Truckers, lets see your rigs!

Yellow Jacket said:
Is there an easy way to raise supply fuel supply pressure? I've never put a gauge on it, but my brother's 3406b we are gonna sled pull in a couple weeks. If I piggy backed a low pressure Larger FASS pump like a 240 (at 16 psi or so) to the factory lift pump, would that help or hurt?
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You can take the factory mechanical transfer pump apart and shim it with a few washers and increase the pressures. But you shouldn't have to worry about it to much if you're still running factory nozzles.

My dad ran his for years with the fuel screws out of the injection pump with no fueling issues. He went to 100% over nozzles and it quit at the end of the track.

I'm not sure if the heavy duty pumps function differently that the pickup pumps, but my dad runs a 220 gph and I have a 150 gph pump.

BRE said:
At that rate wouldn't it be easier to outfit the fass to be a standalone?
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Both my truck and my dads truck have a FASS plumbed into the stock transfer pump. You'd have to make a block off plate and such if you wanted to eliminate it. My dad drives his around with just the mechanical pump and turns the FASS on when he pulls, my FASS is wired into the key and is always on. My FASS will make 50 psi at an idle and I've never seen it drop below 45 psi.
 
At the point a B/C starts dropping pressure it would be pointless to try and shim the pump, it is a plunger style pump and all the spring does is return the plunger/piston to the open position.
 
Yellow Jacket said:
Is there an easy way to raise supply fuel supply pressure? I've never put a gauge on it, but my brother's 3406b we are gonna sled pull in a couple weeks. If I piggy backed a low pressure Larger FASS pump like a 240 (at 16 psi or so) to the factory lift pump, would that help or hurt?
Click to expand...

If pressure is not dropping past 32-34 under a hard pull then there will be little to gain with a fass.
 
BRE said:
At that rate wouldn't it be easier to outfit the fass to be a standalone?
Click to expand...

Depends if you want to leave yourself in a postition to have your truck where is wouldn't run at all or one where you could still limp it somewhere.

In the moment that a standalone electric pump fails you would be stranded, even a bad mechanical transfer pump doesn't fully quit working, you could still limp it home or to a shop.
 
SmokinCAT said:
At the point a B/C starts dropping pressure it would be pointless to try and shim the pump, it is a plunger style pump and all the spring does is return the plunger/piston to the open position.
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I must have missed that it was a BC. I was thinking it was a Cat...

If you're going to run a transfer pump on a mechanical cummins you need some sort of regulator to regulate the fuel pressure of the transfer pump in relation to engine speed. If you buy a FASS or Air Dog kit for an 855 it comes with a oil pressure regulator that regulates the pump. If you just try to run the pump without regulating the pump speed at low rpms it will push the fuel through the injectors.

A friend of mine thought he would do that with his truck. Turned the electric transfer pump on while the engine wasn't running and filled the oil pan full of fuel.
 
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SmokinCAT said:
Depends if you want to leave yourself in a postition to have your truck where is wouldn't run at all or one where you could still limp it somewhere.



In the moment that a standalone electric pump fails you would be stranded, even a bad mechanical transfer pump doesn't fully quit working, you could still limp it home or to a shop.
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I was under the impression it wasn't a working truck. Otherwise I completely agree with you.
 
BRE said:
I was under the impression it wasn't a working truck. Otherwise I completely agree with you.
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I couldn't remember if they pulled that duramax around with it or not, even I couldn't bring myself to just run an electric, my stock transfer pump will pull 40psi at an idle through my electric so I don't have to run it unless I'm at heavy throttle app.
 
So I found a Pete Cabover with a 12v71 sitting out in the weeds today...

Pics to come when I get home
 
D74C53B0-4378-4B20-807D-11CF1E545DF0.jpg

5AA468FE-1CD9-4E95-9ECC-C81578867890.jpg
 
Actually I think it is. Lots of trucks and equipment for sale there. I'm going to call Wednesday and see what he wants for it
 
That thing would be neat for a toy only since all it is good for is turning diesel fuel into noise.
 
SmokinCAT said:
That thing would be neat for a toy only since all it is good for is turning diesel fuel into noise.
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Basically. There are several twin turbo 12v71 in equipment around there, maybe I'll snag one of those too

I'd imagine it's somewhat rare, probably someone out there who would want more than me
 
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SmokinCAT said:
If pressure is not dropping past 32-34 under a hard pull then there will be little to gain with a fass.
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Ok, I will get a gauge on it and verify the pressure.

