QS Articles

 I plan on starting a section here with mini-articles regarding automobiles. I am aware that it is small but bear with me until I can develop this further.

2000 Toyota Tacoma Fuel Economy Trials -Raw Data


 QS Comments

 Just brief explanations I have made in comments.

Anti Knock Index and Fuel Ratings:

"AKI Anti-Knock Index is the number displayed(87, 89, 91, 93 etc). The higher you go the slower the fuel burns. (Higher) AKI is good for many reasons, where it also can result in no/minimal gains. A few examples of possible gains are high compression engines, or forced induction engines. The Engine management system has knock sensors which help the car determine proper timing. It is a general rule that the more advanced the timing the better performance (power wise). Higher octane is good for this scenario because gasoline has the potential to detonate without spark or ignite (expand) prematurely also known as (knock). Compression ignition or timing that is too advanced while running high boost from a turbo/supercharger or high compression engine is commonly a result from using too low of an octane for the specific application. ECU's do have an ability to advance or retard timing (to a CERTAIN limit). In a NA 4.2 V8 you will see minimal gains from using 94 octane, assuming the the minimum is 91 octane like in the US VAG market vehicles.You will typically see the ECU adapt more in the forced induction applications because the ECU can manipulate more than just the timing curve such as boost levels."

Ur Quattro Vs. Sport Quattro:

US Original Quattro: Steel body construction. 10 Valve Turbo. Mechanical Fuel Injection. Iron Block. K24 Turbo. Long Wheel Base. Can purchase one for about $10,000 in decent condition.

Sport Quattro: Carbon Kevlar Body Components. Tubular reinforcements. 20 Valve Turbo. Electronic Fuel Injection. Alloy Block. K27 Turbo. Short wheel base. If you can find one for sale they go for around $300,000.

Audi Direct Injection Maintenance Tips:
If you want your car to last longer(if you are considering keeping the car after your Audi care plan) do oil changes every 5k (miles) rather than every 10k. Even oil marketed to last 10k miles has been shown to loose viscosity under normal driving conditions in less than 5k. Carbon buildup on pistons is common with the direct injection engines. Fuel additive cleaners can help with this but Audi specialist shops could/should provide decarbonizing services. Fuels or fuel additives that advertise cleaning of intake valves and intake components won't work (since your fuel is injected into the cylinders).

Modern Wastgate operation:
On the majority of factory turbocharged vehicles a manifold absolute pressure sensor is a transducer which sends intake vacuum/pressure data to the ECU which then sends a signal to a frequency valve which controls pressure to the wastegate diaphram.

Air leaks on cars with a mass airflow sensor:
The most common problem that causes a strong misfire is a leak in the intake track(turbo Audi). Have a shop familiar with turbocharged vehicles (or even better an Audi specialist) smoke test the intake system. It has to do with the fact there is a leak after the Mass Air Flow Sensor. This means that there is unmetered air (air that is not calculated by the ECU) getting into the intake that in turn causes it to run lean.

Hand Controls in a vehicle:
The guy in the video was talking about how he didn't get why there is twist throttle. I'll explain why. Ie. Some of our clients go to track days and like to "Left foot brake" which is not possible with that setup (Pulling to gas, pushing to brake). Just food for thought.