M112 sc400

LP1

New Member
I thought I would detail my M112 install on my 95 SC400. Objective was for about 300 rwhp and an overall stock look, it had to fit under the hood! The M112 was chosen as it is a good looking piece of kit and they are relatively cheap and easy to find. Needless to say it is a tight fit.

Specs: Ford Mustang M112, 8+ psi with a 3.5”pulley, 7MGTE 315cc injectors, water methanol injection
 

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LP1

New Member
Supercharger Manifold

Available manifolds were investigated but I did not have a lot of confidence that the end result would fit under the hood so I decided to fabricate my own. A reference height from the top of the thermostat housing to the underside of the hood was taken. The positioning of the M112 and the maximum allowable manifold height was estimated. The bottom is angled up to clear the starter, width is determined by the outside flange of the M112. It needs to be as narrow as possible to leave room for the fuel injection rails.

Intake runners were cut from the stock intake using a jig and carbide tip blade on table saw. Sleeves were installed on the intake manifold studs to center the runners on the studs and a spare engine was used for the welding jig. I thought I could use the existing fuel rail studs but the M112 is too wide and new studs need to be installed.

Studs were installed for the M112 and the fuel rails. Studs are threaded through and lock bolted from the underside. A bump out for the water return line was incorporated. Manifold was TIG’d and MIG’d by a local welder for cheap. $180 including supercharger intake manifold and water bypass manifold.
 

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Lextreme

Just call me "Lex"
Nice job.... and video?

Mitch P. supposed to come to my place this Thursday to install the AEM and hoping we can get the M112 5.2L start up....
 

LP1

New Member
Front Water Manifold

Sorry no video yet. The following is the work needed to modify the water manifold.

The slope of the M112 snout interferes with the original water bypass manifold so the manifold needs to be pushed forward. There are limits as to how far forward the bypass manifold can be pushed and still line up with the water pump. 1x3” aluminum channel was used to push the body of the manifold down and about ¾” forward. A spacer was needed to connect the thermostat housing to the water pump. The original round collar for the housing was cut out and positioned on the new manifold. The top radiator hose connection was moved slightly to the left at the same time to align with the super charger belt routing. Sensor housings were left in their original positions (note that the ‘95 does not have a cold start temperature sensor, the cold start sensor would have to be moved if it is needed). As before the original manifold pieces were centered on the studs for welding, and the engine was used as a welding jig.

A brass colar was installed in the top radiator hose to provide a little more clearance for the surpercharger belt. See first picture on this thread (M112 SC400).
 

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JustenGT8

New Member
A lot of work there, good effort. What sort of boost are you looking to run? It'll be interesting to see how it compares to the M122
 

LP1

New Member
Boost

We had no boost number in mind, we were thinking of a mild 6 psi. The boost builds fast and I haven't really run it out yet. The 'problem' is that the engine revs out so quick that the boost doesn't have time to build before you need to shift. It hit 8.6 psi during testing and I think we were in third and started at a low rpm to work the engine and allow the boost to build.
 

markstoys

New Member
Very nice work. I went the easy (high rise) way because I didn't want to mess with the fuel rails or water bridge. But I think it sticks out too much--even for my car. I may copy your design if/when I redo mine. And that close up shot is just the mock-up--I don't have any pics yet of the finished manifold.





Mark
 

LP1

New Member
Manifold

Actually the fabrication went very well. There was some head scratching on the water bridge as the space is very tight and the connection to the waterpump forces the mainfold to be very exact.
 

LP1

New Member
M112 Prep

There are plenty of ports at the back of the supercharger. It’s a tight area when installed so some pre-planning is needed. Lower flange is removed as it would interfere with the manifold intake runners. Taking the front snout off to change the pulley is straightforward, supercharger oil is available through GM for cheap, and you are supposed to use anaerobic gasket maker to re-seal the snout. The stock pulley is not eager to come off but the new one fits easily.
 

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LP1

New Member
M112 Fitment

The extra mounting lugs etc on the M112 for the Ford install were removed and the case smoothed for aesthetics. The M112 front left mounting leg was moved to accommodate the fuel rail bolt location, however, the M112 is slightly too wide for the original fuel rail mounts. Next time, I would modify the fuel rail mounts and not the M112. It’s hard to tell from the picture but the fuel rails are about five degrees outward of their original positions due to the fuel rail mounting flanges – no apparent operational issues, they work fine. Fuel feed pipes can be re-used with some bending. The rear is easy, the front is ugly due to space limitations. I would fabricate a new front pipe and route it under the manifold next time.
 

