Our donor engine (Holden 5litre EFI V8) is given a wash and an oil change prior to mounting it on the engine dyno. After installing the engine on the dyno a fresh load of mineral based "Martini" 20w-50w oil is added with a new GM filter. New NGK spark plugs are fitted after a compression test on all cylinders is performed. Ideally the engine should be warm to test compressions but our main goal was to determine that all cylinders are fairly healthy. With 125-130psi per hole all looked good. The goal here is to baseline the power and torque output of a dead stock engine fitted with aftermarket extractors and stock as well as optimised computer program. We started with 1 3/4" Tri-Y headers and switching to 1 5/8" Tri-Y pipes. Both are Pacemaker brand that we have always used on our dyno. They both have 3" collectors welded to each bank of pipes into an open non muffled exhaust.
We are running the engine as is with stock water pump and alternator, stock Bosch # 960 injectors, stock distributor with base timing set at the factory specified 10 degrees before top dead centre. Power approaching 300bhp and over 330 ft.lbs torque is an excellent result for a dead stock engine with only pipe and software upgrade.
We will remove the engine next. Fit an upgrade camshaft, valve springs and timing set to evaluate the relative gains of these changes.
The plan here however is to "over" cam the engine followed by a more rational camshaft choice. We hear of people everyday fitting relatively large cams with durations of 230 degrees @.050" or larger to one of these otherwise stock 8:1 compression engines. The standard line is "I want a really lumpy idle". The fact that a Hyundai Excell can blow their doors off at a set of lights does not seem to dampen the apparent desire to have a pro stock type idle in preferance to maximum acceleration. I must be getting too old, I just don't get it.
Lets wait for some more results so we can really quantify what these BIG cams are doing to these engines. I may be wrong but too small a cam is always better than one that is too big. I will apologise to everyone publically if I'm proven to be incorrect in my assumptions.