Malaysia
Boleh Engine Tuning
Part 4 - Leveling the AFM versus gravity
18th June 2003 Evening
Disclaimer : - for stock EFI system, actually there is no such thing as "tuning".
Mr. Wong Yee Yong pointed out that the AFM was installed NOT flat / level, where the earth's gravity may be pulling / assisting the flap to close instead of letting it free flow.
So, the AFM was repositioned, AFM's Flap tension reduce to negative, then increase slowly one notch at one time until it is closed, where the fuel pump engage pin is not in_contact.
Start the car - idles fine at 1,050 rpm
Rev the engine - sounds good :) strong :) sexy :)
Turn AFM's by-pass valve from bottom up, fully closed to open, in hope to reduce idling rpm. Turned 8 rounds up, no idling change, although the engine sound changed.
Don't care - drive into the city..............
Yeah, good, no sudden power burst like last time. Smooth, very smooth. Very acceptable stable driving. Rev easy up, not like before when the AFM's Flap tension was too strong. Always reluctant to rev up. Only until 4,000 rpm + very strong.
Now strong / easy rev up all over :)
So, thanks goes to Mr. Wong Yee Yong and I hope no one else made this mistakes.
Aftermath
19th June 2003 Morning
Carefully open the engine oil drain and collected extra oil during last oil change, where nearly all 4 liters used. A 500 ml mineral water bottle was used to collect the extra oil, very carefully.
Check the engine oil dip stick and could still see oil level over the F mark. I was late for work, therefore quickly shower and went to work.
Drive car - feels better, engine feels lighter. May be psychology, hehehehehhee.
Evening
After work at KLCC Car Park still dressed in office clothing. Rolled up my sleeve, out come the mini 2 tons jack, tools box and old news paper.
Got another 500 ml mineral water bottle from the office and collected another bottle.
Check engine oil dip stick and estimate just right on the F mark. Since there was some oil left over along the dip stick passage, therefore can't say for sure of the level.
Doesn't matter, it's definitely not low and dangerous.
Hence, drive car home - feels OK, better too I think.
So, tomorrow morning I'll have to check the engine oil level to be sure. Can't believe I let my mech. put in so much extra. A full liter :(
Objective
Oh yeah, the objective of this write up is not so much about removing extra engine oil and collect it properly without polluting the environment further.
Regarding the no power burst statement from before or above. It's back, but not severe and definitely not often, can be lived with. Still it exist.
There are more as the extra engine oil was removed in the 2 stage sequence.
Stupid idea
If I may add, initially it was thought that the 10w-60 engine oil was too heavy and caused lost of engine performance (slow rev up), therefore it is thought that one could skim the flywheel lighter in hope to compensate, so that it can rev up faster???
But seeing now, lightening the flywheel would further worsen the power burst / jerk problem. Still lighten the flywheel it will be to around 4.5 kg from 6.5 kg if not mistaken.
Consensus
Actually the AFM construction is pretty lucky for the engineer who invented it. Unless the engineer took this issue into serious consideration / account, then he is bloody brilliant.
When the AFM is level with the gravity, it is free flow. Assume ideal conditions as in study. When the car is climbing a fill, the gravity would assist to open it, therefore ease the power lost due to air pushing the flap. As the car is going down a hill, then gravity would pull the flap closed more than open. However thank goodness, because normally speed is easily gained through fall, therefore won't feel the power lost.
Imagine if the engineer were to invent the AFM where it's Flap motion is the opposite round? How disastrous it might have been on revving up speed.
shxt, I know it, don't say it, I think too much :) It's not my fault, don't blame me, blame the GODs :)
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