Disty re-curving? anyone know how it gets more low end torque?

[Phizinza]

I am interested in the disty re-curving option for modded power bands. I don't actually want to re-curve my disty, I have plans for electronic spark on my engine. So I just want to know how it gets more low end torque.

 

I gather that the recurving process is really just reweighting and respringing the disty to change when and where it uses its mechanical advance.

 

The same rules apply to the electronic spark things I would assume (haven't looked into them just yet, just figuring out what it would do for me.)

 

I am guessing that there would be a perfect possition to have the spark at any given RPM range. Am I right? This possition would give maximum torque I guess. I have heard a few accounts of people getting there disty re-curved and seeing vast improvments on low end torque from doing so. Has anyone done it here? Speak up if you have had experiences with it please.

 

Just wondering, thats all.. Cheers for any help.

[NorthWet]

The general concept is close to what you said: Given any set of engine mechanicals, RPM, load, fuel, and temp there is an optimum amount of ignition advance. The mechanical advance tries to deal with RPM variances and the vacuum advance with load variances (based on what the manufacturer expects the engine to be like and what fuel will likely be used).

 

The manufacturer can't anticipate individual situations of engine wear/mods, temperature variation or fuel quality. They handle this by making the timing curves conservative so that detonation is unlikely to occur. Recurving allows you to adjust things closer to the ragged edge, risking detonation to do so.

[bgd73]

A tight intake can make a torque monster at expense of high rpms acheived not so quickly. Timing advance is quite simple not to be overthought.Strong fire and disty spinning off the cam correct- thats about it for spark.

The spfi is about as tight as it gets -- the carbs are tight new but get sloppy. mpfi? don't count on low end torque until higher rpms. If the curve you're refering to is whole range and timing advance is set correctly, target fuel/air ,even exhaust system, not spark curve. fuel/air is most complicated part of torque and when it gets it, and when it gets rid of it. - so many variables change every run. The larger the cfm, the more errors you will have. The best snappy torque and keeping it I have encountered is by far a good running spfi- they just aren't very fast.

[4x4_Welder]

Having the advance come in sooner will perk up the low end a bit, but doing a dual-stage mechanical system gets a bit complex. If the advance comes in too much, too soon, you wind up with spark knock in the low end and midrange, but the power at top end will pretty much stay the same.