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By Fred - 13 Years Ago
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Does anyone know of an optimal timing system for street and highway usage with the goal of achieving the highest mileage possible? I would think it would include a knock sensor and various other sensors to real time determine how far to advance the timing. Any suggestions Fred
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By pegleg - 13 Years Ago
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Not to confuse the issue but, there's not one simple answer for that. Compression ratios, head design, Compression chamber design and efficiency, cam design, gear ratios, vehicle weight and type of driving all factor into that one. Advance it until it pings then back off a couple degrees, or use a dyno and time it for maximum power or brake specific. that's a start.
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By Fred - 13 Years Ago
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ok but aren't there any aftermarket systems that include a knock sensor? i would guess that a knock sensor could compensate for lots of dyno time under a multitude of operating conditions. Fred
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By Pete 55Tbird - 13 Years Ago
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Fred All you have to do is adapt the Ford EEC IV EFI system to your Yblock. All the hard work has been done by Ford. Pete
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By charliemccraney - 13 Years Ago
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Some ignition boxes designed for boost (turbo, supercharger) have a retard function. Don't know if it would work on a naturally aspirated application. Don't really see the benefit either.
Even on OEM EFI vehicles with computer controlled timing, the curve is predetermined and does not rely on the knock sensor to get the correct timing. For all intents and purposes a properly tuned mechanical system will function just as well as an electronic system. The difference is that the mechanical system cannot compensate for variables which are out of your control, like bad gas. Put another way, if you need a knock sensor to keep it timed right, it's not timed right.
A computer controlled system may offer slight benefits because you will be able to pick a very specific amount or rate of timing at a given rpm and load but a system that can do that is likely to be expensive and require a lot of time to tune to take advantage of the benefit, either trial and error on the street, or dyno time, which can be costly. The benefit will not be worth the cost to most. Of course, with the mechanical system, you're limited to what can be done with springs and weights; if you want it to advance at an additional .5 degree rate for a few hundred rpm at some point between initial and max, you won't be able do it.
Simply a good, well tuned ignition will do what you want. Pick your favorite brand. However, if you're the adventurous type, I'm sure you can figure out a way to use an oem efi computer to do what you want. Use it only for the timing function - for now.
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By miker - 13 Years Ago
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I have to agree with all the above post. I've used MSD timing computers, with and without boost retard, on a Y block, and two aftermarket computers with knock sensors on other makes. They are difficult to set up at best, and have not performed anything like the factory systems I've had on turbo cars (4 of them) when I had to use lower octane fuels. I could have spent the money for a 57 tach drive dizzy 15 years ago, and saved enough money to buy gas for the rest of my life. But I learned a few things along the way.
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By pegleg - 13 Years Ago
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miker (4/28/2012)
and saved enough money to buy gas for the rest of my life. But I learned a few things along the way. Yer right on that Mike  
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By LordMrFord - 13 Years Ago
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With crank trigger you can get more accurate spark timing when there is no timing chain and dizzy gear between crank and trigger.
With multiple coils you can get more spark energy when coil loading times are longer.
EDIS with wasted spark got 4 times more loading time when compared to single coil.
And coil-on-plug system got 8 times more.
Naturally aspired low-RPM street-Y can survive with one coil, I think.
Good tuned ignition system dont need knock sensors. Best advance point is not necessarily just beneath knocking line, it can be something else too.
...my few simple thoughts.
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