Technology has come a long way. Not too long ago, the thought of a 9.5:1 engine, running 12lbs of boost, on pump gas, making 2hp per ci, with a full warranty off the showroom floor, was a crazy concept. Now, every dodge dealer has a couple sitting on their lot. I know its not a "boat " engine, but each hellcat engine gets ran on a dyno for 42 minutes, at 5000rpm, with 90% load. Not 42 seconds, but 42 minutes. Thats a long time. So its not some "oh its a 10 second drag race engine". Show me one aftermarket marine engine builder that validates an engine like that on their dyno. Most do a couple 10 second dyno pulls and thats their claim to endurance testing and tuning. Guys are beating the crap out of those engines off the showroom floor slamming down 9 and 10 sec 1/4 mile times in a 4500lb car all over the place, and then driving them to work monday morning.

My point is, not too long ago, the average marine supercharged engine ran locked timing, read spark plugs for fuel mixture (many dont know how to read a plug), never monitored intake air temperatures, and so on. Thats all you heard about was blower motors burning down. Today, you can do alot more careful tuning with ignition maps, wideband, and so on.

It doesnt end there though. You need the whole package. The right engine tolerances, parts, spark plugs, head gaskets, valves, valve seats, valvetrain, temperature control, and so on if you are building for reliablity. Theres so much more to it, than 2psi of boost, whether or not the engine will succeed. 5lbs with a crappy tune, is worse than 7lbs with a good tune imo.

All very good points...I'm still trying to wrap my head around the timing "maps" I understand what is being said with it but I'm still trying to figure out real world in the boat not on a dyno how do I judge if the timing is coming in too early too late not enough timing too much timing etc...that's my biggest concern at this point....I think the boost will stay where its at for now and like you guys have said I will up it later once I get all the other bugs worked out...I think changing too many variables at one time trying to get max performance out of it while tuning is just asking for trouble...I'm sure that I'm over thinking all of this from the fear of hurting the engine...gonna try to settle down and try some things slowly and see what happens...or all else fails I'll buy a keg and trailer it to Chicago and look for MT hahahaha

I will be researching and buying an IAT gauge soon as the intake is off now so I plan to at least drill and tap it before it goes back on...should the sensor be located directly under the blower I'm assuming...like where a boost gauge would be mounted??

Thanks guys!!

Here is one of many posts on line of how to read a spark plug. https://www.dragstuff.com/techarticl...ark-plugs.html

I wouldn't hold the engine at WOT for 1/4-1/2 mile to check the plugs. If your tune is pretty far off you could cause substantial damage.

very good read!! thanks for sharing def helps me a lot!!

IMO and I am no expert but boost numbers dont mean alot as an overall. boost only exists due to restriction between the blower and cylinder. you are at 5 pounds making 'X' amount of power but if you are at the limit of what can be pushed through the ports, valves, and cam allows then you could raise the boost to 40 pounds and maybe only make another 20-30 horsepower. if you are at 5 pounds and all the other factors are capable of more then 8 pounds could net 100 hp. I have seen plenty of motors that made 600 hp at 5 pounds and with a cam change made 700 hp at 3 pounds. why? the cam was holding it back and the new cam let the air and fuel fully fill the cylinder. egt would tell a lot about how well the cylinder is really filling plus o2 sensors to let you know what is going on under load.

the problem with detonation, is the temperature and pressures spike hugely when it occurs.

take spark advance for example. You can increase spark advance, and increase cylinder pressure/tempeature However, that doesnt necessarily equate to more output at the flywheel. A simple adjustment of the timing curve, can have a detrimental effect to the combustion process.

this is a reason I dont get worked up over egt's. You can advance the timing, and see egts cool down. However, that doesn't mean the cylinders peak temperature is cooler. All you did was light the fire sooner, and the spent gasses the probe sees have cooled down sooner. If you had a temp probe on the intake valve, youd see the intake valve get hotter, while the egts get cooler with more spark advance. The spark plug will tell a better story imo. Of course, this is where tuning ignition curves on a dyno is enlightening. Egts are great to see if somethings going wrong, but im not sure id want to tune my engine around them.

then theres the fuel mixture. Pure Gasoline makes its best power at 12.5:1, or with an ethanol blend, maybe 12.2:1. Youll see guys saying their engines made best power at 13.5:1, or 11.5:1. Imo, its not that air fuel ratio that made the best power, its that their timing setting caused it to make best power there.

meaning, if you made best power at 11.5:1, you prob had too much spark advance in it. If you made best power at 13.5:1, you probably didnt have enough spark advance in it. Simply put, rich mixtures need lots of advance, lean mixtures dont. A guaranteed way to burn a supercharged engine down, is a lean mixture with lots of timing. Prob why many years ago, guys were scared to run more than 28 or 30* total timing. It prob wasnt the timing that hurt the engine, it was the mixture.

at any rate, today we can get away with alot more, if youre willing to invest in the tools to learn whats going on in the engine. Id love to get a dyno in my barn, with some tfx pressure transducers to monitor cyl pressures, along with an 8 pack o2 setup.

this looks like it could be very enlightening
http://www.tfxengine.com/faqs5.html#TFX1