I just fitted a pair of 7.6Ah Li-fe batteries to my Proton, backed up by the cap bank that I've had for years and has been through several cars.
In short, WOW. Best ~$100 I've spent in a long time.
Now I had a Li-fe in my Fiat before, but it seems that the smart alt meant that most of the difference between chemistries was masked (smart alt cars are designed to run at low voltages - around 11.5v- for one).
The Proton just runs a regular 'dumb' alternator.
In short I've got more power, a smoother idle, better throttle response, and less engine noise. All my electrical systems are much more snappy, the power windows wizz up and down, the headlights don't dim at all while cranking.
The alternator holds 14.2v, but even after the longest EOC I still have 12.8v vs the 11.8 odd that the Pb battery had. The Pb battery was fairly new, not one that was already dieing. I didn't see any gains in cranking power as I already had the supercap connected the day I bought the car.
My guess is that the alternator isn't anywhere near as taxed as before, and that the remaining improvement might be coming from the ECU, sensors, injectors, coils etc running more efficiently. Some racers run 16v Pb batteries for that reason.
The 1.5 SOHC now feels like a DOHC. At the very least it feels like the ECU's been remapped.
Too soon to judge economy, but it seems to be on the up. Very happy
