DESS vs Non-DESS MEPMs ?

[NoRdO]

Hey Folks,

Currently building out a couple older skis and had a question about MEPM differences.

I believe sometime around 96', seadoo switched to the DESS system. Are there significant differences between older mepms and newer mepms for 587-717 motors.

I'm currently swapping a 657x motor into an older ski and have the following mepms:

2 - 94 sp mepms (full electronics box...)
1 - 96 GTI mepm w/dess (full electronics box, etc w/key...)

Are the ignition curves different between the older and newer mepms? Would it be worth running the newer mepm w/dess? I would prefer not to use dess system out of simplicity but if there is performance to be gained, I don't want to pass it up.

Thanks....

 

[SabrToothSqrl]

DESS is security. No performance change.

 

[NoRdO]

Are there differences in the ignition curve, I.E. electronics for 587 vs 657 & 657x vs 717? Are the electronics interchangeable? Example would be installing a 717 in a 587 hull and using all of the 587 electronics.... I am aware of 5 vs 4 wire stators.

 

[Matt Braley]

The timing differences are not significant enough to risk damaging the engine. I've done it a bunch and never had issues. The older ones have a lower rev limit that may hold a 717 back but you could also use a taller pitched impeller or smaller nozzles to bring rpm down.