Ruaraidh,

Thanks, that clarifies a lot.

In my layman's opinion the J&S sysyem's ability to control knock on a cylinder by cylinder basis is a no brainer best approach.

For someone without the high end data acquisition and processing capability that you describe, would it be safe to assume that engine knock discrimination capability always should be better at sensor frequencies above 9kHz for a 4"+ diameter piston v-8 (Mercruiser 496)? Any v-8?

For those that haven't seen a knock controller in action, here's a clip I made last week after installing one on an F150 Harley Davidson Edition.

This supercharged truck makes 19 psi after swapping out the Eaton blower and changing pulleys. It has a factory water/air intercooler with outlet temps at 108°.

It's tuned for 91 octane, and has been running on this set up and tune for two years, then we added the knock controller last month. He ran it on straight 89 for two weeks just to prove it could be done, without changing the tune.

The truck has a mix of 89 and 91 octane in this clip.

I won't post it since I'm not a vendor, so go to google and type: google video "knock controller" with the quotes

http://video.google.com/videoplay?do...90325318074993
John, I hope to have mine up and running in the next few weeks,

Welp, another year has gone by. I redesigned the "standard automotive version (not waterproof) and added a few new features including two rev limits, cranking retard and nitrous retard. Guess I should put pics up on my site.

I reloaded the video in the link above, so it no longer works. Google "knock controller demo" to see it.

The version for distributor ignition works in the same fashion, except the knock-finder display is not compatible.

Has anyone here on OSO tried the Safeguard yet?

I'm having a hard time getting in contact with John...

I'm back. I was out of town on another project.

Ah, cool.

I'll send you another email!

Just googling around and I saw a twin turbo Fountain Renegade that has the system (listed near the bottom of the page):

http://www.boatsmiami.com/4088fountain.htm

I have been running John's Safeguard system now for a while.

Since I blew a piston last year and decreased the timing and enrichened it quite a bit... I mounted the Safeguard but back then I didn't regain the courage to tune the motor to spec again.

The all time top speed record was 89MPH but that was about 3 years ago, and I never got more than 86MPH since I redid the interior and changed the center of gravity.

This summer I started tuning the motor, I increased the timing 6 degrees to 32. At first I set it locked at 30 at idle but later I noticed that above 2500 it decreased 5 degrees (not very uncommon for the MSD distributor...) So I reset it to 32 degrees at 2500rpm.

After some labbing with the fuel and ending up setting it as on the dyno, and 6degrees more timing, I started seeing some results...

At the rpm limiter at 6000rpm I'm now seeing some occasional knocks on two cylinders and the Safeguard is retarding the timing on those two with 2 degrees +/- 1 degree. I have now since I started the tuning process increased speed with 6mph (92.2MPH) and I'm going out tomorrow to see if there's some more to gain...

John has given me the best support on this and I can't do anything else but praise the Safeguard module and John's support!

IS j&s still make this unit, tryed to contact but cant get him to answer I would like to get one let me know thanks rod