hammerdown500

I may have missed this in an earlier comment
But what about converting or connecting the ecm and engine harness to the existing boat harness. How hard is it to make the big plug conversion

hammerdown500

Also does anyone have any experience with using the fast efi 2.0
setup on our mpi ramjet intakes

launchpad475

iTrader: (1)

Fairly straight forward, depending on what you are starting with. I just say that because the 502 charging harness and the 500EFI charging harness are different. But on mine, the 500.. There is a Key on, tach, blue with tan and tan with blue for alarms and temp. The 500 has water temp going thru the ECU, so its slightly different. Then you make the plug on the other end to match the Holley pigtails.

Tibbstoy2

iTrader: (1)

I made the switch a couple years ago from Bravo drives to Arnesons (with BAM transmissions) and I turn 34p 18" diameter SSM #6 props. Shifting in gear usually causes a stall (drops RPM from 1000 to 500) - IF I don't touch the throttle. I've learned to bump the throttle slightly (more air) and it reacts normally without a change in RPM. It seems the IAC doesn't react quickly enough to overcome this. The issue here is you need to have lots of hands in a tough docking situation.

I run the HP EFI on my NA 540's with multiport injection and DIS ignition. My cams aren't too wild, but the engines currently don't like to idle much below 600 (with carbs 750 used to be iffy).

I'm curious what idle tuning you can do to help big-propped boats fine tune this and counteract the stall? I've tried several techniques, curious what the pro's do?

hadleycat

This is what solved the stalling for me and I was taught about this by Alex Haxby . On the timing table note which cells you idle in. I set the timing to about 8 degrees in these cells. Now I look at the cells I move to when I bump the boat into gear. I advance the timing to 22 degrees in those cells. The timing will react much quicker than the IAC motor and help save the stall.

indysupra

iTrader: (3)

Tibb like Hadley stated its all in the timing. I've got 33's on my fountain and it took 20-30 min to get both motors acting right in and out of gear. I run more than 22deg in gear and that has helped me. If you need any help your more than welcome to call me. 317-538-3100. Haxby has saved me tons of time over the last two builds. He is the man!!

Tibbstoy2

iTrader: (1)

This is what I needed to hear!

I actually had been increasing my timing below idle, and noticed it helped... but only by changing columns (not rows relating to MAP pressure changes).
Here's the "basic version":


I haven't seen any tables/global folders with timing at 8 degrees at an idle? I use cranking timing of 15 degrees and idle around 28.5 degrees at 950 rpm. If the rpm drops at that RPM, I ramp up to 31 degrees by 800 rpm and 35 if it stumbles to 400.

Should I be drastically changing my idle timing? My engines seem to like high idle timing, will retarding the timing this drastically help the engine cope with the load? I assumed 30+ degrees under the load of shifting was a good thing based on how it likes to idle there.

indysupra

iTrader: (3)

I run as high as 35 deg in gear idle. The bigger the props/load the more it helps. What is your iac percentage at idle in neutral?

Tibbstoy2

iTrader: (1)

IAC % at hot idle is ~3%. I've actually programmed in an IAC kick (originally intended for AC fans kicking on) to work in time with my shifter mechanism. I use a limit switch with a cam that rotates to give the IAC a heads up that I'm shifting. This worked pretty well with Bravo drives since the cone clutch had a delay, but I pretty much can't get it to react fast enough with the BAM tranny. It makes complete sense that timing could be the answer since the Holley system is intended to trim timing instantaneously - instead of waiting for an IAC motor.

35 Degrees of timing in gear makes sense... you're still getting the reduced cranking timing to help the start, but it sounds like I'm not giving it enough timing fast enough.

I read your post above that you "run more than 22 deg in gear"... how low do you run out of gear? Can you possibly post a picture of your timing table? I guess what I'm looking to see is how fast your chart changes and by how many degrees. Thanks!

indysupra

iTrader: (3)

I'm 10 deg out of gear. I can send you a timing table email address?