Installed an M112. whats wrong?


Sheetmetal pro
i installed an M112 supercharger on my 3.8 5 speed and im not sure whats going on. when im driving and i shift gears the rpm's drop extremely fast and makes for a rough shift. also when first starting it up it doesnt want to idle. and it almost sounds like it wants to miss. once warmed up it idles ok. i havent had it tuned yet, but i havent driven it into boost either. could it be a vacuum leak or a misrouted vacuum line?:confused:


I drive a V6
Please tell me you have it tuned. and dyno tuned at that

we got fast and the furious up in this bitch?

How the hell can you see how the front window


I Like Turtles
14psi on a m112???? and 100 SHOT! .... i foresee epic failure

edit- nvm, engine is built :( ...walnuts


I Like Turtles
01-04 3.8 block bored .030 over

Long Rod 4.3 Stroker:
New 4.2 crank, SCAT forged 351/408Wstroker H-beam “long rods”, ARP rod bolts, Wiseco forged pistons, rings, pins, and lox

Heads, Cam, Intake:
Ported lower intake with IMRC delete, Custom aluminum M112 adapter, Stage 3 SuperHeads with 1.94/1.56 stainless steel valves and stud mount 1.7 roller rockers, SSM custom ground CompCams billet cam

looks like he has engine build but the intake temps on an m112 are too high and will cause problems...get underdrive pulley...and more than likely youll make more power.





Sheetmetal pro
has forged bottom end. and i haven't driven it hard since i haven't made it to the tuner yet. my intake temps haven't been over 140 even after driving all day. Ive used my SCT livewire to get the tune as close as i can, but those **** things suck. they are very limited. my car likes to die on me when i first start it. i have a 3.65 pulley, 3.1 pulley, and a 2.9 pulley.


Boosted V6
What is the a/f reading?Are you tuned for the larger injectors?It sounds like a vaccum leak.Can you post a sound clip?


Sheetmetal pro
no, its not tuned at all besides a little tweaking Ive done with the livewire. i can post a sound clip tomorrow. i don't think its the tune, because the car still acts up even when the belt is off of the supercharger.

xtreme 2

New Member
definitely sounds like vacuum to me. Is your throttle body sealing when you let off the throttle body? Did you use OE gaskets everywhere? Everything plugged in correctly?


Sheetmetal pro
yea, the throttlebody blades are sealing. and i used OE gaskets everywhere except between the adapter and supercharger i just used rtv. ill post a video in a bit to show my vacuum lines, how my exhaust sounds, and my vacuum at idle.


Under the Wrench.....
first off dude check your vacuum lines to see if routed correctly. a lot of people, myself included, put fuel pressure regulator to wrong spot.
please get it tuned, you wouldn't want to damage your engine build. i know it's supposed to be safe to drive without boosting but not if it's having fuel delivery problem.


bored and stroked
On the lower intake there are dowel pins that line up where upper intake should be, did you rtv them real good? The gasket does NOT seal these.


Sheetmetal pro
i found 2 vacuum leaks so far. idk if it has fixed the problem yet. and i sealed around the dowel pins really good when i was putting it together. ill go back and check all my vacuum lines to be sure they are routed correctly. what should vacuum read at idle?