Rage

Yes, I do. As far as I am aware Whipple is the only one liscenced by Merc to reflash the PCM555 ECU that comes with the Merc 496HO & Mag engine. Lots of people can do the various MEFI computers but buyer beware. Software is available to purchase where you could do the MEFI recals as well.

imagecat

Dustin charges $1000 right ?? Is that each time or what?

Rage

It was $800 back in 2006 for my first custom recal. Half of that went to Mercury for the ECU unlock code. After that ~$150 - $200 each time depending what you needed to be done. But for custom recals you have to supply the AFR and MAP vs rpm data from idle to WOT to Dustin so he knows what needs adjustment. These must be accurate or wrong adjustments may be made. The AFR vs rpm would come from instrument like Innovate LM-1 with an rpm converter. The MAP vs rpm would come from a Diacom recording. These two data streams would need to be combined and normalized to the same rpm. Then there is the issue as to if the AFR you are supplying is of a single cylinder of the eight available, one manifold collector combining all four cylinders from that bank or both banks or all eight individual cylinders. You would need to discuss this with Dustin Whipple. Optimum (and quickest) would be to provide the engine to Dustin to calibrate on the dyno.

toolsinbox

so I take from this; if you have accepted that spending several thousand dollars; on exaust alone; will give you several mph gain; you are misinformed; foolish; and setting youself up for poor results.

I see it as a combination of upgrades and adjustments of parts, often hinging on an exaust upgrade, to maximize speed.

type of boat, setup, and conditions, not withstanding.

Keith Atlanta

From my experience of tweaking almost everything on a 496, you are
spot on. But again, alot depends on the size of the boat.

imagecat

Okay you don't think it would be better in the long run to switch ECM's to something that you can adjust yourself. I know this isn't cheaper but I'm hands on like you obviously are. It would just bother me that I have to send my ecm off if I switch anything. Mefi computers are hard to come by. I know you have considered this

dana marine products

With any upgrade, something has to change. You have to move more water somehow. You either have to spin your prop faster, or get a bigger prop. Simply adding horsepower to an engine means nothing if you can't put the rubber to the ground.

As far as adding exhaust alone to give you xtra MPH, well, that depends. If you're running a 496 HO and your spinning a prop at 4700 rpm, we have some room to spin that prop up. Add the exhaust, now you'll be turning that same prop @ 4900-5000 rpm equalling more speed. So in that case, you would pick up speed from just an exhaust install. That statement however cannot be made for all exhaust systems as there are many that are no better than stock exhaust and will not yield extra performance.

And that's not to say that another prop couldn't work even better.

If you're running 5000 rpm with the stock engine, adding exhaust is only going to park you on the rev limiter, you need more bite. So in that case, you would need to prop up 1 pitch so you can get back in the 5000 rpm range. The difference is now your slinging a bigger blade at that RPM equaling more speed.

Rage

If you can afford it and are comfortable giving up the Merc 'Guardian' system, changing over to an ECU that you can program yourself on the fly in the boat while you are running is the best in my mind. You will need the ECU, its harness, appropriate sensors, laptop and the programing software. Since I have never done this there may be more. Talk to pros who know how to do this. Either way you need an AFR meter (with data logger capability to record AFR vs RPM is a very useful option). I suspect it cost me about the same reprograming the PCM555 given all the incremental engine changes made over time. Also Dustin has to do the programing personally in addition to his full time job as the president of the company. He is very busy except in the winter so recals can take a very long time. My last recal was requested in May and was not completed until September. You get the picture. If you have the 496HO ECU it is very saleable.

Raylar

We recalibrate PCM555's for the 496 all the time and no we don't pay Mercury for any unlock code as Dustin -USED TO DO? We have our own software and we keep all the Guardian turned on a working after re-programming. We do this programming for Mag to HO upgrades and various Raylar kit packages and engine we specially build. We won't re-tune an ECM for a stock engine without modifications for supposed hidden power!
Its Raylar's experience that unless you are upgrading a stock 496-375HP Mag to a 425HP HO or such no reprogramming is really going to make a big difference in a stock 496 . If you bump in a lot of extra timing you will put the cast pistons closer to the edge of detonation and possible damage. We also don't think its wise to up the rpm limit on the HO of 5150rpm on a stock head and valve spring engine as the springs are a bit lite in poundage and a little valve float will also possibly make a BASKET engine assembly!
I am always surprised how many boaters think and equate ECM retuning to extra power like some see in emissions engines in today's vehicles. Most marine OEM engines carry a tune in the ECM that allows the engine to make good reliable power, they are not de-tuned and lazy like a lot of emissions engines in vehicles.
You can push the timing limit and fueling on stock marine engine and sometimes gain 15-30HP but its not significant and the risk to the engine is not really a smart long term move.
ECM retuning is always needed and necessary when moderate to major engine changes are made with cams, heads,compression, cubic inches, etc. Again' there ain't no cheap horsepower in most marine engines, if you find a lot cheap, let me know, I would like to sell It!

Best Regards,
Ray @ Raylar

robby dmax

hi ray
been following this thread
just purchased a daytona with a 496 with your 525 package and the dana exhaust on it, did the ecm get flashed or just the fuel pressure get raised ?
and what are the benefits of flashing the ecm with your package?
how can we tell if it was flashed?
thanks