Does turbo installed in a car save fuel?

No. It won’t. That’s not why Turbochargers are used or for what they are designed.

It depends how you tune and drive the car. If it does save fuel it would be because you drive very carefully and dont speed. The purpose of a turbo is to gain more power. This can result in better fuel efficiency because you wont have to pushthe gas so hard to accelerate and drive. Chances are that if you have the extra power you will use all or most of it so you will end up with a less efficient car. The main result that you will get is a faster car. I guess people dont realize much about a properly set up turbo. The new BMW 335i has a twin turbo set up and gets better gas mileage than last years 330i. The 335 also has more power.

they will make it worse lol

First .What is a perodua whatever?? No they don’t.

I have no earthly idea of what kind of car or engine you’re talking about, but I do know that turbos burn more gas than without. The turbo pushes more fuel into your cylinders, and thus you burn more

By turbo, I assume you mean a turbocharger, and by no means will it help your gas mileage, if anything it will hurt it. A turbocharger is installed to gain extra power cramming your exaust air back into the intake causing a more powerful explosion. The only advantage is power, and I guess resale value, but keep in mind that installing a turbocharger is expensive, especially if it breaks. If you can spend the money there is no better way to get power, but look into maybe a cold air intake or ram air.