"Ok, it sounds like I just convinced myself out of the usefullness of a more complicated loop controller. I think the simple loop controller is all anyone would need. I'm gointg to try to make my questions a little more specific this time. From some of the comments, it sounds like the loop controller shouldn't activate that much. Mostly I'm concerned with our computer's "learning" abilities. What if the boost threshold was lower(like for my high compression examples) and it does activate often? Does the computer learn timing curves like it does with fuel trim? Would there be any drawbacks(while using a loop controller) with the amount of time the computer is "learning"? "

From what i understand, *please* someone correct me if i'm wrong, that the ONLY thing that tells our ecu to go into open loop is the TPS sensor location, eg.. TPS voltage. I think we need to be more concerned with part throttle, low boost, closed loop boost more than we think. I know, for me anyway, that I spend WAY more time in closed loop boost then at WOT open loop boost. Only when racing, or at the track do i go to full WOT boost. Unless some of you guys like to be speed demons when daily driving.. IMO, if we run the J&S safeguard, 15 degrees of timing at low boost will give us very little power, esp for light acceleration. If you think about it...We are going from almost 30 degrees of timing advance at 1 or 2 hg's of vacum, to an instant 15 degrees of timing advance at 0 psi of boost. IMO, we wont feel any real noticable "pull" until 3-5 psi of boost,to make up for the less timing advance in low boost. Daily drivabilty will for sure be affected, and lower boost will most def just seem like a waste of gas. We will have to use more throttle to boost more psi to get moving. With me so far?

This point makes me think of why running a higher compression motor with the J&S more advantageous. That way, when under low boost, we will make more HP with less timing (15 degrees) than stock compression. Then we can set the J&S to start retard in at like 3 or 4 psi of boost, and on up. Remember, the J&S can pull upwards of a full 26 degrees of timing retard, which would be PLENTY of retard for a high compression motor running up to 20 psi IMO. I think Metaljim and I are coming to the same conclusion of a dual stage retard, with one set of values for closed loop, and antoher set for open loop. Now factor in that most of the "built" motor guys are running lower compression, that the J&S will hurt low boost performance, and driveabilty even MORE than the stock compression ratio, as lower compression makes less HP per each PSI of boost. We would then need to boost even MORE, lets say 5-6 psi in light throttle to feel any big power pulling of the car. 15 degrees of timing advance at lower boost is not at all good for power. ESP for 8.5:1 engines. I stil come back to my idea, of closed loop retard starting at 5 or 6 psi for stock comp motors, and 3 or 4 psi for low comp motors, then a second retard setting of open loop retard at 8 psi on stock comp, and 9 or 10 psi on low comp. The MSD DIS2 looks like a good candidate, but the whole switching thing is the question. How does it switch between the 2 settings? From what it says above in the quote, its great for N2o. This means that sending a 12v signal from a soleniod can put the MDS-2 into its other setting. If we need to switch using TPS voltage, its not going to happen, not without metaljim's "loop controller". Maybe the MSD can actually do this, I'm just not to knowledgable about that unit yet. The J&S still seems a better way to go..ESP with the knock retard feature. As Matt_95tgs pointed out, different variables will affect detonation, and when it can occur. Timing needs to be adjusted for that, automatically, which the J&S does, not like the MSD DIS2. The MSD cant detect knock, and pull timing, which is detramental for running high boost, lets say on a really hot day.

Now, if we could get the J&S to go into open loop at MORE than 0 psi, lets say at 5 or 6 psi, then that would be ideal. I dont think it can at this time though. This way, we can still maintain our closed loop, part throttle boost power, with 30 degrees of timing. Then have the ecu go into open loop at 5 or 6 psi, at 15 degrees of timing, and then start its actual retard at 8 psi and on up. This might be able to be done with something as simple as a manual boost controller going into the J&S. That way, when we are at 5 or 6 psi, the J&S will only see 0 psi, and only then will it go into open loop ecu timing. Boost retard and how much retard with boost is fully adjustable with the J&S using a dash mounted controll knob.

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)