If you want to add a turbo on a naturally aspirated engine and you are not a specialist in the field, the costs for this operation will clearly be quite high, depending on many aspects, especially your power target which involves a larger or smaller budget.
Turning now to the subject, we must first talk about the engine. If we refer to a small and simple engine such as 1.4 8v or 1.6 16v, engines that are made for the ordinary driver, engines who have no hidden potential for performance and are installed on cars to carry the driver from point A to point B, and here I refer strictly to these simple engines, not to mention other naturally-aspired engines like VTEC from Honda or RS engines from Renault or M engines from BMW which have some potential from the factory.
These smaller engines that I mentioned (1.4, 1.6, 1.8) withstand very little extra power than the manufacturer mentions because they are naturally aspirated engines with a small torque and obviously the manufacturers will not equip them with quality connecting rods because of the costs and also the assembly that is in motion in the engine to be harder for nothing. So the connecting rods of these engines are some light ones that do not resist to much power.
Usually, turbocharging these engines is limited to 0.4 bar, 0.5 bar, 0.6 bar maybe even a little more, but generally below 1 bar turbo pressure and obviously the powers that can be achieved are quite small.
To transform a stock engine into a turbo engine you will need several parts, some of these parts will not be needed especially if you have a limited budget and do not modify the engine.
The main idea if you want this conversion of the naturally aspirated engine into a turbocharged one, is mainly to change the connecting rods. These connecting rods are, so to speak, the weak link in any engine, the pistons often withstand more power than the stock, and these parts will fail only in the event of a malfunction.
And if we talk about connecting rods, a recommendation of cheap connecting rods are the ones from MAXPEEDINGRODS, very accessible in price and with quite good performance, with ARP2000 screws, being a considerable upgrade from the stock.
These connecting rods start at the price of $ 240 -250.
There are other connecting rods with much higher quality, but also more expensive like FCP, Integrated Engineering and so on.
For the rest of the article, we set as a target a small budget for conversion.
We talked about connecting rods which are the most vulnerable part when thinking about adding a turbo to the stock engine because the mechanical stress caused by the power mainly affects the connecting rods.
Parts you need for adding a turbo to a stock engine
Many have the impression that you get a turbocharger, you install it and that’s it, you are ready. With the turbo, things are as follows, and we are talking mainly about universal turbochargers because we refer to a naturally aspired engine that did not have a turbo from the factory.
Therefore we need a turbo with an internal or external wastegate. For small engines, the turbo usually has an internal wastegate because it can handle the gas quantity that the turbo needs. Larger turbochargers have an external wastegate.
Turbo prices with internal wastegate start at $ 260.
An important aspect to mention here is that the turbochargers at these prices are clones of Garret or other turbo models and in general there is a small lottery with them. Some can go very well, without any problem, others fail. But above I said that we are talking about a smaller budget, so give them a try
For an external wastegate turbo, prices range from $ 350-450$.
Here the problem is simple if you did not have a factory turbo, the stock exhaust gallery does not fit this conversion, so it is necessary to install another exhaust gallery, and regarding the prices, there is no good news, these prices start from $ 250 – $ 350 for medium quality cast galleries.
If we have the possibility to make a custom exhaust gallery, not the one drained but the welded one made with the flange and so on then the costs reach $ 550 – 600 $
For the exhaust route, the prices start from $ 360 – $ 400, obviously, you can not upgrade the power with a stock exhaust.
Prices for a single intercooler start at $ 80- $ 90 and can reach $ 300 or more. The assembly, like the turbocharger, is more complicated, because if the engine was stock and did not have a turbo, an intercooler route must be made.
In order to benefit from the respective intercooler, you need to make an intercooler route. The starting prices for such an operation are 360 $ and can be even more expensive.
The intake route
The route from the turbo to the air filter, the cheapest route starts from a price of 120$-130$, there are also intake kits at 400 $ depending on your preferences.
You need this boost controller to control the turbocharger. Prices range from $ 40-50 for the mechanical ones which are the cheapest option, but they are not preferred by those who do this operation to the engine, reaching up to 300$ – 350$ for electronic controllers that show you what pressure you are going to and can manage multiple power maps. These power settings can be changed so you can go on low, medium or high pressure, unlike mechanical boost controllers that have a certain pressure and nothing more.
The costs depend very much on what kind of injectors you want to put on the engine you have. The costs for the injectors of petrol cars are cheaper and start at $ 150 – $ 250 being plug and play injectors but can reach thousands of dollars for the very efficient ones.
If we are talking about cheap injectors, there is generally no need to upgrade the ramp and adapters, but if you need a gasoline ramp it starts at the price of $ 200 plus other costs of the adapters if necessary
The price of some fuel pumps for upgrades starts from $ 80- $ 120, reaching the price of $ 230, especially for the BOSCH 044 pump, which is the most used for this type of engine upgrade
These pieces are pretty cheap starting at $ 10 clones, but something very quality is priced at $ 100 -200
The supply route
If this route is made with those braided hoses and with AN fittings those are more expensive, but here it must be something qualitative so as not to disintegrate the hose or to lose pressure.
Coils and spark plugs
To upgrade a stock engine to a turbo it is necessary to change the coils and spark plugs, the stock ones do not cope with the upgrade.
Let’s not forget about the electronic side
Here I refer to the fact that most modern cars have a computer (ECU) that manages absolutely everything that happens under the hood so we have to think about the control of new parts installed above.
Most ECUs on cars with a naturally aspirated engine “do not know” how to handle the pressure part, the turbo part, they are programmed from the factory to go on the vacuum side as the naturally aspirated engines go and you do not have many ways to write a software that controls the newly installed parts.
However, there are some ECUs on simple engines that allow software for turbo engines, but it is not a rule, it is not standard, many need a PIGGYBACK ECU to manage everything and be connected to the stock computer of the car. The price of a PIGGYBACK ECU in the simplest version is about $ 300, but its functionality is relatively limited.
You can also mount a STANDALONE ECU whose price starts at $ 900 – $ 1130.
The prices above include only the computer, piggyback or standalone. But they also need different sensors that are not necessarily included in the price like oxygen sensor and so on.
Additional ECU installation costs
For PIGGYBACK ECUs prices start at $ 300, but if we talk about a STANDALONE ECU and an installation that is not easy to do, it can reach and exceed the threshold of $ 900.
In addition to these prices of the ECU and the installation, we also add the new software part that is not included in these prices.
Whether we are talking about stock electronics or the two ECUs, the price of software can start for example at PIGGYBACK from $ 300, and at STANDALONE from $ 550. In general, turbo conversions are quite difficult to program because it is not like a car that is with factory turbo where some values need to be increased and calculated, here the software tables have to be calculated from 0 being the reason why the costs are so high.
These are the minimum costs to expect when you want to put a turbo on a stock engine, I hope I did not miss something, everything was calculated at a minimum budget. My advice is that seeing what the steps are to make this upgrade there are two possibilities: to be satisfied with the engine you have or to buy a turbo car from the factory.