SAC vs VCO

How to make it go fast

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Re: SAC vs VCO

Postby RCCUMMINS89 » Thu Nov 12, 2015 7:52 pm

Popping the fss can be eliminated by how you let off the throttle. Let off slowly, it won't happen.

One can not judge injector flow by cross sectional area, very misleading.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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Re: SAC vs VCO

Postby spencerdiesel » Fri Nov 13, 2015 7:47 pm

Sorry I meant the 4x13 being .000531, and the 5x12 being .000565. Or is that what you meant by cross sectional area? Thanks for the letting out slow part, that will help my fss live.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: SAC vs VCO

Postby RCCUMMINS89 » Fri Nov 13, 2015 9:15 pm

That's what I meant.

For example.........5x17 show some crazy "percentage over stock" with cross sectional area. In reality they flow 100% over stock. Cross sectional area is unbelievably misleading. Also, vco flow more than sac, per size. Quite a bit in some nozzles.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
RCCUMMINS89
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Re: SAC vs VCO

Postby spencerdiesel » Sun Nov 15, 2015 9:09 am

Had no idea, Appreciate it greatly. Is the percentage of flow contributed to the low pressures of the VE, or is flow of the IP not a factor here?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: SAC vs VCO

Postby RCCUMMINS89 » Sun Nov 15, 2015 9:27 am

That is test bench flow, not ip flow. Therefore the pressure of an injection pump is not a factor in what they test flow.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
RCCUMMINS89
14mm rotor
 
Posts: 4825
Joined: Mon Oct 03, 2011 4:19 pm
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Re: SAC vs VCO

Postby spencerdiesel » Sun Nov 15, 2015 10:02 am

The water is clearer now, thanks.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
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Re: SAC vs VCO

Postby spencerdiesel » Wed Nov 25, 2015 4:27 pm

One of my friends has a IC 5 speed w/ 384k on it. He's blended WMO for the past 220k and is still on factory sticks........so as you can imagine they are ready to be retired.

Only mods are 4in exhaust, 16cm housing, Airdog, BD pin and spring, and fuel screw 1 turn from bottoming. He will definitely get a different turbo when he gets injectors of course.

Truck is a DD, and tows every once in a while.

He wants to get roughly a 5x14 size for room to grow (I know they need a LOT more air, not to mention taking 3 turns out of the screw until he gets the air). What turbo would you recommend for him?

I realize the towing part throws a wrench in things, but he will never try and use near all the fuel while towing. Thanks
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: SAC vs VCO

Postby RCCUMMINS89 » Wed Nov 25, 2015 6:55 pm

Depends on how he uses the truck and how fast he wants it to spool.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
RCCUMMINS89
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Joined: Mon Oct 03, 2011 4:19 pm
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Re: SAC vs VCO

Postby spencerdiesel » Wed Nov 25, 2015 8:04 pm

He would be fine with similar spool to the h1c/16. Slightly doggier spool would be acceptable
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: SAC vs VCO

Postby RCCUMMINS89 » Wed Nov 25, 2015 8:20 pm

62fmw would be the best for "future power". With 5x14, with good tuning......would spool about the same as the stock turbo with a 18 or 21cm housing.

Stock like spool..........60/68/.70. A little quicker, would be the S300G
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
RCCUMMINS89
14mm rotor
 
Posts: 4825
Joined: Mon Oct 03, 2011 4:19 pm
Location: Spirit Lake, ID
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Re: SAC vs VCO

Postby spencerdiesel » Wed Nov 25, 2015 8:35 pm

Thanks. He might be considering a 351cw, and just throttle managing EGT's when towing. I know that's the small side, but he probably has no use for more than 375 hp when playing, and he'd right-foot-regulate when towing.

I should have mentioned the power goals to begin with, but it's a meh guess.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: SAC vs VCO

Postby RCCUMMINS89 » Wed Nov 25, 2015 8:38 pm

And that'll work fine. Just have to dial it way back.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
RCCUMMINS89
14mm rotor
 
Posts: 4825
Joined: Mon Oct 03, 2011 4:19 pm
Location: Spirit Lake, ID
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Re: SAC vs VCO

Postby spencerdiesel » Sat Jan 02, 2016 7:56 pm

Someone theorized one time that large injectors caused timing (when spacer was used) to retard at higher revs, is this true?

And at what injector size/flow might this be an issue?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: SAC vs VCO

Postby RCCUMMINS89 » Sat Jan 02, 2016 8:15 pm

Only if one is dropping case pressure. Stock injectors can drop case pressure. But this can be fixed by raising case pressure, and inlet pressure. A test bench, or at minimum a case pressure gauge is only way to monitor this.

A timing spacer would have no bearing on the above.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
RCCUMMINS89
14mm rotor
 
Posts: 4825
Joined: Mon Oct 03, 2011 4:19 pm
Location: Spirit Lake, ID
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Re: SAC vs VCO

Postby spencerdiesel » Sat Jan 02, 2016 8:20 pm

Good to know, I didn't think something that just allows the piston to travel farther would affect that
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 1022
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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