BHG – How to find optimal air-to-fuel ratio for your TDi

This article is part of infamous Brutally Honest Guide to car hacking. Our fist air-to-fuel article has been met with great outcry from duners, chiptuners and other forms of tExperts desperately defending their truth. No matter what facts you present, people love to hear only what they believe is true in their belief system.

PLEASE READ WARNINGS BEFORE YOU PROCEED !!!

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SUMMARY

• If you have no feedback such as EGT sensor, keep it with stock AFR
• If you want real power, interpolate stock values and find max. boost
• Never change EGT limiter without HW changes

In this article we will use analytical approach and common sense because we have no data acquistion systems worth thousands of Euro. Only car manufacturers, with racing teams (such as Audi), can preach about the reality of performance TDi or pioneer in aftermarket ECO TDi performance Banks Power.

After release of first article there were many chiptuners claiming diesel AFR below 18:1 makes more torque/power and even AFR 14.5:1 doesn’t smoke. Yet, when I asked for some proof or results from tests…there was awkward silence or just excuses from desperate fools.

It makes me wonder how those guys measure smoke-free car – usual dyno session uses air conditioning system. Common smoke test is during driving where you see no smoke because it is diluted by air flow under car. Just because you cannot see during driving, it doesn’t mean it doesn’t smoke.

I doubt normal car user bothers about ecology and some smoke opacity of their cars. All matters is more power at all costs, even if you got just placebo “power” comonly sold by commercial chiptuners.

Automotive industry uses various methods of measuring exhaust gases/smoke opacity. Above by is an example of Bosch BEA 950 S1 UNI and mobile version BEA 550.

We will use computer simulation, theoretical calculations and prove it in field as usually. Full article is only for supporters of Hajes Racing.

Let me guess “this article is expensive” you think, just imagine how much money you save just in fuel…If I knew earlier, I wouldn’t waste money for replacing turbo and placebo power output with lots of smoke in my car.