Don Terrill’s Speed-Talk

Can't you just calculate the required injector duty cycle depending on the MAF reading? No you can't even in ideal conditions because you have variations in fuel. O2 sensor gives a feedback loop which is used to calibrate every other sensor and fine tuning for fuel used. Gasoline isn't regulated - ...

Another idea is "loosely" heating the intake manifold, so at high rpm the air and fuel will cool the intake so the fuel would naturally evaporate less, but at low rpm low load it would heat back up. This would not respond quickly tho, maybe if the intake was made out of thin polymer it wo...

Ricin oil is used with methanol to protect metal parts from corrosion.

Yes but that’s not what they’re chasing. You have a later EVO down low for more work on the crank, but as rpm’s rise, you go earlier and earlier due to balancing pumping losses. Leave it too late and it noses over as the pumping losses on the exhaust stroke hurt it too much. I'm not familiar Coyote...

If three-peace oil ring is assembled wrongly it will stick to it's groove. Sealing rings have to assembled on top of spacer. Pretty common mistake to install them wrongly.

You need different kind of calculations for 180 degree headers. It's not about reflecting harmonics but next firing cylinder exhaust pulse to suck vacuum to previous cylinders overlap period. And as exhaust flow took some time after EVO it is possible tune that scavenging to pretty wide rpm range. 4...

I understand the math. That said, a question to ask is: On an asymmetrical lobe is the centreline half way between IVO and IVC? As in the same number of degrees? Or is the point of maximum lift? As its name gives a hint, it's primarily lobe center. Max lift happens at lobe center on normal symmetri...

The only change I had intended was to extend the intake duration on the closing side. No other changes. And when you do that intake intake center increases half of those degrees, and LSA increases 1/4. That's pure math, LSA is just a way to compress cam timing info to easily comparable numbers. Asy...

When we know valve events as per crank degrees, then we can calculate duration, lobe centers and LSA. I was trying to explain this using my drawing.. Im not sure what you mean by saying to calculate all possible valve events for given duration measure point. You don't know valve events when you ord...

What you say is absolutely true. But the lobe centers have no contribution to performance; it is the actual valve events that do the work. Many different events can be used to present the same lobe centers. For normal symmetrical cam profiles you need to know duration and LSA to calculate all possi...

It doesn’t cancel themselves because advancing the intake by a couple degrees doesn’t mean the exhaust cam wants to either. Variable timing DOHC cam strategies show this to be true. You missed my point. In your example you only have one camsaft timed differently. It's a 106 LSA cam with installed a...

LSA = (Intake Centerline + Exhaust Centerline)/2 . 100 ICL and 112ECL is 106 LSA as is 104 ICL and 108 ECL, and so would 106 ICL and 106 ECL. Those cams would run completely different. If the valve lift profiles are asymmetrical, they would all be different still. You are describing just one cam, t...

I know a couple of guys who dyno alot,they say if the IVC is correct for the valve size,cubic inches and where peak rpm hp is set as per induction system CSA the engine will tolerate the other 3 valve events being a bit off,what those events are you have to test for yourself. But - for absolutely b...

You can change the intake opening 5 degrees one way or the other and not much different happens, if that intake closing remains the same. Change the intake closing by 5 degrees one way or the other, keeping the intake opening the same and a whole lot of things happen differently. I believed that in...

It's well known that consuming metal in spark increases spark quality a lot. But electrodes made with soft metal wear rapidly. So in this design they introduce yttrium metal as neutral electrode. Very interesting design.