So I emailed J&S today.
Quote:
Hi
I have a J&S for my 2000 Honda Prelude. It is a 'version 2' with the MAP limiter, and unlike the ones featured on your website, this unit has 6 DIP switches on the back instead of 5. The car has a Jackson Racing Supercharger installed on it.
When the unit is hooked up, power below 5000 rpm suffers heavily. I've verified this on a dyno. The unit is not pulling timing for knock when this
happens. I know that knock control is working because on rare occassion I have seen the unit pull timing (I have the dual monitor). These instances were repeatable and corrected with timing adjustments (I have programmable management).
When the J&S is bypassed, this power problem below 5k rpm disappears.
I would like assistance troubleshooting the issue, and if it appears there is a need, I can send the unit to you for inspection. I am not the original owner of the unit, and have had it for several years, so I do understand that the unit would be out of warranty.
Looking forward to your response.
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Here is John's response:
Quote:
David:
How do you have the boost retard knobs set? How much boost are you running?
The unit also has RPM retard to prevent tip-in detonation. The max amount is selected with switches 3 and 4. See table below:
3 4 Retard
up up 8°
up dn 6°
dn up 4°
dn dn 2°
The RPM based retard starts at 2500 RPM and ramps up to the selected max by 3500 RPM. At 4000 RPM, it starts to re-advance, reaching stock
timing by 5000 RPM.
Below 2psi, no RPM retard. The retard increases with boost, reaching the selected maximum above 5psi.
John
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I've misunderstood the purpose of switches 3 and 4, thinking they set the retard range for when there was knock. I've been running 3 and 4 both UP.
Note to J&S users: this feature is INDEPENDENT of the boost retard start and rate knobs. If you have programmable management, you do not need this feature at all and should run both switches DOWN. Even with them both down there is still a midrange timing retard up to 2°. I am trying to find out from John if this feature can be disabled entirely, cause I don't need it!!!