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Old 07-01-2008, 01:50 PM   #69 (permalink)
Master EcoModder
Join Date: Jun 2008
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Originally Posted by Johnny Mullet View Post
Is your Metro a 5 speed with the 1.0L 3 cylinder? You should be able to get 50MPG with that car by now. How does it run? Have you performed a compression test on all the cylinders to see if the engine is in need of internal repairs?
yep. 1 liter, 3cyl 5-sp. w/86k miles on the clock, but still only averaging 45mpg with 80% freeway commute driving at 65mph. 210-200-210 compression. Seems to run good, but idles a lot rougher than any 4,6, or V8 I am used to (typical of a 3 cylinder?). My trans is the same as yours 4.39 (I counted the teeth on the crown wheel, has 79). I've done the usual tune up stuff, plugs, wires, cap, rotor, didn't make much difference in mpg.

Originally Posted by Johnny Mullet View Post
This is where I get my fuel mileage. My route is a 55MPH country road for 80% of my trip. I usually drive anywhere from 50-55 on this road and keep a steady throttle the whole way. No Interstate travel.
Maybe I should try slowing down to 55mph... I learned on one 200mile trip, if I drive 70 or 75mph, my mileage drops like a stone to about 36mpg. I live and commute through the SF Bay Area, anyone from here knows that while driving 55mph on the freeway, you get run over... I'll have to think about that. I think I may swap the crown gear or entire trans to get a taller final drive. Not sure I want to tackle that this summer, but we'll see. My goal is still 65mph commute, and 50mpg average, day in and day out (not just a magic tankful every now and again).

Originally Posted by Johnny Mullet View Post
I did not change the cam, but experimented with drilling holes in a spare cam gear to do timing advance (not the same as ignition advance) and found that I screwed the drilling up and was way off on my reading.
I 'degree in' each cam I install in the few aircooled VW race engnes I build (I don't want to sound to much like a blow-hard, but I've built a few bad a$$ vw race engines). What I do is use a degree wheel, and mock up the valvetrain without any indexing pin between the gear and cam (I also use readily available aftermarket vw cam gears with slotted holes, very different than the metro) I go through the degreeing process, rotating the cam gear a little either direction until I get what I'm after, lock it down and carefully pull the cam and gear unit out and 'match drill' the cam and gear together. Then knock in an 1/8" roll pin, which holds the setting. A different arrangement than Suzuki I know, but I bet we could do something like that with a metro cam and gear. The key here is to learn how to (if you don't already know) degree in a cam using a degree wheel and dial indicator... You also need to degree in TDC with respect to the crankshaft timing mark (indicator tip through the spark plug hole, bend the timing tab as needed). Either using the 'split overlap' or 'intake opening at .050" ' methods, it's a whole process that I couldn't begin to describe in text here.

I've learned that knowing where the cam is dialed with respect to crankshaft TDC is key to being able to evaluate what changes did what, and what I should do next. BTW, in general with combinations I've played with and dyno'ed, advancing a race cam 2-4 degrees in a race engine does in fact move the entire torque curve (as a unit) down the rpm range, noticable on the dyno and at the track (again, with combination I've personally worked with). My experience has been very consitant with what I have been reading on the forums with respect to advancing the lesser duration XFi cam or stock 1 liter cams.
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