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>So say you are using an AFC and running 15psi and get way >too much advance everytime you get on it and hit a certain >rev range. So the J&S has to pull timing every time the >cylinder fires? Isn't that like covering up the problem >instead of tuning w/ an ignition to not get so much advance? > Am I making any sense or do I have it all wrong?
Well the SAFC makes it a whole new ball game really. As we have seen, the SAFC does in fact add some timing, which is not good for preventing detonation. IMO, more power can be made by more accurate, consistant, per- cylinder ignition timing, than using a SAFC to meddle around with fuel. I will prob not ever get SAFC, for this reason. I think the biggest problem when using the SAFC, is timing under part throttle, closed loop, higher boost, say 8+ psi. By this i mean the ecu is still in closed loop, 80% or less throttle. Since the ecu doesnt know we are boosting, it advances timing for max power and fuel economy, but we dont want that under closed loop, as this will def put too much timing in with a SAFC, and will lead to major detonation. If i remember, when i datalogged my car, WOT boosted runs saw around 15 degrees of timing advance, but it didnt go any higher, because the ecu doesnt advance timing in open loop(at least I didnt notice it on the datalogger). But, when part throttle boosting, my advance went upwards of 30 degrees of advance, thats NOT good. The J&S will only retard the detonating cylinder. Remember, not all cylinders will be detonating at the same time, it usually happens on a per cylinder basis. So by retarding all cylinders at the same time, like by using the Crane, you will most liley loose some HP, as retarding timing hurts HP. But, if you only retard on a per cylinder basis, HP will be much higher, for one- its only retarding the detonating cylinder, compared to all cylinders, and 2- max power is made right on the "verge" of detonation, or right before it happens, and the J&S will listen to each cylinder for this point in time in the cumbustion process. So in reality, the J&S will keep all your cylinders firing at max cylinder pressure, which is the pressure right before detonation happens. You cant do that with a general all cylinder timing retard module. So basically, the J&S is keeping your engine at max HP, at max cylinder pressure by controlling spark timing retard, thus making your engine able to create max HP out of each cylinder, witout detonation. I hope this makes sense..This gets complicated very quickly, hehe.. I'd say if you have the SAFC, then using a Crane type of ign retard may be a good way to go, as the J&S will have to almost always be pulling timing. Even better yet, use both 
 13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
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