I have Sterling 572's with quad rotors that needs additional timing under 4500 to prevent detonation. Ignition now is MSD. I am also interested in how this product works.
The boat is a Skater not the Formula in the avitar.
Thanks, John B

HP350SC:

Some people have their minds made up about knock sensors. They've heard "knock sensors don't work" so many times, they believe it. As Rush Limbaugh says, "Thinking is hard work."

It is true, however, that knock sensors work best on quiet engines. The biggest interfering noise comes from piston slap, due to loose fitting forged pistons.

GM makes many knock sensors, but, according to a list sent me several years ago by a GM engineer, they are tuned for just three frequency bands.

The different thread styles and internal load resistor values account for the many part numbers. Note that the value of the load resistor is important only when connected to a GM processor.

Engines with a bore greater than about four inches should use the sensor with the lowest frequency band, which is centered around 5.2kHz.

GM sensors are not tuned for some magic or "perfect" knock frequency. They are tuned for a bandwith, about 1kHz wide.

The medium frequency sensor is 6.0kHz, and the highest frequency is 7.0kHz, which is used on the Saturn and the Fiero. I have since read that they aso make an 8kHz sensor, but that would suit the smallest bore engines.

I talked to LB the other day, and told him that the MSD Knock Alert ships with the medium frequency sensor. I had him read off the part number of the sensor included with the Anson gauge, and it is also the medium frequency. Note the the frequency bands overlap, so these sensors would still work on a large bore engine, but may not be the best choice.

I guess it would be wise to spend the extra money and get the marine unit.

CcanDo, any news yet?

Tuesday,next week.....let you know then!

Photo of LB's evaluation kit is available on our site. Click on products, then new marine racing version. It's the first photo.

John,I like your new product pictures........Two questions. What does the knock sensor pickup look like?And,as I visualize the nitrous circuit;could the circuit be " closed " until a predetermined Rpm was reached and then "open".The purpose in so doing would be to "add" timing,rather than retard.That is, if the circuit normally retards timing, subject to seeing a dry contact closure such as when the nitrous circuit is activated.If so,thence the amount of advance would be determined by the position of the nitrous switch.However,the "rate"of change would be the last hurdle. As you know,an Rpm activated switch is a shelf item.

Wish lists are also a shelf item.

Are you asking if I can add an advance curve? I can do that. Some of our units have a retard/advance curve. For example, see the figure at the bottom of the Focus installation page.

The advance curve would be a "straight line" curve, advancing linearly with RPM, between two predetermined RPM points. The amount of advance could be set in software, or you could choose to have it set by what is now the "nitrous retard" knob. If that's the case, then the "nitrous retard" wire could be programmed as another on/off function.

John,With the unit you shipped LB,is it possible to set the base timing 10*--15*or even 20*back of 38*and start adding timing at approx. 1500 RPM to be all in at 3000 RPM

Yes, I can program a curve like that. As I said above, pick start and stop RPM points, and an amount.