Waterslinger

Thinking about having the Ecm on my 496 reprogramed. Any one had good or bad exp with this effort?

stock - plates in ex. 26 Velocity 25 hydro

Raylar

My educated opinion as a 496 engine builder and ecm re-programmer.
Don't look for hidden power and rpms in a stock 496 HO program
Reasons:
1. Engine has iron heads that are a lousy design and tend to detonate badly with juiced up advanced ignition timing!
2. The stock valve train will not reliably take additional rpms that some programmers try to pass of as additional power!
3. Today's sometimes crazy blended and additive rich fuels with moisture really need a conservative timing map to stay out of detonation.
4.STOCK GM 496 (8.1l) HYPER-EUTECTIC PISTONS DO NOT LIKE DETONATION!!!!!!!!!!!
5. Got a stock 496 Merc engine, want to add good reliable power??
Then budget and plan for good workable upgrades depending on the horsepower and torque level you are wanting to achieve.
Good exhaust upgrades can add power fairly inexpensively with Good Header manifold designs ONLY! Other than that only good mechanical, (camshaft, heads, intakes, superchargers ONLY with forged internal upgrades, etc.) upgrades which really improve the efficiency of the engine with additional air flow will really develop good power increases and some will keep the engine from having issues with the additional power. Others available may deliver the engine to you on the floor of your garage or shop in buckets and baskets!! after just short "Everything is Great experiences!"

Bottom Line! There are no simple cheap upgrades & additions in most marine performance engines that will deliver any appreciable power increases. You probably sometimes have more to be gained inexpensively from a good bottom and prop work than from any simple re-program. Performance marine engines are not automobile emissions engines!

FREE Advice Here: "DON'T GO LOOKING FOR SIMPLE CHEAP POWER IN A MARINE PERFORMANCE ENGINE, YOU WILL ALWAYS COME UP SHORT, POSSIBLY BROKEN AND FRUSTRATED!"

Best Regards,
Ray @ Raylar

Waterslinger

Thanks Ray as a long time drag racer I understand motors and what cheap parts do when pushed. Just thinking some tuner may have a tune up for 93 pump gas.

Wish the coin was available to drop for one of you full tilt kits but it’s not in the cards right now.

Have you thought about doing some step 1 step 2 type kits?
You know cam and springs, cam and Dana exhaust etc etc.

Raylar

If you are a knowledgeable tech racer you would realize that the step process in the HO engine does not work. The engine is an air pump with a bad camshaft and a bad set of cylinder heads that both of which don't breathe for a damn. that's why this 500 cubic inch engine does not even make 1.0 hp per cubic inch, lousy right!
Fix the camshaft and the heads and then add an intake that can support that breathing above 4800 rpms and WHOLA! you have a pretty nice 525-570HP engine that breathes.
Also, try not to equate Octane of the fuel, ie: 93 as a power adder. Octane does not make power! In some cases where an engine needs lot more advance to make peak power, lets say 36 -39 degrees (from a slow burn combustion chamber or radical camshaft timing), then a 91-93 octane fuel or higher can discourage detonation and knock and is useful.
The weak iron heads on this engine don't like timing above about 32 degrees and they tend to detonate very easy when pushed and we all know what happens to hyper-eutectic cast pistons when they get a bad case of detonation and knock like this engine!
A good exhaust like the Dana system can add about 35-40hp easily and is a fairly moderate cost addition.
Save your hard earned dollars for a Raylar BCK103 engine kit and then you will have a reliable high powered 496 package that you can enjoy without the threat of destruction!

I will repeat: There is no safe power adder hidden in Merc 496 ECM's without engine exhaust or component upgrades!

Best Regards,
Ray @ Raylar

low_psi

I had whipple do their stage 2 tune +120 degree T-Stat on my 496 mag (non ho) PCM. I also removed the "turbulator" plates in the exhaust risers at the same time. I now have a noticable increase in mid range torque (seat of pants feel) and have picked up 4 mph (on the GPS). I think the Velocity hull (pad bottom) reacts well to minor motor changes, where other boats may see very little gain. I am no expert, just speaking from experience with my 496 in my Velocity 260.

See this thread I posted last week: http://www.offshoreonly.com/forums/v...top-speed.html