Couple of days back I happend to see a launch video of a water based spray - Eco spray & Eco Radi for improved FE in both petrol & diesel cars. This was first featured in one of the Automotive TV show 'Fast Track' in Manorama News channel in Kerala. The parent company is Eishin based in Japan and the India wide launch of these products happened in Hotel Abad Plaza, Kochi very recently. Manorama News | Fast Track
[This link provides the information on the product, scroll from 12:40 onwards]
The coverage is in Malayalam and what it says is that it is tested in multiple vehicles and improves the FE by 20%!!!
More links on this given here:
The company claims that it can be used for both gasoline & diesel engines and the mode of operation is very simple. Take out the air filter, apply the spray and see the change. I am not very sure on what the exact content of this spray is but it seems its a non toxic one and made from natural products. The usage interval is one year or 10,000kms whichever comes first. For 1000cc engines 10ml should be applied, 2000cc engines 20ml, 3000cc & above it should be 30ml.
While doing some secondary search on this i came across their website eco-SPRAY
Rediff shopping quotes the price of one bottle as Rs 1900/- not sure on the volume. Buy Eco-spray - Helps You Save On Fuel Cost Online | Best Prices in India: Rediff Shopping
If this product turns out to be authentic and if it returns better FE then i am sure this will be going to be a huge hit among Indian customers. If anyone has more inputs on these products do share your suggestions here.