But what about the real test? Pump gas on boost. Well, we were not disappointed, especially since we had to back the timing way down from what it was with the high-octane fuel (from 36 degrees to 28). Despite the loss of timing, the difference in horsepower and torque readings between good gas and pump gas measured only a slight loss of 6.6 percent in horsepower and a minute 3.2 percent drop in torque. That meant that our street-worthy 383 stroker has a legitimate 686 ponies and 671 ft-lbs of torque on tap, on drive-through 92-octane junk fuel.
As for drivability, the peak horse reading was at 5,700, which is where the dyno stopped the test (yup, it was still climbing), while torque peaked at a tractor-like 4,900rpm. This engine, with a maximum of 9.7 pounds of boost, made 504 ft-lbs of torque at 3,100 and was still making 634 ft-lbs at 5,700 when we shut her down. And, the temperature needle never got hotter than 212 degrees F (which is about normal for late-model reverse-cooling LT1s).
In summary, this engine may have more horsepower than most of us will ever be able to use on the street. But, for the cost of good parts and the ATI D-1 Procharger, you can have a bona fide 700-horse street engine that is tame enough to sit in traffic or wild enough to propel its nearly two-ton carriage down the quarter-mile in the 10-second zone. That part of our project still remains to be seen. But stay tuned-in the coming months we will attempt to swap out our donor car's original low-mileage LT1 and stab in this potent 383 stroker in its place.
Hot BoxI'm a hot rodder to the core, but as most of you know, my roots are in high-winding small-blocks with carburetors and solid-lifter roller cams, not electronics and fuel injection. I don't profess to know a lot about the computer controllers that can wring out the most power from today's EFI machines. Sequential port fuel injection; bank-to-bank firing, individual cylinder timing. It all sounds like space-age jargon to me. But with the help of BDS's Craig Railsback and the Federal-Mogul Speed-Pro C-Com electronic engine management control system, I'm learning.
First, the C-Com software is designed for those wishing to have the most control over their EFI machines. It's designed for competition, not to circumvent the factory OBD-11 computer for street use. The C-Com allows the engine tuner to choose what sort of fuel-injection control best suits the conditions. Two systems are available.
First, for most applications, the Bank-To-Bank system is perfect. This controller fires half of the engine's injectors each 180 degrees of crankshaft rotation. This gives the engine improved fuel delivery and performance, and, for street applications, better driveability. This system is ideal for converting an engine from a carburetor to EFI. Other items that this system can control are the idle air, fan, fuel pump, single-stage nitrous, and program knock retard. A wide-band O2 sensor for closed-loop can also be used. And, it can be upgraded to the Sequential system, if the need arises.
The Sequential Electronic Fuel Injection system was designed for the ultimate in power production and tuning. It uses technology that will individually fire each injector for optimizing fuel delivery. It can also be equipped with options that allow for individual cylinder fuel/timing, and will facilitate adding a two-stage nitrous setup.
Both systems can be individually programmed by using a PC-based (386 and higher) laptop computer. With this capacity, you can literally program the engine to recognize the special needs of specific cams, superchargers, compression ratios, etc.
In our case, we were able to tell the engine that it needed to have driveability as well as maximum power output. And, when the 383 finds its way into the Camaro's engine bay, if the need arises to add a little more fuel or back the timing off, our PC won't be too far away.