XR7 Dave
Registered User
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.
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.