Offshoreonly.com - Upgraded 496, Fuel Pressure and AFR

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Quote:

Originally Posted by articfriends (Post 3525788)

When I tuned my Normally aspirated setup ecu on the water, I ran boat at all rpm settings from idle to rev limiter, part throttle, wide open throttle, I ran with a short prop, I ran with a tall prop, I ran dragging the tabs hard, etc, etc. By doing this I was able to vary the load and the "map" setting motor was at at different rpm's-example at 4000 rpm's with 24 pitch, it might be at 70 map (light load) and 14.5-1 afr, at 4000 rpm's with tabs dragging and a 28 pitch (heavy load), it might be at 95 map and 13.5-1 afr so when I go into my fuel tables I would increase my injector time at 4000 rpm's and 70 map by 10% to try to achieve 13-1 afr and I might change my mili seconds/injector time at 100 map by 5% to achieve 12.80 afr and my 90 map ms by 7% to get something in between, that is why (as you probably already know) that you can't just turn fuel press up or down. If you had a O2 sensor and a engine scanner that would show you what map your at your reprogrammer could do a lot to straighten out your fuel curve. Something else to remember though, I think you mentioned earlier about still changing your intake to something better, MAKE ALL YOUR COMPONENT CHANGES BEFORE TUNING IT, other wise your really wasting your time as things change. I tried to get my boat to run in as many map settings as possible when I tuned it on the water, by doing this my fuel curve/afr's matched the load and rpm's pretty good without just making it pig rich acrossed the board and if I am running light or loaded down hard it won't melt down either, Smitty

Smitty, thank you for the detailed reply and clearing up the "load". I am not going to do anything until I figure out what the final setup will be. I will need a new intake either way and now the seed was planted that Dart makes a carb/intake conversion for the 496 now. Good thing we are going into Winter.

Quote:

Originally Posted by GPM (Post 3525881)

You can't tune EFI properly by fuel pressure, unless it's rich or lean across the board.

GPM, thank you... this is what I was thinking as well. I advised that I should get an adjustable fuel pressure regulator and now I am stuck trying to figure this all out and blow thousands on computer programing on this ECM of mine in the process.

Thank you again for the HELP!!

You could always use an aftermarket ECM with your efi. Fast offers self tuning, after the basic set up just drive it around and it tunes itself. You can also link it to any computer and tune it from anywhere, real time, while you're running the boat. Preferably a shop that knows the system.

[QUOTE=TW720HVY;3526330]Smitty, thank you for the detailed reply and clearing up the "load". I am not going to do anything until I figure out what the final setup will be. I will need a new intake either way and now the seed was planted that Dart makes a carb/intake conversion for the 496 now. Good thing we are going into Winter.

GPM, thank you... this is what I was thinking as well. I advised that I should get an adjustable fuel pressure regulator and now I am stuck trying to figure this all out and blow thousands on computer programing on this ECM of mine in the process.
It shouldn't cost you "thousands" to get your ecu reprogrammed, not sure of the 555 guys but the norm out there for most tuners is they charge you a certain amount to tune your ecu mail order and you keep sending it back and forth at no further charge except s/h until you are happy, Smitty

Smitty, sending them back and forth sounds like a pain in the ass, what's the chances of them ever getting it right. Would any of these tuners travel and tune in the boat. Didn't you have Tyler tune yours ?

Quote:

Originally Posted by GPM (Post 3526878)

Believe it or not, 12 plus years ago mail order tunes were the only option and it was pretty much AZSM back then. The real problem is the fact it is a mefi 555, if it was mefi4 or older anyone could tune it these days. I haven't spoke to Tyler in a while but as of last year as far as I know he did NOT have 555 tuning capability. Doing a mail order tune, would it ever be right, well, it will be close at best unless you build the EXACT motor your tuner regularly builds in his own shop and has perfected on the dyno. If he could get the tuner to travel to him and tune his boat on the water it would be worth every penny to have a perfectly tuned boat , Smitty

Quote:

Originally Posted by GPM (Post 3526668)

What is the compatibility of the after market ECM to the current ECM/wiring set up of the 496?

Quote:

Originally Posted by GPM (Post 3526878)

Smitty, sending them back and forth sounds like a pain in the ass, what's the chances of them ever getting it right. Would any of these tuners travel and tune in the boat.

That would be the best option but since it is my understanding there are only 3 555 tuners out there the chances are slim. I will would more than likely have to bring it to them in California.

And yes, sending them back and forth is a pain in the ass, because there is always something that would need to be tweaked. Not to mention if the SOB is lost or damaged!

Quote:

Originally Posted by articfriends (Post 3527077)

The real problem is the fact it is a mefi 555, if it was mefi4 or older anyone could tune it these days. I haven't spoke to Tyler in a while but as of last year as far as I know he did NOT have 555 tuning capability.

Two true statements.

Thank you again for all the help.

Quote:

Originally Posted by TW720HVY (Post 3527217)

What is the compatibility of the after market ECM to the current ECM/wiring set up of the 496?

That would be the best option but since it is my understanding there are only 3 555 tuners out there the chances are slim. I will would more than likely have to bring it to them in California.

And yes, sending them back and forth is a pain in the ass, because there is always something that would need to be tweaked. Not to mention if the SOB is lost or damaged!

Two true statements.

Thank you again for all the help.

Mail order tunes are still the norm. Trying an aftermarket ECU yourself is not a good idea. "Self tuning" is not typically a good thing, especially in marine. It takes a significant of "know-how" to properly tune anything.

13:1 at cruising speed is not a problem, same as a stock motor. Higher fuel psi is needed to keep injectors in range of working so I would just recommend lowering accel enrichment and leaning idle/part throttle up. To do so properly, you already have the AF readings, now that just has to correspond to manifold pressure/rpm.

[QUOTE=TW720HVY;3527217]What is the compatibility of the after market ECM to the current ECM/wiring set up of the 496

I haven't touched a factory ECM since I went aftermarket in 1992. I don't know if your harness would plug in, you would have to call, the sensors would work. I only use the Fast stuff, there are other brands out there. And as Dustin said, it's not for the beginner, but there are shops out there that can set up the ECU so the boat starts and runs. Then like I said before, you can link up your laptop to their computer and they can tune your boat from anywhere there is an internet signal. You drive the boat, they tune in real time, you can actually see and feel the changes as they're made. They can run data logs, run closed loop to keep from melting the motor down during the process. It's not for everyone, it's just an option.

Quote:

"Self tuning" is not typically a good thing, especially in marine. It takes a significant of "know-how" to properly tune anything.

While it may not be for everyone, you can successfully self tune with a little research. NA applications are obviously easier.

I have the Holley Comander 950 with wideband O2, tune mine on the fly. You can run datalogs and make changes later.