"What we're not doing at this point," says Gallant, "is radically changing the valvetrain. We could certainly lighten the stock valvetrain, but with compound supercharging this motor is designed to make power with boost and airflow rather than rpm. We're not installing big valves, seats, bronze guides, and we're not using exotic materials like aluminum-ceramics in the valvetrain. We're not raising the roofs .200 because there's not enough material and we'd be at the casting limits."

The 1MZ has decent factory valves with good, thin stem Honda-type valves, says Gallant. GTP's Stage II 1MZ MR6 heads use 35mm intake and 27.4mm exhaust valves. Gallant assures us there's room for bigger valves should it come to that.

Stay tuned as we'll cover engine assembly and testing in the next Project MR6 installment.

Spark Solutions
Ignition Solutions Coil-On-Plug StrategyThe stock Toyota coils did not like the lengthy, 6-milli-sec dwell period we'd been feeding it to get the kind of ignition power needed to fire plugs through the vastly thicker mixtures of a compound-boosted powerplant.

After a long Texas-to-California road trip, we replaced the stock Toyota coil-on-plug units with super-duty coil-on-plug plasma-direct coils from Ignition Solutions. Ignition Solutions' Ulf Arens provided the following chart correlating dwell time (programmable in the MoTeC M48 engine management system) to current in spark energy. Arens decided we should run a dwell time of 2.5 milli-sec, which he computed would provide a vast increase in spark energy compared to stock Toyota coils.

Coil Calculation
Dwell Current Energy
(msec) (Ampere) (Milli Joule)
1.00 2.2 11.68
1.50 3.3 25.13
2.00 4.5 46.73
2.50 5.7 74.97
3.00 7.0 113.07

Says Arens, "The Plasma-Direct replacement ignition coil is built using Ignition Solutions' 'booster' technology to amplify secondary spark current by 100 percent (two times as much as OEM) and release about four times as much energy at the initial moment of spark.

"The Plasma-Direct coils are designed to provide a 100-percent secondary current (spark amperage) increase from 50mA to more than 100mA on most systems, with four times spark energy increase for the initial spark discharge (E=1/2*L*i*i). An added benefit is each coil's external LED that indicates power firing of the coil.

Automotive Racing Products (ARP)
531 Spectrum Circle
CA  93030
Gallant Technical Performance (GTP)
Alamo Autosports Ignition Solutions
Bell Engineering Group Majestic Turbo
Bosch Norwood Autocraft
Dept. MM
P.O. Box 7988
IL  60680
Toyota Racing Development
Clark Copper Head Gaskets TSW
Clutch Masters Wiseco Pistons
Crower Cams and Equipment
3333 Main St.
Chula Vista
CA  91911