brodysZ28

I am interested in purchasing one of these units and asked John at J&S about a possible group buy if anyone else is interested. The universal model is $595, knock sensor kit is $55, and the knock monitor gauge is $89 for a total of $739 plus shipping.

Discounts:
10% if 2 or 3 are purchased ($739 down to $665.10)
15% if 4 or more are purchased ($739 down to $628.15)

The big selling point on this unit is the knock detection algorithm and the ability to retard timing in total or by cylinder which it is detecting knock on. It kind of sounds too good to be true, but I have done a lot of reading on it and those who have tried it have a lot of good things to say about it. However, I kind of see that as a bonus feature. I will use it in place of an MSD box, as it provides additional spark energy and includes tons of features as seen in the copy and paste from the website below.

John does mention that piston to wall clearance of more than 0.006" may produce false knock signals, especially during engine warm-up.

http://www.jandssafeguard.com/NewUni...alVersion.html

Features include:

• Two Rev Limits (Staging and Top End)

• Cranking Retard: **** allows up to 20° retard. Re-advances one dgree per spark event.

• Nitrous Retard: **** allows up to 20° retard when activated by 12v.

• Boost Retard/Vacuum Advance with Start and Rate control

• Individual Cylinder Knock Retard

• High Energy Inductive ignition with variable dwell

• Knock sensor sensitivity adjust

• Triggers from points, OEM electronic, magnetic pickup, Hall effect.

• Can trigger MSD or other CDI box



• How it works:

The system makes a spark, then decides if there was knock. If knock is detected, software "knows" it had to come from the cylinder that just fired, and that cylinder won't fire again for two revolutons.

When that cylinder comes up to fire the next time, software dials in the calculated amount of knock retard. It does this as each cylinder goes by, building up a different timing curve for each cylinder if knock is detected.

The unit retards in steps, a total of ten steps are possible. Each step is one or two degrees, depending on a user mode switch. When knock is detected, software retards in proportion to knock intensity.

The unit responds to inaudible knock, and retards quickly enough to prevent knock from becoming audible. The re-advance rate is one step every twenty revolutions. Note that the unit will not advance beyond stock timing. Of course, you may choose to bump the timing a bit after installing the unit.