maverick1

I'm running a 502 EFI in 24' outlaw. What does it take to get more speed?????

I'm running 66 to 68 PGS depending on conditions, but I've added EFI reprograming (more fuel), CMIs, Crane roller cam with lift of .544, Hardin Marine spark arrestor, prop labbed, etc. etc. and I may have gained 1/2 a MPH.?!?!?!?

I did check my fuel rail pressures, which ran 38# @ startup and steadily fell to 30# @ WOT --- Soooo I pulled apart the VST tank and cleaned the screen on the high pressure pump.

I then ran the boat and NO GAIN -- I did NOT check the pressures while running (this time) , but did so in frustration on the trailer on the ramp with lower unit in water.... and .... 38# at idle and up to 3,000 rpms ( I stopped @ 3,000 becuase without a load on the system I feared I could damage something).

Short of more cubes or a blower - what does a guy have to do??

MAV

Without a blower

maverick1

Yeap - little to no gain over stock.

The original cam lost #8 exhaust - I replaced it with a crane roller cam & roller lifters.

MY cam is : Crane ...
13 HR 00078 duration .212 / .220
life @ .050 .543 / .564
lobe seperation of 114 deg.


Thoughts??? My pressure at speed and under load MAY still be down. I was just so frustrated on the water I didn't check it then - also my guage leaks during hook up - and I didn't feel like screwing with it - but after getting on the trailer - I couldn't leave with water without at least checking it there.

MAV

H2Xmark

who mapped your ECM? sounds like they did not get a good calibration for you, did they tell you to run 38lbs? also what do your spark plugs look like after a run? are they white are they burning a nice tan/brown color? what is your ignition timing set at? and what kind of rpm's are you turning now on top end? maybe hitting the rev limit?

Johno

Maverick1,
First off, I own a 24 Outlaw, you'll throw more money into this boat than what I believe they are worth to get that magic #. The 24 is a great "smaller" rough water boat. They as you know handle the rough real good for their size. The hull design is just not efficient for speed. I have a HP 500 in mine(+- 530hp) = low 70's. Check the post in Baja section & do a general search on the 24 Outlaw. One guy has almost a 1000hp in his & still has not hit 100mph. I am real happy with my Outlaw, but the fact is the hull is not efficient for flat out speed.
Good luck
PS try running a REV 4 prop made a huge difference. Also chat with Allan4 .

bobl

Sounds like fuel pressure is hurting you. It should not drop at WOT. In fact it should increase under load. I know the pumps used in the VST tanks don't flow much. That pump may just not be large enough. I've always replaced the VST system on the older engines I've modifed. Also, that cam is not going to give you any major increase over stock. The exhaust should wake it up a little. So, with your changes I would not expect more than 2-3 MPH anyway. Fix the fuel pressure before looking any where else for your problem

Dennis Moore

The camshaft is a real loser for a 502. I would think that it isn't as powerfull as the stock cam. How did you ever end up with it?
Dennis Moore

maverick1

The cam choice was after over ten calls to the Crane Cams Tech line. I've since realized that duration around .223 / .234 would have made more sense.

My prop is a mirage 25 ( with a little work), rpms are 4,600 to 4750 depending on conditions.

How would you change the pump to get away from the VST tank???

MAV

p.s. - To everyone - thanks for the feedback!

bobl

Mav...You can switch it to the "cool fuel" arrangement Merc uses, or make up your own system. Install a fuel cooler and external pump. Route the return line through the cooler to the fuel seperator.

Formula....reprogramming the ECU increases the pulse width of the injectors, thereby richening the fuel mixture. Raising the fuel pressure further richens the mixture. However, raising the pressure does not increase volume. If the pump doesn't supply enough fuel volume, raising the pressure will hurt the condition. Also, raising the pressure effects the mixture accross the board, from idle to WOT. Reprogramming would normally only alter the fuel curve under load, leaving the idle alone. I normally don't mess with pressure if I reprogram, other than fine tuning.

maverick1

I've tried two different mirage 23s and both gave me 5,000 rpms but no more speed and a poor mid-range.

Soooo, I've stuck with the 25.

next time out I'll check the pressure with the boat under load and see if my pressures are still dropping off as the rpms get up there.

MAV

ursus

the problem as several have already stated is the cam,,, you went smaller than stock 212/220 versus 224/224, hence, you have less power than before especially in the 4000-5000 range, the addition of CMI's and labbing the props probably gained you back what you lost from the cam so you broke even. The cam is your weak link now.