It is a '88 3406B I believe, I have the screws in the ashtray. And I have a s480 with a 1.58 a/r currently. Gonna switch to a s478 with 1.32 a/r before next Friday night's pull. It has a 15spd double overdrive and 24.5 tall aggressive field rubber. We pull in 7th or 8th, whichever runs 25mph at Rev limiter....

His '93 DDEC 2 with 550hp Cal and s475 billet 6 blade has outpulled it last 2 years in 4th gear on a 10 SPD, but the extra rpm plays in the favor of the Detroit it seams...

Because the Cat will eat the 12.7 for lunch over the road hauling grain... But sled pulling the gearing doesn't seem to work in it's lower rpm favor
 
Yellow Jacket said:
Ok, I will get a gauge on it and verify the pressure.



It is a '88 3406B I believe, I have the screws in the ashtray. And I have a s480 with a 1.58 a/r currently. Gonna switch to a s478 with 1.32 a/r before next Friday night's pull. It has a 15spd double overdrive and 24.5 tall aggressive field rubber. We pull in 7th or 8th, whichever runs 25mph at Rev limiter....



His '93 DDEC 2 with 550hp Cal and s475 billet 6 blade has outpulled it last 2 years in 4th gear on a 10 SPD, but the extra rpm plays in the favor of the Detroit it seams...



Because the Cat will eat the 12.7 for lunch over the road hauling grain... But sled pulling the gearing doesn't seem to work in it's lower rpm favor
Click to expand...



Friendly FYI, there is no such thing as a 15 double over.
 
Chrisd91 said:
Basically. There are several twin turbo 12v71 in equipment around there, maybe I'll snag one of those too

I'd imagine it's somewhat rare, probably someone out there who would want more than me
Click to expand...

They had truck twin turbos as well, didn't help make up the god awful lack of torque.
 
Yellow Jacket said:
Ok, I will get a gauge on it and verify the pressure.

It is a '88 3406B I believe, I have the screws in the ashtray. And I have a s480 with a 1.58 a/r currently. Gonna switch to a s478 with 1.32 a/r before next Friday night's pull. It has a 15spd double overdrive and 24.5 tall aggressive field rubber. We pull in 7th or 8th, whichever runs 25mph at Rev limiter....

His '93 DDEC 2 with 550hp Cal and s475 billet 6 blade has outpulled it last 2 years in 4th gear on a 10 SPD, but the extra rpm plays in the favor of the Detroit it seams...

Because the Cat will eat the 12.7 for lunch over the road hauling grain... But sled pulling the gearing doesn't seem to work in it's lower rpm favor
Click to expand...

Your B will handle 26-2700rpm easily.

Like BRE said, all 15spds with OD re a single over, the over drive is in the main box which is why high is up against the dash, along with the transmission just being an RTO and not a RTX series.
 
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Yellow Jacket said:
Ok, I will get a gauge on it and verify the pressure.



It is a '88 3406B I believe, I have the screws in the ashtray. And I have a s480 with a 1.58 a/r currently. Gonna switch to a s478 with 1.32 a/r before next Friday night's pull. It has a 15spd double overdrive and 24.5 tall aggressive field rubber. We pull in 7th or 8th, whichever runs 25mph at Rev limiter....



His '93 DDEC 2 with 550hp Cal and s475 billet 6 blade has outpulled it last 2 years in 4th gear on a 10 SPD, but the extra rpm plays in the favor of the Detroit it seams...



Because the Cat will eat the 12.7 for lunch over the road hauling grain... But sled pulling the gearing doesn't seem to work in it's lower rpm favor
Click to expand...


15 speed double over?....

What gear ratio are in your rear ends?

My Freightliner has a 3406b, 15 speed and 3.90 gear ratio. Last season with the fuel screws out and a BW factory cat replacement charger I pulled mostly in 4th gear on the low side (which is not counting the deep reduction gears). I would be up against the governor (2700 rpm) about 150-200 feet and spin out at the end. If I pulled in 5th gear it would only carry about 1800-2000 rpm down the track and get under the charger at the end. It seemed to pull better in 4th gear.

I put together a speed calculator spreadsheet 4th gear agains the governor was like 24-25 mph, 5th gear at 1800-2000 rpm is around 20-21 mph, IIRC.
 
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