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LP1

New Member
Throttle Body Manifold

The supercharger throttle body manifold was fabricated by cutting the Ford manifold and welding on a flange for the Lexus throttle body. You need to transition quickly from the flat Ford manifold to the round Lexus flange. Pieces of 3 ½ inch aluminum thick wall tube were used top and bottom to make the transition, flat pieces were used on the sides. Note the addition of a 90 degree flange on the right side which is needed to attach the throttle cable hold down. Manifold was fabricated with a slight down angle and after supercharger was installed to make sure there was clearance from the valve covers. The throttle body manifold was kept as short and low as possible, there is a far bit of vertical room below the hood so low is not critical. The Lexus IAC valve was positioned on the side of the new manifold by way of a new flange, IAC air filter was not used in the final fit. Plumbing the water lines for the IAC is a bitch due to lack of space.
 

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SC400TT

Moderator
Very nice work and attention to detail. I like your welding beads too.Looking forward to seeing the end product.

Ryan
 

LP1

New Member
Welding

The welding was done by a pro with direction to make it pretty. It was mostly TIG'd.
 

LP1

New Member
Pulleys and Belt

Fore/aft positioning of the M112 was determined by the original pulley position. M90 pulleys are 6 rib, readily available, and have the same shaft diameter as the M112. You’ll need a press to get the original pulley off, you need to remove the snout to do this. I got the 3.5” 6 rib from American Supercharger, they use a collar which can be reversed, bottom line is there is a little wiggle room on positioning the pulley fore/aft to ensure correct alignment. Small idler pulleys are difficult to source and the quality of some of them is suspect. I ended up using Lexus timing belt pulleys as idler pulleys. The center one mounts directly to the original idler pulley location. I installed a ½” aluminum plate bolted at three existing bolt locations to secure the second pulley. You have to cut into the left hand engine cover to make room for the pulley and idler bracket. Longer belts are readily available, reference marks were made on the original belt at known locations. The belt was then rerouted over the supercharger and new idler pulleys to determine the longer length of belt needed. Idler pulleys are nice and wide, no issues with belt stretch or tracking (make sure the pulley plate/bracket is perfectly in plane with the belt path).
 

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LP1

New Member
Final Fit

The engine is largely stock with larger 7MGTE injectors installed to provide the extra fuel. IMF headers were added, they flow very well and a good choice for the supercharger. The top of the engine was tidied up, some of the VSVs were moved to the left side. The ‘95 has an EGR with a temperature probe. The EGR valve was wired up and abandoned in the engine valley and the temperature probe was connected to the available port in the left header. The objective was to ensure there were no engine codes which worked out. All four O2 sensors are installed although the two front cats are missing – again no codes.

A Snow water methanol injection system was installed to prevent detonation. The tank was placed ahead of the radiator above the plastic deflection shield. The controller reads boost and is programmable for pulse width and/or boost. The controller is installed and hidden behind the ashtray door. I’m running the 200ml nozzle as the larger nozzles made the engine feel like it was being quenched using a 50/50 mix.

The install is very tight. There is a lot of stuff hanging off the back of the supercharger which prevents getting the optimal engine angle for removing/installing the engine. I ended up removing the IAC and shortening the hose that goes from the back of engine to heater water to ‘help’ with the install. The water heater valve assembly had to be moved to the right about an inch to make room for the throttle body. The stock throttle cable and traction control cable fit fine although the throttle cable is stressed to make it, it could stand to be a few inches longer. The height of the super charger leaves about an inch of room from the hood, but the insulation is loosely fitted at the pulley location and the pulley was started to cut the insulation. I cut a small c-section into the hood insulation and glued to the hood which provides enough clearance.

The W-58 was probably not a good choice for this application. Unfortunately, I had long committed to that path before deciding to supercharge. It’s a real nice transmission and will probably be fine if I keep my foot out of it.
 

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LP1

New Member
Drivability and Issues

The drivability with the supercharger is excellent. You wouldn’t even know it was there unless you put your foot into it, then you definitely know it is there. The cold start fuel map is challenged probably by the larger injectors. The ’95 does not have a cold start injector and the stock ECU over controls resulting in a +/- 50 rpm when first started. The over control gets worse, to the point of stall, if you touch the throttle while the ECU is working on finding the right rpm (takes about 90 seconds). The options are to not touch the throttle or step up the idle with your foot.

The stock ECU handles the supercharger very well. It feels a little sluggish at low boost and light throttle, it would benefit from a tune. At medium to full throttle it is a freight train torque monster and has no issues, the M112 builds boost quickly and steadily to red line. Traction control gets a little excited, but that’s no surprise.

Issues

•Need to upgrade the exhaust, the stock exhaust doesn’t cut the extra flow under boost.
•I have a no name stage 2 clutch which is not cutting it. Need to beef up the clutch to handle the torque.
•Need to upgrade the rear suspension. The rear suspension is torque steering under boost.
•Gearing too short. With the five speed and boost the engine hits red line in first and second before you think to shift. With some training and track time I’m sure it would be fine. However, I installed the later model 3.27 differential which greatly improved highway performance and provides more than adequate street performance.

Bottom line is I like it a lot!
 

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