Hi guys, here are some real world dyno figures of how to make your engine more efficient, and by that you save fuel. This is the result of a test done with the purpose to get as much power for least amount of money spent as possible. I present this just to show what can be accomplished, regardless of car make. The car is a Nissan Micra, with a four cylinder 1 litre injected engine, manual 4 speed, 130000 km on the odometer. They were given access to a chassis dyno, so all runs are made on the same Dynapack, at least 3 runs after each change.
Starting point: 39.6 Ps @ 5547 rpm / 62.2 Nm @ 4098 rpm
Made a compression test and cylinder leakdown test, and found that all cylinders were in the same range.
1) New air filter + 1.5 Ps
Modification of air intake to filter, removal of restrictions + 1.8-2 Ps
2) Spark plugs: Original plugs NGK. Changed to new NGK - only tiny increase, less than 1 Ps.
The brand matters! Worst spark plug (Beru) DOWN 3 Ps!
Best spark plug: Bosch Super 4 (4 electrode type, better over 3500 rpm) + 1.5 Ps
Result so far: + 4.7 Ps and + 7.1 Nm
3) Old carbon high resistance spark plug wires measured 3 K ohm resistance in the worst (the longest) wire.
Change to copper core spark plug wires, done 20 test runs + 1.9 Ps
Comparison to brand new OEM carbon wires: DOWN 2.6 Ps, actually worse than the old originals!
4) Motor oil changed from 10W40 mineral oil to Red Line 5W20 synthetic
Gave oil pressure right away, rattling noises disappeared and did not return since + 1.6 Ps
Gear oil changed to Red Line MT-90 , after 6 runs + 0.5 Ps
Just for fun, a test of snake oil: Pro-Long motor oil additive, after 9 runs, and to everybodys big surprise, + 1.8 Ps
After 3 additional runs: 49.3 Ps @ 5699 rpm, 75.5 Nm @ 3216 rpm
Test after driving ~300 Km (~190 miles): 50.0 Ps @ 5787 rpm and 75.8 Nm @ 3225 rpm
That is up 10.4 Hp and 13.6 Nm from start, a massive increase of power ~26% and torque ~23% for this tiny engine for a very low cost.
All these things can ANYONE do!
Additional tuning of injection system, modifying exhaust manifold, and camshaft from a 1.3 litre engine with app. 2 mm higher lift, gave:
62.3 Ps, that is 22.7 Ps up from starting point 39.6 Ps, and 81.8 Nm, up 19.6 Nm form starting point 62.2 Nm, but this is not relevant here.
More than 300 runs were made in total, some were gadget tests, and unless they delivered - not mentioned.
I guess most of you don’t read norwegian, after all that is why I translated this test, but here’s a link with plenty graphs from the Dynapack if you want the figures: Micro Micra. Oh, and Ps is a european norm, short for 'Pferdestärke' which is 'Horsepower' in german.
Ok, so this is a tiny engine not related to slantsix, but this is one of the few multi-run dyno tests I have seen that very carefully presents all the data in public. For example, the results for synthetic oil should be better in a bigger engine, and the other results coinside with the suggested mods for the slantsix in general, the biggest gains for the slant can probably be made from valve adjustment and distributor recurving. Re. air filters: Testing has shown that the average stock air cleaner assembly with a new filter drops the typical 700 CFM carburetor to 480 CFM. Adding a second snorkel got it up to 550 CFM. A 14 inch in diameter, 2 inch tall open element air cleaner gave 675 CFM. Two such air filters stacked gave the full 700 CFM. And remember: a 7.2 degree change in air temperature causes a 1% horsepower change. Efficiency = fuel economy.
BTW, one of the best suggestions earlier in this thread: Get rid of unnecessary weight! See this link from dippy.org that gives some weight losses for the Dodge Diplomat.
Olaf
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