300x VST W/EXTERNAL PUMP PROJECT

[Liberator*21]

Just got done with this project. Wanted to be able to adjust fuel pressure using an external regulator but didn't want to remove the VST and run a return line to the tank and have to worry about what to do with the bleed line going to the VST if I removed it, so this was my way of having my cake and eating it too..........

https://skydrive.live.com/redi...9g%24 (https://skydrive.live.com/redir.aspx?cid=ce928b49df3c74f8&page=play&resid=CE928B49DF3C74F8!388&authkey=6zF!CxZc49g%24)

[cali kid]

Hi,nice work.What have you determined for best fuel pressure?What have you tried and what were the the results?
Thanks ~Randy

[Liberator*21]

Randy,
Just start'n out on playing with the pressure. I did mod my o'l OEM pressure reg to put out 39 PSI, ran good at that. It's gonna take a little time to dial it in, but now at least I can dial it in.........LOL.

[Dave Strong]

Nice job!!

Dave

[Liberator*21]

Thanks Dave, appreciate it...........:cheers:

[mrcrsr]

gary, the vst belongs in the dumpster, lol!! the fuel pump is not big enough for any kind of real performance, alot of the engines i get in here are blown up because of issues w/ the vst, not to mention you have 2 fuel pumps and a needle/seat that can have issues. captn steves engine is patterned on a 300x, and runs an x computer, and uses a bosch 044 pump in the boat. i believe we found 40 psi to be the best compromise, the issues w/ the x computer are that it is lean at idle, rich in the mid range and slitely rich on top, but you cannot reduce the fuel pressure any more then that otherwise the idle becomes too lean. i still could spend a lil more timing playing w/ tps settings to try and correct it, but this is where the wolf should enter the door!! in hindsite though, you'd lose your oil injection if you were to plumb it for an external pump, which is the downside of this, but then again, oil injection is great when mercury is warrantying the engine, when you have to warranty the powerhead yourself because of an oil injection failure, well.....

[PanRonnie]

if you go down that route it might be an idea to hook up a DDT/diagnostic software to your present engine and take some
TPS/Map * RPM = Injec/ms values prefferbly while towing something as to get the base injec value without acceleration compensation
can take out a lot of the gues work

[Liberator*21]

gary, the vst belongs in the dumpster, lol!! the fuel pump is not big enough for any kind of real performance, alot of the engines i get in here are blown up because of issues w/ the vst, not to mention you have 2 fuel pumps and a needle/seat that can have issues. captn steves engine is patterned on a 300x, and runs an x computer, and uses a bosch 044 pump in the boat. i believe we found 40 psi to be the best compromise, the issues w/ the x computer are that it is lean at idle, rich in the mid range and slitely rich on top, but you cannot reduce the fuel pressure any more then that otherwise the idle becomes too lean. i still could spend a lil more timing playing w/ tps settings to try and correct it, but this is where the wolf should enter the door!! in hindsite though, you'd lose your oil injection if you were to plumb it for an external pump, which is the downside of this, but then again, oil injection is great when mercury is warrantying the engine, when you have to warranty the powerhead yourself because of an oil injection failure, well.....

Charlie,
Thanks for the info. As you know I had a Wolf V500 ECU, and I'm just not tech savy enough to use it, hell I went into brain overload just trying to resolve my idle issues...........LMAO. You and Dave got the know how on the Wolf......

I had pre-mix on my last motor and it does provide a measure of safety, it's a pure pain in the ass.............LOL. I hear what your saying, but I'm gonna stick with this set up for awhile and play with it. Injectors are coming out over the winter for clean & flow because there running a little fat right now since I end up with a black prop back on the trailer..........
Thx,



if you go down that route it might be an idea to hook up a DDT/diagnostic software to your present engine and take some
TPS/Map * RPM = Injec/ms values prefferbly while towing something as to get the base injec value without acceleration compensation
can take out a lot of the gues work

Ronnie,

That's a great idea, why didn't I think of that. I've got a DDT so that's no problem, but the towing might be..........it's already Fall here and the water temps have dropped a bunch, so towing one of my over weight buddies in a tube is out...LMAO. But I'll try that first chance I get.
Thx,