benhart16
Well-known member
Greetings,
I recently took the plunge and started tuning on my 2000 Jetta (manual trans, south bend clutch stage 2 daily with SMF, stock vnt15 turbo replaced with rotomaster cartridge). I previously swapped in an 11mm injector pump, and stayed with my stock 0.184 nozzles. After reading through all the tutorials on how to tune, it became obvious the N146 table MUST be correct, otherwise all the other calculations will be off (ie the AFRs in the smoke limiter map), because if the injectors were swapped to larger ones, the engine will be getting more fuel than the ECU thinks it's giving.
If there is a factory 11mm pump/0.184 nozzle map someone could point me to, I would be ecstatic!
However, I did some searching, and I read the 11mm pumps only came on the ALH and AHH engines, and those were only sold in 90hp configuration. I hope this is wrong. . . Anyway, assuming I'm out of luck, what are good estimates for my configuration? It seems all of the tables talked about for various injectors are with the more common 10mm plunger. . .
Here is a table with Maths:
Area calculator. . . Nozzles. . . .Noz. . .Volts. . .V. .Plunger . Noz . . Noz
Smaller. . . . . . . . 0.184 . . . 0.184. . .1.5. . . .4.2 . .10 . 0.138 . 0.158
Larger. . . . . . . . .0.206 . . . .0.216 . .1.75 . . .4.7 . .11 . 0.17 . 0.184
% difference. . . . .24.13. . . . 37.8. . .36.11 . .25.2 . 21 . 51.7 . 35.62
.184 nozzles will need about 4.7V*
.216 nozzles will need about 4.2V
*Found in one tutorial I read. I am only using this to compare %diff of voltage and nozzle size.
I read the measured values for stock manual and automatic nozzles, while claimed to be 0.184 and 0.158, were actually .170 and 0.138, respectively. So while the plunger area difference is 21%, the actual difference between nozzles is ~52%. The stock manual map voltages are about 3% higher at max flow, and around 6-7% higher at low flow over the automatic map (this makes sense as the larger plunger would spike pressures faster). So, is the increased flow of 11mm pump with 0.184 nozzles closer to 21% or 52%?
The real question is what is the correlation between voltage and flow? If I adjust the voltage by 10%, does this only change flow by 10%, or is it closer to 20%. Based on one example I read, the 0.184 nozzles had 4.7v for max flow, and the 0.216 nozzles needed 4.2v. This is a ~25% difference in voltage, but the nozzle size difference is ~38%.
In hindsight, I would have logged boost, MAF and EGTs under set road conditions on a stock map and hardware. Then I would have swapped hardware, adjusted the idle flow to the correct spot with the hammer method, then adjusted the voltage map downward on the high end until the same road test produced the previous boost and MAF readings. Oh well. . .
Anyway, if anyone could point me in the right direction, I would be highly appreciative.
I recently took the plunge and started tuning on my 2000 Jetta (manual trans, south bend clutch stage 2 daily with SMF, stock vnt15 turbo replaced with rotomaster cartridge). I previously swapped in an 11mm injector pump, and stayed with my stock 0.184 nozzles. After reading through all the tutorials on how to tune, it became obvious the N146 table MUST be correct, otherwise all the other calculations will be off (ie the AFRs in the smoke limiter map), because if the injectors were swapped to larger ones, the engine will be getting more fuel than the ECU thinks it's giving.
If there is a factory 11mm pump/0.184 nozzle map someone could point me to, I would be ecstatic!
However, I did some searching, and I read the 11mm pumps only came on the ALH and AHH engines, and those were only sold in 90hp configuration. I hope this is wrong. . . Anyway, assuming I'm out of luck, what are good estimates for my configuration? It seems all of the tables talked about for various injectors are with the more common 10mm plunger. . .
Here is a table with Maths:
Area calculator. . . Nozzles. . . .Noz. . .Volts. . .V. .Plunger . Noz . . Noz
Smaller. . . . . . . . 0.184 . . . 0.184. . .1.5. . . .4.2 . .10 . 0.138 . 0.158
Larger. . . . . . . . .0.206 . . . .0.216 . .1.75 . . .4.7 . .11 . 0.17 . 0.184
% difference. . . . .24.13. . . . 37.8. . .36.11 . .25.2 . 21 . 51.7 . 35.62
.184 nozzles will need about 4.7V*
.216 nozzles will need about 4.2V
*Found in one tutorial I read. I am only using this to compare %diff of voltage and nozzle size.
I read the measured values for stock manual and automatic nozzles, while claimed to be 0.184 and 0.158, were actually .170 and 0.138, respectively. So while the plunger area difference is 21%, the actual difference between nozzles is ~52%. The stock manual map voltages are about 3% higher at max flow, and around 6-7% higher at low flow over the automatic map (this makes sense as the larger plunger would spike pressures faster). So, is the increased flow of 11mm pump with 0.184 nozzles closer to 21% or 52%?
The real question is what is the correlation between voltage and flow? If I adjust the voltage by 10%, does this only change flow by 10%, or is it closer to 20%. Based on one example I read, the 0.184 nozzles had 4.7v for max flow, and the 0.216 nozzles needed 4.2v. This is a ~25% difference in voltage, but the nozzle size difference is ~38%.
In hindsight, I would have logged boost, MAF and EGTs under set road conditions on a stock map and hardware. Then I would have swapped hardware, adjusted the idle flow to the correct spot with the hammer method, then adjusted the voltage map downward on the high end until the same road test produced the previous boost and MAF readings. Oh well. . .
Anyway, if anyone could point me in the right direction, I would be highly appreciative.
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