oflynno wrote:what is the best way to fine tune this engine
Hello Bloke,
From the questions and answers so far, it sounds like you are running a bog standard Rover SD1 Flapper, single plenum system.
Mind you - 23 years on - it could be modified in many ways, but assuming that your engine is in good mechanical condition with correct cam/lifter performance and timing, good compression within acceptable limits on all eight cylinders, good exhaust system with no leaks and fresh engine lubrication plus new filter if required, then:
There are 15 things that you can do with your Rover SD1 Efi Flapper System that can change or improve performance from its current condition.
1 Clean all ignition components externally and internally (where possible), spray with moisture inhibitor such as WD40 and wipe dry.
2 Check security and eliminate any corrosion on all ignition LT connections right back to the ignition switch, including local earths.
3 Clean and re-gap the spark plugs - replace if necessary.
4 Check for damaged or out of spec (suppression resistance) HT leads, Clean and replace if necsssary.
5 Set up ignition timing to just eliminate pinking with your chosen fuel.
6 Ensure that the plenum idle air gallery is clear and not contaminated with goo.
7 Likewise the plenum breather gallery, flame trap and LH rocker cover breather filter
8 Ensure the throttle disc(s) is correctly seated at idle to prevent idle speed hang-up and that the whole throttle mechanism is free of unwanted friction right thro from accelerator pedal to throttle pot. (Note - items 6, 7 and 8, Plenum actions are best done on the workbench).
9 Set the AFM CO content at 1.5%, the mid point of the preferred setting for the Rover SD1 Efi system and reset the idle speed to about 875 rpm, give or take.
10 Set the throttle pot residual voltage to 325 millivolts.
11 Verify the fuel pressure operates in the range 26 to 36 psi. not more, not less.
12 Check the integrity of the plenum and all its air/vacuum hoses for rogue air-leaks.
13 Check all Efi loom wiring and connections for faults/corrosion including the Efi engine earth AND the engine earth strap.
14 Check and replace fuel filter if necessary (also make sure the fuel tank is not emitting crud).
15 (If the Plenum is removed for cleaning) consider lifting and cleaning the injectors, replacing the filter baskets and pintle caps.
None of the above will add anything over and above the engine performance that was not there when it was new.
To improve performance beyond its original spec there are three relatively simple things to do.
1 Fit an upgraded adjustable ECU available in the aftermarket.
2 Fit a rising rate fuel pressure regulator that may give a bit more oomph at the top end.
3 Fit a sports exhaust system that has the effect of improving the overall breathing and minimising exhaust system losses, as opposed to simply adding power which is not possible.
Because you are a newbie you may want to consider some reading material on any of the above suggestions, component by component. If so, trawl thro' my website for the needed information.
Good Luck.
