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A friend removed the excess weight of the AC grooves off of a Geo Metro crankshaft pulley for me.

With bathroom scales (I know it isn't ISO 9004 compliant)...I might be able to get a better measurement of weight reduction tonight at work with more accurate kitchen scales. Anyway with my bathroom scales the stock one is 4lbs and the modded one is 2lbs.

Update on the weight reduction with kitchen scales.
Stock: 3lb, 10oz, 3grams
Mod: 1lb, 15oz, 5grams

Shaved off 1lb, 10oz, 26 grams! :woot:

Next step is to take it to my brothers machine shop and see what making 10 of them will cost made out of 7075 aircraft aluminum. Yes, I have to pay for machine work at my brothers shop. My plan is to offer them for sale on mod sites that have Geo members like http://www.teamswift.net/ and other more ecologically minded modding sites. ;)

I can turn the outside diameter smaller and regroove it, making it an under-drive pulley but I have concerns with it not spinning the alternator enough to recharge the battery because of the frequent FASing and almost always night time driving that I do.

My friend who turned this for me is running one that is 3-5/8" O.D., the two pictured have a stock diameter of 5-1/4" O.D. He doesn't do any FASing or night time driving as he just retired and has only used 3 gallons of gas in the past two months.

Perhaps I'll do 5 of each diameter and sell 4 pairs to cover my costs. I wanted you guys to see the first pics.

I also have to talk to my pro engine builder and find out how important balancing the old steel and new aluminum pulleys will be. It may not be as much of an issue with the lighter aluminum ones but I have to know before I can feel safe marketing them.

This will explain why I'm doing it. It is in the context of high performance at this site: http://www.motorexonline.com/faq.html

http://www.cleanmpg.com/photos/data/522/medium/Geo_Crank_Pulley_January_14th_2010_002.jpg

http://www.cleanmpg.com/photos/data/522/medium/Geo_Crank_Pulley_January_14th_2010_003.jpg

:D - Dale

Good stuff man. I'll be looking forward to seeing your progress on this. I installed a shorter serp belt that bypasses the a/c compressor not that long ago. It's kinda hard to tell right now, but it seems i've gained about 2% in f/e from bypassing it.

Dropped it off at the machine shop today. I'm getting a quote for 1, 5 and 10 pieces.

I also increased my air to fuel mixture ratio. I now idle at 775-875 rpms compared to my previous 1000-1100 rpms. I also reduced the fuel pump pressure on the injector valve by placing a .010" gasket between the valve body and rubber diaphram. I'll be pulling spark plugs and see how they look Thursday after a night of driving.

My friend Mark has a year newer Geo Metro Convertible and he idles at 800-900 rpm stock. So I'm not excessive in my adjustments. You've gotta be careful with a too lean mixture or detonation can do some catastrophic damage quickly.

I'm hitting pretty consistent 46+mpg tanks in the last two weeks if tomorrow's fill up is in line with my estimates, all with more focused hypermiling techniques and no new mods.

I've only had one 50mpg tank and that was after seftonm gave me the "change gears at 1500-1800 rpms lesson", after that class I was more concerned with FE than speed at work and business was slow enough to accommodate for that tank. I haven't seen it since. I'll be looking for a 48-50mpg tank around Sunday with these fuel mods. It ain't the big leagues but I look forward to the new field nonetheless. :D - Dale
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