Has anyone done the 100hp upgrade to their 454mag mpi's or 502 mag mpi's.. I have the upgraded exhaust and breather already.. So you can send them your heads and they will do headwork,, send you back heads, new cam, roller rockers and programing of the ECU to match. Just wondering out there.

I have 502 MPIs and installed 500 EFI cams, larger valve heads (done by Tyler for another customer and I purchased them used) and Stainless Marine Exhaust. When I talked to Tyler he said he had a Tune for my MEFI 1s with this engine combination. The first time out with this set up I broke an outdrive so testing was cut short but even after the short trip the transom was covered with soot. After talking with Tyler he told me with this Tune I needed to install adjustable fuel pressure regulators and set them to 36 psi. Over the next winter I installed the regulators and made several other changes to the boat. The next summer the boat never made as much power as expected (slower). At the end of the summer I connected a PC with Rinda software and found there was a lot of spark retard going on. Knowing I had stock compression and a mild cam profile and fuel pressure set for the computer tune I looked for other reasons for the spark retard. I read here on OSO that the stellings drive shafts I was using could set off the knock sensors and have the computer pull spark. With that I disconnected the knock sensors. Bad move, I melted the number 3 cylinder spark plug center electrodes and the number 6 pistons in both motors. I again called Tyler with this long saga and he then told me that 36 psi was too low but should have been a good starting point for tuning but 38 psi would have been better. The bottom line is that when modifying and EFI engine a dyno tune is the best way to go... Off The Shelf Tunes are risky... This all happened 2 years ago and I have not gone back to that project.

That was a nice project Tyler, did back then. I remember the magazine article. The cost and effective results in porting the cast heads, just doesn't seem to match what you could get with a set of aftermarket heads. Machining the intake runner entrance will help, ECM changes for sure, cam and lifters.
Give Bob, @ Marine Kinetics, a call. I am know he could set you up with a complete package that will give you performance results that are proven in the boat.

I have those T.C. 509`s, they have about a 100 hrs on them. Only issues I have are .. the oil gets a bit dark pretty fast after oil change and after installing AFR gauges my ratios are not where I`d like them to be.

11.7 at idle
and just too rich anything under 3,000rpms.
WOT one motor is 11.9ish the other is 13.4ish so I just don`t open it up all the way.

Only point where its good is around 4,000rpms they both are right at 12.5ish


Otherwise the motors have been running without any issues. Made 520hp 620tq

He added about 150 hp to mine. I had Tyler dyno it, then I installed it and ran it for a little bit.
Then I went back and had him hook his lap top to it and adjust it in the boat. Mine was rich at first. Left a black transom. Took it back and he dialed it in. Have had no problems and I have run it hard at times. If this economy ever comes back he will be adding more horsepower to mine.

I did the 100hp kit on a 454 mpi installed in a Nordic Rage. Tyler sent me the components and I had a local machine shop do the head work. Tyler reprogramed the computer, checked and flowed the injectors. The boat ran great with no issues and the tune was correct the first time. No black transom at all. I picked up about 5 mph. Tyler was available by phone to answer my questions. I would not hesitate to do it again.