a guest Jul 21st, 2019 239 Never
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- A while ago I did a post on maintenance. So hopefully all your cars are well maintained now, with no oil leaks and ready to tackle the next 100km without throwing a fault code. Here is some information about engine tuning which may be helpful to beginners.
- For most people, this is what you want to do to make power on stock turbos:
- Tune - This is something that generates a lot of discussion and arguments. A flash tune is what you want, this reprograms the factory ECU (called the DME) with the updated parameters. There is actually a lot of stuff in a tune, and it goes beyond just increasing the boost. More on that in a minute.
- In the early days of the platform, the first things that came out were piggybacks. There was Vishnu Procede, and BMS's JB4 (was "Juicebox" back then). These piggybacks were required because the factory ECU was locked and you could not make changes to it. If you wanted more power, you needed a piggyback. What is a piggyback? It is basically a box that has a harness that sits between the car's electronics and the DME. It sends fake signals to the DME to keep it happy and not throw any codes, and then controls the boost solenoids directly, giving you more boost without codes. The piggybacks have features like clearing codes and hijacking the gauge cluster to show boost, which many people like.
- Disadvantages to piggyback tuning are quite numerous. Lets use JB4 as an example as you can't get Procede anymore. JB4 does not adjust engine timing, and the increased torque output of the engine is not correctly reported to the rest of the car (transmission uses torque values to decide how much clamp force to use). Shifts on DCT and auto will also be poor when the torque is not reported correctly the transmission. The logging parameters are not that comphrehensive (the JB4 has no access to the internal values of the DME), poor resolution of values, weird scalings just make it a pain to use.
- There is also an "autotuning" map on these piggybacks which works in a particularly dodgy fashion, it basically increases boost until the engine knocks, then the DME decreases the engine timing to prevent damage. This 'feedback' mechanism is how the autotuning works, very crude and results in poor power delivery and driveability.
- This is particularly dangerous when this product is advertised to work on ethanol mixes without any other mods, the piggybacks have no means to adjust the fuel scalars in the tune, which means the fuel trims max out. The DME controls the fuel system and only adjusts up to +-34% of fuel adjustment until it maxes out and doesn't give you any more fuel, until you adjust the fuel scalar. Once the fuel trims max out, the DME cannot add any more fuel to correct the A/F ratio and the engine runs lean and hot. The Piggybacks don't adjust AFR (air fuel ratio) either, which is a huge fundamental of tuning.
- Basically the only reason why the piggybacks work at all, is due to the excellent DME with fully closed loop fuel adjustment and the sensitive knock sensors. Most other cars only have a narrowband O2 sensor which only gives you readings on cruise, wideband gives you a reading even on cruise and full throttle driving. If you used a JB4 on a JDM car with narrowband O2 sensors you'd have a ruined engine pretty quickly.
- To compensate for these shortcomings, theres things called "backend" flashes, which allow you to flash a tune onto the DME while keeping the piggyback. This means the piggyback is only used for boost control while the flash tune does the rest. This seems a bit redundant to me, it’s basically admitting the piggyback is deficient if you need to disable most of the features on it for it to be good! The only reason imo you'd need a piggyback is to activate external devices like port injection or methanol injection which cannot be triggered by the DME. Even then, you can still trigger these devices with the ECUs that the PI and methanol kits come with.
- So flash tune is what you want, basically you will want a DCAN cable, OTG cable and Android phone or tablet. No it does not work on Apple stuff.
- Bimmergeeks DCAN cable: https://www.bimmergeeks.net/product-p…/bimmergeeks-pro-cable
- OTG cable will need to be sourced based on your android device, they cost around $1-$5 off ebay.
- This is a quality OTG cable if you're tired of crap ones: https://www.ebay.com.au/itm/232990064223
- Most Android devices can be used for MHD, for people who use an iPhone, your best option is to buy a cheap android tablet like this:
- Stage 1 - For cars with stock downpipes Stage1+ would be for cars with upgraded intercoolers
- Stage 2 - For cars with catless downpipes, Stage 2+ is for cars with upgraded intercoolers.
- With the off the shelf MHD maps you will get a few timing corrections on these maps but the 95 maps would feel a lot slower. This is due to the octane of our 98 fuels in Australia is lower due to not having 10% ethanol of the USA pumps. If this bothers you, you should go for a custom tune which I would highly recommend. If you run OTS maps then make sure the plugs are kept fresh and the coils have been replaced, to minimise timing corrections.
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