bypassing the FDC

[whistlingdeuce]

I am wondering how much trouble it is to bypass the FDC. Or whatever it is called. I know that you need to install a pyro and a boost gauge wouldn't be bad iddea either but what exactly needs to be done. is it pretty easy or a real PITA??? Thanks for any and all info.

 

[Westech]

its not that bad to bypass the fdc. Use the searh in the Utilities (on the left of the page)there have been many many very good post with pics to help you along the way.

 

[houdel]

I am wondering how much trouble it is to bypass the FDC.

Why do you want to bypass the FDC? There is no reason to do so unless your FDC is leaking fuel into the oil. If you are looking for more power, there are easier ways to get more power than bypassing the FDC. Just make sure you install a pyrometer first!

 

[whistlingdeuce]

RE: Re: bypassing the FDC

what else can be done to get a some more power out of them without goin crazy???

 

[houdel]

RE: Re: bypassing the FDC

Following is the link to adjusting the fuel delivery. Bypassing the FDC is claimed to be about the same as increasing the fuel delivery adjustment by about one full turn. WARNING! One full turn increase in the fuel delivery is dangerous. You get gobs of power, but you also run the risk of raising your Exhaust Gas Temperature (EGT) to the point of damaging or destroying your turbo. If you do not have a pyrometer installed to measure EGT, I would recommend you do not turn up the fuel more than 1/3 turn (2 flats on the adjusting nut), and even then use caution when driving. 1/3 turn will give you increased power, driveability and starting. Do not go any further until you have a good pyrometer installed. Then adjust your fuel rate to the point that you do NOT exceed 1250F EGT pre-turbo under the worst driving conditions (heavy load, long uphill climb).

http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=303

 

[jimk]

RE: Re: bypassing the FDC

I disabled it.Took 2 1/3 turns to get the boost down to what it was before(12psi at 2500). This is up 4-6 psi from stock LDT, from what I have read. Had turned down another 1-1/2(?)earlier, from where it was set as a LD. For bypass I had to replace the plastic line from filter, it was too short to reach the new port. Honing out the two self align furrels [for reuse] was no fun and took some time. Having new ones handy would have been betterbut have not found them local. I figured I'd play it safe with the fuel/oil issue. Pretty much stick with diesel anyways. The thing is still a multi-fuel, just reduced power with other fuels.JimK

 

[houdel]

RE: Re: bypassing the FDC

JIMK - Did you retime the injection pump when you added the turbo? As best I can recall, LDs inject 24 or 25 degrees BTDC, turbos inject at 20 degrees BTDC.

 

[cranetruck]

Re: RE: Re: bypassing the FDC

.....Pretty much stick with diesel anyways. The thing is still a multi-fuel, just reduced power with other fuels.JimK

Except for biodiesel and veggie oil. The FDC reduces the amount of fuel delivered and you are better off with it bypassed in this case.
Biofuels are more viscous than diesel, but the BTU values are lower and don't fit the curve. The FDC only works and is calibrated for the fuels listed in the TM.

 

[jimk]

RE: Re: RE: Re: bypassing the FDC

Lee, Yes, I retimed the IP to 20*. Cranetruck's piece in MVMag made the job easy.

Whistlingdeuce, Bypassing FDC, and adjusting fuel delivery rate, are both easy tasks. I think a pyrometer is a must have, or at least run one for a while. As Lee points out the IP needs to be set correctly. A boost gage is nice, too. Results of an adjustment can be seen immediately on the boost gage. The pyrometer takes time, and effort, to reach peak EGT. You'll need to run under full load for an extended period of time. A big hill and/or heavy trailer works better than the brakes. At 12psi I found high EGT's only at the lower end of operating range. A downshift, probably overdue, lowers the EGT immediately. The factory LDT IP setting would probably never let EGT to get too hot. Everyone should consider adding a pyrometer . Someone, or something, could have changed the setting during the past 20-40 years. There may be some additional HP available depending on which turbo you have. My D turbo may be adding 20-30% at 12psi. It can easily peg the boost gage(15+) with a small increase in fuel delivery. The pyro will respond with higher EGT's. JimK

 

[m-35tom]

RE: Re: RE: Re: bypassing the FDC

a pyro made by vdo ( which is the dc amp type of powered meter) is available from summit racing for around $60, complete kit. add a resistor to use on 24 volt. i don't remember the value but i got mine at radio shack. let me know if you need the specs and i will get them.

