The market is completely flooded with chip tuning boxes for diesel engines, and chip tuning boxes for petrol engines are becoming easier to get. The question is, which one should you choose?
Key Points
1. High quality case, non generic for the high end boxes
2. High quality automotive spec connectors.
3. Quoted power gains, high end tuning boxes should give dynographs
4. Adjustability on high end units. Extremely useful/important on diesel engines. Also useful on petrol engines if you sometimes want to run your car on race fuel/with race fuel additive/with 100RON fuel.
5. Minimum 2 year warranty on the box itself
6. Engine and gearbox warranties are overated in my opinion so I would not worry if a box had one or not.
7. Aftersales support. You want to be able to contact someone quickly if you have any questions
In-depth look
Let me start off by saying which ones you should avoid. If your car does NOT have a turbo then avoid any product claiming that they will increase the power of your engine, especially if the price is less than a couple of hundred Euro. It is very hard to get more power from a normally aspirated engine by just changing the engine program.
In short, it is not worth it. If you want more power from your normally aspirated engine then you need to look at turbo conversions, performance camshafts, performance header/manifold etc etc, the same parts people have been using for years.
Going back to turbo chip tuning. As I said at the start, there are many companies offering tuning boxes for Diesel engines. As long as they quote how much extra power their product gives your car you should be fine. Diesel engine tuning is relatively straightforward it is only when you want to get the absolute maximum power possible that the higher end units make sense.
Something else to look at when choosing a chip tuning box, for Diesel or Petrol engines is the quality of the case and especially the quality of the connectors. The box will be mounted in the engine bay and be exposed to heat, vibration and dirt, the case, the connectors and the cables need to be up to the task. Iffy connectors are not going to do the job in the long term.
High-end chip tuning boxes – what you get for your money
Lower end products will have average cases for the boxes, average connectors and may or may not have quoted power gains. High end chip tuning boxes will have high quality, non generic cases. Personally I prefer boxes which do not conduct electricity but tuning boxes with metal cases are fine, you just need to be more careful where you mount the box. High end chip tuning boxes will have the finest quality connectors available. In the grand scheme of things, even the best connectors do not cost much money in relation to the price of the box itself so they will not cut corners here.
Adjustability is a very nice feature to have. It will allow you to take advantage of running high quality fuel, you can adjust the box for race fuel and adjust it back for normal fuel for example. For diesel engines having adjustability really allows you to exploit any modifications you have made to the engine, for example a bigger air filter, bigger turbo, freer flowing exhaust and so on.
A diesel chip tuning box that is not adjustable will be tuned to give maximum power on a standard engine, if you have fitted a cone filter for example there will be a lot more power potential that you cannot access if the box is not adjustable. Petrol engine tuning is more complicated. The limit you are fighting is the knock limit of the engine and the way tuning boxes work there is no real way to get around this. You need to increase the knock limit of the engine which takes us back to race fuel.
Fuel RON
Your car is probably designed to run on 95 RON fuel, if you put 100 RON fuel in the tank the engine will probably not be able to get the maximum from it or it could take a while for the engine to adjust and by then you may be refilling again with 95. Adjustability in your tuning box will allow you to get the maximum power immediately. It will take some testing to find the settings you need for 100RON fuel but once you know what they are you just need to set the box to the setting and you are good to go.
Chip tuning boxes for petrol engines do not generally alter the fuelling of the engine, they work by increasing boost pressure. Injecting more fuel into the engine will suppress engine knock so while a chip tuning box for does not normally change fuelling there are adjustable fuel pressure regulators which will let you run more fuel pressure which will give you more fuel but the problem with this approach is that you have higher fuel pressure all of the time which is not normally what you want.
Basically adjustable chip tuning boxes on petrol engines are limited by the knock limit of your engine and the only way to overcome to make a big increase of the quoted power increase is to run high octane fuel or to run a race fuel additive. You can also inject water and or methanol into your engine but if you are going to go to this expense you are probably better off going with a custom program that adjusts factory ECU coding or to install a piggyback engine management computer that can control the lambda sensor.
Turbo diesel engines on the other hand are not knock limited. If you are considering fitting a better exhaust or air filter to your diesel engine in the future, you should get an adjustable chip tuning box.
Chip Tuning Box – Summary
1. The best chip tuning boxes will have unique cases with high quality connectors.
2. The manufacturer will quote you a figure with regards to how much extra power you can expect and they will support this with a dynograph
3. The box should come with a minimum of a 2 year warranty.
4. You should be able to contact the dealer you are buying the tuning box from quickly and easily. Street & Circuit is an authorised dealer and distributor of RaceChip products in Greece. We believe RaceChip products are amongst the finest on the market and fulfill all of our requirements with regards to what a high end chip tuning box should offer. 
You can buy your RaceChip from Street & Circuit here https://streetandcircuit.gr/racechip-chip-tuning-c-169435.html
