To clear up a few things in relation to DieslTRONIC -
1. Increase in power and torque does increase stress levels on the engine and drivetrain, but for street use on DT these levels are kept to within manufacturer tolerance limits
2. Calibration optimizations for driving pleasure, rather than maximum increase in torque and power
3. Normal usage pattern (explained later on)
The DT is a device that modulates the fuel delivery to an engine, based on a preprogrammed map on board that is used as a basis of how much of fuel has to be increased/decreased and when and how. This summary is for one part of operation using a generic base map, without going into the self-learning and adapting module that comes over this layer.
Typical fuel quantity increase map (indicative only, not true map) –
Fuel increase/decrease quantity is always lower at full throttle conditions than part throttle conditions, which makes the vehicle very drivable and responsive in lower throttle conditions and engine and drivetrain stresses are well below full throttle conditions, with a safe increase in full throttle conditions set within manufacturer tolerances. Do note the fuel reduction towards higher RPMs.
The DT is a single channel system, but there are certain ways to predict RPMs and torque request (throttle pedal position) from just this one channel, which gives a reference for the fuel map.
http://www.team-bhp.com/forum/attach...1&d=1359952629
Where we don’t have to worry about safe limits,power and torque gains on diesels can be impressive. Like an example attached of a RDpiggyback ECU on a Laura TDI below ( On a standalone diesel ECU - which is dedicated for motorsport use only - gains get much higher! ) where torque at 2200RPM went up by ~81% and all overall power increased by ~50% at the same turbo boost pressure. The new stock clutch that did about 10k kms with moderate power gains started slipping with this new calibration before it even went on the dyno –
http://www.team-bhp.com/forum/attach...1&d=1359952629
As far as testing goes, we have vehicles on road since the XM400 (predecessor to DT) days, examples have clocked well more than 1.5L kms. It is not uncommon to see DT users clocking close to 1L mark. Applications have been cars, MUVs, LMVs,HCVs, etc.
It is known peak engine and drivetrain stresses occur at wide open throttle (WOT) conditions, summary of driving data that was logged on 2 vehicles. Just to show how much of WOT our rides take -
Vehicles: Swift Vdi and Punto
Total drivers: 8. Includes sedate to racer boy types
Distance: approx 400km each driver city and highway, identical driving conditions.
Results-
(a) ‘Street use’, 86% of the time is spend with throttle less than 60% , with about 2% of time at WOT
(b) ‘Highway use’, 77% of the travel time is spent at throttle position less than 60%, with about 4% of time at WOT.
http://www.team-bhp.com/forum/attach...1&d=1359952629
Another explanation as to why tuning boxes, reflashes, etc. increase fuel efficiency. With increase in torque at lower RPMs, drivers tend to shift earlier and quicker and using lesser throttle which results in increase in efficiency. As you can see from the graph, more time is spent at lower throttle positions when using P2 mode. More info about driver dynamics in power and efficiency relation coming later on..
Do remember-
-Vehicles that were the first generation CRDI such as the Hyundai Accent, we do not recommend tuning boxes as the fuel systems are not robust enough. However, second generation CRDi onwards work absolutely fine with tuning boxes.
- If a vehicle is badly maintained (clogged filters, blocked/damaged EGR valves, oil not replaced on time, defective fuel systems, brakes, etc.) a tuning box (or any power enhancing device) might accelerate a probable failure of the affected part which would have failed either ways. We have seen factory fresh vehicles with leaking fuel supply lines, busted electric fuel pumps, etc. well before anything was installed on them!
- More often than not on high mileage vehicles, stock exhaust catalyst, DPF, clutch, etc. might have reached the end of its service life (unless replaced at manufacturer set intervals), and using the DT or any power enhancing device might make this factor more noticeable or may call for replacement right away.
- Placement of tuning box. While the DT is an automotive grade product that can withstand high engine bay temperatures and water splashes (IP65), try place it in a location away from heat and water.