Further competition for the...
Further competition for the Hemi D.U.I. would be your typical street type ignition. Vic Palumbo's '66 Charger features a Indy-headed 493-inch Wedge, and the ignition is an MSD Pro Billet distributor and a 6AL box and Blaster coil, with 8.5mm Super Conductor plug wires. We baseline tested the MSD ignition on SLP's SuperFlow SF840 chassis dyno.
Since the 440 D.U.I. will not fit a Wedge engine with Indy heads, we felt that maybe the Hemi D.U.I. would be tall enough to fit one. Good friend Vic Palombo graciously lent us his '66 Charger with an Indy-headed RB, and our buddies at SLP welcomed the Charger for a flogging on their chassis dyno. This time the Hemi D.U.I. would be up against the MSD Pro Billet distributor with a more street-like MSD 6AL ignition box and MSD Blaster coil. For our baseline pull, the rwhp was 457 at 6,200 rpm, and the air/fuel (A/F) mixture ratio was a good-looking 12.8 at WOT (wide open throttle). Timing was at 39 degrees total-right where this Indy-headed Wedge makes its most power. We made three more pulls to confirm there was consistent power production.
At Vic's home garage, all the MSD ignition components and wiring were removed. This really cleaned up the engine compartment (see pics). We used the stock 12-volt wire that originally juiced the positive side of the coil to power the D.U.I. distributor. The original ballast resistor was bypassed. With the Hemi D.U.I. dropped in place, the stroked Wedge fired right up. We immediately noticed that it was running smoother and with better throttle response.
The fender well area gained...
The fender well area gained a cleaner appearance without the MSD ignition box, coil, and wiring. The DUI distributor made its presence known-it's big, tall and intimidating. We set the timing at the same 39-degrees total, and the Wedge idled noticeably smoother and the throttle response felt better. Ditto for our road test.
Now back at SLP, we made certain the timing was set at the same 39 degrees. With the Charger securely strapped down, the moment of truth came when SLP's Hank Denieki (Chief Engineer) punched the pedal down. We were very pleased to learn we picked up 5 rwhp. With the A/F at the same 12.8 we didn't need to reach into our boxes of Holley tuning supplies. Again, we made three more pulls to check consistency.
As an added bonus to our testing of the Hemi D.U.I., we wanted to see if Performance Distributors' Mini VIP (18-volt step-up regulator) would step up the power. The Mini VIP was plugged into the D.U.I. and another spin of the roller showed us 5 more horsepower to the wheels. That's enough of a power increase to be worth a tenth at the track. The additional spark output changed the combustion burn to a lean and mean 13.0 A/F. This was on an exceptionally warm and humid December day (72 degrees, 77 percent humidity). If it was cool and dry we would have richened it up for a few more hp but we left well enough alone.
Conclusion
Testing ignitions and seeing and hearing the new Street Hemi make 650 hp was amazing, considering we did no special tuning (using only an 830 Holley HP with 30 degrees timing, and unported heads and intake) on the mild-mill. Most enthusiasts with a Hemi or Indy-headed Wedge will see more power using the Hemi D.U.I.-if it will fit under the hood!
The MP finned aluminum valve...
The MP finned aluminum valve cover sits roughly a 1/2-inch higher on the raised port Indy head. In this situation the Hemi D.U.I. clears the MP valve cover by an 1/8-inch. Note: the 440 D.U.I. will not fit a RB engine with Indy heads. This was why we trial fitted the Hemi D.U.I. on this Indy headed RB motor.
Back on SLP's dyno the D.U.I....
Back on SLP's dyno the D.U.I. put out five more rwhp than the team of MSD ignition components. We did reuse the MSD Super Conductor plug wires for a fair comparison. After testing we changed to Performance Distributor's Livewires plug wires. The Livewires are a high-quality spiral core wire with a heat resistant sleeve for protection from exhaust heat.
On this '66 Charger we can...
On this '66 Charger we can see the Hemi DUI sticking through the hole of the Hemi hood scoop in the fiberglass AAR hood. The '66-'67 Charger and Coronet use the same hood. In our case, it fit under the hood of our Coronet but not the Charger. Remember, the Hemi DUI will only fit under a limited number of Mopar hoods.
Previous testing has shown...
Previous testing has shown the Mini VIP helps the ignition produce a stronger spark for better combustion-that means more power. We mounted the Mini VIP (18-volt step-up regulator) right where the ballast resistor once resided. We plugged in the Mini VIP, which changed the 13.5 volts that went to the D.U.I. into 18-volts. In return the D.U.I's increased voltage to the plugs gave us a gain of five hp to the tires. The added firepower changed the A/F from 12.8 to a lean and mean 13.0. On a cooler day (it was 72-degrees, 77-percent humidity) we would have re-jetted the carb to a richer fuel mixture for a few more hp. Realizing over 10-more rwhp from the Performance Distributor products, we felt that was quite an accomplishment with less clutter under the hood.