I purchased the boat with the Arizona Speed and Marine 'performance' kit (extruded intake, flame arrestor, fuel press. reg. and ecu). I have since had the engine rebuilt with different heads, block and exhaust (picked up about 75hp). My question is, would it be advisable to have another tune done by ASM? I've already purchased the software and associated plugs to interface with the ECU. I've called ASM when I was first having problems with the motor (before the rebuild) and they had mentioned they could send me an updated program to download to my ECU if I provided them with a 'capture' of my data from the boat being ran. I've since had some tell me this type of tune is not always the best way to go....Thoughts anyone????

Thanks in advance!

Mail order tunes are sketchy at best unless it comes from a guy who has built a motor with EXACTLY same combination as yours. I have tuned several boats on the water this year w mefi burn and on my dyno and there ALWAYS seems to be lean and rich spots that need to be cleaned up, fwiw, Smitty

So, with that being said, is there an option (suggested contact) to do a tune without having the motor on a dyno?

^^^Yes, in the water as Articfriends suggested and does for some people. You will need a Wideband bung or two in your exhaust. In the water is 1 million percent better than a mail order tune and 500,000 percent better than on an engine dyno tune.

If the original tune was good, than you are for sure lean now. You need 75hp of extra gas in the new tune, plus adjustments across the rpm range. Timing might need to be changed as well.

I believe when you change the combo you should always retune and I'll go one further anytime you freshen a motor and make the slightest of changes you should retune there's no one tune fits all and furthermore when we build and tune something for a customer here on the dyno we always explain we always want to final tune for driveability in the water I don't feel you can do this as accurately as you would want it as a customer over the internet if it can be done real time over the internet then yes but to send you a file and you load it and try it I don't think your getting the best for your buck. Maybe ask the original engine builder if there's a way to data log a run and he can look at the data to make the appropriate changes. Best of luck Laz

It looks like you are less then three hours from Eddie Young at Young Performance. Contact him about doing a on water tune. He is one of the best anywhere. Don't wait too long as he gets very busy.

Padraig

Here at MEFITUNING.com I can help you out, should you wish to venture this way, or pay for me to come to you.

Thanks

I would not use ASM.

Not necessarily. Overly rich tunes can sap power too. His power gain could have been from changes that moved towards a more optimal AFR.