goes..I dont think Keven or RIco are near optimal now
    They don't call me "SLOWPOKE" for nothin!
    http://www.sccoa.com/forums/garage_v...vehicle&id=110
    Quote Originally Posted by ricardoa1 View Post
    I love the filter. Its pimp. paper element and 10Mircron filtration, 12" long cause size matters.

  10. #10
    Join Date
    Jan 2004
    Location
    Outside KC MO
    Posts
    5,791
    I see a few problems in this comparison. First, comparing the VE of the engine of the 5.4 to that of the 3.8. Sure, people like Kevin can probably get close to the same flow from his car that a slightly modified Lightning can do, but look to see how much air a highly modified one will move. I guess I just dont get how the same style blower is having problems against its little brother. Is the inlet "blocking" the flow causing the cavitation? Is it the inlet opening of the blower? Is it something that can be improved upon with the 112?

    Dont get me wrong, I think the MPX is long overdue (lets see...bought the MPIII from Niebert in 05, sold that for the Whipple, had to have custom parts made...car still sitting). If the MPX would have been available two years ago, I would already be driving my SC.

    So, is there a new rotor design in the works, like the three lobe that I have been hearing about? For either blower? Or do they have to be totally redesigned?

    Chris

  11. #11
    Join Date
    May 2002
    Location
    NYC
    Posts
    17,429
    chris totally redesigned..My concern is that an m90 case MPX or otherwise may actually impede the flow of teh m112 rotors. I really want to see what Kenny comes up with. Wish I had one to play with
    They don't call me "SLOWPOKE" for nothin!
    http://www.sccoa.com/forums/garage_v...vehicle&id=110
    Quote Originally Posted by ricardoa1 View Post
    I love the filter. Its pimp. paper element and 10Mircron filtration, 12" long cause size matters.

  12. #12
    Join Date
    Apr 2002
    Location
    St. Charles, MO
    Posts
    20,886
    I look at Ricardo1s m112 and see many draw backs to its design the m90 case is too restrictive as vee is in wrong place bad outlet flow .
    Manny,

    Good point on the location of the blower outlet. It got me thinking that with the outlet in the same place as an M90, you lose much of the advantage of having the longer M112 rotors, because the rotor seal time is the same as the M90 when the spacer is added to the front of the case. Not sure what is happening with the air from the portion of the rotors that are housed in the spacer. I assume that air is being pushed back towards the outlet and probably creating some additional turbulence in the process. If the spacer were added to the rear of the case it would probably work much better, but that really isn't pratical.

    Ken, are you using a spacer like Ricardo or an m112 case with shortened snout ?

    David
    1991 SC AOD 4.2..2.3 Whipple..........10.910 @ 125.61
    2016 SRT Challenger Hellcat...............707HP/650TQ

    My Garage

  13. #13
    Join Date
    Aug 2007
    Posts
    31
    ............................
    Last edited by panic; 11-03-2007 at 05:12 PM.

  14. #14
    Join Date
    Apr 2002
    Location
    Madison, Ohio
    Posts
    17,532
    The point of this post was to talk about some things directly relating to the M90 and M112. It is not meant to be a downer for anyone with an M112.

    When I tested Ricardo's hybrid I was surprised to see that it made very large boost down low (23-24psi) but then fell off at higher rpms and this hybrid already has what is probably the best inlet design you are likely to see on any ported M112. Unfortunately the hybrid has a poor outlet configuration which is undoubtedly adding to the heat and reducing efficiency somewhat. To what degree I don't know but it is clear that to get high rpm efficiency from the M112 will result in some really crazy boost at low rpm which is not going to help the head gasket issues.

    I brought this up to Charles and he agreed that there are some problems with the outlet design but he was very clear that his testing has shown that even a ported M112 case will not fill the rotors at high rpm. This is why he made the new case for the Lightnings. Charles says that without a doubt the MPX case will flow more air than a ported M112. The only question Charles ever had about his MPX was related to belt grip and high rpms associated with lots of OD. However, recent testing has shown that the problem is close to being addressed with the 10 rib belt system and the other parts that he has come out with over the past year.

    The reason I started this post is that I feel it is important and worthwhile to make sure that people understand the physics and engineering that is on the table here. We are on the verge of possibly losing any further efforts on the part of MP, and like it or not Charles is the only person I've heard of who has done this type of R&D on the old school Eaton roots blowers. If we let this go (which may be inevitable anyway, who knows?) I don't want people to take 5 steps backward when it isn't necessary to do so.

    So what does this have to do with the M112? Just that I was surprised to learn that the MPX has better high rpm efficiency than an M112.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  15. #15
    Join Date
    Apr 2002
    Location
    Madison, Ohio
    Posts
    17,532
    Quote Originally Posted by panic View Post
    Has anyone tried to get more intake flow area by raising the case above (for example) the 1st 25% of the rotor length, in a V just like the exhaust but reversed? As seen in elevation, first an original Eaton dwg., than the roof extended to cover more of the rotors. If this is possible, a larger throttle body etc. will help by removing the remaining up-stream restriction.
    Those diagrams are misleading regarding airflow patterns into the blower (at least in the case of a hipo version like the MPX).

    The original 89-93 M90 has a cavity in the bottom (or as your picture shows, top) of the case for air to enter along the bottom of the rotors. However, testing showed that bringing in air at the bottom of the rotors is not the most efficient way to fill the case. Instead the air is brought in from the ends of the rotors only. By keeping the air flowing in a straight line along the axis of the rotors to the front of the case airflow is kept more linear and efficiency increases. The MPX does not bring in any air from under the rotors but instead extends the amount of time that the ends of the rotors are exposed to the inlet to improve high rpm case filling.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

Similar Threads

  1. M112 rotors in a M90 case
    By supercatxr7 in forum Technical Forum
    Replies: 5
    Last Post: 12-04-2005, 07:00 PM
  2. m90 or M112????
    By Baz21 in forum Technical Forum
    Replies: 1
    Last Post: 06-17-2005, 03:30 AM
  3. M90 to M112??
    By doodaa in forum Non Technical Forum
    Replies: 5
    Last Post: 06-05-2005, 04:43 AM
  4. M112 rotors in SC M90
    By daivd z in forum Technical Forum
    Replies: 7
    Last Post: 11-14-2004, 02:01 PM

Posting Permissions

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