Distributor Dyno Test - Firepower!

The module is also specialized for racing. The ignition module is the equivalent of the system's brain. It controls the current sent to the coil. Obviously, if the coil is fed a higher current it can continue to send the proper amount of energy to the plugs, even when high rpm levels significantly cut into the dwell time. (Dwell is the amount of time the coil has to recharge between firing the spark plugs.) It is also possible to use this module to increase the duration of the spark, or even act as a rev limiter.

This time, the engine ran strong all the way through the dyno sweep. The dyno results showed a much smoother horsepower graph, and it sounded much healthier. Best of all, maximum power with the stock distributor was 401.7 hp at 5,900 rpm. The DUI distributor not only smoothed out the power dips that plagued the stock distributor, it also bettered it by 2 hp, maxing out at 403.8 at 6,000 rpm. Although we are only displaying results from two dyno pulls, several pulls were made with both ignitions to ensure we were getting consistent results.

Honestly, in this test it was easy to determine the winner even before the dyno results were printed. Just by listening, it was easy to tell that the stock ignition, even with the fresh coil, cap, and rotor, was causing the engine to misfire and skip once the rpm exceeded 5,500. With the DUI, this simply wasn't a problem. Although our dyno sweep only goes to 6,400 rpm (because power dropped off significantly after that), Troutman says he has seen this ignition perform well to 7,000 rpm and beyond.

And even though we will never sneeze at an improvement of 2 hp, the biggest benefit of a racing-specific HEI ignition over stock is the ability to eliminate the dreaded high-rpm miss. Plus, for Limited Stock engines, there is no difference between the performance of this HEI ignition and that of a high-end unit with an external coil and brain box. In terms of both simplicity and performance, a racing-specific HEI ignition like this unit from Performance Distributors is really hard to beat.

We've all heard that running thinner oil can help your engine make power, but how much is it really good for?

While we had our Limited Late Model Chevrolet race motor on the dyno, we wanted to squeeze all the information out of it we could. Between tuning sessions and after completing our ignition test, we begged engine builder Ken Troutman for extra dyno pulls.

One topic that often comes up during bench-racing sessions is motor oil. What kind is the best? Is it okay to break in a new engine with synthetic? How much oil pressure do I need to properly protect the engine? And then there's our personal favorite: How much is lightweight motor oil really worth in terms of power?

Our test engine is the same Chevy small-block used in the ignition test, so almost all of the stats for the engine are the same as listed there. The Performance Distributors HEI ignition was used for both tests. The only significant difference is we switched carburetors between the ignition tests and the following oil tests. This does not affect the numbers for the oil tests, so those can still be compared. However, it means you shouldn't compare dyno numbers between this test and the previous dyno session testing ignition systems.

Our baseline is a mineral-based oil with a 15W-40 viscosity. We chose this for several reasons. First, mineral-based oils are popular in Street Stock racing classes because they are significantly cheaper than synthetic oils. The 15W-40 viscosity is also a popular weight. Often, racers feel that if they are racing in a class in which stock-style engine components are required, there is little to be gained by a high-end racing oil. After all, if you are forced to use heavier rotating components and a standard oil pump, thinner oil would just be wasted, right?

Troutman assured us that although our test engine uses very nice internal components and the bearings clearances are all blueprinted and held to the acceptable minimums for good oil control, anything found on the dyno here would also apply to everything, all the way down to a completely stock engine.