M112 Lessons Learned

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LP1

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56
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Courtenay, BC, Can
I thought I would provide an update as we have been running M112s on a 93 SC400 with, 315cc injectors, R-154, upgraded suspension, clutch, LSD, S&S short headers, and on a 95 SC400, W-58, 315cc injectors, uprated clutch, LMF long headers. Both with a 3” pulley and stock throttle body.

The M112 works very well on the 1UZ with a stock computer but it has limitations. Notably the transition to boost is hesitant unless WOT, the throttle body looks and seems restrictive, decel fuel is set up for an automatic therefore it can be rough when decelerating quickly, the 315cc injector plus the cold start injector is way too rich on start and generally too rich at low rpm. The 95 computer without the cold start injector does run rich at idle but runs well. The traction control gets real sensitive under boost and chokes off the throttle body way too quickly.
 
Those are the M112 I want on the SC. Lol. I'm not sure if the M112 causes the hesistation or not, but I know for sure running rich causes the hesistation from start acceleration. And when the car is WOT, that's when it gets the chance to burn the extra fuel and makes the car run fast. 315 cc injectors with stock ECU causes rich. Perhaps you need a piggyback ECU or standalone to tune the fuel right. Nice setups!
 
Update

I was having trouble uploading pictures to finish my post, seems to be working now. We just upgraded the 93 with MegaSquirt and the Ford throttle body, it works unbelievably good. I was so smooth, we weren't sure if it was boosting properly (it was). Money is always the issue, so using the stock computer to start is a good plan
 
The Clutch

If you are running a manual transmission, you’ll need a serious clutch to handle the torque. We just upgraded the clutch (again) to the ACT heavy duty on a modified 3SGTE flywheel. Xcessive Engineering modifies the flywheel for $96, the fit is perfect. We just put more power to the 93 SC 400 and the clutch is very good (and heavy).
 

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Traction Control

If you are going to play, you’ll need to turn off the traction control. Or better yet find a LSD. By the way the big boy Supra one bolts right in. The adapter for our solid driveshaft supplied by Driftmotion accommodates the regular flange and the larger Supra flange as well. We had no issue using the stock left hand drive shaft, we did push the cage as far right as possible while tightening it in place and installed the drive shaft before the LSD. No binding and lots of shaft play through the whole range of motion. I suspect we won’t be able to remove the left hand driveshaft without dropping the differential. I’ll post the build on Drivetrain.
 

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Suspension

The stock suspension is way too soft for the supercharger power. The rear bushings flex with the power and the rear end torque steers down the road. We installed Prothane bushings all round on the 93 SC400 and it is perfect. I’ll document when I do the 95, we installed grease fittings all round and have had no squeaking issues. We have some concern as the SC cage is not as strong as the Supra cage.
 

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Injector Size

The 315cc seems to be about the right size for moderate boost. BlackUZZ31 reported having just enough fuel with stock injectors. I’d stick with a stock injector if you plan to run the cold start injector. The 93 was really gummed up after about a year of use, the 95 is rich but okay.
 

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Stock Throttle Body and Computer

The stock throttle body is adequate but limits the air. Pain in the butt to plumb the water lines with the M112. The stock Ford throttle body provides more than enough air and fits nicely in the SC configuration, and no water lines to plumb!

The M112 with the stock computer is awesome. The M112 with a tuned computer is frickin awesome. We just put the 93 on the road with MegaSquirt and a rough tune and it is hugely impressive. Smooth, impressive power from idle to full boost. I’ll post the dyno results when we get it done. (You’re going to need water/meth.)


Bottom line is the M112 mod is well worth doing. To get the most out of it the mod you’ll need to do the rest of the upgrades. Plan on doing a computer upgrade eventually. I’ll post the computer upgrade, it’s a pain to integrate into an existing car primarily because of pre-existing issues (less than ideal grounds, sensors, connectors). If you are transplanting a 1UZ, do the aftermarket computer as part of the process, the stock computer has way too much crap you don't want or need.
 

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Perfect. This is exactly what I wanted to see! Im grabbing some GTE injectors as we speak and purchasing a haltech sprint 500 at the end of october. It's all slowly coming together.... good stuff!
 
The stock suspension is way too soft for the supercharger power. The rear bushings flex with the power and the rear end torque steers down the road. We installed Prothane bushings all round on the 93 SC400 and it is perfect. I’ll document when I do the 95, we installed grease fittings all round and have had no squeaking issues. We have some concern as the SC cage is not as strong as the Supra cage.
That's the nice manual tranny setup. I bought a set of Prothane bushing kit for the rear as well, but I decided to buy the fluid urethane to make my own bushings with 1 step softer than the bushing kit. As regarding to your concern about the strength of the chassis, it should be good enough to handle lots of power. I boosted at 15 psi and it's rigid. There're more than a handful of guys running 10 seconds or less on the SC chassis. I'm not sure if they've modified the chassis, but it's still a strong chassis.
 
I have a question for my set up. when you said the stock injectors were at their edge, is that with a 3 inch pulley? Will the factory ecu run with a 3" pulley and stock injectors?

nvm just saw that blackuzz31 is running a 3.3 inch pulley. can i run a factory ecu at 8 psi?
 
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