Don Terrill’s Speed-Talk

I recall ages ago in the early 80's I knew a punk who on spite wanted to ruin a 2 stroke engine on some moped he swiped from some kid he hated :? He ran and ran that little bike with the cheapest gasoline sold which was the old leaded 89 octane, after the 3rd tank the engine still seem to be runnin...

What I have done when road tuning ever since I started tuning is to log the engine speed and/or road speed and plot the d/dt of that to analyse acceleration across the rev range as well as just making timed marks every 1000RPM. Then I've compared different logs to observe if the changes I'm making t...

Realistically, you need double the volume flow to remove the same heat, that's compared to straight water. That's assuming the inlet temperature into the engine remains the same. In reality the lower specific heat means that unless your radiator was way oversized already, you are going to see a lar...

I've run plenty of water+methanol as well as water+ethanol mixture through some diesels. There is a noticable increase in power as well as exhaust temperature, I see a lot of people claiming it reduces EGT but my experience is that it's an increase (and logically so, you're adding fuel through the a...

Re torquing aluminium heads fixes lots of problems lots of times. Usually the bolt washer sinks into the softer aluminium of the head. I've stripped hundreds of dead engines and made a point of taking note of how many and which head bolts were loose on dis assembly. Aluminium heads, the loading of ...

Subarus are the absolute worst when it comes to head gasket seal in high power applications. With only 6 11mm bolts on each head, although it may look like the same amount of bolts around each hole as a regular engine, it's not just the bolts around the hole that is firing that take the load. They r...

The only proper way to deal with a wide variation in elevation is to use the throttle pedal input for "torque request", because part throttle climbing up a hill can be 80kpa at sea level or at 6000ft. At sea level that would be 80% of the available pressure but at 6000ft it would be 100% ...

The only proper way to deal with a wide variation in elevation is to use the throttle pedal input for "torque request", because part throttle climbing up a hill can be 80kpa at sea level or at 6000ft. At sea level that would be 80% of the available pressure but at 6000ft it would be 100% t...

You also need a working medium that gets heated and expands. Atmospheric nitrogen serves this purpose and also acts as a moderator for the speed of combustion. Also carbon dioxide is more dense that air so I get the feeling that the oxygen portion that is consumed by combustion, because it combines...

According to DIN EN228 as published in the Bosch Automotive handbook, dated january 2013, the 95RON sold in Germany is at least 85 MON and the 98RON is 88MON. These give values of 90 and 93 respectively for averages of RON/MON.

Modern engines with variable valve timing tend to use the valve timing to limit scavenging when needed, replacing the need for a separate EGR circuit.

i always check my results after the pull, the torque and horsepower to meet at 5252 rpms if not i need to recalibrate That's completely false. The torque and horsepower will always match at 5252RPM if both are displayed with the same correction factor, no matter how badly off the calibration is. An...

Just over a decade ago I needed lower compression for a Suzuki engine I was doubling the power of by turbocharging, and with no budget for new parts. I started by cutting apart an old piston to be able to measure its cross section. I then designed a cutout that would leave an acceptable cross sectio...

Methanol's low octane rating stems from the standard rating method where the detonation resistance is rated at a certain equivalence ratio using a heated charge. Methanol's real life detonation resistance stems from its high latent heat of evaporation and its ability to combust at very rich air:fuel...

I know of an old Ferrari race V12 that developed water leaks around some of the inlet guides. Every attempt to fix the leaks with oversize guides had short lived success or was an outright failure. The owner's mechanic's "it's off to a new owner" solution was to connect the engine to the ...