2020 Jimny tuning

Before racing off and doing any ECU mods, I scoured the internet for firsthand experiences. Those that have actually taken the plunge. Found this post and a couple more posts/youtube videos (no dyno figures, just I feel - both in support of and against). After reading this thread, I was pretty convinced it was a waste of time and money. In the end, I made multiple mods. 

The reality is that the ECU remap alone can indeed give you gains in excess of 10hp, dyno tested, actually a bit more than that (12.8hp). Can you make those changes with the regulations enforced in your country, probably not. If, however, emissions control is not an issue or as stringent, then the very emissions controls enforced by the ECU do allow for gains in excess of 10hp. In as far as torque gains, air filter and exhaust give the greatest gains. Probably still less emissions that a large diesel 4x4.

Some asked, why more power is required. If you use the Gen 4 on the open road, unladen at altitude, say 5000ft, it can't hold 100-120kph (bring on the metric) as the gradient increase, say past 4-5%. So, those looking for more power aren't looking to drag race, not even challenge a Vespa, they simply want the car to be usable on the open road. Possibly more a problem in non-EU countries where we have long undulating open roads and speed limits between 100 and 120kph on these roads. One would have expected this to be achievable out the box, certainly was with the Gen 3. 

My final dyno figures are now representative of what one would expect of a modern 1.5 NA engine (84.7KW/164NM). My driving experience and "seat of pants" assessment concurs. Just exceedingly frustrating that I had to go to these extremes, the engine should have been correctly matched to the vehicle out the box with all emissions controls in place.

Side note, recall seeing a query on this post about the Jimny possibly running leaner for emissions reasons. It is the opposite, the Gen 3 did, the Gen 4 doesn't, on the rich side (the experience on mine - visibly and based on the exhaust gas measurements on the dyno and the experience of the tuner in general with the Gen 4 - at least at a bit of altitude). Note, air/fuel ratio was not tampered with during remap, just monitored. Considering I now have better fuel consumption, my effective emissions may actually be more favourable.

Hope this is of help to others, who like myself, wanted insight from firsthand owner experiences. 

 

daxiet wrote:

Note, air/fuel ratio was not tampered with during remap, just monitored. Considering I now have better fuel consumption, my effective emissions may actually be more favourable.
 

I can't help but wonder if I am missing something - maybe misreading or misunderstanding something - if the air/fuel ratio was not "tampered with" during the remap, where has the additional power come from, where has the better fuel consumption come from?

10% more power at the same time as better fuel consumption would be every man's dream, but doing it without tampering with air/fuel ratios, something does not add up - it's theoretically possible to get more power by changing the valve timing, if I'm not mistaken the K15b has dual VVTi and the ECU can vary the timing and therefore the overlap, but more power generally requires more air & fuel and that means the fuel consumption increases.

daxiet wrote:

Some asked, why more power is required. If you use the Gen 4 on the open road, unladen at altitude, say 5000ft, it can't hold 100-120kph (bring on the metric) as the gradient increase, say past 4-5%. So, those looking for more power aren't looking to drag race, not even challenge a Vespa, they simply want the car to be usable on the open road. Possibly more a problem in non-EU countries where we have long undulating open roads and speed limits between 100 and 120kph on these roads. One would have expected this to be achievable out the box, certainly was with the Gen 3. 

 

More power is never more than a gear change away, unless you're already down into 3rd gear in those situations? And are you suggesting the 100hp Gen 4 is slower than an 85hp Gen 3?

It also doesn't really make sense how you say the remap gave more power, but the intake/exhaust mods gave more torque. An engine that can breathe more easily will make more power and more torque. The remap simply programmes the ECU to take advantage of this.