How injector flow quantity is adjusted and pilot injection delete

Houpty GT

Veteran Member
Joined
Aug 31, 2008
Location
South Carolina
TDI
Corrado TDI, 2000 Golf, 1996 B4 Variant
This was the only thread I found about staged flow settings that certain vendors are selling.
http://forums.tdiclub.com/showthread.php?t=448355&highlight=injector+nozzle+flow+setting
The Kerma description of the stages are a little different ....

STAGE 1- LOW SMOKE FOR CLEANEST OPERATION [ IDEAL FOR STOCK OR LIGHTLY MODIFIED VEHICLES, OR FOR MODIFIED VEHICLES SEEKING BEST FUEL ECONOMY ]

STAGE 2 - LOW SMOKE FOR TUNED VEHICLES
PLEASE NOTE: STAGE 1 IS THE MOST POPULAR SETTING AND WE CAN ALWAYS RECALIBRATE

STAGE 3- FOR VEHICLES WITH TURBO, TUNE, CLUTCH AND ALSO EXHAUST, CAMSHAFT, AND INTERCOOLER UPGRADES
PLEASE NOTE: STAGE 1 IS THE MOST POPULAR SETTING AND WE CAN ALWAYS RECALIBRATE


STAGE 4 - FOR VEHICLES WITH ALL OF THE ABOVE AND FULL UPGRADES INCLUDING CAMSHAFT, EXHAUST, INTAKES AND CYLINDER HEAD WORK HIGHER SMOKE, REDUCED MPG'S AND NOT FOR DAILY DRIVERS

STAGE 5 - EXTREME CUSTOM SETTINGS FOR VERY HIGHLY MODIFIED VEHICLES
So what changes are these flow settings? Since they make no changes to the nozzles and they can not control the pump, that leaves them with
1. shims controlling spring preloads. Reducing the cracking pressure for the main injection so it opens sooner and closes later. This makes sense since they say, "fuel delivery will occur over a slightly longer period of time."
2. spring stiffness. Changing to a different spring so that the needle will lift higher and longer but not sooner.

Would be the same deal with the increased pilot injection?

Has anyone eliminated their pilot injection for more power or economy? I recall it was worth 3 or 5% in some scientific journal.

See this thread on information on diesel injector function and some discussion on removing the pilot injection: http://forums.tdiclub.com/showthread.php?t=352275

 
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Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
i have no freaking idea, but i do know that when i send money to kerma, i get more fun vroom vroom and get to roll more coal on the hippies and Porsches, loving my PP764 staged 4
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
isn't this how Frank was setting main event pressures at Dan's gtg ? by replacing the pilot spring with a solid pellet? ... go for it ! i'm interested to see the results in economy/power as well as sound ... i'm sure it'll have mas clatter :D
 

Exenos

Veteran Member
Joined
Apr 29, 2014
Location
Ontario
TDI
02 Golf
isn't this how Frank was setting main event pressures at Dan's gtg ? by replacing the pilot spring with a solid pellet? ... go for it ! i'm interested to see the results in economy/power as well as sound ... i'm sure it'll have mas clatter :D
Would It make more sense that he would be shimming the pilot spring with that pellet? It looks like the pilot still needs to be able to move.
 

Houpty GT

Veteran Member
Joined
Aug 31, 2008
Location
South Carolina
TDI
Corrado TDI, 2000 Golf, 1996 B4 Variant
Jimbo, I don't remember any of that. With no pilot, I think it would need a degree or 2 less advance since the power stroke would come on quicker than it normally expects.
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
More emissions, PCP and diesel clatter are not desirable trade-offs to me for an unnoticeable difference in real world FE when similar magnitudes can be achieved with less compromising measures elsewhere. Three steps backward and (barely) 1 forward...
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
If you've got a surface grinder it's pretty easy to jig up the pintles to take a few thousandths off the spring end of them and get more lift, it also increases the amount of fuel delivered on the first stage of operation, which I've seen as an additional touted 'benefit' of the same people. Retains the two stage operation as the central rod for the first stage spring will still reach down into the nozzle body to push on the shorter pintle.

on mine I just cut the shelf off the top hat shaped bit, then took it down another .004"
single stage operation (able to set up with a simple pop tester) and similar 'more lift' without needing to grind on the nozzle components

ETA:simple little MS paint drawing on how the single stage conversion works
 
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