sutphen 30

yes and yes

i have mefi4b's and i can tune them really good but even i jumped ship to big stuff 3 on 1200hp mills .soon i'll be building 1500hp mills and again using big stuff 3.both builds have seperate coils,no more distriburors.
holley looks to be a great product,hell i even have an old commander 950 complete sitting on the self.dood info as usual hax's,thanks for the schooling.

onesickpantera

iTrader: (1)

X2, I am curious as well. Can you adjust timing tables as well? Is there a knock sensor? Etc?

I have a Holley system but a MEFI computer.

Griswald

The folks over at Serious asked me to write a short article on my EFI tuning experiences. Some on this thread may find it a decent read. Like Trash, I've had an absolute blast learning EFI and tuning my boat.

Click Here

Uncle Dave

Great article.

Given you live in Texas how did Bob at OBD in Redondo Beach out here in my backyard get involved?

I cant imagine you dont have anyone in your time zone you could call.

All in soup to nuts and dollars how much money and time did you put in?

Thanks!

UD

sutphen 30

i know on the mefi4b's i use,the knock sensors work.i tune to just tickle them when cruising in relatively flat water.i could watch them pull timing out.helped me be the total piker on fuel milage.
one time about 6yrs ago,i was learning the ignition maps for boost.knock sensors pulled the timing back as i had 5lbs boost and 40.5deg's of timing.engines are still in my boat running(never had to pulled them out).thank god for total advance limit of 40.5deg's i had put in.until i figured it out,i limited total advance to 34deg's and left it there.
all is good now.

Griswald

Bob sold me the MefiBurn software so he was the logical choice when I had questions.

I would guess total dollars to be around $17-1800 for the new Mefi4, AFR meter, and Mefi Software.

Time? IMO, irrelevant. I'm still playing with it to this day just to appease myself and try make it better and better. I see it as a learning experience more than anything and gives me something to do.

The Holley system looks appealing and it all comes down to a matter of choice and what one is willing to dive into.

Good thread.

ThisIsLivin

[QUOTE=Trash;3572805]Just use bigger injectors so you have more head room to avoid the 80% duty cycle issue.

From what I have discovered most EFI manufacturers including the guys at Kinsler who build the injection systems for the Indy cars use 80% as the limit for duty cycle. I have just for fun, using 242 degrees @.050" of intake timing which I'm currently running, and calculated that the Intake is off its seat 33.6% of the 720 degrees it takes to complete a full power cycle. Using this value in an injector calculator and accounting for enough flow to support my 675hp @50psi fuel pressure, I will need a 116lb injector. Now I realize this is impractical as controlling fuel flow at idle will be difficult at best. I have thought about using duel injectors. I would love to move to EFI but, When trying to wring out every last HP out of an engine, you have to consider everything. Fuel atomization is critical along with charge density. and squirting fuel into a puddle on top of the Intake valve is not the most efficient method of fuel delivery. Especially if your running in batch mode. Will the MEFI 4b support sequential and if so what is everyone using for crank position sensing? I know ACCEL and Fast have a distributor with a pulse ring. I have even thought about using an E38 ECM from a late model LS motor with EFILive. But the killer is how to attach a reluctor wheel to my BBC which is already shoe horned into my boat. By the way if no one here has tried EFILive it is much easier than I thought it would be.

HaxbySpeed

Biggstuff3 is a great system, and has been the system of choice at the track for years now.

Uncle Dave

Super informative thread.

Thanks Haxby Sutphen and Griswald.

I think the way this is likely to go for me is that Ill likely have Alexi at boostpower put it in, and walk me through it. Alexi had to put up with me in Florida, and I still feel bad for him. (lets just say a three hour long car ride after chorizo burritos)

I'll watch the tune and then be able to dial it at the lake using the same methods.

This thread grabbed me because I'm keeping my little boat

Ive optimized everything else this last fall note recirculation systems removal, and EFI is the last step. Only a very few 21ft tunnels have an ITS and fully hydraulic steering and are this nice overall. The reason I even care is that this little boat has a unique documented history that adds to its appeal to me personally, and keeping it trick throughout the decades has been fun and in my mind an 8 stack injector is about as cool as it ever going to make it .

Also likley the last step in this particular boats evolution. (yeah right)

Id say I am pretty good mechanic, and I could probably pull it off, but it would take significant time which I no longer have. I would pay to be given a live tour of this so I can "learn to fish" and take it from there.



Uncle Dave

Uncle Dave

Back to soup to nuts....

Go with your number for the electronics lets say

1800

+ stacks 5K, (more like 2K if a throttle body type?)

+ Injector kit 500

+ Fuel pump & high quality (weldon etc.) recirculating fuel assembly say 1,500

PLus polish job 1K so it looks like it belongs in a magazine

(maybe another 1K for custom matching pait worry about that later)

I got about 9800 Just in parts...to realize my dream- That about right?

UD