I heard a while back from Wyatt that it's good to retard timing 1-1.5 degrees for every pound of boost over 5 psi. Can I just use an MSD or something comparible? It seemed that Xtreme had no problems with the stock internals at 10 psi, just detonation.

From personal experience, I believe our stock pistons could handle 10 psi daily. It's detonation that is the problem. When my pistons went there were bad signs of detonation. I knew I had enough fuel.

As for timing retard, I think .75-1.0 degree per pound of boost should be sufficient. I tried retarding 1.0-1.25 degree/lb. and the car would feel very sluggish. I could "feel" the "hesitation" or "pull" from too much timing retard. However, I only based this from driving the car. I don't have datalogger yet, so I really don't know for sure. The only best way will be to dyno tune the car.

Hehe, read my post in the turbo section about the J&S. I totally agree with fly, our stock pistons should handle 10 psi without failure. Detonation will kill them without hesitation. As for how much timing to pull when boosting, well thats a whole new topic, go check out my post. From what i have learned, max HP is made when just enough timing is pulled to not detonate. This needs to be done on a per-cylinder basis, as detonation doesnt happen on all cylinders at the same time. You can retard all cylinders with units like the Crane, but like said above, you will feel the power loss. Thats whre the J&S comes into play. Lots of technical stuff to read up on, hehe..I'm still learning..head hurts :)

generally you should need to pull more timing on the middle two cylinders because they get hotter then the outter two.. even if it is only a mild difference.. it's enough to cause detonation on the middle two and not the outter two.. atleast that's my general knowledge of engines. I know lots of fuel injected motorcycles (and even some carburated ones) use different fuel maps/timming maps for the middle two cylinders (in the I4 motorcycles) because they run at a different temperate then the outter two.. seems to make sense to me. and we all know motorcycles squeeze the most power stock per liter out of their motors.

for some strange reason, cylinder 2 gets hottest. Should be cylinder 1, since it is the furthest in the fuel rail from the fuel source, but hey, empirical evidence outweighs theoretical reasoning.
-=B-=

Check this out, some very good info here on detonation and how to control it.. http://www.jandssafeguard.com/tech.html

As for Breezio's theory, I detonated and cracked 2 piston ring landings on my #4 piston. All other 3 pistons were perfect..wierd..It makes sense though, hotter temps= greater chance for detonation..

I definitely plan to get the J&S, even if it's just good for detonation control--the #1 REAL concern. The Crane or MSD unit is too broad and static when it comes to timing retard relative to boost.

yep, indeed. But another good thing with the J&S, is that it can ALSO retard timing on all cylinders with each pound of boost, like the Crane units, ect.. So you can dial it in to retard like .5 of a degree per pound of boost, AND set it to retard slightly with detonation. A very nice combo indeed.You can also buy an optional guage to see exactly how much timing is being pulled from detonation. This would make it fairly simple to tune. Just start off by using some retard with boost on all cylinders, then keep adjusting more or less retard until the J&S only retards very little for detonation. Running 15 psi with stock timing and no retard, you will almost def detonate in every cylinder. Maybe try retarding .5 degree for each pound of boost after 5 or 6 psi, then go from there. I'm really surprised no one has used this device yet..I cant wait to get it and hook it up, and then put the car on a dyno at 15 psi :P Maybe i will do a pull or two at 8 or 10 psi without any timing control, then hook up the J&S, and see what happens with power and torqure..

I wonder what our ecu does with knock because we have a knock sensor. I know our ECU uses pulse signals from the camshaft and crankshaft position signals to adjust timing, but does it use these to advance timing only, or does it also retard any timing? If so, I wonder how much timing retard?

The problem with the J&S is that is doesnt amplify the spark. You would need to spend the $550 on the J&S and then also another $250-$300 on the MSD dis2 in order to have amplified spark and timing control. It kinda of expensive for me. I dont think I can spend $800 on a damn ignition system.