BHG – ECU remap facts & myths

Some facts and myths about ECU re-calibration aka ECU remap or chiptuning. Harsh reality of chiptuning/ECU remap that nobody wants you to know. It looks like that very few want to see reality.

PLEASE READ WARNINGS BEFORE YOU PROCEED !!!

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SUMMARY

• everything is optimally calibrated from factory for durability and efficient combustion
• whatever you change screws everything out – otherwise, manufacturers would market more performance already, no?
• max. power on commercial 2.0 TDi is around 180HP with single-stage turbocharging – do you really think you can get 300HP of real performance on TDi as some claim?
• your injectors are too small if you must tinker with injection timing
• if you change AFR, you decrease fuel economy – one wonders about wild claims of improved fuel economy created by chiptuners
• everything is designed for 80-90% of max. mechanical limits
• there is only about +5% increase in real torque/power – unless, you have some car that shares same engine with same HW but different power output
• the only way to get more performance is de-calibrate everything and become ECO terrorist
• beware of fancy dyno graphs – they are good only for slow weekends masturbation

Let’s use our brains for a while

From all ECUs I have seen so far, manufacturers commonly use optimal AFR of around 19:1 (Lambda 1.31) with 17.4:1 (Lambda 1.2) for quick turbo spooling. In other words, you start with low AFR at low revs because heat = power = heat. Once, your turbine is spinning and compressor supplies compressed air (boost) you need optimal combustion for max. torque/power.

As technology progresses, modern cars use commonly 22:1 AFR (Lambda 1.52) because you get more real and clean power rather than expelling unburnt crap with AFR below 18:1 . Of course, there is conflict of interest because duners want it all !

Duners live for 30 seconds power – I wonder if it is related to normal men having sex and giving girls 30 second of hell as they love to brag out (except the sex duration of course). As explained in dyno illusion article, you kill your engine/turbo if you push your car flat out for more than 30 seconds outside the dyno session.

VW 2.0 TDi PPD (used in Skoda Octavia vRS for example) produces 125kW at 4200 rpm. It uses 61mg IQ and 2475mbar MAP (If you are lucky and live exactly at sea level). It translates to MAF around 1100mg, turbocharger compressing air with efficiency over 70%. EGT reaches healthy 740°C at full load.

The Miracle of Chiptuning

You can learn about optimal ECU re-calibration in the legendary HR article HOW TO NOT Destroy your car. We also know how to squeeze maximum air from your turbo charger. Lets check out what commercial and amateur chiptuners do.

We have written about Garrett GT1749V turbocharger in first BHG article where you can learn how much boost this turbo can handle. It is commonly used turbocharger in modern 125kW engines. It can handle 1000°C EGT in short term compared to previous generation of turbochargers with limit at 800°C.

How chiptuners achieve 170+ kW from factory 125kW engine? Dreamy +36% increase in torque/power at 4200rpm. Common chiptuners’ knowledge is “max. boost increase +6%”. It is miracle of chiptuning – a guy in garage with dyno can do better than manufacturers with the best equipment you can buy.

Standard calibration for 125kW TDi is 2475mbar MAP @ 1000hPa and 61mg IQ, AFR 18:1 and MAF around 1100mg. I never had Skoda Octavia vRS so I can’t say how exactly this car works.

We increase boost by +5% to 2600mbar MAP, which translates to roughly 1150mg of MAF. If you wish real power, you increase fueling also by +5% to 64mg IQ. But chiptuners go for 75-80mg per stroke to achieve 230+ HP for 30 seconds until EGT limiter kicks in.

Factory duration maps run to 70mg IQ (lets dream little bit and assume it is 80% of maximal injector capacity) and chiptuners increase it by +14%. You are now at 94% of injector capacity – one wonders how long those injectors last till failure.

If you are usual car user, it doesn’t bother you much but never drive flat out/full load for more than 30 minutes. You will most likely end up as me with broken turbo and clutch.

You can see duners hit easily 920°C EGT in above by picture. No wonder, with “safe” +5% remap, you are pushing your turbo to the limit at 4200rpm. Duners go wild with AFR 14.5:1 – 80mg IQ @ 2600mbar MAP  in 4200rpm.

One day, I wish I could try standard HR test in mountains – I wonder how long such a hardcore remap would last. If you hit, in 30 seconds dyno session, 920°C EGT with barely warmed up engine – in real life, it means in less than 30 seconds your ECU is limiting torque/power and you get engine oil temperatures 120+ °C.

Not to mention clogged DPF every 5 minutes due excessive smoke. If safe long term EGT is 700°C (Banks Power), one wonders why humanoids have dead wish and wet dreams.

Hate to say I told you so

I always wonder whether people, who land on our website, even read what we write because they ask over and over again same stupid questions.

If you are real/spirited or hardcore driver BEWARE OF COMMERCIAL CHIPTUNING !!! You end up with broken car and no fun.

Hilda HR I was once calibrated by tExpert but this guy was unaware that I am not car user as normals. I used to have fuel consumption around 7l/100km…after remap consumption “improved” to 8l/100km. And 20k km later, my turbo died. I have already told you so BEWARE OF CHIPTUNERS !!!

When I finally understood “all” and started to calibrate ECU by myself. My fuel economy is same as factory original but with more torque where it matters most. You cannot have what is not here, do you understand??? I am sure not because you will ask me later if I can calibrate your 140PS engine to 200PS with factory HW.