Need to know if by adding oil additives will the vehicle smoothness and performance improve .
l need to know about the type of additives available which can be used on maruti alto for improving the smoothness of the vehicle.

Is there any additives available for diesel vehicles?

Only use oil designed for your engine, if you do not your warranty will be no good. Ask the dealership you bought the car from.

Yes you can add them... but they will do nothing for the engine, possibly even harm it., and drain your pocket.
Not to mention the warranty might be voided.

No oil additive do not generally improve performance. It may help to reduce noise like a knocking rod but if it is brand new & there is a rod knocking you'd better go get ur money back QUICK. The primary claim of most oil additives is that they extend engine life by stabilizing oil & reducing friction but over time some additives will actually ruin viscosity & cause even more wear on an engine. To make it worse, in the winter time if an additive makes oil too thick from being cold it will cause excessive wear on the oil pump & prevent oil from reaching the upper mechanics of the car like the cylinder heads, cam shafts & all the rest, which is why people let their cars ''warm up'' in the winter, so the oil thins out enough from being warm to reach the top of the engine. If it were mine I'd leave oil additives out of a brand new car & just use good oil like Penzoil & if you're still worried about it change the oil every 2000-2500 miles instead of every 3000 miles

How new is it? If the vehicle has less than 1600 km on it l would not use an additive, or synthetic oil for that matter, unless the maker recommends it. The piston rings have to seat properly against the cylinder walls in a new engine and additives could interfere with that process. Additives MIGHT give you a smoother idle and a slight increase in mileage but their greater benefit is longer life for your motor, assuming you do regular oil changes.

Oil additives will not do nothing for your car!! But if you want performance improvement than try using higher octane fuel when you pump gas or use lower octane fuel and put a bottle of octane booster!! Good luck!!!