Intersting post. Any update on the harness? I've had to make my own in the past. I'd really like to get access to tune a 555 but well... Mercury wont have it that way.

Harness is complete and currently in Beta right now. Factory sensors are all working and communicating with the HEFI, I have sync while cranking over on the dyno, spark in all the correct holes at the correct time. Next week we will put water and fuel to it.

After a week of running with all sensors reading correctly and verified by the sensors on the dyno I feel it’s reasonable to call this project successful

For those not keeping notes, the end product is completely plug and play. No need to swap a single sensor, and uses factory crank/cam sensors and coils.

The technical drawings and bill of materials are going out to a few manufacturers for bid for mass production.

Stock 525EFI vs a Retter Engine Development 525EFI Twin Turbo kit on 6PSI and 87 octane.

I’ll get some videos hosted and linked ASAP.

Precision,

Would this be workable for the 496HO?

Thanks. Brad.

you have to find the italian tuner that has the set up,,but its costly.I found it a while back when we were modifying 1075's.it was easier to just send out the computers to mark at precision marine.

Mark was reluctant to help as it was going to be supporting a competitive to Whipple and he didn’t want to jeopardize that relationship. Which I totally understand and can respect.

Also, they share the development 555 that has live tuning ability.

Hey, Brad.

While they both utilize the 555 the harnesses are wildly different. The 496 is closer to a LS1 than a 525.

With that being said, I could produce them as well. I just need a sample harness with notations for what each connector plugs onto.

Precision,

Fair enough. What I heard you say was something that wasn't "NO". Any potential of a solution for eliminating Merc's (albeit mandated) blockade over these ECMs is a good thing.

Anybody have a Merc 496 ECM harness collecting dust in their shop?

Thanks. Brad.