If the remap is better in every way, why wasn’t it just made like that in the factory? What am I missing?
Power and fuel economy are not the only two variables. Emissions are the biggest thing that comes to mind: your new high-performance remap might put your car outside of the emissions limits for your market.
Some aggressive remaps can also adversely affect how the car drives in normal use. Think rough idle, or jerky acceleration. The vast majority of drivers do not want that.
It can’t do both at the same time.
By remapping I assume you mean changing the ECU (engine control unit) programming.
Depending on what all it controls, usually fuel injectors and ignition, and what it reads, air pressure, rpm, oxygen, throttle input, the mapping adjusts timing of ignition, and how much fuel is injected based on how fast the engine is spinning, and where the throttle is set.
Most cars from the factory have a very simple mapping based around what most drivers do.
A fancy prototype CRX I had back in the 90s had very custom mapping that meant when I drove mellow, it got about 45 mpg, but had very slow acceleration. If I pushed the throttle past a certian point, it spun up like a bat out of hell, but the fuel economy would plummet.
What you can do with custom mapping is change the way the engine behaves under various conditions and based on the inputs. There is no magic get more out of the engine. Want more power? Eat more fuel and lose economy, and likely not burn off all the fuel so more dirty exhaust. Want more range? Limit power and lose acceleration.
It can’t do both at the same time.
That’s what I wasn’t taking into account, thanks.
My car sounds similar to your CRX. It uses either two cylinders, four cylinders or four cylinders and turbo depending on how hard I push the accelerator pedal. It’s very cool :)
Thanks for the comprehensive answer
If something promises to increase power and economy at the same time I assume it’s bullshit.
With that said you can increase one or the other with remapping depending on your focus.
Higher cylinder temperatures will give you more power and better efficiency. It will also produce a lot more nitrous oxides. the engine won’t last as long but that won’t show up for many miles.
That is my uneducated assumption too, but I’ve heard multiple people (some online, some IRL) who have said that about their remaps
All depends on where you’re starting from. If I can map an engine to be worse on both, then a mapping exists that is better on both.