 

[Dave_McConnell]

RE: Re: RE: Re: bypassing the FDC

This was posted on the mil-veh site today by Greg

Hey guys.Just wanted to tell you about something I witnessed this weekend.I attended a truck and tractor pull this weekend at the Crawford County Fair in western Pa.What does this have to do with military vehicles you ask?One of the modified diesel tractors was using a Hercules 478 in his Oliver 2150.He is working some bugs out of it but this thing was screaming.After the pull I asked which Hercules engine that he was using.He said 478.He is turning this thing 6,000 rpm at 85 pounds of boost.He is using the military heads and intake because they flow better than the commercial stuff.Keep in mind that he has copper head gaskets,a dry sump oil system and a fuel injection system.But the bottom end is basically stock.I think I'll turn my pump up a bit.Yes I will watch temperatures too.Adjust at your own risk.Neat though.Greg

Makes you think a bit.

 

[jasonjc]

RE: Re: RE: Re: bypassing the FDC

Yes but can he drive it down the road for hours at a time like that????? How many runs befor a rebuild?????

 

[doghead]

Re: RE: Re: RE: Re: bypassing the FDC

This was posted on the mil-veh site today by Greg

Hey guys.Just wanted to tell you about something I witnessed this weekend.I attended a truck and tractor pull this weekend at the Crawford County Fair in western Pa.What does this have to do with military vehicles you ask?One of the modified diesel tractors was using a Hercules 478 in his Oliver 2150.He is working some bugs out of it but this thing was screaming.After the pull I asked which Hercules engine that he was using.He said 478.He is turning this thing 6,000 rpm at 85 pounds of boost.He is using the military heads and intake because they flow better than the commercial stuff.Keep in mind that he has copper head gaskets,a dry sump oil system and a fuel injection system.But the bottom end is basically stock.I think I'll turn my pump up a bit.Yes I will watch temperatures too.Adjust at your own risk.Neat though.Greg

Makes you think a bit.

He is most likely injecting water into the intake or cylinders directly(to cool the pistons). Also most likely at full revs for about 15-20 seconds, max. "He is turning this thing 6,000 rpm at 85 pounds of boost" I dare anyone to try that for a mile or more on the highway! "I think I'll turn my pump up a bit. Yes I will watch temperatures too. Adjust at your own risk" Makes me think that you are going to be shopping for an engine soon, I bet!

 

[Dave_McConnell]

RE: Re: RE: Re: RE: Re: bypassing the FDC

I only posted the tractor puller engine info because I thought the amount of boost they were using was interesting. I like the slow, stock engine myself. I put over 300 miles on my truck this weekend going to the Clare Michigan show. Did it mostly at 50 mph. The truck actually feels best at 45mph.

 

[doghead]

RE: Re: RE: Re: RE: Re: bypassing the FDC

No need to feel the need to be defensive, I was interested too(seeing this can definitely give you some confidence in a multi-fuel)! I have seen a couple of the Oliver motors used in pulling tractors, myself. I am amazed anytime I see a motor that was built to run less than 2500 rpm, run around 5000-6000 rpm! Just remember,Tractor pullers are a rare breed that can only see 300 feet ahead!

 

[Dave_McConnell]

RE: Re: RE: Re: RE: Re: bypassing the FDC

I just get tired reading posts knocking the multifuel. I like the motor and it was nice reading about someone get a whole lot out of it, even if for a short distance. Plus he used military heads and intake!

 

[cranetruck]

RE: Re: RE: Re: RE: Re: bypassing the FDC

I like it Dave and get your point.
The multifuels are not rated, like most commercial engines, which can only run at "full power" for a certain amount of time, like one hour on one hour at a lower power type of thing.
The multies can run at full power 100% of the time. The lds465-2 in the 8x8 is coupled to an automatic transmission and is set to shift at 2,800 rpm, close to the goverened 3,000 high, IIRC.
High rpm's are not only for high speed, you see them in any gear, of course.

 

[jasonjc]

RE: Re: RE: Re: RE: Re: bypassing the FDC

That is a great point about the full power 100% of the time. Alot of people look at this big eng and don't understand why the HP is so low. It has more to do how it is usee. You can crank up the power but than you can't run as hard as long.