Quote:
Originally Posted by Piotrsko
Traditionally water injection includes some form of alcohol additive. All the high hp and diesel kits use either proprietary fluids or window washer fluid.
Solves both the detonation and freezing problems.
Stock aircooled vw's are typically 10% rich for a cooler temp
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From what I've researched and tested on my own air cooled VW, the jetting became stoichiometric, if not a bit leaner, like all the other cars by the early 70's. I was running between 15.5:1 to 14.5:1 at cruise and around 13:1 at full throttle with stock jetting on a 1974 carburetor. Of course the worn throttle bushings may have contributed a leaner cruise, but even after addressing them I didn't get much of a difference. And this was with a thermostatic air cleaner and running at 5,000ft altitude!
However, it was and still is a common practice to jet them richer for assumption that they needed it to run cooler. On the other hand, some of the guys that have had years of experience building these engines say they run cooler if you jet them to around 16:1 or leaner at cruise and leave full throttle at 13:1.
Personally I tried all sorts of jets and with my Oxygen sensor A/F ratio gauge and assortment of temp sensors I have to say that they were right about running lean at cruise is actually better for both a cooler engine and better fuel mileage.